Publications by authors named "Martin Clauss"

48 Publications

Scope and Limits of Teriparatide Use in Delayed and Nonunions: A Case Series.

Clin Pract 2021 Jan 29;11(1):47-57. Epub 2021 Jan 29.

Department of Orthopaedics and Traumatology, University Hospital Basel, Spitalstrasse 21, 4031 Basel, Switzerland.

Nonunion is known to occur in up to 10% of all bone fractures. Until recently, the treatment options considered in cases of delayed union and nonunion focused on revision surgery and improvement of local healing. Lately, teriparatide has been introduced as an osteoanabolic factor that induces fracture healing in cases with delayed or nonunions. We report on a series of five cases of delayed and nonunions treated with teriparatide: delayed unions of an atypical femoral fracture, of a multifragmentary clavicle fracture, and of a periprosthetic humeral fracture; nonunion of a tibial and fibular fracture; and infected nonunion of a tibial and fibular fracture. Based on this series, the indications and limits of application of teriparatide in cases of impaired fracture healing are discussed. Due to the "off-label" character of this application, informed consent, and cost coverage from the healthcare insurance must be obtained prior to treatment. In our experience and according to the limited existing literature, teriparatide is a safe feasible treatment in cases of delayed and nonunions with a reasonable need of resources. While adequate biomechanical stability remains the cornerstone of fracture healing, as well as healing of nonunions, teriparatide could help avoid repetitive surgeries, especially in atrophic delayed and nonunions, as well as in patients with impaired fracture healing undergoing bisphosphonate therapy. There is an urgent need for widely accepted definitions, standardized protocols, as well as further clinical trials in the field of impaired fracture healing.
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http://dx.doi.org/10.3390/clinpract11010009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7931020PMC
January 2021

The EBJIS definition of periprosthetic joint infection.

Bone Joint J 2021 Jan;103-B(1):18-25

Orthopaedic Hospital Valdoltra, Ankaran, Slovenia.

Aims: The diagnosis of periprosthetic joint infection (PJI) can be difficult. All current diagnostic tests have problems with accuracy and interpretation of results. Many new tests have been proposed, but there is no consensus on the place of many of these in the diagnostic pathway. Previous attempts to develop a definition of PJI have not been universally accepted and there remains no reference standard definition.

Methods: This paper reports the outcome of a project developed by the European Bone and Joint Infection Society (EBJIS), and supported by the Musculoskeletal Infection Society (MSIS) and the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group for Implant-Associated Infections (ESGIAI). It comprised a comprehensive review of the literature, open discussion with Society members and conference delegates, and an expert panel assessment of the results to produce the final guidance.

Results: This process evolved a three-level approach to the diagnostic continuum, resulting in a definition set and guidance, which has been fully endorsed by EBJIS, MSIS, and ESGIAI.

Conclusion: The definition presents a novel three-level approach to diagnosis, based on the most robust evidence, which will be useful to clinicians in daily practice. Cite this article: 2021;103-B(1):18-25.
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http://dx.doi.org/10.1302/0301-620X.103B1.BJJ-2020-1381.R1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7954183PMC
January 2021

The Impact of Surgical Strategy and Rifampin on Treatment Outcome in Cutibacterium Periprosthetic Joint Infections.

Clin Infect Dis 2021 Jun;72(12):e1064-e1073

Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.

Background: Cutibacterium species are common pathogens in periprosthetic joint infections (PJI). These infections are often treated with β-lactams or clindamycin as monotherapy, or in combination with rifampin. Clinical evidence supporting the value of adding rifampin for treatment of Cutibacterium PJI is lacking.

Methods: In this multicenter retrospective study, we evaluated patients with Cutibacterium PJI and a minimal follow-up of 12 months. The primary endpoint was clinical success, defined by the absence of infection relapse or new infection. We used Fisher's exact tests and Cox proportional hazards models to analyze the effect of rifampin and other factors on clinical success after PJI.

Results: We included 187 patients (72.2% male, median age 67 years) with a median follow-up of 36 months. The surgical intervention was a 2-stage exchange in 95 (50.8%), 1-stage exchange in 51 (27.3%), debridement and implant retention (DAIR) in 34 (18.2%), and explantation without reimplantation in 7 (3.7%) patients. Rifampin was included in the antibiotic regimen in 81 (43.3%) cases. Infection relapse occurred in 28 (15.0%), and new infection in 13 (7.0%) cases. In the time-to-event analysis, DAIR (adjusted hazard ratio [HR] = 2.15, P = .03) and antibiotic treatment over 6 weeks (adjusted HR = 0.29, P = .0002) significantly influenced treatment failure. We observed a tentative evidence for a beneficial effect of adding rifampin to the antibiotic treatment-though not statistically significant for treatment failure (adjusted HR = 0.5, P = .07) and not for relapses (adjusted HR = 0.5, P = .10).

Conclusions: We conclude that a rifampin combination is not markedly superior in Cutibacterium PJI, but a dedicated prospective multicenter study is needed.
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http://dx.doi.org/10.1093/cid/ciaa1839DOI Listing
June 2021

[Periprosthetic Joint Infections - An Overview].

Ther Umsch 2020 ;77(10):529-534

Zentrum für muskuloskelettale Infektionen, Universitätsspital Basel.

Periprosthetic Joint Infections - An Overview Diagnostics and treatment of periprosthetic joint infections (PJI) is an interdisciplinary challenge. The key for success in the treatment of PJI is a rapid and adequate diagnostic and treatment in close cooperation between the general practitioner (GP), a specialised orthopaedic surgeon and an infectious disease specialist (ID). Acute PJI mostly occur peri- and early postoperative but can occur also lifelong due to haematogenous / lymphogenic seeding of the germs on the prosthesis. Both situations must be considered as an emergency scenario and patients should be transferred to the operating surgeon or even in a specialised centre for further diagnostics and treatment immediately. An acute infection (either < 4 weeks after implantation or < 3 weeks after the onset of symptoms with haematogenous / lymphogenic seeding) can frequently be cured by debridement, antibiotics and implant retention (DAIR) and should be the favoured approach in this scenario. In chronic PJI an interdisciplinary approach with complete exchange of the implant combined with an elaborated antibiotic therapy is always needed. Optimised and targeted diagnostic as well as an interdisciplinary planning of the treatment are mandatory for curing the infection, therefore patients with chronic PJI should be referred to a specialised centre. Surgery alone without adequate antibiotic therapy will mostly result in failure to cure PJI, same is true for exclusive antibiotic therapy without an adequate surgical procedure.
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http://dx.doi.org/10.1024/0040-5930/a001221DOI Listing
December 2020

Kinematic changes in severe hip osteoarthritis measured at matched gait speeds.

