Evidence-based objective performance criteria for the evaluation of hip and knee replacement devices and technologies.

BACKGROUND: Objective performance criteria (OPC) is a novel method to provide minimum performance standards and improve the regulated introduction of original or incremental device innovations in order to prevent patients from being exposed to potentially inferior designs whilst allowing timely access to improvements. We developed 2-year safety and effectiveness OPC for total hip and knee replacement (THR and TKR). METHODS: Analyses of large databases were conducted using various data sources: a systematic literature review; a direct data analysis from The Functional Outcomes Research for Comparative Effectiveness in Total Joint Replacement and Quality Improvement Registry (FORCE-TJR) and the Kaiser Permanente Implant Registry (KPIR); and claims data analyses from longitudinal discharge data in New York and California states. The literature review included U.S. patients (≥18 years) who received THR or TKR for primary end-stage osteoarthritis and prospectively collected data on patient-reported outcome measures (PROMs) from at least 100 subjects and/or 2-year implant survival for at least 250 implants. Random effects models were used for meta-analysis. RESULTS: Data were available from a total of 951 100 patients. After screening of 7979 abstracts, 294 studies underwent full-text review and 31 studies contributed to the evidence synthesis (333 995 implants). Direct data analysis of FORCE-TJR contributed 9223 joint replacement patients to the construction of OPC for effectiveness; KPIR contributed 262 044 patients for the construction of OPC for safety. Claims database analysis contributed 345 838 patients to the construction of safety OPC. OPC for safety were constructed for cumulative incidences of 2-year all-cause and septic revision (THR/TKR 2.0%/1.6% and 0.6%/0.7%), and OPC for effectiveness were constructed based on four disease-specific and three general health-related quality of life PROMs (HOOS/KOOS 87.1/80.6; HSS/KSS function 94.4/90.6; SF-12/SF-36, PCS 46.5/41.9, EQ-5D 0.88/0.84). CONCLUSION: This study is the first to construct a 2-year OPC for the safety and effectiveness of THR and TKR based on U.S. real-world data. Based on these OPC, potential benchmarks for (single-arm study) evaluation of new device innovations are suggested for a regulated and safe introduction to the (commercial) market.

Meniscal allograft transplantation in The Netherlands: long-term survival, patient-reported outcomes, and their association with preoperative complaints and interventions.

PURPOSE: Evaluation of survival of meniscal allograft transplantation (MAT) and postoperative patient-reported outcome (PRO), and their association with prior interventions of the knee. METHODS: A prospective consecutive study of 109 consecutive patients who had an arthroscopic meniscal allograft transplantation (MAT) between 1999 and 2017 by a single surgeon. Patients were assessed with KOOS scores, preoperative and after a minimal follow-up of 2 years. Furthermore, two anchor questions (whether expectations were met and overall satisfaction, on a five-point Likert scale) were asked. Additionally, prior interventions to MAT were evaluated. RESULTS: Prior to MAT, patients had undergone an average of 2.8 (range 1-14) of surgical procedures of the knee. Overall, mean allograft survival was 16.1 years (95% CI 14.8-17.5 years). Higher age at surgery was associated with lower MAT survival: hazard ratio for MAT failure was 1.19 per year increase (95% CI 1.04 to 1.36, p = 0.009). At 4.5 years (IQR, 2-9) of follow-up, all KOOS score were still improved compared to baseline. Age below 35 years, simultaneous anterior cruciate ligament reconstruction and number of knee surgeries before MAT were associated with lower KOOS scores. Overall patient expectations and overall satisfaction after MAT were not associated with preoperative patient characteristics nor with the number or kind of preoperative interventions. CONCLUSION: Meniscal allograft transplantation has a good overall survival with a clinically relevant improvement. Both meniscal allograft survival and PRO were associated with age. PRO was lower in patients younger than 35 years at time of MAT and meniscal allograft survival was worse in patients older than 50 years. PRO was associated with preoperative patient characteristics and number of surgical procedures prior to MAT. All patients reported improved postoperative satisfaction and met expectations after MAT, both independent of the preoperative history of knee interventions. LEVEL OF EVIDENCE: Level III. Trial registration Medical ethical review board (METC) number: 17-104 (7 August 2017). Dutch Trial Register (NTR) number: NTR6630 (4 July 2017).

Fixation of the short global tissue-sparing hip stem.

