Publications by authors named "Marc-Antoine Rousseau"

45 Publications

Displaced three and four part proximal humeral fractures: prospective controlled randomized open-label two-arm study comparing intramedullary nailing and locking plate.

Int Orthop 2021 11 23;45(11):2917-2926. Epub 2021 Sep 23.

Orthopaedic Surgery Department, Université de Paris, Hôpital, Bichat 46 Henri Huchard, 75018, Paris, France.

Purpose: The aim of this study was (1) to compare clinical and radiological outcomes of 3- and 4-part proximal humeral fractures using either IMN or LP (2) and to report complications related to each technique.

Methods: A prospective controlled randomized open-label two-arm study was performed. Ninety-nine consecutive adult patients with a 3- and 4-part displaced acute proximal humeral fractures were randomized to be treated with IMN (n = 49) or LP (n = 50). Constant, ASES and SST scores were recorded by the surgeon. Range of motion was evaluated. A visual analog scale (VAS) was used to assess shoulder pain. Complications and revision surgeries were reported.

Results: Eighty-five patients were analyzed, nine were lost, and five died during the follow-up period. The mean age was 73.7 years (± 13.3,, and the mean follow-up was 66 months (± 13.5). At last follow-up, VAS was lower in the IMN group (0.9 (± 1.1) vs. 1.9 (± 1.7), p = 0.001). The median Constant score was significantly higher in the IMN group (81.6 (± 10.9) points) vs. in the LP group (75.6 (± 19.5) points) (p = 0.043), and ASES score was also significantly higher in the IMN group (86.3 (± 9.5) vs. 75.2 (± 19.6), p = 0.001). There was no difference in the range of motion or SST scores between the two groups. Complications were seen higher in the LP group (9 (21%) vs. 22 (52%), p = 0.003). Revision surgery was higher in the LP group (37% vs. 21%).

Conclusion: Satisfactory results were accomplished in both groups according to the reported clinical outcomes. Complication and revision rates were higher in LP group.
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http://dx.doi.org/10.1007/s00264-021-05217-9DOI Listing
November 2021

Biomechanical comparative evaluation of percutaneous fixations with vertebral expansion for vertebral compression fractures: an experimental and finite element study.

Comput Methods Biomech Biomed Engin 2021 Aug 3:1-12. Epub 2021 Aug 3.

Institut de Biomecanique Humaine Georges Charpak, Paris, France.

This study uses in vitro experiments and validated finite element models (FEM) to analyze the effect of posterior fixation, alone or associated with expandable device (ED) and/or cement. 3-dimensional FEMs of intact, fractured and instrumented spine were built and compared with experimental load-displacement curves. FEM ranges of motion were within the experimental corridors. Stresses appeared sensitive to both implant configuration and fracture severity with a stress reduction up to 84%. The FEM highlighted that for a same instrumental strategy, different biomechanical performances were observed according to fracture severity. When bone continuity is altered, both ED and cement may be needed.
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http://dx.doi.org/10.1080/10255842.2021.1959919DOI Listing
August 2021

Arthroscopic Reduction and Fixation With a Knotless Double-Row Construct Provides Good Results for Displaced Greater Tuberosity Fractures.

Arthrosc Sports Med Rehabil 2021 Apr 11;3(2):e499-e504. Epub 2021 Mar 11.

University of Paris, Paris, France.

Purpose: The purpose of the study is to describe the functional and structural outcomes of the arthroscopic 4-strand, knotless, double-row construct with suture tapes for the surgical treatment of displaced and/or comminuted greater tuberosity fractures of the humerus.

Methods: Patients were enrolled between December 2012 and January 2018. The main inclusion criteria were a comminuted and/or displaced tuberosity fracture with a displacement of at least 5 mm in any plane fixed under arthroscopy using a 4-strand, knotless, double-row construct. The technique involves reducing the displaced fragment with 2 medially placed, transtendinous anchors and compressing the greater tuberosity using the tapes from these medial anchors in 2 laterally placed anchors. The exclusion criteria were a fracture that was more than 10 days old at the time of surgery or a history of shoulder surgery and 3- or 4-part fractures. The postoperative rehabilitation protocol was similar for all patients. Constant scores, Quick Dash, return to work and sport, and complications were reported after a minimum follow-up period of 24 months. Bone healing was systematically evaluated on standardized radiographs, including lateral scapula view and anteroposterior views.

Results: Twenty-one patients were enrolled in this study. One patient did not complete the follow-up examination period and thus was excluded, leaving 20 patients in this study. At a median (SD) follow-up of 32 (9) months, the median (SD) Constant score was 94.7 (7.3) points, the median (SD) Quick Dash was 1.7 (4) points, and median (SD) visual analog scale score was 0.5 (1.4). All patients returned to previous work and sport level. No malunions or nonunions were seen. One conversion to open surgery was required for failure of the lateral row during surgery in a 62-year-old woman with osteopenic bone. Two patients experienced complex regional pain syndrome in the postoperative period that resolved after nonoperative treatment.

Conclusions: In this series, the use of arthroscopy combined with the biomechanical properties of knotless double-row constructs contributed to postoperative satisfactory functional results and healing of greater tuberosity fracture. In addition, range of motion was early, and no hardware removal was required. However, care should be taken with osteopenic bone where anchorage can fail.

Level Of Evidence: Level IV, case series.
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http://dx.doi.org/10.1016/j.asmr.2020.10.014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8129452PMC
April 2021

Arthroscopic knotless repair: an effective technique for small-sized supraspinatus tendon tears.

Knee Surg Sports Traumatol Arthrosc 2021 Jul 9;29(7):2305-2311. Epub 2020 Sep 9.

Orthopedics Department, Bichat Hospital, Paris Diderot University, Assistance Publique Hôpitaux de Paris, Paris, France.

Purpose: The purpose was to evaluate the clinical and radiological results of knotless repair with flat-braided suture in full small-sized supraspinatus tendon tears (< 1 cm).

Methods: A consecutive series of 54 patients with isolated small supraspinatus tendon tear (< 1 cm and Goutallier index < 2) was evaluated in the study. Patients underwent a knotless arthroscopic repair using flat-braided suture (2 mm wide). Minimal follow-up required was 5 years. Changes in Murley-Constant score, ASES score, strength, and pain relief were assessed. The Sugaya score was used to confirm the tendon repair on MRI. Data were analyzed in two subgroups: technique with additional U point for dog ear deformity (group 1) and technique without additional U point (group 2). The immobilization period was 3 weeks long. Passive mobilization was immediate.

Results: Fifty-four patients were included. Mean age was 57 ± 4 years. The average follow-up was 68 ± 10 months. Average preoperative score of Constant was 51.2 ± 8.5 and 83.1 ± 14.6 at the end of the follow-up (p < 0.001). Mean VAS went from 5.8 ± 1.8 to 1.9 ± 2.1 (p < 0.001). Average forward elevation of the shoulder went from 86.3° ± 9 preoperatively to 169.6° ± 15.9 at the end of the follow-up (p < 0.001). The strength score was significantly higher post-operatively (18.4 vs. 8.3, p < 0.001.). The ASES score was significantly improved 49.1 ± 13.1 vs. 88.6 ± 15.8, p < 0.001). The MRI assessment revealed 94% of Sugaya 1-2. No significant difference was observed between group 1 and 2 regarding all clinical outcomes. Two complex regional pain syndromes were described with a favorable evolution. Three patients presented a retear requiring an iterative arthroscopic repair.

