Association of osteotomy, age, and component fixation with the outcomes of total hip arthroplasty in patients with hip dysplasia: a Dutch population-based registry study.

BACKGROUND AND PURPOSE:  Hip dysplasia can present challenges for total hip arthroplasty (THA) due to anatomic abnormalities. We aimed to assess the association of age, sex, osteotomies prior to THA, and fixation method on 5- and 10-year revision-free implant survival and patient-reported outcome measures (PROMs) of THAs in patients with hip dysplasia. METHODS: Using Dutch Arthroplasty Register data, we studied hip dysplasia patients receiving primary THAs in 2007-2021 (n = 7,465). THAs were categorized by age, pelvic osteotomy prior to THA (yes/no), and fixation (cemented, uncemented, hybrid, reverse hybrid). Kaplan-Meier and multivariable Cox models were used to determine 5- and 10-year revision-free implant survival and adjusted hazard ratios including 95% confidence intervals (CIs). Reasons for revision and PROMs were compared within the categories. RESULTS:  We found a 10-year revision-free implant survival of 94.9% (CI 94.3-95.5). Patients younger than 50 years had a 10-year implant survival of 93.3% (CI 91.9-94.7), Patients with prior pelvic osteotomy had a 10-year implant survival of 92.0% (CI 89.8-94.2). Fixation method and sex were not associated with implant survival. Patients with a prior pelvic osteotomy had more revisions due to cup loosening and reported lower PROM scores than patients without earlier osteotomy. CONCLUSION:  5- and 10-year revision-free implant survival rates of THA for hip dysplasia are 96.4% and 94.9%. Age and prior osteotomies were associated with decreased implant survival rates in patients with hip dysplasia, while fixation method was not. Prior osteotomies were also associated with reduced PROM scores.

Outcome One Year after Acetabular Rim Extension Using a Customized Titanium Implant for Treating Hip Dysplasia in Dogs.

The acetabular rim extension (ACE-X) implant is a custom-made three-dimensionally printed titanium device designed for the treatment of canine hip dysplasia. In this study, 34 dogs (61 hips) underwent ACE-X implantation, and assessments were conducted using computed tomography, force plate analysis, Ortolani's test, and the Helsinki chronic pain index (HCPI) questionnaires at five intervals: the pre-operative day, the surgery day, and the 1.5-month, 3-month, and 12-month follow-ups. Statistically significant increases in femoral head coverage with a negative Ortolani subluxation test were observed immediately after surgery and persisted throughout the study. Osteoarthritis (OA) scores remained stable, but osteophyte size significantly increased between the surgery day and the 12-month follow-up, especially in hips with a baseline OA score of 2 compared to those with a score of 1. The force plate data showed no significant changes during the study. The HCPI demonstrated a significant decrease in pain score from pre-operative value to six-week follow-up and gradually decreased over time. Major complications were identified in six hips (9.8%) of four dogs. In conclusion, the ACE-X implant effectively increased femoral head coverage, eliminated subluxation, and provided long-term pain relief with minimal complications, benefiting over 90% of the study population. The study supports the ACE-X implant as a valuable alternative treatment for canine hip dysplasia.

Acetabular rim extension using a personalized titanium implant for treatment of hip dysplasia in dogs: short-term results.

