Publications by authors named "Edward Ebramzadeh"

120 Publications

Load Sharing in the Femur Using Strut Allografts: A Biomechanical Study.

Arthroplast Today 2022 Jun 12;15:68-74. Epub 2022 Apr 12.

The J. Vernon Luck, Sr., M.D. Orthopaedic Research Center, Orthopaedic Institute for Children and UCLA Department of Orthopaedic Surgery, Los Angeles, CA, USA.

Background: Femoral strut allografts are used in revision hip arthroplasty for management of bone loss associated with implant failure or periprosthetic fractures. They have also been used to treat unremitting thigh pain in well-fixed cementless femoral stems, to address the differential in structural stiffness between the stem and femoral shaft. Our study used an in vitro biomechanical model to measure the effect of placement of allografts on femoral strains, to determine their load-sharing capacity.

Material And Methods: Three rosette strain gauges were applied to the femoral surface of each of 6 cadaveric femurs, at the stem tip level on anterior, medial, and lateral cortices. After stem implantation, cortical strut allografts were applied to the lateral femoral shaft and secured with 4 Dall-Miles cables. A fourth gauge was placed on the midpoint of the allograft. Strains were recorded in the intact femur, then the implanted femur with and without the allograft under simulated physiologic loading in a load frame.

Results: Reduction in distal femoral principal strains, between 12% and 59%, was seen in all cortices following placement of the allograft. Under axial loading, 30% of the strain in the lateral cortex was borne by the allograft. Greater reductions in strain, by as much as 59%, occurred under axial load and torque.

Conclusion: The results of this biomechanical model indicate that by placement of an allograft, cortical strains can be reduced to levels approaching those in an intact femur, supporting this technique for treatment of unremitting thigh pain in well-fixed prostheses.
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http://dx.doi.org/10.1016/j.artd.2022.02.010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9018542PMC
June 2022

Taper Material Loss in Total Hip Replacements: Is It Affected by Joint Friction?

J Bone Joint Surg Am 2022 05 15;104(9):796-804. Epub 2022 Feb 15.

The J. Vernon Luck, Sr., M.D. Orthopaedic Research Center, Orthopaedic Institute for Children in Alliance with UCLA, Los Angeles, California.

Background: Metal debris and corrosion products generated from the taper junctions of modular joint replacements have been recognized as contributors to failure. Therefore, understanding the factors associated with increased taper wear and corrosion is fundamental to improving implant performance.

Methods: A cohort of 85 large-diameter metal-on-metal heads and cups retrieved at revision surgery, after 10 to 96 months of service, was evaluated. First, metrology was conducted to quantify head taper material loss and implant articular surface wear. Then, joint frictional moments for each retrieved head-and-cup pair were measured during 10 cycles of simulated physiological gait in a biomechanical model. Taper material loss was evaluated for correlations with frictional moments, articular wear, head diameter, head-cup clearance, and time in vivo.

Results: Peak resultant frictional moments ranged from 9.1 to 26.3 Nm, averaging 17.3 ± 2.7 Nm. Fretting and corrosion damage during in vivo service resulted in material loss from the head tapers ranging between 0.04 and 25.57 mm3, compared with combined head and cup articular wear of 0.80 to 351.75 mm3 in this cohort. Taper material loss was not correlated with higher frictional moments (R = -0.20 to 0.11, p = 0.07 to 0.81). Higher frictional moments from axial rotation were correlated with higher head and cup wear (R = 0.33, p < 0.01). The correlation between taper material loss and head diameter was weak and did not reach statistical significance (R = 0.20, p = 0.07). Taper material loss was not correlated with nominal head-cup clearance (R = 0.06, p = 0.6). Finally, taper material loss increased significantly over time (R = 0.34, p < 0.01).

Conclusions: Despite serious concerns regarding trunnionosis, volumes of head taper wear were generally lower than those of articular surface wear. There was no statistical correlation between taper wear and frictional moments. Therefore, the results suggest that high friction in metal-on-metal implants does not contribute to higher material loss at the head taper, despite high bending moments.

Clinical Relevance: The amount of metal debris and corrosion products from taper junctions of the joint arthroplasties, widely recognized as an insidious cause of failure, was not correlated with joint frictional moments. Multiple factors affect taper wear: implant design, material, size, surface finish, and patient weight and activity level. However, in the present cohort, high friction of metal-on-metal total hip replacements likely did not contribute to increased volume of material loss at taper interfaces, despite increased moments at the locations of taper material loss.
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http://dx.doi.org/10.2106/JBJS.21.00579DOI Listing
May 2022

The lexicon for periprosthetic bone loss versus osteolysis after cervical disc arthroplasty: a systematic review.

Eur Spine J 2022 04 9;31(4):830-842. Epub 2022 Jan 9.

The J. Vernon Luck, Sr., M.D. Orthopaedic Research Center, Orthopaedic Institute for Children in Alliance With UCLA, 403 W. Adams Blvd, Los Angeles, CA, 90007, USA.

Background: Periprosthetic bone loss is a common observation following arthroplasty. Recognizing and understanding the nature of bone loss is vital as it determines the subsequent performance of the device and the overall outcome. Despite its significance, the term "bone loss" is often misused to describe inflammatory osteolysis, a complication with vastly different clinical outcomes and treatment plans. Therefore, the goal of this review was to report major findings related to vertebral radiographic bone changes around cervical disc replacements, mitigate discrepancies in clinical reports by introducing uniform terminology to the field, and establish a precedence that can be used to identify the important nuances between these distinct complications.

Methods: A systematic review of the literature was conducted following PRISMA guidelines, using the keywords "cervical," "disc replacement," "osteolysis," "bone loss," "radiograph," and "complications." A total of 23 articles met the inclusion criteria with the majority being retrospective or case reports.

Results: Fourteen studies reported periprosthetic osteolysis in a total of 46 patients with onset ranging from 15-96 months after the index procedure. Reported causes included: metal hypersensitivity, infection, mechanical failure, and wear debris. Osteolysis was generally progressive and led to reoperation. Nine articles reported non-inflammatory bone loss in 527 patients (52.5%), typically within 3-6 months following implantation. The reported causes included: micromotion, stress shielding, and interrupted blood supply. With one exception, bone loss was reported to be non-progressive and had no effect on clinical outcome measures.

Conclusions: Non-progressive, early onset bone loss is a common finding after CDA and typically does not affect the reported short-term pain scores or lead to early revision. By contrast, osteolysis was less common, presenting more than a year post-operative and often accompanied by additional complications, leading to revision surgery. A greater understanding of the clinical significance is limited by the lack of long-term studies, inconsistent terminology, and infrequent use of histology and explant analyses. Uniform reporting and adoption of consistent terminology can mitigate some of these limitations. Executing these actionable items is critical to assess device performance and the risk of revision.