AIMS: Short, bone-conserving femoral components are increasingly used in total hip arthroplasty (THA). They are expected to allow tissue-conserving implantation and to render future revision surgery more straightforward but the long-term data on such components is limited. One such component is the global tissue-sparing (GTS) stem. Following the model for stepwise introduction of new orthopaedic implants, we evaluated early implant fixation and clinical outcome of this novel short-stem THA and compared it to that of a component with established good long-term clinical outcome. METHODS: In total, 50 consecutive patients ≤ 70 years old with end-stage symptomatic osteo-arthritis were randomized to receive THA with the GTS stem or the conventional Taperloc stem using the anterior supine intermuscular approach by two experienced hip surgeons in two hospitals in the Netherlands. Primary outcome was implant migration. Patients were followed using routine clinical examination, patient reported outcome using Harris Hip Score (HHS), Hip Disability And Osteoarthritis Outcome Score (HOOS), EuroQol five-dimension questionnaire (EQ5D), and Roentgen Stereophotogrammetric Analysis (RSA) at three, six, 12, and 24 months. This study evaluated the two-year follow-up results. RESULTS: In addition to the initial migration pattern of distal migration (subsidence, Y-translation) and retroversion (Y-rotation) also exhibited by the Taperloc stem, the GTS stem showed an initial migration pattern of varization (X-translation combined with Z-rotation) and posterior translation (Z-translation). However, all components stabilized aside from one Taperloc stem which became loose secondary to malposition and was later revised. Clinical outcomes and complications were not statistically significantly different with the numbers available. CONCLUSION: A substantially different and more extensive initial migration pattern was seen for the GTS stem compared to the Taperloc stem. Although implant stabilization was achieved, excellent long-term survival similar to that of the Taperloc stem should not be inferred. Especially in the absence of clinically proven relevant improvement, widespread usage should be postponed until long-term safety has been established. Cite this article: Bone Joint J 2020;102-B(6):699-708.

What Range of Motion is Achieved 5 Years After External Rotationplasty of the Shoulder in Infants with an Obstetric Brachial Plexus Injury?

BACKGROUND: Obstetric brachial plexus injuries result from traction injuries during delivery, and 30% of these children have persisting functional limitations related to an external rotation deficit of the shoulder. Little is known about the long-term effect of soft-tissue procedures of the shoulder in patients with obstetric brachial plexus injuries. QUESTIONS/PURPOSES: (1) After soft-tissue release for patients with passive external rotation less than 20° and age younger than 2 years and for patients older than 2 years with good external rotation strength, what are the improvements in passive external rotation and abduction arcs at 1 and 5 years? (2) For patients who underwent staged tendon transfer after soft-tissue release, what are the improvements in active external rotation and abduction arcs at 1 and 5 years? (3) For patients with passive external rotation less than 20° and no active external rotation, what are the improvements in active external rotation and abduction arcs at 1 and 5 years? METHODS: This was a retrospective analysis of a longitudinally maintained institutional database. Between 1996 and 2009, 149 children underwent a soft-tissue procedure of the shoulder for an internal rotation contracture. The inclusion criteria were treatment with an internal contracture release and/or tendon transfer, a maximum age of 18 years at the time of surgery, and a minimum follow-up period of 2 years. Six patients were older than 18 years at the time of surgery and 31 children were seen at our clinic until 1 year postoperatively, but because they had good clinical results and lived far away from our center, these children were discharged to physical therapists in their hometown for annual follow-up. Thus, 112 children (59 boys) were available for analysis. Patients with passive external rotation less than 20° and age younger than 2 years and patients older than 2 years with good external rotation strength received soft-tissue release only (n = 37). Of these patients, 17 children did not have adequate active external rotation, and second-stage tendon transfer surgery was performed. For patients with passive external rotation less than 20° with no active external rotation, single-stage contracture release with tendon transfer was performed (n = 68). When no contracture was present (greater than 20° of external rotation) but the patient had an active deficit (n = 7), tendon transfer alone was performed; this group was not analyzed. A functional assessment of the shoulder was performed preoperatively and postoperatively at 6 weeks, 3 months, and annually thereafter and included abduction, external rotation in adduction and abduction, and the Mallet scale. RESULTS: Internal contracture release resulted in an improvement in passive external rotation in adduction and abduction of 29° (95% confidence interval, 21 to 38; p < 0.001) and 17° (95% CI, 10 to 24; p < 0.001) at 1 year of follow-up and 25° (95% CI, 15-35; p < 0.001) and 15° (95% CI, 7 to 24; p = 0.001) at 5 years. Because of insufficient strength of the external rotators after release, 46% of the children (17 of 37) underwent an additional tendon transfer for active external rotation, resulting in an improvement in active external rotation in adduction and abduction at each successive follow-up visit. Patients with staged transfers had improved active function; improvements in active external rotation in adduction and abduction were 49° (95% CI, 28 to 69; p < 0.05) and 45° (95% CI, 11 to 79; p < 0.001) at 1 year of follow-up and 38° (95% CI, 19 to 58; p < 0.05) and 23° (95% CI, -8 to 55; p < 0.001) at 5 years. In patients starting with less than 20° of passive external rotation and no active external rotation, after single-stage contracture release and tendon transfer, active ROM was improved. Active external rotation in adduction and abduction were 75° (95% CI, 66 to 84; p < 0.001) and 50° (95% CI, 43 to 57; p < 0.001) at 1 year of follow-up and 65° (95% CI, 50 to 79; p < 0.001) and 40° (95% CI, 28 to 52; p < 0.001) at 5 years. CONCLUSION: Young children with obstetric brachial plexus injuries who have internal rotation contractures may benefit from soft-tissue release. When active external rotation is lacking, soft-tissue release combined with tendon transfer improved active external rotation in this small series. Future studies on the degree of glenohumeral deformities and functional outcome might give more insight into the level of increase in external rotation. LEVEL OF EVIDENCE: Level III, therapeutic study.