Hip dysplasia (HD) is a common orthopedic problem in young dogs. To decrease the laxity of the hip joint related to HD, the surgical treatments are recommended to increase femoral head coverage. ACEtabular rim eXtension (ACE-X) using a personalized 3-dimensional printed titanium shelf implant is a new surgical treatment to increase femoral head coverage and decrease laxity of the dysplastic hip joint, however, the efficacy is less know. Client-owned dogs older than 6 months with clinical signs of coxofemoral joint subluxation and radiographic evidence of HD with no or mild osteoarthritis (OA) were included. The Norberg angle (NA), linear percentage of femoral head overlap (LFO), and percentage of femoral head coverage (PC) were investigated radiographically and with computed tomography (CT) before and after surgery. OA was graded (scores 0-3) according to the maximum osteophyte size measured on CT. In addition, joint laxity (Ortolani) test results, gait analysis, and the Helsinki chronic pain index (HCPI) questionnaire were obtained at preoperative, immediately postoperative and at 1.5- and 3-month evaluations. Acetabular rim extension was performed in 61 hips of 34 dogs; NA, LFO, and PC were significantly higher immediately postoperatively and at the 1.5- and 3-month follow-up examinations compared with preoperative values (p < 0.05). Osteophyte size gradually increased over time (p < 0.05). The OA score significantly increased between preoperatively and directly postoperatively, and between preoperatively and at 3-month follow-up (p < 0.05). The laxity test normalized in 59 out of 61 hips after surgery, and the HCPI questionnaire showed that the pain score decreased significantly at 1.5 and 3 months, postoperatively. The force plate showed no significant improvement during the 3 months follow-up. Although pain reduction by the implant was unclear in short-term results, a personalized shelf implant significantly increased femoral head coverage and eliminated subluxation of the dysplastic hip joint. Further studies are required to study the long-term efficacy of gait, chronic pain, and progression of osteoarthritis.

Targeted Radionuclide Therapy of Cancer and Infections.

Targeted radionuclide therapy (TRT) has been burgeoning worldwide, with several radiopharmaceuticals for the treatment of metastatic cancers being approved for clinical use [...].

Evaluating the Targeting of a Staphylococcus-aureus-Infected Implant with a Radiolabeled Antibody In Vivo.

Implant infections caused by Staphylococcus aureus are difficult to treat due to biofilm formation, which complicates surgical and antibiotic treatment. We introduce an alternative approach using monoclonal antibodies (mAbs) targeting S. aureus and provide evidence of the specificity and biodistribution of S.-aureus-targeting antibodies in a mouse implant infection model. The monoclonal antibody 4497-IgG1 targeting wall teichoic acid in S. aureus was labeled with indium-111 using CHX-A"-DTPA as a chelator. Single Photon Emission Computed Tomography/computed tomographyscans were performed at 24, 72 and 120 h after administration of the 111In-4497 mAb in Balb/cAnNCrl mice with a subcutaneous implant that was pre-colonized with S. aureus biofilm. The biodistribution of this labelled antibody over various organs was visualized and quantified using SPECT/CT imaging, and was compared to the uptake at the target tissue with the implanted infection. Uptake of the 111In-4497 mAbs at the infected implant gradually increased from 8.34 %ID/cm3 at 24 h to 9.22 %ID/cm3 at 120 h. Uptake at the heart/blood pool decreased over time from 11.60 to 7.58 %ID/cm3, whereas the uptake in the other organs decreased from 7.26 to less than 4.66 %ID/cm3 at 120 h. The effective half-life of 111In-4497 mAbs was determined to be 59 h. In conclusion, 111In-4497 mAbs were found to specifically detect S. aureus and its biofilm with excellent and prolonged accumulation at the site of the colonized implant. Therefore, it has the potential to serve as a drug delivery system for the diagnostic and bactericidal treatment of biofilm.

Reinfection rates after one- and two-stage revision surgery for hip and knee arthroplasty: a systematic review and meta-analysis.

PURPOSE: Revisions for periprosthetic joint infection of knee and hip arthroplasty can be performed following one- or two-stage treatment protocols. Current literature is inconclusive whether one protocol is superior to the other, as prior literature reported similar reinfection rates for both treatment options. We aimed to provide a systematic review and meta-analysis of current literature on septic arthroplasty revisions. METHODS: Between April 2015 and December 2020, Medline, Embase, and The Cochrane Library were searched for studies reporting reinfection outcomes in patients treated with one-stage and two-stage knee or hip revision arthroplasty. Two reviewers independently extracted data and disagreements were resolved by a third investigator. We utilized a double arcsine transformation, prior to pooling using a random-effects model. RESULTS: For hip revision arthroplasty, we identified 14 one-stage studies (n = 1237) with a pooled reinfection rate of 5.7% (95% CI 3.7-8.1%), and 46 two-stage studies (n = 5009) with a reinfection rate of 8.4% (95% CI 6.9-9.9%). For knee revision arthroplasty, 6 one-stage studies (n = 527) and 48 two-stage studies (n = 4344) were identified with reinfection rates of 12.7% (7.0-19.7%) and 16.2% (13.7-19.0%), respectively. Overall, reinfection rates did not vary substantially after subgroup analysis. Limitations of our study are the limited amount of one-stage studies that introduce a potential bias. CONCLUSION: The reinfection rates following one- and two-stage hip and knee arthroplasty revisions were similar. Knee reinfection rates have increased compared to the previous analysis. Individual patient characteristics and adequate treatment algorithms are needed for a more individual selection approach, until a randomized trial is performed.