Level Of Evidence Iv: Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding.
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http://dx.doi.org/10.1007/s00586-021-07092-9DOI Listing
April 2022

Cross-Sectional Areas and Volumes Occupied by Implants in Simulated Scaphoid Fractures.

J Hand Surg Am 2022 03 7;47(3):228-236. Epub 2021 Dec 7.

The J. Vernon Luck, Sr., M.D. Orthopaedic Research Center, Orthopaedic Institute for Children and UCLA Department of Orthopaedic Surgery, Los Angeles, CA.

Purpose: This study determined the volume of bone replaced by an implant at the proximal and distal poles of simulated scaphoid fractures. We also measured the cross-sectional area of the implant relative to the cross-sectional area of the scaphoid at 2 different simulated fracture locations.

Methods: Microcomputed tomograhy scans of 7 cadaveric scaphoids were used to create 3-dimensional models in which transverse proximal pole and midwaist fractures were simulated. The volume occupied by 5 commonly used implants and the cross-sectional area occupied at the surface of the fractures was measured using a computer modeling software.

Results: For simulated proximal pole fractures, the implants replaced 1.5%-7.4% of the fracture cross-sectional area and 1.2%-6.4% of the proximal fragment bone volume. For midwaist fractures, the implants replaced 1.5%-6.8% of the fracture cross-sectional area and 1.8%-4.6% of the proximal pole volume. Although the different implant designs replaced different areas and volumes, all these differences were small and below 4%.

Conclusions: This study provides data that relate to one aspect of fracture healing, specifically, the surface area occupied by 5 different implants in proximal and midwaist scaphoid fractures as well as the volume of bone replaced by the implant.

Clinical Relevance: As opposed to the impression provided by 2-dimensional planar imaging, when studied using a 3-dimensional model, the volume and surface area replaced by an implant represent a minimal percentage of scaphoid bone, suggesting a negligible clinical effect.
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http://dx.doi.org/10.1016/j.jhsa.2021.10.019DOI Listing
March 2022

The insidious risk of periprosthetic fracture in clinically functional total hip arthroplasties: A biomechanical study of willed joints.

J Orthop Res 2021 Oct 25. Epub 2021 Oct 25.

Department of Orthopaedic Surgery, David Geffen School of Medicine, Los Angeles Orthopaedic Center, University of California, Los Angeles, California, USA.

Femoral bone quality is a major risk factor of periprosthetic fracture after total hip arthroplasty (THA), which has mortality similar to native hip fractures but higher short-term morbidity. The goal of this study was to quantify cortical strains at the site of expected Vancouver Type-B periprosthetic fracture as a function of bone mineral density, femoral stem material, and fixation method using a series of 29 autopsy-retrieved, clinically asymptomatic hip joints with THA. Periprosthetic bone mineral content and density was assessed using dual-energy X-ray absorptiometry by Gruen Zone. Specimens then underwent combined cyclic axial and torsional loading, increasing incrementally from 100 N and ±1 Nm to peaks of 700 N and ±5 Nm. All specimens experienced significantly higher strains on the lateral surface than on the anterior surface, indicating that the bending loads in the frontal plane, rather than axial/torsional loads, had the predominant effect. Multiple significant relationships (p = 0.04, p = 0.02) were found between predicted periprosthetic strains calculated from radiographic measurements and observed principal strains. Though THA in the present study were in successful clinical service, the produced results indicated that some femurs with rigid cemented or noncemented implants were potentially at high risk for Vancouver Type-B fractures, which may be predicted radiographically.
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http://dx.doi.org/10.1002/jor.25203DOI Listing
October 2021

CORR Insights®: A Modeling Study of a Patient-specific Safe Zone for THA: Calculation, Validation, and Key Factors Based on Standing and Sitting Sagittal Pelvic Tilt.

Clin Orthop Relat Res 2022 01;480(1):206-208

Director, The J. Vernon Luck Sr. Orthopaedic Research Center, Orthopaedic Institute for Children in Alliance with UCLA Department of Orthopaedic Surgery, Los Angeles, CA, USA.

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http://dx.doi.org/10.1097/CORR.0000000000001976DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8673973PMC
January 2022

Objective analysis of intermediate-term outcome of the Ponseti technique: a review of the experience from Los Angeles.

Ann Transl Med 2021 Jul;9(13):1101

The J. Vernon Luck, Sr., MD Orthopedic Research Center, Orthopaedic Institute for Children and the Department of Orthopedic Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.

The Ponseti method of manipulative treatment for clubfoot deformity became widely adopted by pediatric orthopaedic surgeons beginning in the mid-1990s. The technique allows correction of most idiopathic clubfeet using gentle manipulation and cast application. The treatment represents a marked advance over past efforts to gain correction of the foot through extensive release surgery. In 2006, we began a Clubfoot Clinic at the Orthopaedic Institute for Children in Los Angeles, California dedicated to managing clubfoot patients using Ponseti's method. An IRB-approved database of patient-related, treatment related, and demographic variables was assembled and used to ascertain the outcome of treatment as well as to address parental questions regarding certain aspects of treatment. Here, we present a review of our body of work, which has improved clinical decision making as well as our ability to better inform our patients' parents regarding the treatment and prognosis of the Ponseti method. Studies from our institution showed that while relapses and the need for extra-articular tibialis anterior tendon transfer (TATT) surgery remain common to the Ponseti method, these events do not adversely affect overall patient function or satisfaction. These findings were not unlike those of classic studies reported from Ponseti's institution. We conclude that the Ponseti method is not only a technique to achieve initial correction of an idiopathic clubfoot, but also how to manage relapses that will inevitably occur in many patients. While relapses and tendon transfer surgery are likely to remain common with this treatment method, these events do not adversely affect overall patient function or satisfaction. The parents of infants whose clubfeet are managed using the Ponseti method should be counselled accordingly.
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http://dx.doi.org/10.21037/atm-20-7774DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8339808PMC
July 2021

A novel intramedullary nail to control interfragmentary motion in diaphyseal tibial fractures.

J Orthop Res 2022 05 12;40(5):1053-1064. Epub 2021 Jul 12.

The J. Vernon Luck, Sr., M.D. Orthopaedic Research Center, Orthopaedic Institute for Children in Alliance with UCLA, Los Angeles, California, USA.