Early subsidence of shape-closed hip arthroplasty stems is associated with late revision. A systematic review and meta-analysis of 24 RSA studies and 56 survival studies.

BACKGROUND AND PURPOSE: Few studies have addressed the association between early migration of femoral stems and late aseptic revision in total hip arthroplasty. We performed a meta-regression analysis on 2 parallel systematic reviews and meta-analyses to determine the association between early migration and late aseptic revision of femoral stems. PATIENTS AND METHODS: Of the 2 reviews, one covered early migration data obtained from radiostereometric analysis (RSA) studies and the other covered long-term aseptic revision rates obtained from survival studies with endpoint revision for aseptic loosening. Stems were stratified according to the design concept: cemented shape-closed, cemented force-closed, and uncemented. A weighted regression model was used to assess the association between early migration and late aseptic revision, and to correct for confounders. Thresholds for acceptable and unacceptable migration were determined in accordance with the national joint registries (≤ 5% revision at 10 years) and the NICE criteria (≤ 10% revision at 10 years). RESULTS: 24 studies (731 stems) were included in the RSA review and 56 studies (20,599 stems) were included in the survival analysis review. Combining both reviews for the 3 design concepts showed that for every 0.1-mm increase in 2-year subsidence, as measured with RSA, there was a 4% increase in revision rate for the shape-closed stem designs. This association remained after correction for age, sex, diagnosis, hospital type, continent, and study quality. The threshold for acceptable migration of shape-closed designs was defined at 0.15 mm; stems subsiding less than 0.15 mm in 2 years had revision rates of less than 5% at 10 years, while stems exceeding 0.15 mm subsidence had revision rates of more than 5%. INTERPRETATION: There was a clinically relevant association between early subsidence of shape-closed femoral stems and late revision for aseptic loosening. This association can be used to assess the safety of shape-closed stem designs. The published research is not sufficient to allow us to make any conclusions regarding such an association for the force-closed and uncemented stems.

[The introduction of new medical devices]. / De introductie van nieuwe medische implantaten.

Regulation of the introduction of new or improved medical devices is fundamentally different from that of new drugs and is inadequate in its current form. This was recently demonstrated by large-scale problems with medical devices in various specialist fields. Steps have been taken by scientific professional associations, regulating authorities and industry to prevent these problems from happening in the future. However, these steps have not yet been implemented or have not been sufficiently well implemented, and have not been completely coordinated. The practitioner therefore needs to remain extremely critical when using new medical devices.

Review of clinical outcomes-based anchors of minimum clinically important differences in hip and knee registry-based reports and publications.