A mean 4-year evaluation of infection control rates of hip and knee prosthetic joint infection-related revision arthroplasty: an observational study.

BACKGROUND AND PURPOSE: The long-term results of the 1- or 2-stage revision procedure and infection-free prosthesis survival in a tertiary referral center are unknown. In this retrospective observational study, the long-term results of infection control and infection-free prosthesis survival of the periprosthetic joint infection-related 1- and 2-stage revision procedure are evaluated. Furthermore, the merits of performing an antibiotic-free window in the 2-stage revision is evaluated. PATIENTS AND METHODS: All patients who received a 1- or 2-stage revision procedure of the hip or knee between 2010 and 2017 were included. Data was collected on patient and infection characteristics. The primary treatment aim was successful infection control without the use of antibiotic therapy afterwards. Infection-free survival analysis was performed using the Kaplan-Meier method with type of periprosthetic joint infection-related revision as covariate. Within the group of 2-stage revisions, use of an antibioticfree window was selected as covariate. RESULTS: 128 patients were treated for a periprosthetic joint infection-related revision procedure (81 hips and 47 knees). Successful infection control was achieved in 18 of 21 cases for the 1-stage and 89 out of 107 cases for the 2-stage revision procedure (83%) respectively after follow-up of more than 4 years. In addition, 2-stage revision procedure infection control was achieved in 52 of 60 cases with an antibiotic-free interval and 37 of 45 cases without such interval (p = 0.6). The mean infection-free survival of the 1-stage revision was 90 months (95% CI 75-105) and 98 months (CI 90-106) for the 2-stage revision procedure. INTERPRETATION: There seems to be no difference in infection control and infection-free survival between the 1- and 2-stage revision procedure. Second, an antibiotic-free window in the case of a 2-stage revision did not seem to influence treatment outcome. However, one must be cautious when interpreting these results due to confounding by indication and the small study population. Therefore, no definite conclusion can be drawn.

Good long-term outcomes of the hip Chiari osteotomy in adolescents and adults with hip dysplasia: a systematic review.

BACKGROUND AND PURPOSE: The Chiari osteotomy was a regular treatment for developmental hip dysplasia before it became mostly reserved as a salvage therapy. However, the long-term survival of the Chiari osteotomy has not been systematically investigated. We investigated the survival time of the Chiari osteotomy until conversion to total hip arthroplasty (THA) in patients with primary hip dysplasia, and factors which correlated with survival, complications, and the improvement measured in radiographic parameters. PATIENTS AND METHODS: Studies were included when describing patients (> 16 years) with primary hip dysplasia treated with a Chiari osteotomy procedure with 8 years' follow-up. Data on patient characteristics, indications, complications, radiographic parameters, and survival time (endpoint: conversion to THA) were extracted. RESULTS: 8 studies were included. The average postoperative center-edge angle, acetabular head index, and Sharp angle were generally restored within the target range. 3 studies reported Kaplan-Meier survival rates varying from 96% at 10 years to 72% at 20 years' follow-up. Negative survival factors were high age at intervention and pre-existing advanced preoperative osteoarthritis. Moreover, reported complications ranged between 0% and 28.3 %. INTERPRETATION: The Chiari osteotomy has high reported survival rates and is capable of restoring radiographic hip parameters to healthy values. When carefully selected by young age, and a low osteoarthritis score, patients benefit from the Chiari osteotomy with satisfactory survival rates. The position of the Chiari osteotomy in relation to the periacetabular osteotomies should be further (re-)explored.