Numerous animal and human studies have demonstrated the benefit of controlled interfragmentary motion on fracture healing. In this study, we quantified interfragmentary motion and load transfer in tibial fractures fixed using a novel intramedullary nail (IMN) that allows controlled axial motion. Fifty composite tibias with various fracture patterns were utilized. For all test conditions, two interlocking screws were used to fix the nail in the proximal metaphysis, and two interlocking screws through the distal metaphysis. The nail allowed either no motion (static mode) or 1 mm (dynamic mode) of cyclic axial motion between the two fracture fragments for every fracture pattern tested. As expected, strain shielding was more prominent under static nail conditions. In contrast, specimens tested under dynamic nail conditions transferred axial load between the fracture fragments such that strains near the fracture site were generally similar to those measured on an intact tibia. Maximum shear strains proximal to the fracture were significantly lower in specimens with oblique or butterfly fracture patterns (p < 0.01) compared to intact specimens. This decrease in shear strain indicates that strain shielding effects were likely present due to the implant. However, strain shielding appeared to be reduced in tensile and compressive principal strains. In summary, the novel IMN allowed controlled axial motion between the fragments in a variety of common diaphyseal tibial fracture patterns. Clinical Significance: The present in vitro biomechanical study investigated a novel intramedullary nail capable of controlled axial interfragmentary motion which may potentially enhance fracture healing.
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http://dx.doi.org/10.1002/jor.25134DOI Listing
May 2022

Semi-quantitative histology confirms that the macrophage is the predominant cell type in metal-on-metal hip tissues.

J Orthop Res 2022 02 6;40(2):387-395. Epub 2021 Apr 6.

The J. Vernon Luck, Sr., M.D. Orthopaedic Research Center, Department of Orthopaedic Surgery, Orthopaedic Institute for Children, UCLA, Los Angeles, California, USA.

Numerous studies have examined the histology of metal-on-metal hip tissues for evidence of a dose response to metal wear but have often reported inconclusive or contradictory findings. The aim of the present study was to address these discrepancies using multiple histological scoring methods to characterize the tissue features of one large group of revised metal-on-metal total hips. Periprosthetic tissues from 165 metal-on-metal hip revisions were examined for features of aseptic lymphocytic vasculitis associated lesions (ALVAL) as rated using two scoring systems as well as rankings for macrophage and lymphocyte numbers, intracellular wear debris and necrosis. Correlations between histological features and clinical variables including gender and time to revision and implant variables including articular surface wear volume or visual taper corrosion scores were examined. Both ALVAL scores reflected the macrophage dominated histology with average scores of 5.9/10 and 1.5/3. There was a statistically significant correlation between the original ALVAL score and wear rate per year (correlation coefficient = 0.17, p = .05) and a moderate correlation between the number of macrophages and wear particles and wear volume. There was no statistically significant correlation between wear and any other feature including lymphocytic inflammation or necrosis. Strong correlations between combined cup and ball wear volume and histological characteristics were not observed, although the number of macrophages was more closely correlated with wear than lymphocytes or necrosis.
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http://dx.doi.org/10.1002/jor.25040DOI Listing
February 2022

Quantification of Ankle Dorsiflexion in Ponseti-managed Unilateral Clubfoot Patients During Early Childhood.

J Pediatr Orthop 2021 Feb;41(2):83-87

Orthopaedic Institute for Children and the Department of Orthopedic Surgery, David Geffen School of Medicine at UCLA.

Background: Following the initial correction of a clubfoot using the Ponseti method, diminished passive ankle dorsiflexion may be observed over time, which could represent a possible relapsed deformity. Alternatively, the change may be attributable to patient age or other variables. Our purpose was to quantify passive ankle dorsiflexion in the involved and contralateral unaffected limbs of Ponseti-managed unilateral clubfoot patients, and to determine what patient-related variables influence this finding.

Methods: In total, 132 unilateral clubfoot patients were studied. Passive ankle dorsiflexion was measured in both limbs at each visit. Data were excluded from visits in which patients showed clear evidence of a relapse. Mean ankle dorsiflexion for clubfeet and contralateral unaffected limbs were reported for annual age intervals and compared using paired t tests. A general linear model was established to assess the effects of age, severity, sex, and side on ankle dorsiflexion.

Results: Mean ankle dorsiflexion for unaffected limbs declined with age, measuring 53±6 degrees between 0 and 1 year of age and decreasing to 39±7 degrees by 4 to 5 years of age. Similarly, mean ankle dorsiflexion in treated clubfeet declined with age, measuring 44±7 degrees between 0 and 1 year and 29±7 degrees between 4 and 5 years. Overall, the difference between limbs in these patients averaged ~10 degrees for every age interval through 9 years (P<0.001). Ankle dorsiflexion of clubfeet in 95% of patients aged 0 to 2 years was at least 20 degrees, and in 95% of patients aged 3 to 5 years this was at least 15 degrees. Patient age (P<0.001) and severity of deformity (P<0.001) were found to be the only significant factors affecting ankle dorsiflexion in the affected limbs.

Conclusions: Ankle dorsiflexion in the Ponseti-treated clubfeet was influenced by age of the patient and the initial severity of the affected limb. Furthermore, our data suggest that, in patients who showed no relapse, a minimum of 20 degrees of ankle dorsiflexion in the corrected clubfoot is maintained through age 3 years and a minimum of 15 degrees is maintained through age 5 years.

Level Of Evidence: Level IV-this is a retrospective case series.
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http://dx.doi.org/10.1097/BPO.0000000000001719DOI Listing
February 2021

Is load control necessary to produce physiological AP displacement and axial rotation in wear testing of TAR?

J Orthop Res 2021 04 8;39(4):797-805. Epub 2020 Dec 8.

The J. Vernon Luck, Sr., M.D. Orthopaedic Research Center, Orthopaedic Institute for Children, University of California Los Angeles Department of Orthopaedics, Los Angeles, California, USA.

The International Standard Organization, ISO 22622, specifies two options for joint wear simulator evaluation of total ankle replacements (TARs): load-controlled and displacement-controlled. In the present study, the load-controlled testing parameters were applied to cadaveric specimens to quantify and compare the observed sagittal translations and axial rotations to those specified under the displacement-controlled option. Twelve cadaveric specimens were stripped of extraneous tissues, keeping surrounding ankle ligaments. A halo was used to produce plantarflexion and dorsiflexion of the talus through two screws, while a baseplate resisted axial loads. The axial force and torque were applied to the tibia and fibula under force and torque feedback control. An anterior-posterior force was applied to the tibia. Plantarflexion-dorsiflexion were applied using rotation control. To protect the cadaveric specimens, loads were applied at 50% of the specified load profile while plantarflexion-dorsiflexion rotation was applied as specified. There was variation among specimens in magnitudes of anterior-posterior displacement with peaks ranging from 3.3 mm posteriorly to 3.0 mm anteriorly. Likewise, there was variation among specimens in magnitude of axial rotation, with peaks ranging from 11° external rotation to 4.5° internal rotation. However, the mean magnitudes of AP displacement and axial rotation did not exceed those specified by ISO 22622.
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http://dx.doi.org/10.1002/jor.24931DOI Listing
April 2021

Sagittal Plane Residual Deformity in Pediatric Type II Supracondylar Humerus Fractures.

J Pediatr Orthop 2020 Aug;40(7):e547-e553

Orthopaedic Institute for Children.

