National Joint Registry Research Articles

REOPERATION-FREE SURVIVAL OF COMMON FEMORAL STEM TYPES IN PRIMARY TOTAL HIP ARTHROPLASTY FROM A LARGE NATIONAL DATASET: TIME TO RETHINK GIRFT GUIDANCE? A NATIONAL COHORT STUDY USING AN INTEGRATED NATIONAL JOINT REGISTRY AND HES DATASET

Current advice regarding implant choice is based on estimates of cost-benefit derived from implant survival to an endpoint of revision. Current estimates do not account for many implant failures which are treated with non-revision surgery and may not be accurate. The aim of this study was to estimate survival of major stem implant design groups to an endpoint of reoperation.Primary total hip replacement and linked revision form the National Joint Registry (NJR) and Hospital Episode Statistics (HES) data linked by unique identifier were used. Survival of femoral implant groups (cemented stainless steel polished taper [PTSS], cemented cobalt chrome polished taper [PTCC], cemented composite beam [CB], collarless cementless [NCOL] and collared cementless [COL]) was estimated using Kaplan-Meier method.809,832 patients with valid NJR and HES data from England, were included. Cumulative failure at ten years for PTSS increased overall from 2.9% (95%CI 2.8–2.9) to 3.6% (95%CI 3.6–3.7) after inclusion of reoperations. Cumulative failure at ten years for PTSS increased from 2.5% (95%CI 2.5–2.6) to 3.3% (95%CI 3.2–3.4), for PTCC increased from 3.8% (95%CI 3.5–4.0) to 5.4% (95%CI 5.1–5.6), for CB increased from 3.1% (95%CI 2.9–3.3) to 4.1% (95%CI 3.8–4.3), for NCOL increased from 3.4% (95%CI 3.3–3.5) to 3.9% (95%CI 3.8–4.0), and for COL increased from 2.5% (95%CI 2.4–2.6) to 3.1% (95%CI 2.9–3.2), after inclusion of reoperations.Re-operation for internal fixation is as significant life event for the patient as revision. When a more inclusive metric is used, the patient and clinician's perspective on what constitutes a GIRFT implant may not be the same. Further work is required to update implant selection guidance in view of the change in implant performance.

Revision rate in metal compared to ceramic humeral head total shoulder arthroplasty and hemiarthroplasty.

Metal and ceramic humeral head bearing surfaces are available choices in anatomical shoulder arthroplasties. Wear studies have shown superior performance of ceramic heads, however comparison of clinical outcomes according to bearing surface in total shoulder arthroplasty (TSA) and hemiarthroplasty (HA) is limited. This study aimed to compare the rates of revision and reoperation following metal and ceramic humeral head TSA and HA using data from the National Joint Registry (NJR), which collects data from England, Wales, Northern Ireland, Isle of Man and the States of Guernsey. NJR shoulder arthroplasty records were linked to Hospital Episode Statistics and the National Mortality Register. TSA and HA performed for osteoarthritis (OA) in patients with an intact rotator cuff were included. Metal and ceramic humeral head prostheses were matched within separate TSA and HA groups using propensity scores based on 12 and 11 characteristics, respectively. The primary outcome was time to first revision and the secondary outcome was non-revision reoperation. A total of 4,799 TSAs (3,578 metal, 1,221 ceramic) and 1,363 HAs (1,020 metal, 343 ceramic) were included. The rate of revision was higher for metal compared with ceramic TSA, hazard ratio (HR) 3.31 (95% confidence interval (CI) 1.67 to 6.58). At eight years, prosthesis survival for ceramic TSA was 98.7% (95% CI 97.3 to 99.4) compared with 96.4% (95% CI 95.2 to 97.3) for metal TSA. The majority of revision TSAs were for cuff insufficiency or instability/dislocation. There was no significant difference in the revision rate for ceramic compared with metal head HA (HR 1.33 (95% CI 0.76 to 2.34)). For ceramic HA, eight-year prosthetic survival was 92.8% (95% CI 86.9 to 96.1), compared with 91.6% (95% CI 89.3 to 93.5) for metal HA. The majority of revision HAs were for cuff failure. The rate of all-cause revision was higher following metal compared with ceramic humeral head TSA in patients with OA and an intact rotator cuff. There was no difference in the revision rate for HA according to bearing surface.