J Orthop Res 2021 Jun 28;39(6):1253-1261. Epub 2020 Sep 28.

Department of Orthopaedics and Traumatology, University Hospital Basel, Basel, Switzerland.

Kinematic differences between patients with osteoarthritis (OA) and control participants have been reported to be influenced by gait speed. The purpose of this study was to experimentally detect the effect of walking speed on differences in spatiotemporal parameters and kinematic trajectories between patients with hip OA and age-matched asymptomatic participants using wearable sensors and statistical parametric mapping (SPM). Twenty-four patients with severe unilateral hip OA and 48 control participants were included in this study. Patients walked at a self-selected normal speed and control participants at self-selected normal and slow speeds. Spatiotemporal parameters and kinematic trajectories were measured with the inertial sensor system Rehagait®. Gait parameters were compared between patients with hip OA and control participants for normal and matched speed using SPM with independent sample t-tests. At self-selected normal speed, the patient group walked slower (-0.20 m/s, p < .001) and at lower cadence (-5.0 steps/minute, p < .001) as well as with smaller hip flexion (-7.4°, p < .001) and extension (-4.1°, p = .001), higher knee flexion during terminal stance (+8.0°, p < .001) and higher ankle dorsiflexion and plantarflexion (+7.1°, p < .001). While differences in spatiotemporal parameters and the ankle trajectory disappeared at matched speed, some clinically relevant and statistically significant differences in hip and knee trajectories remained. Most differences in sagittal plane gait kinematics between patients with hip OA and control participants were present for matched speed, and therefore appear to be associated with a disease rather than gait speed. Nevertheless, studies investigating hip kinematics in patients with hip OA should involve trials at matched speeds.
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http://dx.doi.org/10.1002/jor.24858DOI Listing
June 2021

Measuring gait kinematics in patients with severe hip osteoarthritis using wearable sensors.

Gait Posture 2020 09 6;81:49-55. Epub 2020 Jul 6.

Department of Orthopaedics and Traumatology, University Hospital Basel, Basel, Switzerland; Department of Clinical Research, University of Basel, Basel, Switzerland; Department of Biomedical Engineering, University of Basel, Basel, Switzerland; Department of Spine Surgery, University Hospital Basel, Basel, Switzerland.

Background: The popularity of inertial sensors in gait analysis is steadily rising. To date, an application of a wearable inertial sensor system for assessing gait in hip osteoarthritis (OA) has not been reported.

Research Question: Can the known kinematic differences between patients with hip OA and asymptomatic control subjects be measured using the inertial sensor system RehaGait®?

Methods: The patients group consisted of 22 patients with unilateral hip OA scheduled for total hip replacement. Forty-five age matched healthy control subjects served as control group. All subjects walked for a distance of 20 m at their self-selected speed. Spatiotemporal parameters and sagittal kinematics at the hip, knee, and ankle including range of motion (ROM) were measured using the RehaGait® system.

Results: Patients with hip OA walked at a slower walking speed (-0.18 m/s, P < 0.001) and with shorter stride length (-0.16 m, P < 0.001), smaller hip ROM during stance (-11.6°, P < 0.001) and swing (-11.3°, P < 0.001) and smaller knee ROM during terminal stance and swing (-9.0° and-11.5°, P < 0.001). Patients had a smaller hip ROM during stance and swing and smaller knee ROM during terminal stance and swing in the affected compared to the unaffected side (P < 0.001).

Significance: The differences in spatiotemporal and kinematic gait parameters between patients with hip OA and age matched control subjects assessed using the inertial sensor system agree with those documented for camera-based systems. Hence, the RehaGait® system can measure gait kinematics characteristic for hip OA, and its use in daily clinical practice is feasible.
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http://dx.doi.org/10.1016/j.gaitpost.2020.07.004DOI Listing
September 2020

Biohackers and Self-Made Problems: Infection of an Implanted RFID/NFC Chip: A Case Report.

JBJS Case Connect 2020 Apr-Jun;10(2):e0399

1Hand Surgery, Kantonsspital Baselland, Liestal, Switzerland 2Interdisciplinary septic Surgical Unit, Department of Orthopaedics, Kantonsspital Baselland, Liestal, Switzerland 3Department for Orthopaedics and Trauma Surgery, University Hospital Basel, Basel, Switzerland 4Medical Additive Manufacturing Research Lab, Department of Biomedical Engineering, University of Basel, Basel, Switzerland.

Case: We describe the case of a 26-year-old man with an infected Radio-Frequency-Identification/Near Field Communication (RFID/NFC) chip in the middle finger. The RFID/NFC chip was removed, the soft tissue debrided, and a pan-sensitive staphylococcus aureus was detected by sonication of the RFID/NFC chip. The patient was postoperatively treated with amoxicillin and clavulanic acid (24 hours iv, total 11 days) and an intrinsic plus splint which led to complete recovery.

Conclusion: Modern body modifications can lead to infections which shouldn't be underestimated. Interdisciplinary treatment is a key to success.
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http://dx.doi.org/10.2106/JBJS.CC.19.00399DOI Listing
February 2021

Orthoplastics in Periprosthetic Joint Infection of the Knee: Treatment Concept for Composite Soft-tissue Defect with Extensor Apparatus Deficiency.

J Bone Jt Infect 2020 18;5(3):160-171. Epub 2020 May 18.

Centre for Musculoskeletal Infections, University Hospital Basel, Basel, Switzerland.