Introduction: The incidence of residual deformity in the sagittal plane of the humerus (RDSPH) after nonoperative management of type II supracondylar humerus fractures (SCHFs), and the effects of such deformity on the overall arc of motion (AOM) of the elbow, are unknown. Our purpose was to analyze data collected prospectively on a large cohort of type II SCHF's to establish the incidence and extent of RDSPH, and the effects of the deformity on the elbow function, to further support our previously published recommendations on the treatment of type II SCHF.

Methods: The clinical data and radiographs of 1107 pediatric type II SCHFs enrolled in a prospective registry, and followed for a minimum of 8 weeks, were retrospectively reviewed. The radiographs obtained during the latest follow-up appointment were examined for the presence of RDSPH, as demonstrated by the anterior humeral line falling anterior or posterior relative to the center of the capitellum. The amount of RDSPH in the sagittal plane was then calculated. We compared the treatment outcome of elbows with and without RDSPH by assessing the patients' AOM, the arc of flexion (AOF), and relative arcs of motion (R-AOM) and relative arcs of flexion (R-AOF) (as compared with the unaffected, contralateral elbow).

Results: Overall, 799 (72.2%) fractures were treated nonsurgically, and 308 (27.8%) fractures were treated surgically. The overall incidence of RDSPH was 10.2%. None of the fractures managed operatively demonstrated residual deformity. The RDSPH was classified as mild in 35 fractures (3.2%), moderate in 64 fractures (5.7%) and severe in 14 fractures (1.3%). Therefore, the incidence of RDSPH in fractures treated nonoperatively was 14.1%. In fractures treated nonoperatively, the difference in AOM between those without (n=686) and with (n=113) RDSPH was <4 degrees (149.1 vs. 145.8 degrees, P=0.02). Those with and without RDSPH had a clinically similar AOF, with a mean difference of<4 degrees (134.5 vs. 137.9 degrees, P<0.0001). The differences in R-AOM and R-AOF between those with and without RDSPH were minimal (97.3% vs. 95.6% and 96.6% vs. 95.3%, respectively). A satisfactory outcome, defined as an R-AOM of at least 85% when compared with the unaffected, contralateral side at the latest follow-up, was achieved in 91% of fractures with RDSPH, and 93% of fractures without RDSPH.

Discussion And Conclusion: The incidence of RDSPH in type II SCHF treated nonoperatively was 14%. In our cohort, nearly 99% of all RDSPH were mild to moderate. On the basis of the data presented in the current study, nonsurgical treatment of type II SCHF can provide a satisfactory recovery of AOM, AOF, R-AOM, and R-AOF, and a high rate of satisfactory outcomes, even in the presence of RDSPH.
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http://dx.doi.org/10.1097/BPO.0000000000001512DOI Listing
August 2020

Damage patterns in polyethylene fixed bearings of retrieved total ankle replacements.

Foot Ankle Surg 2021 Apr 7;27(3):316-320. Epub 2020 Jul 7.

The J. Vernon Luck, Sr., M.D. Orthopaedic Research Center, Orthopaedic Institute for Children, 403 W. Adams Blvd., Los Angeles, CA 90007, United States. Electronic address:

Introduction: Poor long-term outcomes continue to hinder the universal adoption of total ankle replacements (TAR) for end stage arthritis. In the present study, polyethylene inserts of TARs retrieved at revision surgery were analyzed for burnishing, scratching, mechanical damage, pitting, and embedded particles.

Methods: Fourteen retrieved polyethylene inserts from a fixed bearing total ankle replacement design currently in clinical use were analyzed. Duration of time in vivo was between 11.5 months and 120.1 months. Three investigators independently graded each articular surface in quadrants for five features of damage: burnishing, scratching, mechanical damage, pitting, and embedded particles.

Results: No correlation was found for burnishing between the anterior and posterior aspects (p = 0.47); however, scratching and pitting were significantly higher on the posterior aspect compared to the anterior aspect (p < 0.03). There was a high correlation between burnishing and in vivo duration of the implant (anterior: R = 0.67, p = 0.01, posterior: R = 0.68, p = 0.01).

Conclusion: The higher concentration of posterior damage on these polyethylene inserts suggested that prosthesis-related (design) or surgeon-related (technique) factors might restrict the articulation of the implant. The resulting higher stresses in the posterior articular surfaces may have contributed to the failure of retrieved implants Keywords: Retrieval, Polyethylene Damage, Total Ankle Replacement.
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http://dx.doi.org/10.1016/j.fas.2020.06.012DOI Listing
April 2021

Does generalized joint hypermobility influence the Ponseti treatment of clubfoot patients?

J Pediatr Orthop B 2021 Jan;30(1):66-70

David Geffen School of Medicine.

Previous investigators have suggested a role for generalized joint hypermobility (GJH) in the etiology of clubfoot deformity, while others have suggested its presence may influence treatment outcomes. We sought to determine if GJH was associated with the demographics, treatment, or propensity to relapse of patients whose clubfeet were managed using the Ponseti method. Fifty-seven patients with Ponseti-treated clubfeet comprised the cohort; median age 61 months (range, 38-111 months). A physical therapist evaluated each patient using the nine-point Beighton scale to quantify hypermobility. The scores were then correlated with patient sex, laterality, Dimeglio severity score, treatment, relapse, and surgery. The median Beighton score was 5; 49 of 57 patients (86%) had Beighton scores ≥4. All feet were plantigrade without symptomatic overcorrection at the time of evaluation. Although there was a slightly lower probability of relapse in patients with higher Beighton scores, this was not statistically significant (P = 0.10). Accordingly, the sex, laterality, initial severity, number of pretenotomy casts, need for tenotomy, relapse, and need for tendon transfer surgery were not significantly influenced by the Beighton score. The outcome of Ponseti clubfoot treatment is not altered by the presence of GJH in young children. Joint hypermobility does not appear to influence the likelihood of relapse or surgery. Unlike clubfeet reportedly treated with release surgery, Ponseti-treated clubfeet were not prone to excessive overcorrection regardless of joint laxity. Last, the distribution of Beighton scores in the study's cohort supports an association between GJH and clubfoot deformity.
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http://dx.doi.org/10.1097/BPB.0000000000000747DOI Listing
January 2021

A Systematic Review of Unsystematic Total Ankle Replacement Wear Evaluations.

JBJS Rev 2020 03;8(3):e0091

J. Vernon Luck Sr., MD, Orthopaedic Research Center (JVL) at the Orthopaedic Institute for Children (OIC), in alliance with UCLA, Los Angeles, California.

Background: Numerous studies have reported the use of laboratory multistation joint simulators to successfully predict wear performance and functionality of hip and knee replacements. In contrast, few studies in the peer-reviewed literature have used joint simulation to quantify the wear performance and functionality of ankle replacements. We performed a systematic review of the literature on joint simulator studies that quantified polyethylene wear in total ankle arthroplasty. In addition to the quantified wear results, the load and motion parameters were identified and compared among the studies.