Reverse total shoulder replacement versus anatomical total shoulder replacement for osteoarthritis: population based cohort study using data from the National Joint Registry and Hospital Episode Statistics for England

ObjectivesTo answer a national research priority by comparing the risk-benefit and costs associated with reverse total shoulder replacement (RTSR) and anatomical total shoulder replacement (TSR) in patients having elective primary...

Cementless total knee arthroplasty in young patients using tantalum trabecular implants results in significantly lower rates of aseptic loosening.

The mean age of patients undergoing total knee arthroplasty (TKA) has reduced with time. Younger patients have increased expectations following TKA. Aseptic loosening of the tibial component is the most common cause of failure of TKA in the UK. Interest in cementless TKA has re-emerged due to its encouraging results in the younger patient population. We review a large series of tantalum trabecular metal cementless implants in patients who are at the highest risk of revision surgery. A total of 454 consecutive patients who underwent cementless TKA between August 2004 and December 2021 were reviewed. The mean follow-up was ten years. Plain radiographs were analyzed for radiolucent lines. Patients who underwent revision TKA were recorded, and the cause for revision was determined. Data from the National Joint Registry for England, Wales, Northern Island, the Isle of Man and the States of Guernsey (NJR) were compared with our series. No patients in our series had evidence of radiolucent lines on their latest radiological assessment. Only eight patients out of 454 required revision arthroplasty, and none of these revisions were indicated for aseptic loosening of the tibial baseplate. When compared to data from the NJR annual report, Kaplan-Meier estimates from our series (2.94 (95% confidence interval (CI) 1.24 to 5.87)) show a significant reduction in cumulative estimates of revision compared to all cemented (4.82 (95% CI 4.69 to 4.96)) or cementless TKA (5.65 (95% CI 5.23 to 6.10)). Our data (2.94 (95% CI 1.24 to 5.87)) also show lower cumulative revision rates compared to the most popular implant (PFC Sigma Cemented Knee implant fixation, 4.03 (95% CI 3.75 to 4.33)). The prosthesis time revision rate (PTIR) estimates for our series (2.07 (95% CI 0.95 to 3.83)) were lower than those of cemented cases (4.53 (95% CI 4.49 to 4.57)) from NJR. The NexGen trabecular (tantalum) cementless implant has lower revision rates in our series compared to all cemented implants and other types of cementless implants, and its use in younger patients should be encouraged.

A review of the New Zealand National Joint Registry to evaluate the survivorship and revision rates of Nexel and Coonrad-Morrey total elbow arthroplasty

BackgroundTotal elbow arthroplasty (TEA) is an appropriate surgical treatment option for a variety of conditions ranging from inflammatory arthritis to trauma. Due to a high complication profile, implant companies have attempted to improve patient outcomes with evolving design mechanics and philosophy. However, the Nexel TEA prosthesis has been criticized for its unacceptably high revision rate by other research groups in the literature. The purpose of this study was to evaluate the survivorship and revision rates of the Nexel and Coonrad-Morrey total elbow arthroplasty implant systems in New Zealand. MethodsProspectively collected national joint registry data was used to compare the survival rates of these prostheses. Underlying diagnoses, reasons for revision, and patient demographics were all recorded. Statistical analysis included survival analysis using Kaplan-Meier curves and comparison between groups using independent t-tests. ResultsOver the 23-year study interval, the Nexel and Coonrad-Morrey prostheses showed similar survivorship and revision rates. The revision rates at 5 years were 7.3% for ZN and 4.5% for the Coonrad-Morrey cohorts. The average time to revision for those who are revised was 3.13 ± 1.74 years in the Nexel group and 4.93 ± 4.13 years in the Coonrad-Morrey population. ConclusionOur study confirms a lower revision rate of the Nexel TEA compared to other studies in the literature. Additionally, the Nexel TEA implant performs comparably to its predecessor, the Coonrad-Morrey prosthesis in New Zealand. While it is difficult to explain the discrepancy in results with the study by Morrey et. al, future studies should focus on investigating postoperative radiographs and a deep analysis of the specific surgical technique used for this implant.

Mid-term results of an anatomic total knee replacement design.