Conclusion: The use of a knotless arthroscopic construct with flat-braided suture for small supraspinatus repair achieved excellent structural and clinical results. This technique is fully adequate for the arthroscopic treatment of such tears, enabling early mobilization.

Level Of Evidence: Level III.
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http://dx.doi.org/10.1007/s00167-020-06249-1DOI Listing
July 2021

Safety of shoulder arthroplasty in lung transplant recipients.

Arch Orthop Trauma Surg 2021 May 25;141(5):795-801. Epub 2020 May 25.

Orthopaedic Surgery Department, Universite Paris Diderot UFR de Medecine, Paris, France.

Purpose: Although shoulder arthroplasty is relatively safe in general population, it remains unclear in transplant recipient. Aim of this study was to determine outcomes and morbidity after shoulder arthroplasty in lung transplant recipients.

Methods: A retrospective analysis was performed at our university hospital center from 2001 to 2015. Main inclusion criterion was all lung transplant recipient who underwent shoulder arthroplasty. Clinical outcomes including Constant score, visual analogue scale (VAS), American Shoulder and Elbow Surgeons score (ASES) were determined in pre-operative period and a minimum follow-up of 36 months. Special attention was taken about complications.

Results: Among 700 lung transplant recipients, we identified 12 patients who underwent 14 shoulder arthroplasties. Arthroplasties were performed after proximal humeral avascular necrosis (n = 10), degenerative osteoarthritis (n = 1) and non-union of proximal humeral fracture (n = 1). 8 anatomical total shoulder arthroplasties and 6 reversed shoulder arthroplasties were performed. Mean follow-up was 61.4 months (± 22.1). Mean age was 47.1 (± 9.3) years. All patients had immunosuppression therapy at the time of surgery. Mean Constant score was improved at last follow-up [43(± 9.7) vs 94(± 4), p < 0.001]. VAS decreased from 6.4 (± 1.2) to 0.4 (± 0.8), p < 0.001. Mean ASES was improved from 33 (± 6) to 91 (± 5) at last follow-up (p < 0.001). Range of motion were improved between early post-operative evaluation and last follow-up: forward flexion: 85° (± 8°) vs 119°(± 13°); abduction: 83° (± 14°) vs 106°(± 23°); external rotation (RE1): 26° (± 7°) vs 36°(± 10°). At last follow-up, one revision was required for humeral prothesis loosening at 2 years post-surgery. One patient died due to acute pulmonary decompensation on chronic rejection 66 months after shoulder arthroplasty.

Conclusion: Shoulder arthroplasty is a safe procedure in this vulnerable population of lung transplant recipients. Such results encourage us to continue arthroplasty surgery when required.

Level Of Evidence: IV.
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http://dx.doi.org/10.1007/s00402-020-03485-5DOI Listing
May 2021

Different kinetics of infectious processes in vertebral osteomyelitis of pyogenic or tuberculous origin explain different timing of surgery.

Infect Dis (Lond) 2020 08 20;52(8):563-570. Epub 2020 May 20.

Service de Médecine Interne, Hôpital Beaujon, Assistance Publique-Hôpitaux Paris Nord, Clichy, France.

Whether surgery modalities vary according to kinetics of pathological processes responsible for vertebral osteomyelitis (VO) is unclear. We therefore compared surgical modalities in patients with haematogenous pyogenic VO (HPVO) or tuberculous VO (TVO). Patients who had surgery for HPVO or TVO between January 1997 and June 2018 in a university hospital were included. Surgical indications, timing, and procedures and outcomes were evaluated at the end of treatment. Seventy-eight patients (50 men) were included: 39 with HPVO and 39 with TVO; median age was 64 and 41 years, respectively. In patients with HPVO, surgery was performed early: 17 (44%) had surgery within 72 h of admission; main indication for surgery was neurological deficit in 29 patients that persisted in 12 patients (27%). In patients with TVO, surgery was performed later (<.001), after two weeks in 20 patients (51%), and was indicated by a neurological deficit in 23 patients; among them, only one (4%) had residual deficit. Different kinetic profiles of the infectious processes explain the more rapid indication for surgery in patients with HPVO and the more favourable neurological recovery in patients with TVO.
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http://dx.doi.org/10.1080/23744235.2020.1767299DOI Listing
August 2020

A comparative study of fixation methods in adults with two-thirds distal isolated ulnar shaft fractures with a minimum of 2 year follow-up.

Injury 2020 Apr 18;51(4):964-970. Epub 2020 Feb 18.

Orthopedics Department, Bichat Hospital, Paris Diderot University, Assistance Publique Hôpitaux de Paris, Paris, France.

Background: Adult isolated ulnar shaft fractures (IUSF) are rare. There remains a need to establish the best methods to manage these fractures. The aim of this study was to compare two forms of treatment for IUSF: intramedullary stabilization by k-wire (IMF) versus Open Reduction Internal Fixation by plating (ORIF), in order to identify differences in clinical (1) and radiological outcomes (2), as well as comparative costs (3).

Hypothesis: The hypothesis of this study was assessing whether intramedullary stabilization was as feasible as plating in the treatment of isolated ulnar shaft fractures in clinical practice.

Patients And Methods: A retrospective analysis was undertaken on patients diagnosed IUSF between January 2015 and March 2017 with a minimum of 2 years follow-up. They were treated with IMF (group 1) or ORIF (group 2). Demographic information, clinical outcomes and complications were collected. Cost, including implant cost, operative time, sterilization and inpatient stay were compared. Radiographs were reviewed to evaluate axial angulation, shortening, displacement and residual deformity.

Results: 54 patients with a mean age of 41.2 years were treated by IMF (27/54) and ORIF (27/54). The mechanism of injury included high-energy (55%) and low-energy falls (45%). AO/OTA 2018 fracture classification was simple (39/54), wedge (14/54) and complex (1/54). The locations were 37/54 (70%) distal third and 17/54 (30%) mid-shaft fractures. There was no significant difference pre and post-operatively between the 2 groups regarding radiologic criteria. 3 cases of non-union, 4 delay-union and 1 regional complex syndrome occurred in group 2. No complication was reported in group 1. The function determined by range of motion (ROM) at wrist and elbow was excellent in 72% (group 1) and 80% (group2), 18% satisfactory in group 1 and 20% in group 2. There was no difference for QuickDASH and pain. Implant removal was necessary in 70% of patients without sequelae in nailing, 11% after plating. Average operation time was 29 ± 5 min for ORIF and 18 ± 6 min for IMF. Total estimated cost per patient was 3678.4€ for IMF and 7051.9€ for ORIF.

Conclusions: Compared with ORIF, IMF significantly reduced the operation time and cost with lower complications.

Type Of Study: Retrospective study.

Type Of Proof: Level 4.
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http://dx.doi.org/10.1016/j.injury.2020.02.085DOI Listing
April 2020

Vertebral Compression Fractures Treated in Acute by Instrumented Kyphoplasty: Early and Mid-Term Clinical and Radiological Results.