: Reconstruction of composite soft-tissue defects with extensor apparatus deficiency in patients with periprosthetic joint infection (PJI) of the knee is challenging. We present a single-centre multidisciplinary orthoplastic treatment concept based on a retrospective outcome analysis over 20 years. : One-hundred sixty patients had PJI after total knee arthroplasty. Plastic surgical reconstruction of a concomitant perigenicular soft-tissue defect was indicated in 47 patients. Of these, six presented with extensor apparatus deficiency. One patient underwent primary arthrodesis and five patients underwent reconstruction of the extensor apparatus. The principle to reconstruct missing tissue 'like with like' was thereby favoured: Two patients with a wide soft-tissue defect received a free anterolateral thigh flap with fascia lata; one patient with a smaller soft-tissue defect received a free sensate, extended lateral arm flap with triceps tendon; and two patients who did not qualify for free flap surgery received a pedicled medial sural artery perforator gastrocnemius flap. Despite good functional results 1 year later, long-term follow-up revealed that two patients had to undergo arthrodesis because of recurrent infection and one patient was lost to follow-up. : These results show that PJI of the knee and extensor apparatus deficiency is a dreaded combination with a poor long-term outcome. Standardization of surgical techniques for a defined PJI problem and consensus on study variables may facilitate interinstitutional comparisons of outcome data, and hence, improvement of treatment concepts.
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http://dx.doi.org/10.7150/jbji.47018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7295645PMC
May 2020

Debridement, Antibiotics and Implant Retention for Hip Periprosthetic Joint Infection: Analysis of Implant Survival after Cure of Infection.

J Bone Jt Infect 2020 10;5(1):35-42. Epub 2020 Feb 10.

Center for Muscular-Skeletal Infections, Department of Orthopedics and Traumatology, University Hospital Basel, University of Basel, Basel, Switzerland.

: Debridement, antibiotics and implant retention (DAIR) is a valuable option for treating early and acute periprosthetic joint infection (PJI). The inflammation caused by the infection and the surgical intervention during DAIR may influence the long-term stability of the implant. In this study, we analyzed the sequelae of DAIR on implant survival in hip PJI after cure of infection. : Total hip arthroplasties (THAs) from our database implanted between 1992 and 2016 were included in a retrospective double-cohort study. THAs were exposed (DAIR cohort) or not exposed to DAIR (control cohort). The control cohort comprised patients matched 3:1 to the DAIR cohort. The outcome was implant failure over time. It was evaluated for (i) revision for any reason, (ii) aseptic loosening of any component, and (iii) radiographic evidence of loosening. : 57 THAs (56 patients) were included in the DAIR cohort and 170 THAs (168 patients) in the control cohort. The mean follow-up periods in the DAIR and control cohorts were 6.1 and 7.8 years, respectively. During follow-up, 20 (36%) patients in the DAIR cohort and 54 (32%) in the control cohort died after a mean of 4.1 and 7.2 years, respectively. Revision for any reason was performed in 9 (16%) THAs in the DAIR cohort and in 10 (6%) THAs (p=0.03) in the control cohort, and revision for aseptic loosening of any component in 5 (9%) and 8 (5%) THAs (p=0.32), respectively. Radiological analysis included 56 THAs in the DAIR cohort and 168 THAs in the control cohort. Two (4%) stems and 2 (4%) cups in the DAIR cohort and 7 (4%) and 1 (0.6%) in the control cohort, respectively, demonstrated radiological signs of failure (p=1). : THAs exposed to DAIR were revised for any reason more frequently than were THAs in the control cohort. The difference was mainly caused by septic failures. After cure of PJI, the difference in revisions for aseptic loosening was not significant. There was no significant difference in radiographic evidence of loosening of any component between cohorts. These data suggest that cured hip PJI previously exposed to DAIR do not fail more frequently for aseptic reasons than do THAs not exposed to DAIR.
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http://dx.doi.org/10.7150/jbji.40924DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7045527PMC
February 2020

Is cemented revision total hip arthroplasty a reasonable treatment option in an elderly population?

Orthop Rev (Pavia) 2019 Sep 2;11(3):8263. Epub 2019 Oct 2.

Clinic for Orthopedic and Trauma Surgery, Kantonsspital Baselland, Liestal.

Revision THA is increasingly performed especially in the elderly population. The surgeon's challenge is to provide a solution that supports immediate full weight-bearing, despite poor bone quality. Shape-closed revision stems facilitate that by combining cement fixation with additional press-fit anchoring. The design tolerates varying cement mantle thickness and inconsistent cancellous bone lining of the femoral canal. Following that philosophy, we present our mid-term results using a long version of a cemented Charnley- Kerboull type stem. From 2010 to 2017, 38 long Charnley-Kerboull revision stems (Centris, Mathys European Orthopaedics, Bettlach, Switzerland) were implanted and followed prospectively. Surgery was performed via a Hardinge approach in supine position with a third generation cementing technique. Patients were mobilized using full-weight bearing as early as possible. Survival was determined for stem revision for aseptic loosening and stem and/or cup revision for any reason. 20 stems had a minimum follow-up (f/u) of 2 years and were included for further radiological analysis. Detailed subsidence analysis as an early predictor for later aseptic loosening was performed using EBRA-FCA software. Further, the presence of osteolysis and cement debonding was evaluated. Mean follow- up was 4 years. No patient was lost to f/u.18 died of causes unrelated to THA. Stem survival was 100%. Survival for any re-operation was 82.2% (two early infections, one soft-tissue debridement, one cup exchange for recurrent dislocations). None of the cases revised for septic loosening showed signs of persistent infection at final f/u. EBRA-FCA revealed two oligosymptomatic cases of subsidence of 5mm and 6mm over a course of 2 and 12 months, respectively, with stable implants thereafter. Neither required revision. There was no development of osteolysis or debonding. The stem provides a reliable early fullweight bearing solution for revision THA with excellent mid-term survival in an elderly population. Even in two cases where subsidence was present, mobility was not impaired and re-revision could be avoided.
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http://dx.doi.org/10.4081/or.2019.8263DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6790558PMC
September 2019

Five-year prospective subsidence analysis of 100 cemented polished straight stems: A concise clinical and radiological follow-up observation.

Orthop Rev (Pavia) 2019 May 23;11(2):7984. Epub 2019 May 23.

Department of Orthopedics and Trauma Surgery, Kantonsspital Baselland.