Methods: A search was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to identify articles reporting total ankle replacement polyethylene wear using joint simulators.

Results: Nine studies that used joint simulators and 1 study that used a computer simulation were found. Although all studies used physiological multidirectional motions (i.e., internal/external rotation, plantar flexion/dorsiflexion, anterior/posterior translation), there was large variability among the studies in the magnitudes of these motions. Among these studies, mean non-cross-linked polyethylene wear ranged from 3.3 ± 0.4 to 25.8 ± 3.1 mm per million cycles. In contrast, mean highly cross-linked polyethylene wear ranged from 2.1 ± 0.3 to 3.3 ± 0.4 mm per million cycles. The wide distribution in wear rates was attributable to the highly inconsistent kinematic parameters and loads applied as well as differences in implant design and materials.

Conclusions: There is a severe lack of clinically applicable data on wear performance of total ankle replacements in the peer-reviewed literature. No universal set of kinematic load parameters has been established. Furthermore, only 2 of the published studies have validated their findings using independently derived data, such as retrieval analysis. These shortcomings make it difficult to compare findings as a function of design parameters and materials, or to draw clinically relevant conclusions from these simulations. More work is required to enhance the predictive capability of in vitro simulations of total ankle replacements.

Clinical Relevance: The results of joint wear simulator studies may not accurately represent in vivo wear of total ankle replacements. Joint simulator studies should establish that they are accurately replicating in vivo wear, thus enabling use of their predictive capabilities for new materials and designs.
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http://dx.doi.org/10.2106/JBJS.RVW.19.00091DOI Listing
March 2020

Increasing loads and diminishing returns: a biomechanical study of direct vertebral rotation.

Spine Deform 2020 08 5;8(4):577-584. Epub 2020 Feb 5.

J. Vernon Luck Sr, M.D. Orthopaedic Research Center (JVL), Orthopaedic Institute for Children (OIC)/UCLA, Los Angeles, CA, USA.

Study Design: Biomechanical simulation of DVR and pure-moment testing on thoracic spines.

Objectives: Characterize load-deformation response of thoracic spines under DVR maneuvers until failure, and compare to pure-moment testing of same spines. Despite reports of surgical complications, few studies exist on increase in ROM under DVR torque. Biomechanical models predicting increases from surgical releases have consistently used "pure-moments", a standard established for non-destructive measurement of ROM. Yet, DVR torque is not accurately modeled using pure moments and, moreover, magnitudes of torque applied during DVR maneuvers may be substantially higher than pure-moment testing.

Methods: Cadaveric thoracic spines (N = 11) were imaged, then prepared. Polyaxial pedicle screws were implanted at T7-T10 after surgical releases. Bilateral facetectomies and Ponte osteotomies were completed at T10-T11. A custom apparatus, mounted into an 8-dof MTS load frame, was used to attach to pedicle screws, allowing simulation of surgical DVR maneuvers. Motions of vertebrae were measured using optical motion tracking. Torque was increased until rupture of the T10-T11 disc or fracture at the pedicle screw sites at any level. The torque-rotation behavior was compared to its behavior under pure-moment testing performed prior to the DVR maneuver.

Results: Under DVR maneuvers, failure of the T10-T11 discs accompanied in most cases by pedicle screw loosening, occurred at 13.7-54.7 Nm torque, increasing axial rotation by 1.4°-8.9°. In contrast, pure-moment testing (4 Nm) increased axial rotation by only 0.0°-0.9°.

Conclusions: DVR resulted in substantially greater correction potential increases compared to pure-moment testing even at the same torque. These results suggest increased flexibility obtained by osteotomies and facetectomies is underestimated using pure-moment testing, misrepresenting clinical expectations. The present study is an important and necessary step toward the establishment of a more accurate and ultimately surgically applied model.

Level Of Evidence: III.
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http://dx.doi.org/10.1007/s43390-020-00061-0DOI Listing
August 2020

Telehealth: a novel approach for the treatment of nondisplaced pediatric elbow fractures.

J Pediatr Orthop B 2019 Nov;28(6):542-548

Orthopaedic Institute for Children.

Telehealth has seldom been used in the field of pediatric orthopaedics. The purpose of this study is to assess the efficacy of telehealth as a tool for the follow-up of children with nondisplaced elbow fractures. We hypothesize that patients treated via telehealth will have comparable clinical outcomes as those treated at our institution, with increased patient satisfaction. We conducted a randomized trial, which included 52 children with type I supracondylar humeral fractures, or occult elbow injuries, divided in two groups, based on the type of care provided during the fourth-week follow-up appointment: cast removal at our institution (group A) or cast removal at home via telehealth appointment (group B). The time duration and professional fees for this week 4 follow-up were calculated. Patients in both groups returned to our institution for a final follow-up in week 8. We measured the amount of fracture displacement, range of motion, pain, and patient satisfaction. There was no statistically significant difference in fracture displacement, range of motion, or pain scores between groups. The mean length of the fourth-week clinical encounter was higher in group A than group B (47.2 vs. 17.6 min, respectively; P < 0.001). Initially, the mean patient satisfaction scores were nearly identical in both groups (97%) until patients in group A were made aware of this difference in time duration, at which their mean satisfaction score decreased to 76.4% (P = 0.05). The use of telehealth as a tool in the treatment of nondisplaced pediatric elbow fractures is appealing. Patients managed via telehealth had higher satisfaction rates and spent only a third of the time for their clinical encounter.
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http://dx.doi.org/10.1097/BPB.0000000000000576DOI Listing
November 2019

Is the "Appropriate Use Criteria" for Type II Supracondylar Humerus Fractures Really Appropriate?

J Pediatr Orthop 2019 08;39(7):e563-e564

Orthopaedic Institute for Children.

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http://dx.doi.org/10.1097/BPO.0000000000001225DOI Listing
August 2019

Relapse Rates in Patients with Clubfoot Treated Using the Ponseti Method Increase with Time: A Systematic Review.

JBJS Rev 2019 05;7(5):e6

Orthopaedic Institute for Children, The J. Vernon Luck, Sr., M.D. Orthopaedic Research Center, Los Angeles, California.

Background: The Ponseti method is the preferred technique to manage idiopathic clubfoot deformity; however, there is no consensus on the expected relapse rate or the percentage of patients who will ultimately require a corrective surgical procedure. The objective of the present systematic review was to determine how reported rates of relapsed deformity and rates of a secondary surgical procedure are influenced by each study's length of follow-up.