Biomed Res Int 2019 10;2019:1386510. Epub 2019 Dec 10.

Department of Orthopedic and Trauma Surgery, Hopital Bichat - Beaujon, Assistance Publique - Hopitaux de Paris, Paris, France.

The treatment of traumatic low-degree vertebral compression fracture remains in a wide range between functional treatment, bracing, vertebroplasty, kyphoplasty, and even surgical fixation. The objective was to assess the innovation of instrumented kyphoplasty and to report the early and mid-term functional and radiological results. This study is a retrospective review of patients enrolled from 2012 to 2017. 104 consecutive endovertebral implantations of instrumented kyphoplasty were reviewed for the study. There were 56 women and 48 men. 93 of 104 patients were evaluated, of whom 27 were evaluated only by retrospective medical record review and 66 with follow-up visit. Clinical parameters were the pain rating scale (VAS) and the Oswestry score questionnaire. The radiological parameters were the vertebral kyphosis, vertebral height, lumbar lordosis, and adjacent disc degeneration (UCLA scale). Statistical correlations between before/after surgery/last follow-up were performed. The average follow-up was 26.7 months (3 to 55). The average VAS decreased from 8.2 to 3.2 the day after surgery, allowing immediate standup. The average Oswestry score was 14.6 at follow-up. The average vertebral kyphosis decreased from 12.9° to 6.5° post-op and stabilized at 8.0° at the last follow-up, corresponding to 28% gain on vertebral height. The lumbar lordosis was restored (+6.6°). Adjacent disc degeneration increased by 1 UCLA grade in 17 patients (16.3%) at follow-up. The instrumented kyphoplasty in acute led to immediate and lasting pain relief, with no bracing or bed rest, short stay in hospital, and quick return to daily life including professional activities. The good clinical results were associated to a stable radiological restoration of the vertebral anatomy.
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http://dx.doi.org/10.1155/2019/1386510DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6925826PMC
May 2020

Outcomes of reverse shoulder arthroplasty using a short stem through a superolateral approach.

J Shoulder Elbow Surg 2020 Jun 4;29(6):1197-1205. Epub 2019 Dec 4.

Université Paris Diderot, Bichat Hospital, service d'orthopédie, Paris, France.

Background: Reverse shoulder arthroplasties have progressed in recent decades to become the most popular type of arthroplasty. Short stems with metaphyseal fixation have been developed to preserve bone stock and facilitate possible revision. Accurate positioning of these implants can be challenging using the superolateral approach.

Objective: This study aimed to evaluate the clinical and radiologic results of reverse short-stem arthroplasties using a superolateral approach with a minimum of 2 years' follow-up.

Methods: Between January 2015 and December 2016, a total of 76 patients underwent reverse shoulder arthroplasty surgery (79 shoulders) using a short uncemented humeral stem for shoulder arthritis with irreparable rotator cuff tear. Arthroplasties for post-traumatic osteoarthritis were excluded. Functional outcomes were assessed using Constant Score, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), visual analog scale (VAS), and range of motion. Radiographic analysis was used to evaluate component loosening, implant position, and implant filling ratio.

Results: The mean age was 70.8 years. At a mean of 38.8-month follow-up, there were significant improvements in Constant score (44.2 to 87.9, P < .001), ASES score (36.2 to 84.3, P < .001), and VAS score (6.8 to 0.4, P < .001). Forward flexion improved from 89°to 131°(P < .001), and external rotation improved from 25° to 36°(P < .001). No evidence of periprosthetic loosening was visible. Mean varus of the humeral stem was 1°(±6°). The mean glenoidal inclination was 98°(±7°), which corresponds to a lower tilt of 8°. The average filling ratio was between 50% and 60% in both the metaphysis and the diaphysis.

Conclusion: The clinical results obtained in this study were satisfying, with a significantly low complication rate. Hence, short-stem reverse shoulder arthroplasty using a superolateral approach, while taking particular care to protect the deltoid, remains our method of choice.
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http://dx.doi.org/10.1016/j.jse.2019.09.025DOI Listing
June 2020

More complications in cervical than in non-cervical spine tuberculosis.

Infect Dis (Lond) 2020 03 13;52(3):170-176. Epub 2019 Nov 13.

Service de Médecine Interne, Hôpital Beaujon, Assistance Publique Hôpitaux Paris Nord, Clichy, France.

Cervical spine tuberculosis (CST) is a rare disease that may lead to severe neurological complications. The goal of the study was to compare the characteristics of patients with CST with those of patients with non-cervical spine tuberculosis (NCST). Between 1997 and 2016, we reviewed all cases of proven tuberculosis from a cohort of spine infections in a tertiary care hospital. Clinical, biological, and imaging data were collected at baseline and after treatment. Fifty-one cases of spine tuberculosis were included: 14 with CST on imaging (27%) and 37 with no cervical localization. Median age was 39 y. Demographic characteristics, duration of symptoms and neurological findings of spine compression were similarly present at presentation in CST and NCST patients. On imaging, lesions were more often multifocal in CST than in NCST patients (9/14 [64%] versus 10/37 [27%],  = .014). Spinal surgery was required in 32/51 (63%) patients. At the end of follow-up (median: 20 months), cure rates were similar in CST and NCST patients but motor and/or sensitive functional sequel were more frequent in CST than NCST patients (6/14 [43%] versus 2/37 [5%],  = .003). Cervical involvement is present in more than a quarter of patients with spinal tuberculosis. Patients with CST had more frequent neurological sequelae than patients with NCST. This was mainly due to a more multifocal disease at presentation. Screening for cervical localization should be systematic in patients with spinal tuberculosis even in the absence of cervical symptoms.
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http://dx.doi.org/10.1080/23744235.2019.1690675DOI Listing
March 2020

Arthroscopic knotless tape bridging with autologous platelet-rich fibrin gel augmentation: functional and structural results.

Phys Sportsmed 2019 11 3;47(4):455-462. Epub 2019 Jun 3.

Université Paris Diderot, Bichat Hospital, service d'orthopédie, Paris, France.

: Rotator cuff repairs remain a source of iterative ruptures and disappointing functional results. In this goal, autologous platelet-rich plasma (PRP) has been used to improve tendon healing. This prospective study assessed the contribution of fully autologous gel concentrates (platelet concentrates and thrombin) on healing after cuff repair.: A consecutive series of 69 patients who underwent primary arthroscopic knotless tape bridging primary cuff repair of supraspinatus tear were evaluated. Two groups were created (A: n = 32, B: n = 37). Autologous PRP gel, obtained preoperatively by PRP mixed with autologous thrombin extracted from platelet-poor plasma, was injected at bone-tendon interface at end of repair in group A. Gel structure avoided evacuation of concentrates with irrigation liquid. Constant, QuickDash and Visual Analogue Scale (VAS) scores were assessed pre-operatively and then successively post-operatively. Healing was assessed by 24-month control MRI according to Sugaya's classification. Sugaya 3, 4, and 5 were considered as iterative ruptures.: Average age was 56 years (±7.8). Mean follow-up was similar: 28.6 months (±3.3) vs 32.4 months (±9.4). Mean preoperative Constant was similar: 53.4 (±3.4) vs 54.6 (±5.4). Group A patients received 3.5 ml (±1.5 ml) of autologous PRP gel. No specific complication of injection was found. We observed higher trend in favour of PRP without significativity: Constant 86.7 (±11.1) vs 81.6 (±14.4), p = 0.11; VAS: 0.6 (±0.3) vs 1.1 (±0.9), p = 0.13; Forward flexion: 139.5° (±14.4°) vs 137.7° (± 16.5°), p = 0.63; Strength score: 17.6 vs 14.8, p = 0.66; QuickDash: 6.2 (±5.3) vs 8.2 (±6.9), p = 0.32 . On MRI, 90% (n = 3) of repairs were healed in group A versus 86% (n = 5) in group B.: In this preliminary study, the group treated with autologous PRP gel showed a trend towards better clinical and radiological results. These results were not significant at the last follow-up. Only significantly higher clinical results were found at 3 months.: Therapeutic prospective comparative cohort study; Level of evidence III.
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http://dx.doi.org/10.1080/00913847.2019.1623994DOI Listing
November 2019