Early subsidence (>1.5mm) has been shown to be an indicator for later aseptic loosening of cemented hip stems. For the cemented twinSys stem we published excellent short-term results at 2 years. Midterm data for this stem are available from national registers (NZL, NL), however in all of these sources, clinical and radiological results are missing. Aim of our study was to analyse mid-term survival and radiological changes around the cemented twinSys stem with special emphasis on subsidence using EBRA-FCA. We conducted a prospective clinical and radiological 5- year follow-up study of 100 consecutive hybrid total hip arthroplasties (THA) using a polished, cemented collarless straight stem (twinSys, Mathys AG Bettlach, Switzerland) with a cementless monobloc pressfit cup (RM pressfit, Mathys AG Bettlach, Switzerland). Median age at surgery was 79 (69 to 93) years. No patient was lost to follow-up. Survival rates were calculated using the Kaplan-Meier method. Clinical (Harris Hip Score [HHS]) and radiological (cementing quality, alignment, osteolysis, debonding and cortical atrophy) outcomes and an in-depth subsidence analysis using EBRA-FCA were performed. 22 patients died in the course of follow-up unrelated to surgery, 21 stems had an incomplete radiological follow-up. 2 stems were revised, both due to an infection. The survival rate for the stem at 5 years was 98.0% (95% CI 95.3-100%). The survival rate of the stem for revision due to aseptic loosening at 5 years was 100%. The HHS improved from 53 (14-86) points preoperatively to 90 (49-100) points 5 years after surgery. Osteolysis was found in 2 stems without clinical symptoms. In 49 out of 55 patients with a complete radiological follow- up, the EBRA-FCA analysis was possible and showed an average subsidence of 0.66 (95% CI 0.46 to 0.86) mm 5 years after surgery. 10 patients showed a subsidence >1 mm, 5 of which bigger than 1.5 mm. Subsidence was independent from radiological changes and cementing quality. The cemented twinSys stem showed excellent clinical and radiological mid-term results at five years' follow-up and seems to be a reliable implant.
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http://dx.doi.org/10.4081/or.2019.7984DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6551455PMC
May 2019

An excellent 5-year survival rate despite a high incidence of distal femoral cortical hypertrophy in a short hip stem.

Hip Int 2020 Mar 22;30(2):152-159. Epub 2019 Apr 22.

Clinic for Orthopaedic and Trauma Surgery, Kantonsspital Baselland, Bruderholz, Switzerland.

Background: Although reported results on short stems sound very promising, the occurrence of distal femoral cortical hypertrophy is often observed. The aim of the present study was to report 5-year survival data of a commercially available trochanter sparing short stem and investigate the clinical impact of distal femoral cortical hypertrophy on the outcome.

Methods: 123 total hip arthroplasties were performed on 120 patients from April 2008 to May 2010 (mean age 62, range 29-89 years; 71 hips from male patients, 58%). Clinical and radiological data were collected preoperative, at 6 weeks, 1, 2, 3, and 5 years postoperative to assess the outcome. Radiographs taken immediately postoperative as well as 1 and 5 years postoperative were used to identify and assess cortical hypertrophy.

Results: 1 stem had to be revised due to aseptic loosening, resulting in a Kaplan-Meier survival analysis with endpoint for stem revision of 99.2% (95% Confidence Interval 94.1-99.9) at 5 years. 96 radiological and 95 clinical follow-ups were analysed 5 years postoperative. 68 (71%) hips showed distal femoral cortical hypertrophy after 5 years. The average Harris Hip Score and Oxford Hip Score improved 33 (standard deviation (SD) 15.1, range 2-70), 18 (SD 12.1, range -10-43) points, respectively. Overall 16% of the patients reported thigh pain, unrelated to the presence of cortical hypertrophy.

Discussion: This short stem shows an excellent 5-year survival rate and good clinical outcome despite a high incidence of cortical hypertrophy. However, the question of the mechanism of load transfer arises.
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http://dx.doi.org/10.1177/1120700019834336DOI Listing
March 2020

2018 international consensus meeting on musculoskeletal infection: Summary from the biofilm workgroup and consensus on biofilm related musculoskeletal infections.

J Orthop Res 2019 05 12;37(5):1007-1017. Epub 2019 Feb 12.

Department of Orthopaedic Surgery at St. Olavs Hospital, Trondheim, Norway.

Biofilm-associated implant-related bone and joint infections are clinically important due to the extensive morbidity, cost of care and socioeconomic burden that they cause. Research in the field of biofilms has expanded in the past two decades, however, there is still an immense knowledge gap related to many clinical challenges of these biofilm-associated infections. This subject was assigned to the Biofilm Workgroup during the second International Consensus Meeting on Musculoskeletal Infection held in Philadelphia USA (ICM 2018) (https://icmphilly.com). The main objective of the Biofilm Workgroup was to prepare a consensus document based on a review of the literature, prepared responses, discussion, and vote on thirteen biofilm related questions. The Workgroup commenced discussing and refining responses prepared before the meeting on day one using Delphi methodology, followed by a tally of responses using an anonymized voting system on the second day of ICM 2018. The Working group derived consensus on information about biofilms deemed relevant to clinical practice, pertaining to: (1) surface modifications to prevent/inhibit biofilm formation; (2) therapies to prevent and treat biofilm infections; (3) polymicrobial biofilms; (4) diagnostics to detect active and dormant biofilm in patients; (5) methods to establish minimal biofilm eradication concentration for biofilm bacteria; and (6) novel anti-infectives that are effective against biofilm bacteria. It was also noted that biomedical research funding agencies and the pharmaceutical industry should recognize these areas as priorities. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.
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http://dx.doi.org/10.1002/jor.24229DOI Listing
May 2019

Long-term results of revision total hip arthroplasty with a cemented femoral component.

Arch Orthop Trauma Surg 2018 Nov 11;138(11):1609-1616. Epub 2018 Aug 11.

Clinic for Orthopedic and Trauma Surgery, Kantonsspital Baselland, Rheinstrasse 26, 4410, Liestal, Switzerland.

Introduction: In revision total hip arthroplasty (THA), the cancellous bone is normally completely removed out of the femoral canal during stem extraction. This situation is comparable to primary THA following the shape-closed concept, with some authors advocating to remove the metaphyseal cancellous bone to enhance press-fit stability ("French paradox"). The aim of this study was to investigate the long-term outcome, regarding survival and radiological results, of a cemented straight stem when used for revision THA and to compare these results to the results of the same stem in primary THA.