Patient-specific 3D-printed shelf implant for the treatment of hip dysplasia tested in an experimental animal pilot in canines.

The concept of a novel patient-specific 3D-printed shelf implant should be evaluated in a relevant large animal model with hip dysplasia. Therefore, three dogs with radiographic bilateral hip dysplasia and a positive subluxation test underwent unilateral acetabular augmentation with a 3D-printed dog-specific titanium implant. The contralateral side served as control. The implants were designed on CT-based pelvic bone segmentations and extended the dysplastic acetabular rim to increase the weight bearing surface without impairing the range of motion. Outcome was assessed by clinical observation, manual subluxation testing, radiography, CT, and gait analysis from 6 weeks preoperatively until termination at 26 weeks postoperatively. Thereafter, all hip joints underwent histopathological examination. The implantation and recovery from surgery was uneventful. Clinical subluxation tests at the intervention side became negative. Imaging showed medialization of the femoral head at the intervention side and the mean (range) CE-angle increased from 94° (84°-99°) preoperative to 119° (117°-120°) postoperative. Gait analysis parameters returned to pre-operative levels after an average follow-up of 6 weeks. Histology showed a thickened synovial capsule between the implant and the femoral head without any evidence of additional damage to the articular cartilage compared to the control side. The surgical implantation of the 3D shelf was safe and feasible. The patient-specific 3D-printed shelf implants restored the femoral head coverage and stability of dysplastic hips without complications. The presented approach holds promise to treat residual hip dysplasia justifying future veterinary clinical trials to establish clinical effectiveness in a larger cohort to prepare for translation to human clinic.

Patient-specific 3D-printed shelf implant for the treatment of hip dysplasia: Anatomical and biomechanical outcomes in a canine model.

A solution for challenging hip dysplasia surgery could be a patient-specific 3D-printed shelf implant that is positioned extra-articular and restores the dysplastic acetabular rim to normal anatomical dimensions. The anatomical correction and biomechanical stability of this concept were tested in a canine model that, like humans, also suffers from hip dysplasia. Using 3D reconstructed computed tomography images the 3D shelf implant was designed to restore the radiological dysplastic hip parameters to healthy parameters. It was tested ex vivo on three dog cadavers (six hips) with hip dysplasia. Each hip was subjected to a biomechanical subluxation test, first without and then with the 3D shelf implant in place. Subsequently, an implant failure test was performed to test the primary implant fixation. At baseline, the dysplastic hips had an average Norberg angle of 88 ± 3° and acetabular coverage of 47 ± 2% and subluxated at an average of 83 ± 2° of femoral adduction. After adding the patient-specific shelf implants the dysplastic hips had an average Norberg angle of 122 ± 2° and acetabular coverage of 67 ± 3% and subluxated at an average of 117 ± 2° of femoral adduction. Implant failure after primary implant fixation occurred at an average of 1330 ± 320 Newton. This showed that the patient-specific shelf implants significantly improved the coverage and stability of dysplastic hips in a canine model with naturally occurring hip dysplasia. The 3D shelf is a promising concept for treating residual hip dysplasia with a straightforward technology-driven approach; however, the clinical safety needs to be further investigated in an experimental proof-of-concept animal study.

Long-term outcome of two-stage revision surgery after hip and knee prosthetic joint infections: an observational study.

Introduction: Two-stage revision surgery is the most frequently performed procedure in patients with a chronic periprosthetic joint infection (PJI). The infection eradication rates in the current literature differ between 54 % and 100 %, which could be attributed to different treatment strategies. The aim of this study was to retrospectively evaluate the infection eradication rate in patients with chronic PJI treated with two-stage revision surgery of the hip or knee in primary and re-revision cases. Methods: All patients treated with a two-stage revision for chronic PJI between 2005 and 2011 were analysed. Patient and infection characteristics were retrieved. Primary outcome was successful infection eradication at last follow-up. Successful eradication is specified as no need for subsequent revision surgery or suppressive antibiotic treatment. Results: Forty-seven patients were treated with a two-stage revision. Infection eradication was achieved in 36 out of 47 cases. Thirty-eight patients had positive cultures: 35 monomicrobial infections and 3 polymicrobial infections. Nine cases of culture-negative infections were identified. Accompanying eradication rates were 26 out of 35 cases, 2 out of 3 cases, and 8 out of 9 cases respectively. Mean follow-up was 128 (27-186) months. For hip and knee revisions the eradication rates were 22 out of 31 cases and 14 out of 16 cases respectively. After primary arthroplasty the infection was eradicated in 29 out of 38 cases and after re-revision in 7 out of 9 cases. Conclusion: In this study, the infection eradication rate for two-stage revision surgery after PJI of the hip and knee in primary and re-revision cases was 77 %. No statistically significant patient, infection and micro-organism characteristics were found which influence the infection eradication rates at long-term follow-up of 128 (27-186) months.