Patient-reported outcome measures are tools that allow clinicians and researchers to gauge patients' level of satisfaction and quality of life after a medical intervention. The use of patient-reported outcome measures and the clinically relevant score differentials over time as they relate to outcomes (minimum clinically important differences) has been proposed as a way to understand success and failure rates in orthopaedics. We conducted a systematic appraisal of literature in peer-reviewed journals and registry reports to measure the use that registries and other large data repositories make of minimum clinically important differences and to understand methodological approaches for such uses. Of the nineteen registry reports and 1052 articles examined, we found that only one report and two studies mentioned the use of patient-reported outcome measures and minimum clinically important differences in the context of revision rates of total knee arthroplasty and total hip arthroplasty. We conclude that although the infrastructure and efforts to routinely collect patient-reported outcome measures at registry levels do exist, there is limited use of minimum clinically important differences to understand and potentially predict clinical outcomes. We suggest advancing the global infrastructure such as the International Consortium of Orthopaedic Registries to address how research related to patient-reported outcome measures can help individual registries collaborate in the development of tools and allow aggregation of data.

Appraisal of evidence base for introduction of new implants in hip and knee replacement: a systematic review of five widely used device technologies.

OBJECTIVE: To determine the evidence of effectiveness and safety for introduction of five recent and ostensibly high value implantable devices in major joint replacement to illustrate the need for change and inform guidance on evidence based introduction of new implants into healthcare. DESIGN: Systematic review of clinical trials, comparative observational studies, and registries for comparative effectiveness and safety of five implantable device innovations. DATA SOURCES: PubMed (Medline), Embase, Web of Science, Cochrane, CINAHL, reference lists of articles, annual reports of major registries, summaries of safety and effectiveness for pre-market application and mandated post-market studies at the US Food and Drug Administration. STUDY SELECTION: The five selected innovations comprised three in total hip replacement (ceramic-on-ceramic bearings, modular femoral necks, and uncemented monoblock cups) and two in total knee replacement (high flexion knee replacement and gender specific knee replacement). All clinical studies of primary total hip or knee replacement for symptomatic osteoarthritis in adults that compared at least one of the clinical outcomes of interest (patient centred outcomes or complications, or both) in the new implant group and control implant group were considered. Data searching, abstraction, and analysis were independently performed and confirmed by at least two authors. Quantitative data syntheses were performed when feasible. RESULTS: After assessment of 10,557 search hits, 118 studies (94 unique study cohorts) met the inclusion criteria and reported data related to 15,384 implants in 13,164 patients. Comparative evidence per device innovation varied from four low to moderate quality retrospective studies (modular femoral necks) to 56 studies of varying quality including seven high quality (randomised) studies (high flexion knee replacement). None of the five device innovations was found to improve functional or patient reported outcomes. National registries reported two to 12 year follow-up for revision occurrence related to more than 200,000 of these implants. Reported comparative data with well established alternative devices (over 1,200,000 implants) did not show improved device survival. Moreover, we found higher revision occurrence associated with modular femoral necks (hazard ratio 1.9) and ceramic-on-ceramic bearings (hazard ratio 1.0-1.6) in hip replacement and with high flexion knee implants (hazard ratio 1.0-1.8). CONCLUSION: We did not find convincing high quality evidence supporting the use of five substantial, well known, and already implemented device innovations in orthopaedics. Moreover, existing devices may be safer to use in total hip or knee replacement. Improved regulation and professional society oversight are necessary to prevent patients from being further exposed to these and future innovations introduced without proper evidence of improved clinical efficacy and safety.

Fixation of high-flexion total knee prostheses: five-year follow-up results of a four-arm randomized controlled clinical and roentgen stereophotogrammetric analysis study.