Materials And Methods: 178 stem revisions performed between 01/1994 and 08/2008 using the Virtec straight stem were included. The cumulative incidence for re-revision was calculated using a competing risk model. Risk factors for re-revision of the stem were analyzed using an absolute risk regression model. Radiographs analyzed for osteolysis, debonding and subsidence had a minimum follow-up of 10 years.

Results: The cumulative incidence for re-revision due to aseptic loosening of the stem was 5.5% (95% CI, 2.9-10.2%) at 10 years. Aseptic loosening was associated with younger age, larger defect size and larger stem size. After a minimum 10-year follow-up, osteolysis was seen in 39 of 80 revision THA. Compared to the results in primary THA, the survival in revision THA with the same implant was inferior.

Conclusions: Cemented straight stems used for revision THA showed excellent long-term results regarding survivorship and radiological outcome. This stem therefore offers a valuable and cost-effective option in revision THA.
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http://dx.doi.org/10.1007/s00402-018-3023-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6182687PMC
November 2018

Long-term survival of the cemented Müller CDH stem: a minimum follow-up of 10 years.

Arch Orthop Trauma Surg 2018 Oct 25;138(10):1471-1477. Epub 2018 Jul 25.

Clinic for Orthopedics and Trauma Surgery, Kantonsspital Baselland, Rheinstrasse 26, 4410, Liestal, Switzerland.

Introduction: Total hip arthroplasty in patients with altered anatomy of the hip and femur, such as in congenital dysplasia of the hip, is challenging and often requires specially designed stems. Müller straight stems have shown excellent long-term results; however, long-term data on the analogous cemented Müller CDH stem are still missing. The aim of this study was to analyze long-term survival, identify potential risk factors for aseptic loosening, and analyze radiological outcome of the cemented Müller CDH stems.

Materials And Methods: Between 01/1985 and 06/2005, 95 Müller CDH stems (Zimmer, Winterthur, Switzerland) made up of 3 different materials were cemented using 2 different bone cements: 38 of stainless steel/high-viscosity cement, 31 of a cobalt-chrome-based alloy (CoCr)/low-viscosity cement, and 26 of a titanium-based alloy (Ti)/low-viscosity cement. All patients had a prospective clinical and radiological follow-up according to the standards of our institution. The cumulative incidence for revision of the stem was calculated using a competing risk model. To identify demographic and implant-related risk factors for aseptic loosening of the stem, a multivariate regression model for competing risks was performed.

Results: The cumulative risk of revision at 15 years was 12.5% (95% CI 6.6-20.5%) for aseptic loosening of the stem as endpoint, with marked differences for the various stem materials used: stainless steel 2.7% (0.2-12.3%), CoCr 12.9% (4.0-27.3%), and Ti 24.5% (9.6-43.1%). Regression modeling revealed that Ti stems in combination with low-viscosity cement (HR 10.2) and implantation with an axis deviation greater than 3° (HR 3.8) are risk factors for aseptic loosening.

Conclusions: Long-term survival of the cemented Müller CDH stem is comparable to other Müller-type straight stems and uncemented implants. Similar to the original Ti Müller straight stem, the Ti Müller CDH stem also showed an increased risk for aseptic loosening and should, therefore, no longer be used.
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http://dx.doi.org/10.1007/s00402-018-3009-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6132943PMC
October 2018

CORR Insights®: Does the Alpha-defensin Immunoassay or the Lateral Flow Test Have Better Diagnostic Value for Periprosthetic Joint Infection? A Systematic Review.

Authors:
Martin Clauss

Clin Orthop Relat Res 2018 05;476(5):1073-1075

M. Clauss, Head Interdisciplinary Unit for Orthopedic Infections, Kantonsspital Baselland, Liestal, Switzerland, and Interdisciplinary Unit for Muscolo-Sceletal Infections University Hospital Basel, Basel, Switzerland.

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http://dx.doi.org/10.1007/s11999.0000000000000287DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5916616PMC
May 2018

Influence of Sonication on Bacterial Regrowth from Antibiotic Loaded PMMA Scaffolds - An Study.

J Bone Jt Infect 2017 17;2(4):213-217. Epub 2017 Nov 17.

Medical University of Graz, Austria.

Periprosthetic joint infection (PJI) is one of the most challenging complications after joint replacement. However, when treated correctly, chances of recovery are good. The most important step in correct diagnosis and management of PJI is the detection of the causative germ. In the last years, the use of sonication in the diagnostic process has become more important. However, this diagnostic methodology has been controversially discussed when used in combination with antibiotic loaded bone cement (PMMA), which is frequently used in joint replacement surgeries. The aim of this study was thus to analyse in vitro bacterial growth in sonication fluid cultures obtained from antibiotic loaded PMMA which were contaminated with various bacterial biofilms. Sonication fluid obtained from antibiotic loaded PMMA (Copal G+V and Copal G+C) and plain Palacos R (control) contaminated either with , , or , were analysed for bacterial re-growth in a standardised setting. In vitro bacterial growth was not interfered by released antibiotics from sonication of antibiotic loaded PMMA for , and However, for bacterial counts were affected by the released antibiotics as well as by the time delay between sonication and analysis. The data suggest sonication to be an easy and sensitive diagnostic modality to detect easy-to-detect bacteria, however, results are alarming for the difficult-to-detect bacteria , indicating that further attention and research is necessary to improve the detection of difficult-to-detect bacteria.
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http://dx.doi.org/10.7150/jbji.22382DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5704003PMC
November 2017

Mid-term results of revision total hip arthroplasty with an uncemented modular femoral component.

Hip Int 2018 Jan;28(1):84-89

1 Clinic for Orthopaedics and Trauma Surgery, Kantonsspital Baselland, Liestal - Switzerland.

Introduction: During revision total hip arthroplasty (THA), the surgeon commonly faces deficient proximal femoral bone. In this situation, distal fixation of the prosthesis is required. The aim of the current retrospective study is to assess the clinical and radiographic mid-term outcome of revision total hip arthroplasty using a modular uncemented, tapered, grit-blasted, distal straight stem system.

Methods: This retrospective study included 70 femoral revisions that were performed in 67 patients using the device of interest. All patients were operated on via an extended trochanteric osteotomy. 60 revisions were performed as 1-stage (12 infected) and 10 as 2-stage (all infected) revisions. At 3 months postoperatively and at final follow-up, patients were assessed radiographically for the presence of osteolysis and for distal integration.