3D-Printed Regenerative Magnesium Phosphate Implant Ensures Stability and Restoration of Hip Dysplasia.

Osteoarthritis of the hip is a painful and debilitating condition commonly occurring in humans and dogs. One of the main causes that leads to hip osteoarthritis is hip dysplasia. Although the current surgical methods to correct dysplasia work satisfactorily in many circumstances, these are associated with serious complications, tissue resorption, and degeneration. In this study, a one-step fabrication of a regenerative hip implant with a patient-specific design and load-bearing properties is reported. The regenerative hip implant is fabricated based on patient imaging files and by an extrusion assisted 3D printing process using a flexible, bone-inducing biomaterial. The novel implant can be fixed with metallic screws to host bone and can be loaded up to physiological loads without signs of critical permanent deformation or failure. Moreover, after exposing the hip implant to accelerated in vitro degradation, it is confirmed that it is still able to support physiological loads even after losing ≈40% of its initial mass. In addition, the osteopromotive properties of the novel hip implant is demonstrated as shown by an increased expression of osteonectin and osteocalcin by cultured human mesenchymal stem cells after 21 days. Overall, the proposed hip implant provides an innovative regenerative and mechanically stable solution for hip dysplasia treatment.

Comparing Hip Dysplasia in Dogs and Humans: A Review.

Hip dysplasia (HD) is common in both humans and dogs. This interconnection is because humans and dogs descended from a common ancestor and therefore have a similar anatomy at micro- and macroscopic levels. Furthermore, dogs are the animals of choice for testing new treatments for human hip dysplasia and orthopedic surgery in general. However, little literature exists comparing HD between the two species. Therefore, the aim of this review is to describe the anatomy, etiology, pathogenesis, diagnostics, and treatment of HD in humans and dogs. HD as an orthopedic condition has many common characteristics in terms of etiology and pathogenesis and most of the differences can be explained by the evolutionary differences between dogs and humans. Likewise, the treatment of HD shows many commonalities between humans and dogs. Conservative treatment and surgical interventions such as femoral osteotomy, pelvic osteotomy and total hip arthroplasty are very similar between humans and dogs. Therefore, future integration of knowledge and experiences for HD between dogs and humans could be beneficial for both species.

Study protocol: Effectiveness of dual-mobility cups compared with uni-polar cups for preventing dislocation after primary total hip arthroplasty in elderly patients - design of a randomized controlled trial nested in the Dutch Arthroplasty Registry.

Background and purpose - Dislocation is the leading reason for early revision surgery after total hip arthroplasty (THA). The dual-mobility (DM) cup was developed to provide more stability and mechanically reduce the risk of dislocation. Despite the increased use of DM cups, high-quality evidence of their (cost-)effectiveness is lacking. The primary objective of this randomized controlled trial (RCT) is to investigate whether there is a difference in the number of hip dislocations following primary THA, using the posterolateral approach, with a DM cup compared with a unipolar (UP) cup in elderly patients 1 year after surgery. Secondary outcomes include the number of revision surgeries, patient-reported outcome measures (PROMs), and cost-effectiveness.Methods and analysis - This is a prospective multicenter nationwide, single-blinded RCT nested in the Dutch Arthroplasty Registry. Patients ≥ 70 years old, undergoing elective primary THA using the posterolateral approach, will be eligible. After written informed consent, 1,100 participants will be randomly allocated to the intervention or control group. The intervention group receives a THA with a DM cup and the control group a THA with a UP cup. PROMs are collected preoperatively, and 3 months, 1 and 2 years postoperatively. Primary outcome is the difference in number of dislocations between the UP and DM cup within 1 year, reported in the registry (revisions), or by the patients (closed or open reduction). Data will be analyzed using multilevel models as appropriate for each outcome (linear/logistic/survival). An economic evaluation will be performed from the healthcare and societal perspective, for dislocation and quality adjusted life years (QALYs).Trial registration - This RCT is registered at www.clinicaltrials.gov with identification number NCT04031820.