Five-year follow-up of clinical and radiological outcomes of LP-ESP elastomeric lumbar total disc replacement in active patients.

Spine J 2019 02 22;19(2):218-224. Epub 2018 May 22.

Department of Orthopaedic Surgery, Hopital Bichat-Beaujon, Assistance Publique-Hôpitaux de Paris, 100 bd General Leclerc 92110 Clichy, France.

Background Context: The surgical treatment of degenerative disc disease at the lumbar spine may involve fusion. Total disc replacement (TDR) is an alternative treatment to avoid fusion-related adverse events, specifically adjacent segment disease. New generation of elastomeric non-articulating devices has been developed to more effectively replicate the shock absorption and flexural stiffness of native disc.

Purpose: To report 5 years clinical and radiographic outcomes, range of motion (ROM), and position of the center of rotation after a viscoelastic lumbar TDR.

Study Design: Prospective observational cohort study PATIENT SAMPLE: Sixty-one patients OUTCOME MEASURES: The clinical evaluation was based on visual analog scale (VAS) for pain, Oswestry disability index (ODI) score, short form-36 (SF-36) including the physical component summary (PCS) and the mental component summary (MCS), and general health questionnaire-28 (GHQ28). The radiological outcomes were ROM and position of the center of rotation at the index and the adjacent levels and the adjacent disc height changes.

Methods: Our study group included 61 consecutive patients with monosegmental disc replacement. We selected patients who could provide a global lumbar spine mobility analysis (intermediate functional activity according to the Baecke score). Hybrid constructs had been excluded. Only the cases with complete clinical and radiological follow-up at 3, 6, 12, 24, and 60 months were included.

Results: There was a significant improvement in VAS (3.3±2.5 vs. 6.6±1.7, p<.001), in ODI (20±17.9 vs. 51.2±14.6, p<.001), GHQ28 (52.6±15.5 vs. 64.2±15.6, p<.001), SF-36 PCS (58.8±4.8 vs. 32.4±3.4, p<.001), and SF-36 MCS (60.7±6 vs. 42.3±3.4, p<.001). The mean location centers of the index level and adjacent discs were comparable to those previously published in asymptomatic patients. According to the definition of Zigler and Delamarter, all of our cases remained grade 0 for adjacent level disc height (within 25% of normal).

Conclusions: This series reports significant improvement in midterm follow-up after TDR, which is consistent with previously published studies but with a lower rate of revision surgery and no adjacent level disease pathologies. The radiographic assessment of the patients demonstrated the quality of functional reconstruction of the lumbar spine after LP-ESP viscoelastic disc replacement.
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http://dx.doi.org/10.1016/j.spinee.2018.05.023DOI Listing
February 2019

Correlation between femoral offset loss and dynamic hip screw cut-out complications after pertrochanteric fractures: a case-control study.

Eur J Orthop Surg Traumatol 2018 Oct 27;28(7):1321-1326. Epub 2018 Apr 27.

Hopital Beaujon, Paris, France.

Background: Screw-plates disassembly incidence after pertrochanteric fracture (PF) amounts to 1 and 16% among the elderly population. The main occurrence is early cervical screw cut-out. The population at highest risk of disassembly remains difficult to identify. The correlation between femoral offset loss and disassembly occurrence has never been surveyed.

Objectives: A radiological prognosis score for screw plate disassembly was defined to reflect trochanteric impaction (TI); it was based on a femoral offset ratio.

Study Design And Methods: Our single-centre retrospective case-control study surveyed patients suffering from Dynamic Hip Screw (DHS, Synthes) disassembly following osteosynthesis of non-pathological osteoporotic PF between 2004 and 2014. All cases were categorised by age and gender and paired to three patients in the control group. The primary endpoint was TI measurement, corresponding to offset loss on the operated hip compared to healthy hip offset and expressed as a percentage. The measurement was done on an immediate postoperative X-ray. The secondary endpoints were tip apex distance (TAD) measurement, Ender and AO classifications, as well as postoperative weight-bearing prescription.

Results: Twenty-three cases and 69 controls were surveyed. The case group's average age was 87; 70% of the cases were women. The main disassembly occurrence delay was after 27 days. Average TI was 26% within the patients global group and 12% within the control group (p < 10). Over a 21% impaction percentage, disassembly occurrence represents a greater risk: OR = 21.95% CI [5.4-104.3], p < 10. Ender 3 type fractures were the most frequent indication for surgery within the case group. Average TAD was 20 mm within the case group, and 17 mm within the control group (p = 0.03). The weight-bearing prescription rate was 52% within the control group and 21% within the case group (p = 0.014). 14.5% of the control group had a TI > 21%.

Conclusions: Using the offset ratio tool, TI measurement was associated with a greater risk of DHS disassembly when it was higher than 21%. The exclusive use of a DHS device does not seem optimal for a TI > 21%. Weight-bearing may be prescribed for all the patients with a TI < 21%, provided good implant positioning is secured.
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http://dx.doi.org/10.1007/s00590-018-2204-0DOI Listing
October 2018

The global alignment in patients with lumbar spinal stenosis: our experience using the EOS full-body images.

Eur J Orthop Surg Traumatol 2016 Oct 30;26(7):713-24. Epub 2016 Aug 30.

Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI, USA.

Lumbar stenosis is frequently observed and treated by spine surgeons. The extent of neurological decompression and the potential spinal fixation are the basic concerns when surgery is planned. But this segmented approach to the problem is sometimes insufficient due to the complex functional situations induced by a sagittal imbalance of the patient and the combination of pathologies known as hip-spine or knee-spine syndromes. A total of 373 consecutive patients included from our EOS and clinical data base. Patients were divided in two groups. Group A included patients presenting exclusive spinal issues (172 cases) out of whom 117 (68 %) had sagittal imbalance. Among 201 patients with associated lower limbs issues (group B), 122 (61 %) had sagittal imbalance. The perception of imbalance was noticed in 54 % (93 cases) in group A and 57 % (115 cases) in group B. In the global series of 239 imbalanced cases, the key point was a spine issue for 165 patients (the 117 patients with only spine problems and 48/122 cases with combined spine and lower limbs problems). But in the patients with combined spine and lower limbs problems, we individualized hip-spine syndromes (24/122 patients) and knee-spine syndromes (13/122 patients). In some cases, (37/122 patients) the anatomical and functional situations were more complex to characterize a spine-hip or a hip-spine problem. The EOS full-body images provide new information regarding the global spinal and lower limbs alignment to improve the understanding of the patient functional posture. This study highlights the importance of the lower limb evaluation not only as compensatory mechanism of the spinal problems but also as an individualized parameter with its own influence on the global balance analysis. Level of evidence IV diagnostic case series.
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http://dx.doi.org/10.1007/s00590-016-1833-4DOI Listing
October 2016

Total Hip Prostheses in Standing, Sitting and Squatting Positions: An Overview of Our 8 Years Practice Using the EOS Imaging Technology.