A significant proportion of patients remain dissatisfied following total knee arthroplasty (TKA) surgery. Reasons for this are unclear. Contemporary implants seek to mirror innate anatomy. Such innovations are necessarily subject to scrutiny to validate their use. The Zimmer-Biomet Persona® Personalized Knee system is such an anatomic TKA. This work seeks to establish medium term survival data and patient reported outcomes for this implant. This was a cohort study of prospectively collected data on all patients undergoing Persona TKA at our institution. Patients were managed using a standardised protocol for intra- and post-operative care. Survivorship data were collected using our National Joint Registry and corroborated with local data. Range of motion, Oxford Knee Score (OKS) and patient satisfaction were recorded at six weeks and one year post-operatively. Hip-knee-ankle radiographs were used to record pre- and post-operative alignment. Data were collected for 749 knees in 679 patients. Overall survivorship was 99.0% at a mean 5.35years, with seven patients undergoing revision surgery during the study period. Significant improvements in the OKS (mean 20.7 points) and range of motion were observed (mean 104.6° at one year). 94.9% of patients were satisfied at one year. Mean correction was to a mechanical femoro-tibial angle of 0.8° varus. We demonstrate excellent medium term survival of the Persona TKA in this large cohort, coupled with improvements in patient reported outcomes, range of motion and patient satisfaction at one year which compare favourably to other implants.

Patient-reported outcomes following total shoulder arthroplasty and hemiarthroplasty: an analysis of data from the National Joint Registry

IntroductionTotal shoulder arthroplasty (TSA) and hemiarthroplasty (HA) are used in the management of end stage glenohumeral arthritis. Improvement in shoulder function and resolution of symptoms are high priorities for patients. The aim of this study was to compare patient-reported outcome measures (PROMs) following TSA and HA. MethodRecords from the National Joint Registry of England, Wales, Northern Ireland and the Isle of Man were linked to the PROMs dataset. The study included anatomical shoulder arthroplasties performed for osteoarthritis in patients with an intact rotator cuff. Patients with preoperative and postoperative Oxford Shoulder Scores (OSSs) were included. The improvement in OSS at 6 months and 5 years, and the trend in scores over time were analyzed for each prosthesis. A cohort of 2,002 patients were matched on 10 variables using propensity scores. OSSs at 6 months following TSA versus HA were compared in the matched sample. ResultsThere was a significant improvement in the OSS in both groups (p<0.001). At 6 months the OSSs were superior following TSA compared to HA (median 42 vs 36, p<0.001). The median score at 5 years was 44 following TSA and 35 following HA. Score distributions were skewed towards the maximum score. The highest possible score (48) was achieved in 28% (134/478) of TSAs and 9% (20/235) of HAs at 5 years. The improvement in the preoperative to 6-month OSS reached the minimal clinically important difference of 5.5 in 92% (1653/1792) of TSAs and 80% (416/523) of HAs. At 5 years this improvement was maintained in 91% (339/374) of TSAs and 78% (136/174) of HAs. ConclusionTSA resulted in superior OSSs at 6 months in patients with osteoarthritis. The median OSS improved from 6 months to 5 years following TSA, however there was a small decline in scores following HA. A ceiling effect was shown in the OSS following TSA at 5 years.

Is American Joint Replacement Registry Data Consistent With International Survivorship in Hip and Knee Arthroplasty? A Comparative Analysis

BackgroundIn collaboration with the Orthopedic Data Evaluation Panel (ODEP), the American Joint Replacement Registry (AJRR) investigated the consistency of hip and knee arthroplasty survivorship results compared to the UK National Joint Registry (NJR). MethodsA total of three primary knee devices and three primary hip devices were selected by AJRR and ODEP with known variation in performance. Implant manufacturers independently produced Kaplan Meier survivorship based on NJR data and submitted to ODEP for comparison. The AJRR mirrored the methodology, and results from both sources were stratified into three cohorts (all-age, < 65, and ≥ 65 years). ResultsThere were 42,671 AJRR and 60,439 NJR primary knee cases and 70,169 AJRR and 422,657 NJR primary total hip arthroplasty cases. For TKA, performance between the AJRR and NJR were consistent, showing similar trends for comparatively high and low performing devices. Both PS and CR devices showed statistical agreement in survivorship for all 3 cohorts. Unicompartmental comparison also showed statistical agreement for the Medicare cohort. The all-age and < 65-year-old cohorts showed similar trends and reached statistical agreement through 7 and 6 years. For total hip arthroplasty, performance between the AJRR and NJR were consistent, showing similar trends for comparatively high and low performing devices; 0.18% average difference in survivorship at final follow-up (8 years). One femoral device did not reach statistical agreement but showed only 0.61% difference in survivorship. The remaining acetabular and femoral devices reached statistical agreement in all-ages and through 7 and 8 years in the ≥ 65-year-old cohort. ConclusionsAJRR and NJR performance trends and survivorship were similar across hip and knee arthroplasty with greatest consistency in the all-age and ≥ 65 cohorts. This focused comparison of survivorship showed encouraging results for reliability of patient outcomes in AJRR compared to the world’s largest joint arthroplasty registry which has strong implications for global improvement in patient safety.