Sonication Leads to Clinically Relevant Changes in Treatment of Periprosthetic Hip or Knee Joint Infection.

Background: Diagnosis of periprosthetic joint infection (PJI) can be troublesome. Sonication can be a helpful tool in culturing bacteria that are difficult to detect with standard tissue cultures. Aim of this study is to evaluate the clinical importance of our standardized sonication protocol in detecting periprosthetic joint infection. Materials and methods: All patients with revision surgery of a hip or knee prosthesis between 2011 and 2016 were retrospectively reviewed and divided in two groups: clinically suspected of infection or not suspected of infection. For both tissue culture and implant sonication, calculations of sensitivity and specificity were performed. Clinical relevance of sonication was evaluated by calculating in which percentage of patients' sonication influenced clinical treatment. Results: 226 patients with revision of a total hip prosthesis (122 patients) or a total knee prosthesis (104 patients) were included. Sensitivity of perioperatively taken tissue cultures was 94.3% and specificity was 99.3%. For sonication sensitivity was 80.5% and specificity was 97.8%. In the infection group eight patients (9%) with only one positive tissue culture and a positive sonication fluid culture with the same pathogen were found. Interpretation: Although sensitivity and specificity of sonication was lower compared to tissue cultures, periprosthetic joint infection could only be established in 8 patients (9%) suspected of infection because of a positive result of the sonication fluid culture. Sonication leads to clinically relevant changes in treatment and seems therefore to be a helpful diagnostic tool in clinical practice.

Can dual mobility cups prevent dislocation without increasing revision rates in primary total hip arthroplasty? A systematic review.

BACKGROUND: Dislocation is one of the leading causes for early revision surgery after total hip arthroplasty (THA). To address this problem, the dual mobility (DM) cup was developed in the 1970s by the French. Despite the increased and, in some countries, broad use of DM cups, high quality evidence of their effectiveness compared to traditional unipolar (UP) cups is lacking. There are a few well-conducted literature reviews, but the level of evidence of the included studies was moderate to low and the rates of revision were not specifically investigated. Therefore, we did a systematic review to investigate whether there is a difference in the rate of dislocations and revisions after primary THA with a DM cup or a UP cup. METHODS: We conducted a systematic literature search in PubMed, Embase and Cochrane databases in July 2019. The articles were selected based upon their quality, relevance and measurement of the predictive factor. We used the MINORS criteria to determine the methodological quality of all studies. RESULTS: The initial search resulted in 702 citations. After application of the inclusion and exclusion criteria, eight articles met our eligibility criteria and were graded. Included studies were of medium to low methodological quality with a mean score of 14/24 (11-16) points following the MINORS criteria. In the case-control studies, a total of 549 DM cups and 649 UP cups were included. In the registry studies, a total of 5.935 DM cups and 217.362 UP cups were included. In the case-control studies, one (0.2%) dislocation was reported for the DM cups and 46 (7.1%) for the UP cup (p=0.009, IQR=0.00-7.00). Nine (1.6%) revisions, of which zero due to dislocation, were reported for the DM cup and 39 (6.0%), of which 30 due to dislocation, for the UP cup (p=0.046, CI=-16.93-5.73). In the registry studies 161 (2.7%) revisions were reported for the DM cup, of which 14 (8.7%) due to dislocation. For the UP cup, 3.332 (1.5%) revisions were reported (p=0.275, IQR=41.00-866.25), of which 1.093 (32.8%) due to dislocation (p=0.050, IQR=3.50-293.25). CONCLUSION: This review suggests lower rates of dislocation and lower rates of revision for dislocation in favor of the DM cups. Concluding, DM cups might be an effective solution to reduce dislocation in primary THA. To evaluate the efficacy of DM cups compared to UP cups, an economic evaluation alongside a randomized controlled trial is needed focusing on patient important endpoints. LEVEL OF EVIDENCE: III, systematic review of level III studies.