Open Orthop J 2015 27;9:26-44. Epub 2015 Feb 27.

Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan, USA.

More total hip arthroplasty (THA) is performed worldwide and especially in younger and more active patients compared to earlier decades. One of the focuses of THA research in the future will be on optimizing the radiological follow-up of these patients using 2D and 3D measurements of implants position while reducing the radiation dose delivered. Low-dose EOS(®) imaging is an innovative slot-scanning radiograph system providing valuable information in patient functional positions (standing, sitting and even squatting positions). EOS has been proven accurate and reliable without significant inconvenience caused by the metallic artifacts of implants. The ability to obtain precise data on implant orientation according to the patient posture opens new perspectives for a comprehensive analysis of the pelvic frontal and sagittal balance and its potential impact on implants function and failures. We report our 8 years experience on our first 300 THA patients using this technology routinely for pre and post op evaluation. Our results will be compared and confronted with the actual literature about this innovative technology. We shall especially emphasize our experience about patients with abnormal posture and the evolution of the subject over time, because the phenomenon of an aging spine is frequently associated with the process of aging hips.
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http://dx.doi.org/10.2174/1874325001509010026DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4384273PMC
April 2015

Relevance of using a compressive preload in the cervical spine: an experimental and numerical simulating investigation.

Eur J Orthop Surg Traumatol 2015 Jul 7;25 Suppl 1:S155-65. Epub 2015 Apr 7.

University Claude Bernard Lyon 1, Lyon, France,

Unlabelled: Simulating compressive action of muscles, a follower load attends to reproduce a more physiological biomechanical behaviour of the cervical spine. Only few experimental studies reported its influence on kinematics and intradiscal pressure in the cervical spine.

Study Design: In vitro human cadaveric and numerical simulating evaluation of a compressive preload in the cervical spine.

Objectives: To analyse the influence of a compressive follower preload on the biomechanical behaviour of the cervical spine.

Methods: The present study was divided into two parts: part 1: in vitro investigation; part 2: numerical simulating analysis. Part 1: Twelve human cadaveric spines from C2 to T2 were evaluated intact and after application of a 50-N follower load. All tests were performed under load control by applying pure moments loading of 2 Nm in flexion/extension (FE), axial rotation (AR) and lateral bending (LB). Three-dimensional displacements were measured using an optoelectronic system, and intradiscal pressures were measured at two levels. Part 2: Using a 3D finite element model, we evaluated the influence of a 50- and 100-N compressive preload on intradiscal loads, facets forces and ranges of motion. Different positions of the follower load along the anteroposterior axis (±5 mm) were also simulated.

Results: Part 1: Mean variation of cervical lordosis was 5° ± 3°. The ROM slightly increased in FE, whereas it consistently decreased in AR and LB. Coupled lateral bending during AR was also reduced. Increase in hysteresis was observed on load-displacement curves only for AR and LB. Intradiscal pressures increased, but the aspect of load-pressure curves was altered in AR and LB. Part 2: Using the FE model, only minimal changes in ROM were noted following the simulation of a 50-N compressive load for the three loading conditions. Compared to intact condition, <10% variation was observed with regard to the different magnitude and positioning simulated. Intradiscal loads and facets forces were systematically increased by applying compressive preload.

Conclusions: Although the follower load represents an attractive option to apply compressive preload during experimental tests, we found that this method could affect the native biomechanical behaviour of spine specimen depending on which movement was considered. Only minimal effects were observed in FE, whereas significant changes in kinematics and intradiscal pressures were observed for AR and LB.
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http://dx.doi.org/10.1007/s00590-015-1625-2DOI Listing
July 2015

Offset and anteversion reconstruction after cemented and uncemented total hip arthroplasty: an evaluation with the low-dose EOS system comparing two- and three-dimensional imaging.

Int Orthop 2015 Jul 20;39(7):1259-67. Epub 2014 Dec 20.

Department of Orthopaedic and Trauma Surgery, Pitié-Salpétrière Hospital Assistance Publique-Hopitaux de Paris, UPMC, 47-83 boulevard de l'hôpital, 75013, Paris, France.

Purpose: Accurate evaluation of femoral offset is difficult with conventional anteroposterior (AP) X-rays. The EOS imaging system is a system that makes the acquisition of simultaneous and orthogonal AP and lateral images of the patient in the standing position possible. These two-dimensional (2D) images are equivalent to standard plane X-rays. Three-dimensional (3D) reconstructions are obtained from these paired images according to a validated protocol. This prospective study explores the value of the EOS imaging system for comparing measurements of femoral offset from these 2D images and the 3D reconstructions.

Methods: We included 110 patients with unilateral total hip arthroplasty (THA). The 2D offset was measured on the AP view with the same protocol as for standard X-rays. The 3D offset was calculated from the reconstructions based on the orthogonal AP and lateral views. Reproducibility and repeatability studies were conducted for each measurement. We compared the 2D and 3D offset for both hips (with and without THA).

Results: For the global series (110 hips with and 110 without THA), 2D offset was 40 mm (SD 7.3; 7-57 mm). The standard deviation was 6.5 mm for repeatability and 7.5 mm for reproducibility. Three-dimensional offset was 43 mm (SD 6.6; 22-62 mm), with a standard deviation of 4.6 for repeatability and 5.5 for reproducibility. Two-dimensional offset for the hips without THA was 40 mm (SD 7.0; 26-56 mm), and 3D offset 43 mm (SD 6.6; 28-62 mm). For THA side, 2D offset was 41 mm (SD 8.2; 7-57 mm) and 3D offset 45 mm (SD 4.8; 22-61 mm). Comparison of the two protocols shows a significant difference between the 2D and 3D measurements, with the 3D offset having higher values. Comparison of the side with and without surgery for each case showed a 5-mm deficit for the offset in 35 % of the patients according to the 2D measurement but in only 26 % according to the 3D calculation.

Conclusions: This study points out the limitations of 2D measurements of femoral offset on standard plane X-rays. The reliability of the EOS 3D models has been previously demonstrated with CT scan reconstructions as a reference. The EOS imaging system could be an option for obtaining accurate and reliable offset measurements while significantly limiting the patient's exposure to radiation.
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http://dx.doi.org/10.1007/s00264-014-2616-3DOI Listing
July 2015

Sagittal rebalancing of the pelvis and the thoracic spine after pedicle subtraction osteotomy at the lumbar level.