BACKGROUND: High-flexion total knee arthroplasty was introduced to meet the demands of daily activity requiring increased knee flexion. However, concerns have been raised regarding the fixation of high-flexion total knee arthroplasty components and increased rates of loosening have been reported. To date, migration, and thus fixation, of high-flexion total knee arthroplasty components has not been analyzed and the preferential bearing type (mobile or fixed) is unknown. METHODS: Of eighty-six consecutive eligible patients, seventy-four patients (seventy-eight knees) scheduled for total knee arthroplasty were randomized to one of four Legacy Posterior Stabilized (LPS) total knee prosthesis designs: (1) LPS-Flex mobile, (2) LPS-Flex fixed, (3) LPS mobile, and (4) LPS fixed. The primary outcome was component migration measured with use of Roentgen stereophotogrammetric analysis, and secondary outcomes were postoperative knee flexion and extension and Knee Society Score. Patients were evaluated postoperatively at six, twelve, twenty-six, and fifty-two weeks and annually thereafter. At the five-year follow-up, eight patients had died and two patients were lost to follow-up. Seventy-seven tibial and forty-two femoral components were suitable for migration measurements. RESULTS: The overall five-year migration of the seventy-seven tibial components was not significantly different among the four total knee prosthesis designs (compared with the LPS fixed design, the range of overall mean differences for the other three designs was 0.02 to 0.25 mm) and migration was comparable at the two and five-year follow-up. Migration stabilized in all but three components (two LPS-Flex mobile and one LPS fixed); one of these components has already been revised and was aseptically loose. The overall five-year migration of the forty-two femoral components was comparable among the four designs (compared with the LPS fixed design, the range of overall mean differences for the other three designs was 0.01 to 0.18 mm) and was similar at two and five years postoperatively. One femoral component (LPS-Flex mobile) migrated excessively. In patients who had a mean postoperative flexion of ≥ 125° or a maximum flexion of ≥ 135° during the one to five-year follow-up period, migration of high-flexion components was comparable with that of conventional components and indicative of appropriate fixation. Postoperative flexion, extension, Knee Society Score, and Knee Society Score function were comparable during the five-year follow-up period and at the two and five-year follow-up. CONCLUSIONS: The LPS-Flex total knee prosthesis with either a mobile or a fixed bearing had migration comparable that of with its conventional counterpart and is expected to have similar (excellent) long-term survival in these patients. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

New vertebral fractures after percutaneous vertebroplasty for painful osteoporotic vertebral compression fractures: a clustered analysis and the relevance of intradiskal cement leakage.

PURPOSE: To perform clustered analysis of fracture-free probabilities of intact nontreated vertebrae after percutaneous vertebroplasty (PVP) in painful long-standing osteoporotic vertebral compression fractures (OVCFs) to determine risk factors for new vertebral fractures and estimate fracture-free probabilities of multiple intact nontreated vertebrae given their patient- and vertebra-specific covariate status. MATERIALS AND METHODS: Informed consent and institutional review board approval were obtained. A total of 115 patients who underwent PVP for 216 painful long-standing OVCFs were prospectively followed up to detect new OVCFs during the 1st postoperative year. A total of 1031 intact vertebrae were available for clustered analysis of fracture-free probabilities by using a Cox proportional hazard frailty model. A clustered analysis takes clustering or correlation of fracture-free survival probabilities of individual intact vertebrae within one patient into account to improve estimates of fracture-free probabilities and risk factors. Relevant patient- and vertebra-specific covariates were included. Volumetric analysis of intradiskal cement leakage was performed by using a receiver operating characteristic curve (ROC). RESULTS: Three- and 12-month vertebral fracture-free probability was 97.0% and 94.5%, respectively. Strong patient-level risk factors included low bone mineral density (hazard ratio [HR], 0.53 per unit increase), high spinal deformity index (HR, 2.23 per five units increase), and low fracture age (HR, 0.52 per 2 months increase). Strong vertebra-specific risk factors were thoracolumbar localization (HR, 2.33), vicinity to the treated level (adjacent level HR, 3.53), and presence of intradiskal cement leakage (HR, 8.21). Fracture-free probabilities of individual vertebrae were clustered within a patient (ie, not independent) (P = .009). The predicted 1-year fracture-free probability of an individual vertebra could be as high as 99.8% or as low as 19.9% based on absence or presence of risk factors, respectively. Larger intradiskal cement leakage volumes were associated with a higher likelihood of occurrence of new adjacent OVCFs (area under the ROC curve, 0.70). CONCLUSION: New vertebral fractures after PVP were clustered within patients and depended heavily on the presence or absence of both patient- and vertebra-specific risk factors. Intradiskal cement leakage was a pronounced augmentation-related risk factor, for which a volumetric association was found.

Clinical outcome in all-arthroscopic versus mini-open rotator cuff repair in small to medium-sized tears: a randomized controlled trial in 100 patients with 1-year follow-up.