Long-term outcomes of the hip shelf arthroplasty in adolescents and adults with residual hip dysplasia: a systematic review.

Background and purpose - The shelf arthroplasty was the regular treatment for residual hip dysplasia before it was substituted by the peri-acetabular osteotomy. Yet, evidence regarding the survival of shelf arthroplasty surgery has never been systematically documented. Hence, we investigated the survival time of the shelf procedure until revision to THA in patients with primary hip dysplasia. Factors that influenced survival and complications were also examined, along with the accuracy of correcting radiographic parameters to characterize dysplasia.Material and methods - The inclusion criteria were studies of human adolescents and adults (> 16 years) with primary or congenital hip dysplasia who were treated with a shelf arthroplasty procedure. Data were extracted concerning patient characteristics, survival time, complications, operative techniques, and accuracy of correcting radiographic parameters.Results - Our inclusion criteria were applicable to 9 studies. The average postoperative Center-Edge Angle and Acetabular Head Index were mostly within target range, but large variations were common. Kaplan-Meier curves (endpoint: conversion to THA) varied between 37% at 20 years' follow-up and 72% at 35 years' follow-up. Clinical failures were commonly associated with pain and radiographic osteoarthritis. Only minor complications were reported with incidences between 17% and 32%.Interpretation - The shelf arthroplasty is capable of restoring normal radiographic hip parameters and is not associated with major complications. When carefully selected on minimal osteoarthritic changes, hip dysplasia patients with a closed triradiate cartilage may benefit from the shelf procedure with satisfactory survival rates. The importance of the shelf arthroplasty in relation to peri-acetabular osteotomies needs to be further (re)explored.

A Novel Treatment for Anterior Shoulder Instability: A Biomechanical Comparison Between a Patient-Specific Implant and the Latarjet Procedure.

BACKGROUND: Anterior glenohumeral instability with >20% glenoid bone loss is a disorder that can be treated with the Latarjet stabilizing procedure; however, complications are common. The purposes of this study were to (1) evaluate the effect of an anatomic-specific titanium implant produced by 3-dimensional (3D) printing as a treatment option for recurrent shoulder instability with substantial glenoid bone loss and (2) compare the use of that implant with the Latarjet procedure. METHODS: Ten fresh-frozen cadaveric shoulders (mean age at the time of death, 78 years) were tested in a biomechanical setup with the humerus in 30° of abduction and in neutral rotation. The shoulders were tested under 5 different conditions: (1) normal situation, (2) creation of an anterior glenoid defect, (3) implantation of an anatomic-specific titanium implant produced by 3D printing, and the Latarjet procedure (4) with and (5) without 10 N of load attached to the conjoined tendon. In each condition, the humerus was translated 10 mm anteriorly relative to the glenoid, and the maximum peak translational force that was necessary for this translation was measured. RESULTS: After creation of the glenoid defect, the mean translational peak force decreased by 30% ± 6% compared with that for the normal shoulder. After restoration of the original glenoid anatomy, the translational force needed to dislocate the humeral head from the glenoid significantly increased compared with that in the defect condition-to 119% ± 16% of normal (p < 0.01) with the 3D-printed anatomic-specific implant and to 121% ± 48% of normal (p < 0.01) following the Latarjet procedure. No significant differences in mean translational force were found between the anatomic-specific implant and the Latarjet procedure (p = 0.72). CONCLUSIONS: The mean translational peak force needed to dislocate the humerus 10 mm anteriorly on the glenoid was higher after glenoid restoration with the 3D-printed anatomic-specific implant compared with when the glenoid had a 20% surface defect but also compared with when the glenoid was intact. No differences in mean translational peak force were found between the 3D-printed anatomic-specific glenoid implant and the Latarjet procedure, although there was less variability in the 3D-implant condition. CLINICAL RELEVANCE: Novel 3D-printing technology could provide a reliable patient-specific alternative to solve problems related to traditional treatment methods for shoulder instability.