Results: The mean follow-up time was 4.3 (2.0-7.6) years. 4 patients had a removal of at least 1 prosthetic component. Stem survival for any reason was 92% after 5 years (95% confidence interval [CI], 83%-100%). With aseptic loosening of the stem as the endpoint of interest, survival after 5 years was 96% (95% CI, 88%-100%). A postoperative subsidence rate of 14.7% was found. No perioperative femoral fractures were found in the current patient series.

Conclusions: This study showed excellent mid-term survival and good clinical and radiographic outcomes in patients who had undergone revision THA with a modular uncemented, tapered, straight design.
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http://dx.doi.org/10.5301/hipint.5000522DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6159842PMC
January 2018

Management of Asymptomatic Bacteriuria, Urinary Catheters and Symptomatic Urinary Tract Infections in Patients Undergoing Surgery for Joint Replacement: A Position Paper of the Expert Group 'Infection' of .

J Bone Jt Infect 2017 25;2(3):154-159. Epub 2017 May 25.

Service of Infectious Diseases, Geneva University Hospitals and Faculty of Medicine, University of Geneva.

In this position paper, we review definitions related to this subject and the corresponding literature. Our recommendations include the following statements. Asymptomatic bacteriuria, asymptomatic leukocyturia, urine discolouration, odd smell or positive nitrite sediments are not an indication for antimicrobial treatment. Antimicrobial treatment of asymptomatic bacteriuria does not prevent periprosthetic joint infection, but is associated with adverse events, costs and antibiotic resistance development. Urine analyses or urine cultures in asymptomatic patients undergoing orthopaedic implants should be avoided. Indwelling urinary catheters are the most frequent reason for healthcare-associated urinary tract infections and should be avoided or removed as soon as possible.
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http://dx.doi.org/10.7150/jbji.20425DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5592375PMC
May 2017

Excellent long-term results of the Müller acetabular reinforcement ring in primary cup revision.

Acta Orthop 2017 Dec 3;88(6):619-626. Epub 2017 Aug 3.

a Department of Orthopedics and Trauma Surgery , Kantonsspital Baselland , Liestal , Switzerland.

Background and purpose - The original Müller acetabular reinforcement ring (ARR) was developed to be used for acetabular revisions with small cavitary and/or segmental defects or poor acetabular bone quality. Long-term data for this device are scarce. We therefore investigated long-term survival and radiographic outcome for revision total hip arthroplasty using the ARR. Patients and methods - Between October 1984 and December 2005, 259 primary acetabular revisions using an ARR were performed in 245 patients (259 hips). The mean follow-up time was 10 (0-27) years; 8 hips were lost to follow-up. The cumulative incidence for revision was calculated using a competing risk model. Radiographic assessment was performed for 90 hips with minimum 10 years' follow-up. It included evaluation of osteolysis, migration and loosening. Results - 16 ARRs were re-revised: 8 for aseptic loosening, 6 for infection, 1 for suspected infection, and 1 due to malpositioning of the cup. The cumulative re-revision rate for aseptic loosening of the ARR at 20 years was 3.7% (95% CI 1.7-6.8%). Assuming all patients lost to follow-up were revised for aseptic loosening, the re-revision rate at 20 years was 6.9% (95% CI 4.1-11%). The overall re-revision rate of the ARR for any reason at 20 years was 7.0% (95% CI 4.1-11%). 21 (23%) of the 90 radiographically examined ARR had radiographic changes: 12 showed isolated signs of osteolysis but were not loose; 9 were determined loose on follow-up, of which 5 were revised. Interpretation - Our data suggest that the long-term survival and radiographic results of the ARR in primary acetabular revision are excellent.
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http://dx.doi.org/10.1080/17453674.2017.1361137DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5694806PMC
December 2017

Antibiotic Prophylaxis During Dental Procedures in Patients with Prosthetic Joints.

J Bone Jt Infect 2016 20;1:42-49. Epub 2016 Jul 20.

Clinic for Orthopedics and Trauma Surgery and Interdisciplinary Septic Surgical Unit, Kantonsspital Baselland Liestal, Switzerland.

In patients with artificial joints, the need for antimicrobial prophylaxis during dental procedures is often raised. The present document describes the pathogenic mechanisms and epidemiological data on the subject of periprosthetic joint infections (PJI) after dental procedures. The document reflects the opinion and recommendations of the expert group 'Infection' of Swiss Orthopaedics. Microorganisms belonging to oral flora can seed haematogenously to an artificial joint. The proof of a causative relation with dental procedures is not possible, because the responsible bacteraemia can originate from the oral cavity at any time, irrespective of when the dental procedure occurs. Good oral hygiene is associated with a lower risk for PJI. Transient bacteraemia occurs during daily oral hygiene activity (e.g., tooth brushing) and thus the cumulative risk for a haematogenous PJI from tooth brushing is higher than that from a dental procedure. PJI after a dental procedure are rarely reported. On the basis of an epidemiological model, several thousand patients with artificial joints must receive antimicrobial prophylaxis to prevent a single PJI. Considering this ratio, the number of adverse events due to the antimicrobial compound exceeds the benefit of administering it by a large magnitude. Therefore, as a rule for the vast majority of cases, antimicrobial prophylaxis during dental procedures is not recommended. It is important that a patient has a good oral health status before joint implantation and that good oral hygiene is continuously maintained in patients with artificial joints.
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http://dx.doi.org/10.7150/jbji.16318DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5423560PMC
July 2016

CORR Insights: Sonication of Arthroplasty Implants Improves Accuracy of Periprosthetic Joint Infection Cultures.

Authors:
Martin Clauss

Clin Orthop Relat Res 2017 07 9;475(7):1837-1839. Epub 2017 May 9.

Clinic for Orthopedic and Trauma Surgery, Interdisciplinary Unit for Orthopedic Infections and Hip Unit, Kantonsspital Baselland (Bruderholz, Liestal, Laufen), Rheinstrasse 26, 4410, Liestal, Switzerland.

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http://dx.doi.org/10.1007/s11999-017-5350-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5449338PMC
July 2017

The Not-So-Good Prognosis of Streptococcal Periprosthetic Joint Infection Managed by Implant Retention: The Results of a Large Multicenter Study.