J Spinal Disord Tech 2014 May;27(3):166-73

*Service de Chirurgie Orthopédique et Traumatologique, Hôpital Pitié Salpétrière, Paris ‡Service de Chirurgie Orthopédique et Traumatologique, Hôpital Belle-Isle, Metz §Institut Regional Readaptation, Nancy ∥Groupe d'Etude de la Scoliose, Hôpital Saint-Joseph, Paris †Biomechanics Lab, Arts et Métiers Paris Tech, France.

Design: Retrospective study of radiologic records of patients who underwent lumbar pedicle subtraction osteotomy (PSO) procedures.

Objective: To evaluate the restoration of spinal balance above and below the osteotomy site after PSO for various causes.

Summary Of Background Data: The normal sagittal balance of the spine has been widely documented. Sagittal imbalance can be surgically treated with vertebral osteotomy. Reports have described its technical aspects and local radiologic results. Less is known about the spontaneous rebalancing of the spine cranially and caudally to the osteotomy site.

Methods: The French Scoliosis Study Group conducted a multicenter retrospective study from the records of a combined cohort of 356 patients. Spinal balance after PSO was assessed radiologically. In this study, we focused specifically on measuring the reorientation of the pelvis and upper thoracic segments and investigated the influence of pelvic incidence, osteotomy level, and regional lordosis gain. The population was classified according to the indication for the procedure: posttraumatic deformity, degenerative kyphosis, scoliosis, or ankylosing spondylarthritis.

Results: The average regional lordosis gain was 26.1 degrees. In the degenerative kyphosis and scoliosis groups, the level of osteotomy and the incidence angle tended to influence pelvic adaptation (better balance of the caudal portion was associated with low-level PSO and low-incidence angle). The posttraumatic deformity cases had a specific pattern: balance changes after PSO were limited to the local lordosis gain, with less pelvic and thoracic reorientation, probably due to spinal flexibility. On the contrary, the spondylarthritis cases showed less pelvic and more thoracic reorientation, probably due to hip and spinal stiffness.

Conclusions: Better knowledge from a large series of the overall spontaneous spinal balance after PSO and the pelvic/thoracic reorientation would be useful for preoperative planning of lumbar osteotomies and predicting pelvic and hip reorientation.

Level Of Evidence: Level II.
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http://dx.doi.org/10.1097/BSD.0b013e318272faafDOI Listing
May 2014

Clinical outcomes, radiologic kinematics, and effects on sagittal balance of the 6 df LP-ESP lumbar disc prosthesis.

Spine J 2014 Sep 19;14(9):1914-20. Epub 2013 Nov 19.

Biomechanics Lab, Arts et Métiers Paristech, 151 boulevard de l'hôpital, 75013 Paris, France; Department of Orthopaedic and Trauma Surgery, Avicenne Hospital, Assistance Publique-Hopitaux de Paris, 125 rue de Stalingrad, 93009 Bobigny, France. Electronic address:

Background Context: Surgical treatment of degenerative disc disease remains a controversial subject. Lumbar fusion has been associated with a potential risk of segmental junctional disease and sagittal balance misalignment. Motion preservation devices have been developed as an alternative to fusion. The LP-ESP disc is a one-piece deformable device achieving 6 df, including shock absorption and elastic return. This is the first clinical report on its use.

Purpose: To assess clinical outcomes and radiologic kinematics in the first 2 years after implantation.

Study Design: Prospective cohort of patients with LP-ESP total disc replacement (TDR) at the lumbar spine.

Patient Sample: Forty-six consecutive patients.

Outcome Measures: Clinical outcomes were the visual analog scale (VAS) for pain, the Oswestry disability index (ODI), and the GHQ28 (General Health Questionnaire) psychological score. Radiologic data were the range of motion (ROM), sagittal balance parameters, and mean center of rotation (MCR).

Methods: Patients had single-level TDR at L4-L5 or L5-S1. Outcomes were prospectively recorded for 2 years (before and at 3, 6, 12, and 24 months after surgery). The SpineView software was used for computed analysis of the radiographic data. Paired t tests were used for statistical comparisons.

Results: No intraoperative complication occurred. All clinical scores improved significantly at 24 months: the back pain VAS scores by a mean of 4.1 points and the ODI by 33 points. The average ROM of the instrumented level was 5.4°±4.8° at 2 years and more than 2° for 76% of prostheses. The MCR was in a physiological area in 73% of cases. The sagittal balance (pelvic tilt, sacral slope, and segmental lordosis) did not change significantly at any point of the follow-up.

Conclusions: Results from the 2-year follow-up indicate that LP-ESP prosthesis recreates lumbar spine function similar to that of the healthy disc in terms of ROM, quality of movement, effect on sagittal balance, and absence of modification in the kinematics of the upper adjacent level.
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http://dx.doi.org/10.1016/j.spinee.2013.11.016DOI Listing
September 2014

Assessment of the axial rotation of the pelvis with the EOS® imaging system: intra- and inter-observer reproducibility and accuracy study.

Eur J Orthop Surg Traumatol 2014 Aug 13;24(6):891-5. Epub 2013 Aug 13.

Department of Orthopaedic Surgery, Hôpital Avicenne-Université Paris 13, Bobigny, France,

Purpose: A source of radiological bias occurs when the axial rotation of the pelvis is disregarded in hip and spine biomechanics analyses. The EOS imaging system (EOS Imaging, France) offers the possibility of detecting and measuring the axial rotation of bones. Reproducibility and accuracy have not been documented in the case of the pelvis.

Methods: A dry pelvis has been X-rayed with the EOS system every 5° from 30° left to 30° right according to a laser line reference goniometer. Three observers have measured the rotation. One observer did it 3 times. The intra- and inter-observer reproducibility and the accuracy have been calculated using the root mean square standard deviation calculation. The relationship between the axial rotation and the offset between the left and right acetabulae on the lateral view was investigated.

Results: The 95 % CI was ±0.23° for the intra-observer and ±0.33° for the inter-observer reliability. The mean of signed differences between the software calculation and the actual axial rotation of the pelvis was -0.39° (SD 0.77°). The lateral acetabular offset was proportional to the sin of the rotation. Approximately, 30 mm offset corresponded to about 10° rotation.

Conclusions: The 3D slot scanning imaging system demonstrated significant reproducibility and accuracy for the assessment of the axial rotation of the pelvis.
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http://dx.doi.org/10.1007/s00590-013-1281-3DOI Listing
August 2014

The LP-ESP(®) lumbar disc prosthesis with 6 degrees of freedom: development and 7 years of clinical experience.

Eur J Orthop Surg Traumatol 2013 Feb 11;23(2):131-43. Epub 2013 Jan 11.

Department of Orthopedic and Trauma Surgery, La Pitié-Salpétrière Hospital, 47-83 boulevard de l'Hôpital, 75013, Paris, France.