Methods: A comprehensive literature search using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was performed to identify relevant articles. The definition of relapse, the percentage of patients who relapsed, the percentage of feet that required a surgical procedure, and the mean duration of follow-up of each study were extracted. Pearson correlations were performed to determine associations among the following variables: mean follow-up duration, percentage of patients who relapsed, percentage of feet that required a joint-sparing surgical procedure, and percentage of feet that required a joint-invasive surgical procedure. Logarithmic curve fit regressions were used to model the relapse rate, the rate of joint-sparing surgical procedures, and the rate of joint-invasive surgical procedures as a function of follow-up time.

Results: Forty-six studies met the inclusion criteria. Four distinct definitions of relapse were identified. The reported relapse rates varied from 3.7% to 67.3% of patients. The mean duration of follow-up was strongly correlated with the relapse rate (Pearson correlation coefficient = 0.44; p < 0.01) and the percentage of feet that required a joint-sparing surgical procedure (Pearson correlation coefficient = 0.59; p < 0.01). Studies with longer follow-up showed significantly larger percentages of relapse and joint-sparing surgical procedures than studies with shorter follow-up (p < 0.05).

Conclusions: Relapses have been reported to occur at as late as 10 years of age; however, very few studies follow patients for at least 8 years. Notwithstanding that, the results indicated that the rate of relapse and percentage of feet requiring a joint-sparing surgical procedure increased as the duration of follow-up increased. Longer-term follow-up studies are required to accurately predict the ultimate risk of relapsed deformity. Patients and their parents should be aware of the possibility of relapse during middle and late childhood, and, thus, follow-up of these patients until skeletal maturity may be warranted.

Level Of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
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http://dx.doi.org/10.2106/JBJS.RVW.18.00124DOI Listing
May 2019

Defining a Safe Zone for All-Inside Lateral Meniscal Repairs in Pediatric Patients: A Magnetic Resonance Imaging Study.

Arthroscopy 2019 01;35(1):166-170

Orthopaedic Institute for Children, University of California, Los Angeles, Los Angeles, California, U.S.A.

Purpose: To establish a safe zone for all-inside meniscal fixation in pediatric patients by use of magnetic resonance imaging (MRI) measurements between the popliteal tendon (PT) and popliteal neurovascular bundle (PNVB).

Methods: Patients aged 5 to 16 years with normal or nearly normal knee MRI scans were included. They were grouped by age: group I, 5 to 7 years (n = 61); group II, 8 to 10 years (n = 59); group III, 11 to 13 years (n = 60); and group IV, 14 to 16 years (n = 70). At the level of the lateral meniscus, 2 lines starting at the lateral patellar tendon border and ending at the medial edge of the PT (D1) and the lateral edge of the PNVB (D2) were made on an axial knee MRI scan. A third line (D3) connected D1 to D2 at the meniscocapsular junction of the posterior horn of the lateral meniscus (PHLM). A fourth line (D4), derived geometrically, was parallel and 8 mm anterior to D3, simulating the anterior edge of the PHLM.

Results: Axial MRI scans of 250 pediatric patients (aged 5-16 years) were retrospectively reviewed. Analysis showed significant correlation between age and sex for D3 (P < .0001). For D3, there were significant differences among all age groups, except between groups III and IV. The average D3 by age group was 14.1 mm (standard deviation [SD], 3.1 mm) for group I, 15.8 mm (SD, 2.5 mm) for group II, 17.0 mm (SD, 3.3 mm) for group III, and 17.2 mm (SD, 3.1 mm) for group IV. The average D4 was 11.39 mm (SD, 2.6 mm), 13.24 mm (SD, 2.24 mm), 14.59 mm (SD, 2.89 mm), and 14.80 mm (SD, 2.79 mm), respectively. There were significant differences in D3 and D4 in male versus female patients (17.6 mm vs 15.7 mm, P < .001, and 14.9 mm vs 13.2 mm, P < .001, respectively), particularly in groups III and IV (17.0 mm vs 13.8 mm and 16.8 mm vs 13.9 mm, respectively).

Conclusions: This study provides normative data of the distance between the PNVB and PT at the meniscocapsular junction (D3) and anterior edge of the PHLM (D4) with the knee in full extension. Combined with previous studies showing that the addition of knee flexion increases the distance between the meniscus and the neurovascular bundle, these data can be used by surgeons to improve the safety of PHLM repair in pediatric patients.

Level Of Evidence: Level III, diagnostic study of nonconsecutive patients.
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http://dx.doi.org/10.1016/j.arthro.2018.07.046DOI Listing
January 2019

Preclinical biomechanical testing models for the tibiotalar joint and its replacements: A systematic review.

Foot Ankle Surg 2020 Jan 23;26(1):14-18. Epub 2018 Dec 23.

The J. Vernon Luck, Sr., M.D. Orthopaedic Research Center, Orthopaedic Institute for Children, 403 W. Adams Blvd., Los Angeles, CA 90007, United States; University of California, Los Angeles Department of Orthopaedic Surgery, Los Angeles, CA, United States. Electronic address:

In recent years, total ankle replacements have gained increasing popularity as an alternative to fusion. Preclinical testing of TARs requires reliable in vitro models which, in turn, need thorough knowledge of the kinematics of the tibiotalar joint. Surprisingly few studies have been published to simulate the in vivo kinematics of the tibiotalar joint. Among these studies, there is a wide range of methods and magnitudes of applied loads. The purpose of the present review was to summarize the applied loads, positions that were tested during static simulations, and ranges of motion simulated that have been used in human cadaveric models of the tibiotalar joint. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, PubMed and Google Scholar were searched for studies pertaining to cadaveric tibiotalar joint kinematics. Our search yielded 12 appropriate articles that were included in the systematic review. While it is well known that loads at the tibiotalar joint are frequently as high as 5 times bodyweight [1], these studies reported applied loads varying from 200N-750N, below average bodyweight. Three studies used dynamic loading of custom apparatuses to drive cadaver limbs along predetermined paths to simulate gait. Conversely, the other nine studies applied static loads (∼300N), performed at discreet points during the stance phase, considerably lower than physiological conditions. The present systematic review calls for an urgent need to establish a consensus for preclinical evaluation of TARs for biomechanical function.
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http://dx.doi.org/10.1016/j.fas.2018.12.007DOI Listing
January 2020

Reply to the Letter to the Editor: Five Hundred Fifty-five Retrieved Metal-on-metal Hip Replacements of a Single Design Show a Wide Range of Wear, Surface Features, and Histopathologic Reactions.

Clin Orthop Relat Res 2018 11;476(11):2280-2281

S.-H. Park, Z. Lu, P. A. Campbell, E. Ebramzadeh, The J. Vernon Luck, Sr, MD Orthopaedic Research Center, Orthopaedic Institute for Children and UCLA Department of Orthopaedic Surgery, Los Angeles, CA, USA R. S. Hastings, DePuy, Inc, Warsaw, IN, USA.