PURPOSE: The purpose of this study was to compare clinical outcomes in the first postoperative year of patients with full-thickness small to medium-sized tears undergoing all-arthroscopic (AA) versus mini-open (MO) rotator cuff repair. METHODS: One hundred patients were randomized to either AA or MO rotator cuff repair at the time of surgery on an intention-to-treat basis. Patients were evaluated before and 6, 12, 26, and 52 weeks after surgery using the Disabilities of the Arm, Shoulder, and Hand (DASH) score as a primary outcome score and the Constant-Murley score, visual analog scale (VAS)-pain/impairment score, and measurement of active forward flexion/external rotation as secondary outcome measures. Ultrasound evaluation was used to assess structural integrity of the repair 1 year postoperatively. RESULTS: Forty-seven patients were analyzed in the AA group and 48 in the MO group. Five patients were lost to follow-up. Mean age was 57.2 (SD 8.0) years in the AA group and 57.8 (SD 7.9) years in the MO group. Primary and secondary outcome measures significantly improved in both groups postoperatively. Overall mean primary and secondary postoperative outcome scores did not statistically significantly differ between the treatment groups (DASH between-group mean difference: -3.4; 95% confidence interval [CI], -10.2 to 3.4; P = .317). However, at the 6-week follow-up, DASH score, VAS-pain and -impairment, and active forward flexion were significantly more improved in the AA group than in the MO group. A retear was seen in 8 patients (17%) in the AA group and 6 patients (13%) in the MO group. Five patients in the AA group (11%) and 6 patients (13%) in the MO group developed adhesive capsulitis. CONCLUSIONS: Functional outcome, pain, range of motion, and complications do not significantly differ between patients treated with all-arthroscopic repair and those treated with mini-open repair in the first year after surgery. Patients do attain the benefits of treatment somewhat sooner (6 weeks) with the arthroscopic procedure. LEVEL OF EVIDENCE: Level II, randomized controlled trial without postoperative blinding.

Early proximal migration of cups is associated with late revision in THA: a systematic review and meta-analysis of 26 RSA studies and 49 survivalstudies.

BACKGROUND AND PURPOSE: The association between excessive early migration of acetabular cups and late aseptic revision has been scantily reported. We therefore performed 2 parallel systematic reviews and meta-analyses to determine the association between early migration of acetabular cups and late aseptic revision. METHODS: One review covered early migration data from radiostereometric analysis (RSA) studies, while the other focused on revision rates for aseptic loosening from long-term survival studies. Thresholds for acceptable and unacceptable migration were classified according the Swedish Hip Arthroplasty Register and the Australian National Joint Replacement Registry: < 5% revision at 10 years. RESULTS: Following an elaborate literature search, 26 studies (involving 700 cups) were included in the RSA review and 49 studies (involving 38,013 cups) were included in the survival review. For every mm increase in 2-year proximal migration, there was a 10% increase in revision rate, which remained after correction for age, sex, diagnosis, hospital type, continent, and study quality. Consequently, proximal migration of up to 0.2 mm was considered acceptable and proximal migration of 1.0 mm or more was considered unacceptable. Cups with proximal migration of between 0.2 and 1.0 mm were considered to be at risk of having revision rates higher than 5% at 10 years. INTERPRETATION: There was a clinically relevant association between early migration of acetabular cups and late revision due to loosening. The proposed migration thresholds can be implemented in a phased evidence-based introduction, since they allow early detection of high-risk cups while exposing a small number of patients.

5-year clinical and radiostereometric analysis (RSA) follow-up of 39 CUT femoral neck total hip prostheses in young osteoarthritis patients.

BACKGROUND: As the number of young patients receiving total hip arthroplasty increases, bone-saving implantations facilitating possible future revision, such as the CUT femoral neck prosthesis, are gaining importance. There have been few medium-term results reported for this prosthesis, however, and its migration pattern has not been analyzed. PATIENTS AND METHODS: 39 consecutive CUT femoral neck prostheses were implanted in 32 patients, mean age 37 (17-58) years, with symptomatic osteoarthritis and either less than 55 years of age or with an anatomic anomaly preventing implantation of a diaphyseal stem (n = 1). Patients were followed prospectively using routine clinical examination and radiostereometric analysis (RSA) at 6, 12, 26, and 52 weeks postoperatively and annually thereafter. This study evaluated the 5-year follow-up results. RESULTS: The mean Harris hip score increased from 26 (3-51) points preoperatively to 84 (66-98), 86 (55-98), and 87 (47-98) points at 3, 12, and 60 months. 3 stems were revised: 1 after luxation following excessive subsidence due to an undersized component and 2 due to persistent strong thigh pain. 5-year survival was 95% (95% CI: 87-100). Initial migration varied widely in magnitude; median total tip migration was 0.42 mm (0.09-9.4) at 6 weeks, 0.92 mm (0.18-5.9) at 1 year, and 1.10 mm (0.13-6.4) at 5 years. Even after high initial migration, stabilization was achieved in 31 of the 35 RSA-evaluable implants. 3 prostheses showed progressive continuous migration throughout the entire follow-up period, and were considered to be loose, suggesting reduced long-term survival. INTERPRETATION: Currently, we cannot recommend the CUT femoral neck prosthesis as a routine treatment option in (young) patients requiring THA. The CUT prosthesis may not reach the 90% survival benchmark at 10 years, and the prosthesis is difficult to implant. If initial stabilization is achieved, however, aseptic loosening is unlikely. A good clinical outcome was seen in the surviving prostheses. We will continue to follow this patient group.