Clin Infect Dis 2017 Jun;64(12):1742-1752

Red Española de Investigación en Patología Infecciosa (REIPI).

Background.: Streptococci are not an infrequent cause of periprosthetic joint infection (PJI). Management by debridement, antibiotics, and implant retention (DAIR) is thought to produce a good prognosis, but little is known about the real likelihood of success.

Methods.: A retrospective, observational, multicenter, international study was performed during 2003-2012. Eligible patients had a streptococcal PJI that was managed with DAIR. The primary endpoint was failure, defined as death related to infection, relapse/persistence of infection, or the need for salvage therapy.

Results.: Overall, 462 cases were included (median age 72 years, 50% men). The most frequent species was Streptococcus agalactiae (34%), and 52% of all cases were hematogenous. Antibiotic treatment was primarily using β-lactams, and 37% of patients received rifampin. Outcomes were evaluable in 444 patients: failure occurred in 187 (42.1%; 95% confidence interval, 37.5%-46.7%) after a median of 62 days from debridement; patients without failure were followed up for a median of 802 days. Independent predictors (hazard ratios) of failure were rheumatoid arthritis (2.36), late post-surgical infection (2.20), and bacteremia (1.69). Independent predictors of success were exchange of removable components (0.60), early use of rifampin (0.98 per day of treatment within the first 30 days), and long treatments (≥21 days) with β-lactams, either as monotherapy (0.48) or in combination with rifampin (0.34).

Conclusions.: This is the largest series to our knowledge of streptococcal PJI managed by DAIR, showing a worse prognosis than previously reported. The beneficial effects of exchanging the removable components and of β-lactams are confirmed and maybe also a potential benefit from adding rifampin.
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http://dx.doi.org/10.1093/cid/cix227DOI Listing
June 2017

Risk of infection in primary, elective total hip arthroplasty with direct anterior approach or lateral transgluteal approach: a prospective cohort study of 1104 hips.

BMC Musculoskelet Disord 2016 11 14;17(1):471. Epub 2016 Nov 14.

Interdisciplinary Unit for Orthopedic Infections, Kantonsspital Baselland, Rheinstrasse 26, 4410, Liestal, Switzerland.

Background: The direct anterior approach (DAA) is increasingly popular for hip replacement. However, the small incision and the location near to the groin might increase the risk of periprosthetic joint infection (PJI). We asked the questions (i) whether there is an increased risk of infection for this approach, and (ii) whether the spectrum of microorganisms differs between patients with DAA and those with lateral transgluteal approach (LAT).

Methods: All patients operated between 08/2006 and 12/2013 were followed prospectively in an in house register. The DAA was introduced as routine in 02/2009 at our hospital. Patients with primary elective hip replacement without previous operations were included. Follow-up was scheduled after 6, 12 weeks and 1, 2 years. PJI was defined according to standardized criteria.

Results: One thousand one hundred four patients were studied, 700 were operated with DAA and 404 with LAT. No patient was lost to follow-up. PJI was diagnosed in 23/1104 (2.1 %) patients, 16 (2.3 %) in the group with DAA, and 7 (1.7 %) in the group with LAT. Patients with infection had a higher BMI (p < 0.001) and a higher ASA score (p < 0.001). Only patients with the DAA had exogenous PJI caused by gramnegative bacilli (35.7 % vs 0 %, p = 0.26). In the DAA-group, the fraction of patients with polymicrobial infection was somewhat higher than in the LAT-group (50 % vs 33 %, P = 0.64).

Conclusion: There was no increased risk of infection for the DAA.
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http://dx.doi.org/10.1186/s12891-016-1332-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5109646PMC
November 2016

Erratum to: The need for secondary resurfacing is affected by trochlear height in total knee arthroplasty.

Knee Surg Sports Traumatol Arthrosc 2017 03;25(3):987

Department of Orthopaedic Surgery and Traumatology, Kantonsspital Baselland (Bruderholz, Liestal, Laufen), 4101, Bruderholz, Switzerland.

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http://dx.doi.org/10.1007/s00167-016-4344-2DOI Listing
March 2017

Eradication of infection, survival, and radiological results of uncemented revision stems in infected total hip arthroplasties.

Acta Orthop 2016 Dec 23;87(6):637-643. Epub 2016 Sep 23.

a Department of Orthopedics and Trauma Surgery and.

Background and purpose - The use of uncemented revision stems is an established option in 2-stage procedures in patients with periprosthetic joint infection (PJI) after total hip arthroplasty (THA). However, in 1-stage procedures, they are still rarely used. There are still no detailed data on radiological outcome after uncemented 1-stage revisions. We assessed (1) the clinical outcome, including reoperation due to persistent infection and any other reoperation, and (2) the radiological outcome after 1- and 2-stage revision, using an uncemented stem. Patients and methods - Between January 1993 and December 2012, an uncemented revision stem was used in 81 THAs revised for PJI. Patients were treated with 1- or 2-stage procedures according to a well-defined algorithm (1-stage: n = 28; 2-stage: n = 53). All hips had a clinical and radiological follow-up. Outcome parameters were eradication of infection, re-revision of the stem, and radiological changes. Survival was calculated using Kaplan-Meier analysis. Radiographs were analyzed for bone restoration and signs of loosening. The mean clinical follow-up time was 7 (2-15) years. Results - The 7-year infection-free survival was 96% (95% CI: 92-100), 100% for 1-stage revision and 94% for 2-stage revision (95% CI: 87-100) (p = 0.2). The 7-year survival for aseptic loosening of the stem was 97% (95% CI: 93-100), 97% for 1-stage revision (95% CI: 90-100) and 97% for 2-stage revision (95% CI: 92-100) (p = 0.3). No further infection or aseptic loosening occurred later than 7 years postoperatively. The radiographic results were similar for 1- and 2-stage procedures. Interpretation - Surgical management of PJI with stratification to 1- or 2-stage exchange according to a well-defined algorithm combined with antibiotic treatment allows the safe use of uncemented revision stems. Eradication of infection can be achieved in most cases, and medium- and long-term results appear to be comparable to those for revisions for aseptic loosening.
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http://dx.doi.org/10.1080/17453674.2016.1237423DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5119449PMC
December 2016

Prospective two-year subsidence analysis of 100 cemented polished straight stems - a short-term clinical and radiological observation.