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http://dx.doi.org/10.1097/CORR.0000000000000518DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6259979PMC
November 2018

Origins of material loss in highly worn acetabular cups of metal-on-metal total hip replacements.

J Orthop Res 2019 01 25;37(1):143-150. Epub 2018 Sep 25.

The J. Vernon Luck, Sr, MD Orthopaedic Research Center, Orthopaedic Institute for Children and UCLA Department of Orthopaedic Surgery, 403 West Adams Boulevard, Los Angeles, California, 90007.

Excessive wear has been one of the major failure modes of metal-on-metal hip implants. From a collection of 541 retrieved ASR metal-on-metal implants, we selected those head-cup pairs with combined wear >100 mm , (N = 42) to assess the distributions of wear volume on cups, and non-conformance in the worn areas at the head-cup interfaces. All 42 had severe cup edge wear (average maximum wear depth 500 μm). On average, 58% of wear volume of cups occurred at the edge areas, whereas 42% occurred well inside the socket, indicating that substantial wear volume of cups was generated well inside the socket. Particularly, in eight cups, more than half of the wear volume occurred well inside the socket. The head-cup conformance in the worn areas was deteriorated. On average, in worn areas, head-cup clearance was approximately eight times greater than in unworn areas, and the sphericity of heads and cups was approximately 36 times and 84 times higher, respectively, than in unworn areas. The radius of curvature of the worn surfaces of heads and cups varied widely, with an average variation of 3 mm (0.6-7 mm) and 11 mm (2-47 mm) for heads and cups, respectively. The severely deteriorated conformance at the edge areas and the areas well inside the socket, due to edge contact, could be the major factor for excessive wear of these 42 pairs. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.
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http://dx.doi.org/10.1002/jor.24139DOI Listing
January 2019

CORR Insights®: Spinal Fusion Is Associated With Changes in Acetabular Orientation and Reductions in Pelvic Mobility.

Clin Orthop Relat Res 2019 02;477(2):331-333

E. Ebramzadeh, Director, The J. Vernon Luck, Sr, MD Orthopaedic Research Center, Orthopaedic Institute for Children, Los Angeles, California, USA.

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http://dx.doi.org/10.1097/CORR.0000000000000438DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6370096PMC
February 2019

Sixty Years On: Ponseti Method for Clubfoot Treatment Produces High Satisfaction Despite Inherent Tendency to Relapse.

J Bone Joint Surg Am 2018 May;100(9):721-728

The J. Vernon Luck, Sr., M.D. Orthopaedic Research Center, Orthopaedic Institute for Children, in alliance with the University of California, Los Angeles, Los Angeles, California.

Background: Developed at the University of Iowa in 1950, the Ponseti method to manage idiopathic clubfoot deformity was slow to gain wide acceptance until the mid-1990s. There is a paucity of intermediate and long-term outcome studies involving this technique, with nearly all such studies coming from a single institution. The purpose of this study is to report the contemporary outcome of patients with clubfoot deformity whose feet were managed with the Ponseti method and who were followed to ≥5 years old, to provide outcome expectations for parents and for clinicians managing patients with idiopathic clubfoot.

Methods: Families of infants seen in our clinic diagnosed with idiopathic clubfoot since July 2006 were prospectively invited to participate in our institutional review board-approved study. Patients who received no prior outside treatment and had a minimum follow-up to the age of 5 years were included. Demographic, treatment, and outcome data were collected. To provide an array of outcome measures, both the Dallas outcome criteria and the Roye disease-specific instrument (DSI) were used.

Results: One hundred and one patients met the inclusion criteria. The mean length of follow-up (and standard deviation) was 81.1 ± 17.1 months. Initial correction was achieved in all feet. Thirty-seven percent of families reported that they were adherent with the bracing protocol; 68% of patients had ≥1 relapse, and 38% underwent a tendon transfer. With the Dallas criteria, 62% had outcomes rated as good, 38% had outcomes rated as fair, and no patient had an outcome rated as poor. With the Roye DSI, most families were generally very satisfied with the function and appearance of the feet.

Conclusions: Satisfactory results at intermediate follow-up were achieved using the Ponseti method. However, despite a better understanding of the Ponseti method and the importance of longer post-corrective brace use, the need for anterior tibial tendon transfer remains an important adjunct to the Ponseti method. Brace adherence also continues to be a critical clinical issue.

Level Of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
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http://dx.doi.org/10.2106/JBJS.17.01024DOI Listing
May 2018

Operative Treatment of Isolated Meniscus Injuries in Adolescent Patients: A Meta-Analysis and Review.

Sports Health 2018 Jul-Aug;10(4):311-316. Epub 2018 Apr 12.

Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California.

Context: With the rise in sports participation and increased athleticism in the adolescent population, there is an ever-growing need to better understand adolescent meniscus pathology and treatment.

Objective: To better understand the operative management of meniscus tears in the adolescent population.

Data Sources: A systematic review of PubMed (MEDLINE) and Google Scholar was performed for all archived years.

Study Selection: Studies that reported on isolated meniscus tears in adolescent patients (age, 10-19 years) were included.

Study Design: Systematic review and meta-analysis.

Level Of Evidence: Level 4.

Data Extraction: Two authors reviewed and extracted data from studies that fulfilled all inclusion criteria.

Results: Nine studies on isolated meniscus tears in adolescent patients were found, with level of evidence ranging from 3 to 4. These studies evaluated a total of 373 patients (248 males, 125 females) and 390 knees. Seven studies were published between 1979 and 2000, all of which discuss meniscectomy as the primary treatment. Two studies were published after 2000 and report on meniscus repair surgery. The mean patient age was 14.4 years. A total of 308 meniscectomies and 64 meniscus repairs were performed. Follow-up ranged from 1.8 to 30 years (mean, 10.8 years). A 37% retear rate was reported for patients undergoing meniscus repair. Different outcome measures were used for meniscectomy versus meniscus repair. Three studies evaluating meniscectomy reported Tapper-Hoover scores, showing 54 patients with an excellent result, 58 with good, 57 with fair, and 23 with poor results.

Conclusion: A shift in the management of isolated adolescent meniscal tears is reflected in the literature, with a recent increase in operative repair. This is likely secondary to poor outcomes after meniscectomy reflected in long-term follow-up studies. The current literature highlights the need for improved description of tear patterns, standardized reporting of outcome measures, and improved study methodologies to help guide orthopaedic surgeons on operative treatment of meniscal tears in adolescent patients.
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http://dx.doi.org/10.1177/1941738118768201DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6044115PMC
July 2018

Five Hundred Fifty-five Retrieved Metal-on-metal Hip Replacements of a Single Design Show a Wide Range of Wear, Surface Features, and Histopathologic Reactions.