Good diagnostic performance of early migration as a predictor of late aseptic loosening of acetabular cups: results from ten years of follow-up with Roentgen stereophotogrammetric analysis (RSA).

BACKGROUND: Excessive early migration of femoral stems following total hip arthroplasty and tibial components following total knee arthroplasty is associated with their long-term survival and allows reliable early evaluation of implant performance. However, a similar relationship involving acetabular components following hip arthroplasty has not been evaluated. This prospective, long-term study with clinical and Roentgen stereophotogrammetric analysis (RSA) follow-up establishes the existence of this relationship and its associated diagnostic performance. METHODS: Thirty-nine consecutive patients (forty-one hips) who underwent total hip arthroplasty with a cemented Exeter stem and a cemented Exeter all-polyethylene cup had prospective clinical and RSA follow-up. Patients were evaluated postoperatively at six weeks, at three, six, and twelve months, and annually thereafter. Conventional anteroposterior and lateral radiographs were made at six weeks and at two, five, and ten years postoperatively as well as when indicated. The mean duration of follow-up (and standard deviation) was 9.4 ± 3.2 years. No patients were lost to follow-up; fifteen patients died during the follow-up period. RESULTS: Eleven acetabular components were observed to be loose on conventional radiographs after a mean of seventy-six months (range, twelve to 140 months). During the first two postoperative years, the failed acetabular components showed markedly greater and more rapid cranial translation and sagittal rotation. Both cranial translation (hazard ratio = 19.9 [95% confidence interval, 4.94 to 80.0], p < 0.001) and sagittal rotation (hazard ratio = 11.1 [95% confidence interval, 2.83 to 43.9], p = 0.001) were strong risk factors for late aseptic loosening. Eight of the eleven failed components showed a distinctive pattern of excessive cranial translation combined with excessive sagittal rotation. The associated diagnostic performance of two-year cranial translation and/or sagittal rotation for predicting late aseptic loosening of the acetabular component was good (area under the receiver operating characteristic curve, 0.88 [95% confidence interval, 0.74 to 1.00; p < 0.001] and 0.84 [95% confidence interval, 0.68 to 1.00; p = 0.001], respectively). CONCLUSIONS: Early migration, as measured by RSA at two years postoperatively, has good diagnostic capabilities for the detection of acetabular components at risk for future aseptic loosening, and this method appears to be an appropriate means of assessing the performance of new implants or implant-related changes.

RSA prediction of high failure rate for the uncoated Interax TKA confirmed by meta-analysis.

BACKGROUND AND PURPOSE: In a previous radiostereometric (RSA) trial the uncoated, uncemented, Interax tibial components showed excessive migration within 2 years compared to HA-coated and cemented tibial components. It was predicted that this type of fixation would have a high failure rate. The purpose of this systematic review and meta-analysis was to investigate whether this RSA prediction was correct. MATERIALS AND METHODS: We performed a systematic review and meta-analysis to determine the revision rate for aseptic loosening of the uncoated and cemented Interax tibial components. RESULTS: 3 studies were included, involving 349 Interax total knee arthroplasties (TKAs) for the comparison of uncoated and cemented fixation. There were 30 revisions: 27 uncoated and 3 cemented components. There was a 3-times higher revision rate for the uncoated Interax components than that for cemented Interax components (OR = 3; 95% CI: 1.4-7.2). INTERPRETATION: This meta-analysis confirms the prediction of a previous RSA trial. The uncoated Interax components showed the highest migration and turned out to have the highest revision rate for aseptic loosening. RSA appears to enable efficient detection of an inferior design as early as 2 years postoperatively in a small group of patients.