A Comparison of the Periprosthetic Fracture Rate of Cemented and Cementless Mobile Bearing Unicompartmental Knee Arthroplasties: An Analysis of Data From the National Joint Registry for England, Wales, Northern Ireland, and the Isle of Man

BackgroundPeriprosthetic fractures are rare but serious complications of unicompartmental knee arthroplasty (UKA). Although cementless UKA has a lower risk of loosening than cemented, there are concerns that tibial fracture risk may be higher given the reliance on interference fit for primary stability. The risk of fracture and the effect of surgical fixation are currently unknown. We compared the periprosthetic fracture rate following cemented and cementless UKA surgery. MethodsA total of 14,122 medial mobile-bearing UKAs (7,061 cemented and 7,061 cementless) from the National Joint Registry and Hospital Episodes Statistics database were propensity score-matched. Cumulative fracture rates were calculated and Cox regressions were used to compare fixation groups. ResultsThe three-month periprosthetic fracture rates were similar (P = .80), being 0.10% in the cemented group and 0.11% in the cementless group. The fracture rates were highest during the first three months postoperatively, but then decreased and remained constant between one and 10 years after surgery. The one-year cumulative fracture rates were 0.2% (confidence interval [CI]: 0.1 to 0.3) for cemented and 0.2% (CI: 0.1 to 0.3) for cementless cases. The 10-year cumulative fracture rates were 0.8% (CI: 0.2 to 1.3) and 0.8% (CI: 0.3 to 1.3), respectively. The hazard ratio during the whole study period was 1.06 (CI: 0.64 to 1.77; P = .79). ConclusionsThe periprosthetic fracture rate following mobile bearing UKA surgery is low, being about 1% at 10 years. There were no significant differences in fracture rates between cemented and cementless implants after matching. We surmise that surgeons are aware of the higher theoretical risk of early fracture with cementless components and take care with tibial preparation. Levels of evidenceIII.

Increasing Use of Total Wrist Arthroplasty-An Australian National Joint Registry Report.

Background and Purpose There is limited literature reporting the long-term results and outcomes of total wrist arthroplasty (TWA). The aim of this study was to describe the incidence, usage, and survival of wrist arthroplasty using data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). Methods Data included all primary TWA procedures from 2006 to 2021. The primary outcome assessed was revision surgery. Utilization of TWA, etiology leading to TWA, patient demographics, and surgical factors were also assessed. Results There were 439 primary TWA procedures performed across the 16-year reporting period. Four prostheses (Motec, Universal 2, Freedom, and ReMotion) have been used, with a recent increased usage toward the Motec, which accounted for 97.4% of prostheses implanted in 2021. There has also been an increase in the number of surgeons performing TWA over time. The most common underlying etiology was osteoarthritis (72.7%), followed by rheumatoid arthritis (15.9%). Implantation for inflammatory arthropathy remained relatively constant across time; however, TWA has been utilized with increasing frequency for the treatment of osteoarthritis and other indications more recently. The cumulative percent revision at 10 years was 18.3%. Loosening accounted for 25.6% of all revisions, followed by osteolysis (12.8%), pain (12.8%), and instability (7.7%). Attempted conversion to an arthrodesis occurred in 10.3% of all revisions. Conclusion There has been an increase in both the volume of TWA performed and the number of surgeons undertaking this procedure in Australia over the past 16 years. The Motec system has become the prosthesis of choice. Medium-term revision rates are inferior when compared with Australian data for hip, knee, and shoulder arthroplasty.

The risk of revision is higher following shoulder hemiarthroplasty compared with total shoulder arthroplasty for osteoarthritis: a matched cohort study of 11,556 patients from the National Joint Registry, UK.