The viscoelastic lumbar disk prosthesis-elastic spine pad (LP-ESP(®)) is an innovative one-piece deformable but cohesive interbody spacer providing 6 full degrees of freedom about the 3 axes, including shock absorption. A 20-year research program has demonstrated that this concept provides mechanical properties very close to those of a natural disk. Improvements in technology have made it possible to solve the problem of the bond between the elastic component and the titanium endplates and to obtain an excellent biostability. The prosthesis geometry allows limited rotation and translation with resistance to motion (elastic return property) aimed at avoiding overload of the posterior facets. The rotation center can vary freely during motion. It thus differs substantially from current prostheses, which are 2- or 3-piece devices involving 1 or 2 bearing surfaces and providing 3 or 5 degrees of freedom. This design and the adhesion-molding technology differentiate the LP-ESP prosthesis from other mono-elastomeric prostheses, for which the constraints of shearing during rotations or movement are absorbed at the endplate interface. Seven years after the first implantation, we can document in a solid and detailed fashion the course of clinical outcomes and the radiological postural and kinematic behavior of this prosthesis.
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http://dx.doi.org/10.1007/s00590-012-1166-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3567327PMC
February 2013

Sacropelvic fixation with iliosacral screws: applications and results in adult spinal deformities.

J Spinal Disord Tech 2013 Jun;26(4):212-7

Pitié-Salpétrière Hospital, Assistance Publique-Hôpitaux de Paris, France.

Study Design: Retrospective radiographic and clinical review.

Objective: To determine the feasibility of iliosacral screw fixation in adult spinal deformations.

Summary Of Background Data: Pelvic fixation is one of the most challenging instrumentation problems. The poor bone quality frequently found within the sacrum and the large lumbosacral loads with cantilever pullout forces across this region explain its frequent failure.

Methods: Fourteen adult patients undergoing pelvic fixation using iliosacral screws with a minimal follow-up of 24 months were analyzed for radiographic outcomes. Radiographic data included the localization of the spinal deformity, the Cobb angle, T4-T12 thoracic kyphosis, L1-S1 lumbar lordosis, the T9 tilt, the pelvic parameters, and the POA. Mechanical and infectious complications were also noted.

Results: The lumbo-pelvic correction was performed with a large reduction of the POA in every case. The frontal and sagittal corrections obtained with this procedure were considered as being effective. There were no mechanical complications due to failure of the instrumentation, loss of sacral fixation, or loss of lumbar lordosis at the time of the last follow-up. One patient experienced local infection on the left iliosacral screw without any residual functional sequel.

Discussion: Iliosacral screwing can offer a pelvic fixation reliable enough to allow restoration of 3-dimensional trunk balance. This technique has a quite short learning curve and adequately permits frontal and sagittal corrections, increases stability, and decreases instrumentation-related complications. Our observations suggest that it is applicable to pelvic fixation in adult surgery.
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http://dx.doi.org/10.1097/BSD.0b013e31823f6280DOI Listing
June 2013

Hip-spine relations and sagittal balance clinical consequences.

Eur Spine J 2011 Sep 28;20 Suppl 5:686-98. Epub 2011 Jul 28.

Service de chirurgie orthopédique, Hôpital Pitié Salpêtrière, Université Pierre et Marie Curie, Assistance Publique-Hôpitaux de Paris, Paris 6, 83 bd de l'hôpital, 75013, Paris, France.

Introduction: The role of the pelvic area in sagittal balance is evident for spinal surgeons, but the influence of the coxofemoral joint is underestimated and inadequately explained by conventional imagery. Comprehensive analysis of the pelvic and subpelvic sectors as part of the sagittal, frontal and cross-sectional balance of the trunk sheds new light on some spinal diseases and their relation to the pelvis.

Methods: This analysis, based on innovative radiologic methods as the EOS(®) technology but also on a new look at conventional imaging makes it possible to better analyze standing lateral images and seated images.

Results: Disturbances can come from atypical morphotypes or from unusual postures as in aging spine. The measurement of available extension and the concept of available flexion provide new information regarding individual's adaptation to the imbalance induced by disorders of the spine or lower limbs.

Conclusion: A comprehensive assessment of each patient and in particular of the complex comprising the spine and the pelvis, is essential for understanding each individual's adaptation to the imbalance induced by disorders of the spine or lower limbs.
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http://dx.doi.org/10.1007/s00586-011-1937-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3175930PMC
September 2011

Three-dimensional assessment of the intervertebral kinematics after Mobi-C total disc replacement at the cervical spine in vivo using the EOS stereoradiography system.

SAS J 2011 1;5(3):63-8. Epub 2011 Sep 1.

Biomechanics Lab, Arts et Métiers ParisTech, Centre national de la recherche scientifique (CNRS), unités mixtes de recherche (UMR) 8005, Paris, France.

Background: Because 3-dimensional computed tomography and magnetic resonance imaging analysis of the spinal architecture is done with the patient in the supine position, stereoradiography may be more clinically relevant for the measurement of the relative displacements of the cervical vertebrae in vivo in the upright position. The innovative EOS stereoradiography system was used for measuring the relative angular displacements of the cervical vertebrae in a limited population to determine its feasibility. The precision and accuracy of the method were investigated.

Methods: In 9 patients with 16 Mobi-C prostheses (LDR Medical, Troyes, France) and 12 healthy subjects, EOS stereoradiography of the lower cervical spine (C3-7) was performed in the neutral upright position of the neck, flexion, extension, left and right lateral bending, and left and right axial rotation. The angular displacements were measured from the neutral position to every other posture. The random error was studied in terms of reproducibility. In addition, an in vitro protocol was performed in 6 specimens to investigate accuracy.

Results: The reproducibility and the accuracy variables varied similarly between 1.2° and 3.2° depending on the axis and direction of rotation under consideration. The Mobi-C group showed less mobility than the control group, whereas the pattern of coupling was similar.

Conclusions: Overall, the feasibility of dynamic EOS stereoradiography was shown. The prosthesis replicates the pattern of motion of the normal cervical spine.
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http://dx.doi.org/10.1016/j.esas.2011.03.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4365625PMC
March 2015

Acetabular anteversion with CT in supine, simulated standing, and sitting positions in a THA patient population.

Clin Orthop Relat Res 2011 Apr 16;469(4):1103-9. Epub 2010 Dec 16.

Department of Orthopaedic Surgery, La Pitié-Salpétrière Hospital, Assistance Publique-Hopitaux de Paris, 47 bd de l'Hôpital, 75013 Paris, France.

Background: Appraisal of the orientation of implants in THA dislocations currently is based on imaging done with the patient in the supine position. However, dislocation occurs in standing or sitting positions. Whether measured anteversion differs in images projected in the position of dislocation is unclear.

Questions/purposes: We compared measured acetabular cup orientations on axial CT scans taken with the patient in a supine position with those from CT sections at angles to the sacral slope reflecting standing and sitting positions.

Methods: We retrospectively reviewed the radiographs of 328 asymptomatic patients who had THAs. Anatomic acetabular anteversion (AAA) was measured from the plain CT scan (supine position, axial CT sections). The AAA also was measured on reformatted CT scans in which the orientation was adjusted individually to the sacral slope on lateral radiographs with patients in the standing and sitting positions.

Results: The mean/(SD) AAA changed from 24.2° (6.9°) in the supine position to 31.7° (5.6°) and 38.8° (5.4°) in simulated standing and sitting positions, respectively. The supine AAA correlated with the standing AAA (r = 0.857) but not with the sitting AAA (r = 0.484).

Conclusions: These data suggest measurement of the AAA on a plain CT scan used in current practice is biased. In patients with recurrent posterior dislocation from a sitting position, accounting for the functional variations in measurement of the position of the acetabular cup provides more relevant information regarding component positioning.
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http://dx.doi.org/10.1007/s11999-010-1732-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3048248PMC
April 2011

Shortening osteotomy and sacro-sacral fixation for U-shaped sacral fractures.