BMC Musculoskelet Disord 2016 09 17;17(1):395. Epub 2016 Sep 17.

Department for Orthopaedics and Trauma Surgery, Kantonsspital Baselland, CH-4410, Liestal, Switzerland.

Background: Cemented stems show good long-term results and the survival of new implants can be predicted by their early subsidence. With EBRA-FCA (Femoral Component Analysis using Einzel-Bild-Röntgen-Analyse) early subsidence as an early indicator for later aseptic loosening can be analysed. For the cemented TwinSys stem mid- and long-term data is only avalible from the New Zeeland Arthroplasty register, thus close monitoring of this implant system is still mandatory.

Methods: We conducted a 2 year follow up of 100 consecutive hybrid THA (Total hip arthroplasty) of a series of 285 primary THA operated between Jan 2009 und Oct 2010. These 100 received a polished, cemented collarless straight stem (twinSys®, Mathys AG® Bettlach, Switzerland) with an uncemented monobloc pressfit cup (RM pressfit®, Mathys AG® Bettlach, Switzerland). The other patients were treated with the uncemented version of this stem and the same cup. Clinical (Harris Hip Score) and radiological (ap and axial x-rays, cementing quality according to Barrack, alignment) outcomes besides an EBRA-FCA subsidence analysis were performed.

Results: Median age at operation was 78 (68 to 93) years. 5 patients died in the course of follow-up unrelated to surgery. The KM (Kaplan-Meier) survival at 2 years for the endpoint reoperation for any reason was 94.9 (95 % confidence interval 90.6-100 %). Survival for the endpoint aseptic loosening at 2 years was 100 %. The HHS (Harris Hip Score) improved from 56 (14-86) preoperatively to 95 (60-100) 2 years after the operation. Cementing results were judged 47 % Grade A, 45 % Grade B and 7 % Grade C. Osteolysis was found in 2 stems without clinical symptoms or correlation to subsidence or cementing quality. The EBRA-FCA analysis showed an average subsidence of -0.30 mm (95 % CI -0.5 mm to -0.1 mm). 11 patients showed a subsidence of more than 1 mm. In this group one patient showed a subsidence of 1.5 mm and one of 3.1 mm without further radiological changes.

Conclusions: The twinSys stem showed excellent clinical and radiologic short term results at 2 years follow-up and seems to be a reliable implant.
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http://dx.doi.org/10.1186/s12891-016-1247-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5027091PMC
September 2016

Similar effect of stem geometry on radiological changes with 2 types of cemented straight stem: The Müller stem and the Virtec stem compared in 711 hips.

Acta Orthop 2016 16;87(2):120-5. Epub 2015 Oct 16.

a Clinic for Orthopedics and Trauma Surgery , Kantonsspital Baselland Liestal , Switzerland.

Background And Purpose: There are 2 basic principles in cemented stem fixation: shape-closed and force-closed. We investigated 2 shape-closed straight stems, the Müller (MSS) and the Virtec (VSS), which differ only in geometrical cross section, to determine whether the difference in stem shape would affect the radiological results or long-term survival.

Patients And Methods: We included 711 hips (in 646 patients) that were operated on between July 1996 and July 2003. Patients randomly received either an MSS (n = 356) or a VSS (n = 355) and were followed prospectively. Radiographs taken at a follow-up of > 10 years were analyzed for osteolysis. Kaplan-Meier (KM) survival analysis was performed using various endpoints. We also performed Cox regression analysis to identify risk factors for aseptic loosening and osteolysis of the stem.

Results: After 10 years, KM survival with "revision of any component for any reason" was 92% (95% CI: 88-95) for the MSS and 95% (CI: 92-97) for the VSS (p = 0.1). With "revision for aseptic loosening of the stem" as the endpoint, KM survival was 96% (CI: 9-98) for the MSS and 98% (CI: 97-100) for the VSS (p = 0.2). Cox regression showed that none of the risk factors analyzed were independent regarding aseptic loosening of the stem or regarding osteolysis.

Interpretation: The MSS and the VSS showed excellent survival for aseptic loosening after 10 years. For the 2 different stem designs, we did not find any independent risk factors for aseptic loosening or development of osteolysis.
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http://dx.doi.org/10.3109/17453674.2015.1104153DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4812072PMC
July 2016

Excellent long-term results of the Müller acetabular reinforcement ring in primary total hip arthroplasty: A prospective study on radiology and survival of 321 hips with a mean follow-up of 11 years.

Acta Orthop 2016 16;87(2):100-5. Epub 2015 Oct 16.

a Department of Orthopedics and Trauma Surgery , Kantonsspital Baselland , Liestal , Switzerland.

Background And Purpose: The original Müller acetabular reinforcement ring (ARR) shows favorable medium-term results for acetabular reconstruction in total hip arthroplasty, where it is used when the acetabular bone stock is deficient. However, there are no data regarding long-term survival of the device. We therefore investigated long-term survival and analyzed radiological modes of failure.

Patients And Methods: Between 1984 and 2002, 321 consecutive primary arthroplasties using an ARR were performed in 291 patients. The mean follow-up time was 11 (0-25) years, and 24 hips were lost to follow-up. For survival analysis, we investigated 321 hips and the end of the follow-up was the date of revision, date of death, or the last patient contact date with implant still in situ. Radiological assessment was performed for 160 hips with a minimum of 10 years of follow-up and with radiographs of sufficient quality. It included evaluation of osteolysis, migration, and loosening.

Results: 12 ARR THAs were revised: 1 isolated ARR revision for aseptic loosening, 4 revisions of the ARR and the stem for aseptic loosening, 6 for infection, and 1 for recurrent dislocation. The cumulative revision rate for all components, for any reason, at 20 years was 15% (95% CI: 10-22), while for the ARR only it was 7% (95% CI: 4-12) for any reason and 3.4% (95% CI: 1-9) for aseptic loosening. 21 (13%) of 160 ARR THAs examined had radiological changes: 7 had osteolysis but were not loose, and 14 were radiologically loose but were not painful and not revised.

Interpretation: Our data suggest that the long-term survival of the ARR is excellent.
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http://dx.doi.org/10.3109/17453674.2015.1103607DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4812069PMC
July 2016