Total shoulder arthroplasty (TSA) and hemiarthroplasty (HA) are used in the management of osteoarthritis of the glenohumeral joint. We aimed to determine whether TSA or HA resulted in a lower risk of adverse outcomes in patients of all ages with osteoarthritis and an intact rotator cuff and in a subgroup of patients aged 60 years or younger. Shoulder arthroplasties recorded in the National Joint Registry, UK, between April 1, 2012 and June 30, 2021, were linked to Hospital Episode Statistics in England. Elective TSAs and HAs were matched on propensity scores based on 11 variables. The primary outcome was all-cause revision. Secondary outcomes were combined revision/non-revision reoperations, 30-day inpatient complications, 1-year mortality, and length of stay. 95% confidence intervals (CI) were reported. 11,556 shoulder arthroplasties were included: 7,641 TSAs, 3,915 HAs. At 8 years 95% (CI 94-96) of TSAs and 91% (CI 90-92) of HAs remained unrevised. The hazard ratio (HR) varied across follow-up: 4-year HR 2.7 (CI 1.9-3.5), 8-year HR 2.0 (CI 0.5-3.5). Rotator cuff insufficiency was the most common revision indication. In patients aged 60 years or younger prosthesis survival at 8 years was 92% (CI 89-94) following TSA and 84% (CI 80-87) following HA. The risk of revision was higher following HA in patients with osteoarthritis and an intact rotator cuff. Patients aged 60 years and younger had a higher risk of revision following HA.

Supporting Regional Upper Limb Arthroplasty: The Impact of Establishing an Upper Limb Orthopaedic Network

Background and Objectives The management of complex upper limb arthroplasty has received national guidelines supporting the use of a regional network. An upper limb network was established for both elbow and shoulder arthroplasty. This study evaluates the impact of establishing this network over a 5-year period. Methods Data were collected from network meetings from June 2017 to December 2022. Hospital-level National Joint Registry data were obtained for analysis of case volume. Results A total of 243 cases were discussed. Network discussion changed the management plan in 53% of cases. Only 8% of cases required transfer to the tertiary center. The proportional caseload at either hub or spoke hospitals did not change after creation of the network. Discussion Regional network discussion aids decision-making for complex cases, with further management options realized in over half of the cases presented. The discussion allowed every patient to gain the advantage of regional expertise while being managed conveniently at their local hospital.

Severe obesity in total knee arthroplasty occurs in younger patients with a greater healthcare burden and complication rate

BackgroundKnee osteoarthritis in the presence of severe obesity (BMI ≥ 40) is becoming an increasing presentation to healthcare services. When progressing to arthroplasty, this group is known to have higher complication rates. MethodA retrospective cohort study at a tertiary referral centre (UK) with all sequential patients undergoing TKA between 2019 and 2020 included following identification from the UK National Joint Registry. Patients were divided by BMI < 40 and BMI ≥ 40 (86, 16.3%). Analysis of BMI with pre-operative parameters including age, ASA, and blood parameters was performed. Primary outcome was re-operation rate. Secondary outcomes included length of stay, complications, and re-admission. ResultsFive hundred and twenty-eight sequential TKA patients were included. The BMI < 40 group (442 patients, 83.7%) were mean 5.4 years younger (p < 0.001), had a higher ASA grade (p < 0.001) lower albumin (p < 0.001) and higher HbA1c (p < 0.001) than the BMI ≥ 40 group (86 patients, 16.3%). The BMI ≥ 40 group had a higher rate of re-operation (8% vs 2%, p = 0.012), and longer length of stay (mean 1.2 days longer p < 0.001), most commonly due to wound discharge, which alongside dehiscence was significantly higher (11.6% vs 4.3% p = 0.02). Overall, re-admission rates were also higher (18.6% vs 6.1% p = 0.06) with wound dehiscence, superficial infection, and deep infection the most common causes. ConclusionsThose patients undergoing TKA with a BMI ≥ 40 are younger and have higher reoperation rates, greater length of stay, higher re-admission rates and more postoperative complications, providing a target for the development of pre-operative optimisation programmes.