Clin Orthop Relat Res 2018 02;476(2):261-278

S.-H. Park, Z. Lu, P. A. Campbell, E. Ebramzadeh, The J. Vernon Luck, Sr, MD Orthopaedic Research Center, Orthopaedic Institute for Children and UCLA Department of Orthopaedic Surgery, Los Angeles, CA, USA R. S. Hastings, DePuy, Inc, Warsaw, IN, USA.

Background: In 2010, a widely used metal-on-metal hip implant design was voluntarily recalled by the manufacturer because of higher than anticipated failure rates at 5 years. Although there was a large published range of revision rates, numerous studies had reported a higher risk of revision for excessive wear and associated adverse tissue reactions when compared with other metal-on-metal total hips. The reasons for this were suggested by some to be related to cup design features.

Questions/purposes: From retrievals of ASR metal-on-metal implants and tissue samples obtained at revision surgery, we asked the following questions: (1) What were the common and uncommon surface features? (2) What were the common and uncommon linear and volumetric wear characteristics? (3) Were there common taper corrosion characteristics? (4) What aseptic lymphocytic vasculitis-associated lesion (ALVAL) features were present in the tissues?

Methods: Five hundred fifty-five ASRs, including 23 resurfacings, were studied at one academic research center. Features of wear (eg, light and moderate scratching), damage (eg, deposits, gouges), and bone attachment on the porous coating were semiquantitatively ranked from 0 (none) to 3 (> 75%) based on the amount of a feature in each region of interest by the same experienced observer throughout the study. Visible features of head taper corrosion were ranked (Goldberg score) from 1 (none) to 4 (severe) by the same observer using a previously published scoring method. An experienced tribologist measured component wear depth using a coordinate measuring machine and quantified wear volume using previously validated methods. All available tissues were sampled and examined for features of ALVAL and scored from 0 to 10 by a single observer using a method they previously developed and published. A score from 0 to 4 is considered low, 5 to 8 is considered moderate, and 9 or 10 is considered high with regard to the risk of metal hypersensitivity features in the tissues.

Results: The most common bearing surface features were light and moderate scratches and removal or postremoval damage. Discoloration and deposits were commonly observed on femoral heads (55% [305 of 553]) and less commonly on cups (30% [165 of 546]). There was no evidence of impingement or dislocation damage. There was typically a small amount of bone attachment in at least one of eight designated regions of interest (84% [460 of 546]); extensive or no bone attachment was uncommon. Edge wear was highly prevalent. The maximum wear of 469 cups (88%) occurred near the edge, whereas the maximum wear of 508 femoral heads (94%) occurred between the pole and 45° from the pole. The median combined head-cup wear volume was 14 mm (range, 1-636 mm). One hundred sixty-nine pairs (32%) had a combined wear volume of < 10 mm, 42 pairs (8%) had volumetric wear of > 100 mm, and 319 pairs (60%) had wear volume between 10 and 100 mm³. Seventy-four percent of tapers (390 of 530) received a Goldberg score of 4, 22% (116 of 530) a score of 3, < 5% (24 of 530) a score of 2, and none received a score of 1. The most frequent ALVAL score was 5 out of 10 (35 of 144 hips [24%]) and ranged from 2 (one hip) to 10 (nine hips); 92 of 144 (64%) had a moderate score, 17 of 144 (12%) had a high score, and 35 (24%) had a low score.

Conclusions: Although edge wear was prevalent, in most cases, this was not associated with high wear. The increased diameter and decreased coverage angle of the ASR design may have resulted in the observed high incidence of edge wear while perhaps decreasing the risk for impingement and dislocation.

Clinical Relevance: The role of bearing wear in the revisions of metal-on-metal implants is controversial, because it is known that there is a large range of in vivo wear rates even within the same implant type and that patient variability affects local tissue responses to wear debris. The observations from our study of 555 retrieved ASR implant sets indicate that there was a wide range of wear including a subset with very high wear. The results suggested that the failure of the ASR and ASR XL was multifactorial, and the failure of different subgroups such as those with low wear may be the result of mechanisms other than reaction to wear debris.
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http://dx.doi.org/10.1007/s11999.0000000000000044DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6259711PMC
February 2018

A Removable Long-arm Soft Cast to Treat Nondisplaced Pediatric Elbow Fractures: A Randomized, Controlled Trial.

J Pediatr Orthop 2018 Apr;38(4):223-229

Orthopaedic Institute for Children.

Background: The ideal type of immobilization for nondisplaced pediatric elbow fractures has not been established. We hypothesized that the use of a long-arm cylinder made of soft cast material will result in similar outcomes to those obtained with a traditional long-arm hard cast.

Methods: We randomly assigned 100 consecutive children who presented with a closed, nondisplaced, type I supracondylar humeral fracture or an occult, closed, acute elbow injury, to 1 of 2 groups: group A (n=50) received a long-arm, traditional fiberglass (hard) cast. Group B (n=50) received a long-arm, soft fiberglass cast. After 4 weeks, the cast was removed in group A by a member of our staff using a cast saw, and in group B by one of the patient's parents by rolling back the soft fiberglass material. We compared the amount of fracture displacement and/or angulation, recovery of range of motion, elbow pain, and patient satisfaction.

Results: There were no instances of unplanned removal of the cast by the patient or parent. No evidence of fracture displacement or angulation was seen in either group. The final carrying angle of the affected elbow was nearly identical of that of the normal, contralateral elbow in both groups (P=0.64). At the latest follow-up appointment, elbows in groups A and B had a similar mean arc of motion (156 vs. 154 degrees; P=0.45), and had achieved identical relative arc of motion of 99.6% and 99.5% of that of the normal, contralateral side, respectively (P=0.94). Main pain scores were low and comparable over the study period. All patients in both groups reported the highest rate of satisfaction at the eighth week of follow-up.

Conclusions: The results indicate that children with nondisplaced supracondylar humeral fractures can be successfully managed with the use of a removable long-arm soft cast, maintaining fracture alignment and resulting in comparable rates of range of motion, pain, and patient satisfaction. The use of a removable immobilization that can reliably maintain fracture alignment and result in similar outcomes, while minimizing the risk of noncompliance, could be advantageous. Although we elected to remove the soft cast during a scheduled follow-up, it appears that such immobilization could be removed easily and safely at home, potentially resulting in a lower number of patient visits, decreased health care costs, and higher patient/parent satisfaction.

Level Of Evidence: Level I.
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http://dx.doi.org/10.1097/BPO.0000000000000802DOI Listing
April 2018

CORR Insights®: Current Total Knee Designs: Does Baseplate Roughness or Locking Mechanism Design Affect Polyethylene Backside Wear?

Clin Orthop Relat Res 2018 03;476(3):615-617

E. Ebramzadeh, Director, The J. Vernon Luck, Sr, MD Orthopaedic Research Center, Orthopaedic Institute for Children, Los Angeles, CA, USA.

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http://dx.doi.org/10.1007/s11999.0000000000000156DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6260023PMC
March 2018
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