Current Pathologic Scoring Systems for Metal-on-metal THA Revisions are not Reproducible.

BACKGROUND: The aseptic lymphocyte vasculitis-associated lesion (ALVAL) score and the modified Oxford ALVAL score are frequently used scoring methods to evaluate the morphologic features of periprosthetic tissues around metal-on-metal (MoM) hip implants. Except for the initial studies of these two morphology scoring methods, to our knowledge, no other studies have reported on intraclass correlation coefficient (ICC) values for interobserver reliability of these scoring methods. QUESTIONS/PURPOSES: Are the ALVAL and Oxford ALVAL scores reproducible? METHODS: The periprosthetic tissue of 37 revisions of 36 patients with failed MoM THAs were independently scored by three experienced pathologists using ALVAL and Oxford ALVAL scoring methods. All patients were included who underwent revision surgery in our hospital until January 2013, with a large-head MoM prosthesis and also met the criteria: blood serum cobalt levels, available MRI scan, and intraarticular cobalt levels. The population included 26 patients with pseudotumors diagnosed by two radiologists using the method described by Matthies et al. The ALVAL describes morphologic features of the synovial lining, tissue organization, and inflammatory cell infiltrate in periprosthetic tissues. The Oxford-ALVAL score uses a semiquantitative measure of the immune response which should be easier to score. RESULTS: The ALVAL score showed an ICC of 0.38 (95% CI, 0.18-0.58) (fair) for the sum score and this improved up to 0.50 (95% CI, 0.31-0.68) (moderate) using the modified Oxford ALVAL score. The individual parameters of the ALVAL score showed an ICC for the scoring of inflammatory infiltrate of 0.37 (95% CI, 0.17-0.57), an ICC of 0.32 (95% CI, 0.12-0.53) for the scoring of tissue organization, and an ICC of 0.14 (95% CI, -0.04 to 0.34) for synovial lining. CONCLUSIONS: Scoring morphologic features of MoM tissue is not reproducible using the ALVAL score or the Oxford ALVAL score. This may reflect heterogeneous morphologic features in tumor tissue and between different tumor tissue samples that cannot be reliably quantified by pathologists using the parameters of these two scoring methods. An alternative, simplified scoring system should be developed to improve the interrater agreement. LEVEL OF EVIDENCE: Level III, diagnostic study.

Long-term results of total hip arthroplasty with the CementLess Spotorno (CLS) system.

BACKGROUND: This study presents the long-term results of the Cementless Spotorno (CLS) total hip arthroplasty system and an analysis of factors associated with clinical and radiographic outcome. METHODS: We studied a series of 120 consecutive CLS arthroplasties in a young patient group (mean age at surgery: 55.9 ± 5.9 years). The Merle d'Aubigné-Postel score, polyethylene (PE) wear, and radiographic status were recorded during follow-up. Survival analyses, repeated-measures analysis of variance, and a nested case-control study were used for statistical evaluation. RESULTS: After a mean follow-up of 14.6 years (range 0.1-24.2 years, including revisions and lost to follow-up), 24 revisions had been performed, 16 of which for aseptic cup loosening. Kaplan-Meier survival analysis showed a 24-year survival of 72.8% (95% CI, 63.0%-82.6%) with revision for any reason as endpoint, and 80.1% (95% CI, 70.9%-89.3%) for revision for aseptic cup loosening. Mean final Merle d'Aubigné-Postel score was 16.1 points (range 7-18). Mean PE wear at final follow-up was 2.3 mm (range 0.6-6.8 mm). A higher rate of PE wear was associated with better clinical scores but also with revision for cup loosening. Factors associated with more PE wear were: younger age at surgery; 32 - mm head; longer follow-up; and steeper inclination angle. CONCLUSIONS: Beyond 10 years, the CLS stem is reliable, but the high revision rate for aseptic cup loosening is concerning, specifically with better performing (cementless) alternatives available.