A Comparison of the Periprosthetic Fracture Rate of Cemented and Cementless Total Knee Arthroplasties: An Analysis of Data From the National Joint Registry

BackgroundPeriprosthetic fractures are serious complications of knee arthroplasty often requiring complex surgery. There is concern of increased periprosthetic fracture risk with cementless components given the reliance on interference fit for primary stability. It is unknown how the periprosthetic fracture risk compares between cemented and cementless total knee arthroplasties (TKAs). MethodsA total of 22,477 cemented and 22,477 cementless TKAs from the National Joint Registry and Hospital Episodes Statistics database were propensity score matched on patient and surgical factors. Cumulative periprosthetic fracture rates were calculated using Kaplan-Meier analyses and compared with Cox regressions. Subgroup analyses were performed in different age, body mass index, and sex groups. ResultsThe 3-month fracture rate in the cemented and cementless TKA groups were 0.02% and 0.04%, respectively. At 10 years, the cumulative fracture rate after cemented TKA was 1.2%, and after cementless was 1.4%. During the study period, there were no significant differences in fracture rates between cemented and cementless TKAs with a hazards ratio 1.14 (confidence interval 0.94 to 1.37, P = .20) at 10 years postoperatively. There were no significant differences in fracture rates between fixation types on subgroup analyses of sex, body mass index, and age groups. Female sex was a risk factor for fracture in both cemented (odds ratio 2.35, P < .001) and cementless TKAs (odds ratio 2.97, P < .001). ConclusionsThe periprosthetic fracture rates following cemented and cementless TKA surgery are low being approximately 1.2% and 1.4%, respectively at 10 years. There were no significant differences in periprosthetic fracture rates requiring readmission between cemented and cementless TKAs. Level of evidenceIII.

Knee

The December 2023 Knee Roundup360 looks at: Obesity is associated with greater improvement in patient-reported outcomes following primary total knee arthroplasty; Does mild flexion of the femoral prosthesis in total knee arthroplasty result in better early postoperative outcomes?; Robotic or manual total knee arthroplasty: a randomized controlled trial; Patient-relevant outcomes following first revision total knee arthroplasty, by diagnosis: an analysis of implant survivorship, mortality, serious medical complications, and patient-reported outcome measures using the National Joint Registry data set; Sagittal alignment in total knee arthroplasty: are there any discrepancies between robotic-assisted and manual axis orientation?; Tourniquet use does not impact recovery trajectory in total knee arthroplasty; Impact of proximal tibial varus anatomy on survivorship after medial unicondylar knee arthroplasty; Bone cement directly to the implant in primary total knee arthroplasty?; Maintaining joint line obliquity optimizes outcomes in patients with constitutionally varus knees.

Early- to Mid-Term Review of a Prospective, Multi-Center, International, Outcomes Study of an Anatomically Designed Implant with Posterior-Stabilized Bearing in Total Knee Arthroplasty.

Background and Objectives: National joint registries report higher total knee arthroplasty (TKA) revision rates in posterior-stabilized (PS) systems compared to non-posterior-stabilized designs. The purpose of this study was to investigate the implant survivorship and clinical outcomes of an anatomic implant with a PS bearing. Materials and Methods: An early- to mid-term follow-up of a prospective, multi-center, non-controlled outcomes study of patients who received primary TKA between November 2014 and June 2017 was performed. A total of 800 cases using PS bearings that were implanted in 664 patients were monitored post-operatively for their implant survivorship and adverse events for up to five years. The Knee Society Knee and Function scores, patient satisfaction, the five-dimensional European Quality of Life questionnaire, and range of motion (ROM) were evaluated pre-operatively and post-operatively at six weeks, six months, one year, two years, three years, and five years. Results: The mean follow-up period was 3.7 ± 1.3 years, and the three-year implant survival rate was 99.3% (95% CI: 98.4%, 99.7%) with five revisions during the five-year follow-up. Patient satisfaction was 96.1% at six weeks and increased to 99.3% at one year. All patient-reported outcome measures significantly (p < 0.0001) increased up to the one-year follow-up and then remained stable up to the five-year follow-up. Conclusions: This study supports the excellent survivorship and patient-reported outcomes of the Persona® Knee system using cemented, fixed bearing, posterior-stabilized components with minimal complications at early- to mid-term follow-up in an international Asian population. Ongoing observations are being performed to investigate the mid- to long-term survivorship and clinical outcomes associated with this knee system.