J Spinal Disord Tech 2010 Oct;23(7):457-60

Department of Orthopaedic Surgery, La Pitié Salpétrière Teaching Hospital, Paris, France.

Study Design: Technical note and retrospective first cases study.

Objective: To present a novel surgical procedure for treating rare and challenging U-shaped fractures of the sacrum.

Summary Of Background Data: U-shaped fractures of the sacrum are not frequent and usually seen in the context of high energy trauma (high-fall injury). There is no consensus about the therapeutic strategy. When surgery is decided on selected patients, the technique raises several issues for the neural decompression, reduction, and fixation. The L5-S1 mobility has to be sacrificed for most authors.

Methods: Based on anatomic considerations, the authors present here the original surgical technique they have been using at their institution and a consecutive series of patients. The procedure associates a shortening osteotomy of the sacrum at the site of the fracture and a sacro-sacral fixation.

Results: The proposed procedure was simple, safe, and effective.

Conclusions: Performing the osteotomy helps in the reduction and allows a short fixation, which spares the mobility of the lumbo-sacral junction.
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http://dx.doi.org/10.1097/BSD.0b013e3181bee88fDOI Listing
October 2010

Three-dimensional analysis of the cervical spine kinematics: effect of age and gender in healthy subjects.

Spine (Phila Pa 1976) 2009 Dec;34(26):2900-6

Laboratoire de Biomécanique, Arts et Métiers ParisTech, CNRS UMR, France.

STUDY DESIGN.: A three-dimensional (3D) analysis of the cervical spine kinematics in vivo about a large asymptomatic database in order to evaluate the impact of age and gender on the neck's performances. OBJECTIVE.: To investigate the effect of age and gender on kinematical parameters of the cervical spine, specifically quantitative parameters concerning coupled movements and proprioception, using the infra-red POLARIS measurement system. SUMMARY OF BACKGROUND DATA.: Cervical spine kinematics has been investigated in vivo by numerous authors using various devices. However, few is known about the influence of gender and age on the 3D cervical biomechanics, specifically regarding coupled movements and proprioceptive abilities. METHODS.: A total of 140 asymptomatic volunteers (70 men and 70 women) aged 20 to 93 years old were enrolled. The noninvasive infrared system Polaris was used to quantify the 3D range of motion (ROM) of cervical spine and to evaluate proprioceptive abilities. For validating the protocol in terms of reproducibility, 12 volunteers were tested 3 times by 2 independent operators. RESULTS.: The standard error of measurement for the maximal ROM in the 3 space planes was 5%. Gender had no significant influence on the 3D cervical ROM, except for the "70-79 years old" group. Age had a significant influence on all main movements showing 0.55 degrees to 0.79 degrees magnitude decrease per decade. Age and gender had no significant influence on coupled movements. "Head-to-Target" proprioception was significantly affected by the age only in the horizontal plane. CONCLUSION.: A data base for cervical ROM, pattern of motion, and proprioceptive capability was established in population of 140 healthy subjects of various age and gender. Significant age-related decrease in ROM and proprioceptive abilities were observed in this study. Coupled movements did not vary with gender or age; however, their role in the cervical performance increased with age since main movements were limited.
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http://dx.doi.org/10.1097/BRS.0b013e3181b4f667DOI Listing
December 2009

Outcome and serum ion determination up to 11 years after implantation of a cemented metal-on-metal hip prosthesis.

Acta Orthop 2009 Apr;80(2):168-73

Department of Orthopaedic Surgery, Pitie-Salpetriere Hospital, Paris, France.

Background And Purpose: Little is known about the long-term outcome of cemented metal-on-metal hip arthroplasties. We evaluated a consecutive series of metal-on-metal polyethylene-backed cemented hip arthroplasties implanted in patients under 60 years of age.

Methods: 109 patients (134 joint replacements) were followed prospectively for mean 9 (7-11) years. The evaluation included clinical score, radiographic assessment, and blood sampling for ion level determination.

Results: At the final review, 12 hips had been revised, mainly because of aseptic loosening of the socket. Using revision for aseptic loosening as the endpoint, the survival rate at 9 years was 91% for the cup and 99% for the stem. In addition, 35 hips showed radiolucent lines at the bone-cement interface of the acetabulum and some were associated with osteolysis. The median serum cobalt and chromium levels were relatively constant over time, and were much higher than the detection level throughout the study period. The cobalt level was 1.5 microg/L 1 year after implantation, and 1.44 microg/L 9 years after implantation.

Interpretation: Revisions for aseptic loosening and radiographic findings in the sockets led us to halt metal-on-metal-backed polyethylene cemented hip arthroplasty procedures. If the rigidity of the cemented socket is a reason for loosening, excessive release of metal ions and particles may be involved. Further investigations are required to confirm this hypothesis and to determine whether subluxation, microseparation, and hypersensitivity also play a role.
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http://dx.doi.org/10.3109/17453670902947408DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2823177PMC
April 2009

Optimization of total hip arthroplasty implantation: is the anterior pelvic plane concept valid?

J Arthroplasty 2009 Jan 1;24(1):22-6. Epub 2008 Nov 1.

Department of Orthopaedic Surgery, La Pitié - Salpétrière hospital, Asistance Publique - Hopitaux de Paris, Paris, France.

The anterior pelvic plane (APP) is currently used as superficial anatomical landmark for three-dimensional orientation during total hip arthroplasty (THA), specifically when using computer aided surgery. However, the actual parameter for characterizing the pelvic orientation is the sacral slope, which correlates with other functional spinal parameters. The goal of the paper was to investigate relationships between APP and sacral slope. Both were measured on 328 lateral radiographs of the pelvis in standing position by two observers. The poor correlation between APP and sacral slope suggest keeping using the reference to the APP for the per-operative orientation in the 3D space, while individually adjusting the preoperative planning to the sacral slope.
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http://dx.doi.org/10.1016/j.arth.2007.12.015DOI Listing
January 2009

Clinical and biological assessment of cemented titanium femoral stems: an 11-year experience.

Int Orthop 2009 Oct 28;33(5):1209-15. Epub 2008 Oct 28.

Department of Orthopaedic and Trauma Surgery, Bichat Hospital, 46 rue Henri Huchard, 75018, Paris, France.

This study prospectively assessed the outcome of 134 cemented titanium stems and serum ion levels. The stems were polished (0.1 microm Ra) with circular cross section. At the end point, only one stem revision was performed for aseptic loosening, and two were planned due to subsidence greater than 5 mm. Non-progressive radiolucencies in zones 1 and 7 were observed in 16 hips at the cement-bone interface without osteolysis. Median serum titanium concentrations were below the detection limit (30 nmol/l) except in patients with failed stems. The overall stem survival rate was 97.7% at nine years, which is comparable to other series of cemented stems. The protective layer of titanium oxide coating the stem and a thick cement mantle may help resist aseptic loosening. In addition, satisfactory monitoring of the stem was reached using titanium serum level determination.
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http://dx.doi.org/10.1007/s00264-008-0678-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2899120PMC
October 2009
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