National Registry Data Analysis on a Unique Highly-Crosslinked Polyethylene for Total Hip Arthroplasty

BackgroundSeveral types of highly-crosslinked polyethylene with different manufacturing processes and mechanical properties are commercially available, including HIGHCROSS (Medacta). The aim of this registry study is to ascertain the long-term safety of the HIGHCROSS liners in total hip arthroplasty and compare the revision rates with its contemporaries using real-world data to establish their safety and generalizability when used by multiple surgeons. MethodsThe Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) and the Swiss National Joint Registry (SIRIS) were selected for the large number of users of Medacta implants and the availability of long-term results. Three reports from SIRIS and 4 reports from AOANJRR were examined to establish the overall and Kaplan-Meier (KM) cumulative revision rate. ResultsAccording to SIRIS, the HIGHCROSS liner was the most commonly used bearing surface with Medacta stems with overall revision rates for wear/osteolysis at 9.7 years of 0.04% and 0.03%, respectively, for AMIStem and Quadra. Based on AOANJRR, the KM cumulative revision rate for any reason of Medacta stems with HIGHCROSS liners was lower than that with ceramic liners at 3 years for MasterLoc and at 10 years for Quadra. The KM cumulative revision rate for any reasons of Medacta cementless cups with HIGHCROSS liners at 12 years was lower than the comparator made of all other implants and tribological couplings (1.6% vs 2.1%). ConclusionsThis real-world data proves that long-term HIGHCROSS survival rates are comparable to other modern bearing surfaces.

RISK OF REVISION FOLLOWING TOTAL HIP AND KNEE ARTHROPLASTY PERFORMED USING COMPUTER-ASSISTED TECHNOLOGIES VERSUS CONVENTIONAL TECHNIQUE: AN ANALYSIS OF NATIONAL JOINT REGISTRY DATA

AbstractIntroductionComponent mal-positioning in total hip replacement (THR) and total knee replacement (TKR) can increase the risk of revision for various reasons. Compared to conventional surgery, relatively improved accuracy of implant positioning can be achieved using computer assisted technologies including navigation, patient-specific jigs, and robotic systems. However, it is not known whether application of these technologies has improved prosthesis survival in the real-world. This study aimed to compare risk of revision for all-causes following primary THR and TKR, and revision for dislocation following primary THR performed using computer assisted technologies compared to conventional technique.MethodsWe performed an observational study using National Joint Registry data. All adult patients undergoing primary THR and TKR for osteoarthritis between 01/04/2003 to 31/12/2020 were eligible. Patients who received metal-on-metal bearing THR were excluded. We generated propensity score weights, using Sturmer weight trimming, based on: age, gender, ASA grade, side, operation funding, year of surgery, approach, and fixation. Specific additional variables included position and bearing for THR and patellar resurfacing for TKR. For THR, effective sample sizes and duration of follow up for conventional versus computer-guided and robotic-assisted analyses were 9,379 and 10,600 procedures, and approximately 18 and 4 years, respectively. For TKR, effective sample sizes and durations of follow up for conventional versus computer-guided, patient-specific jigs, and robotic-assisted groups were 92,579 procedures over 18 years, 11,665 procedures over 8 years, and 644 procedures over 3 years, respectively. Outcomes were assessed using Kaplan-Meier analysis and expressed using hazard ratios (HR) and 95% confidence intervals (CI).ResultsFor THR, analysis comparing computer-guided versus conventional technique demonstrated HR of 0.771 (95%CI 0.573–1.036) p=0.085, and 0.594 (95%CI 0.297–1.190) p=0.142, for revision for all-causes and dislocation, respectively. When comparing robotic-assisted versus conventional technique, HR for revision for all-causes was 0.480 (95%CI 0.067 –3.452) p=0.466. For TKR, compared to conventional surgery, HR for all-cause revision for procedures performed using computer guidance and patient-specific jigs were 0.967 (95% CI 0.888–1.052) p=0.430, and 0.937 (95% CI 0.708–1.241) p=0.65, respectively. HR for analysis comparing robotic-assisted versus conventional technique was 2.0940 (0.2423, 18.0995) p = 0.50.ConclusionsThis is the largest study investigating this topic utilising propensity score analysis methods. We did not find a statistically significant difference in revision for all-causes and dislocation although these analyses are underpowered to detect smaller differences in effect size between groups. Additional comparison for revision for dislocation between robotic-assisted versus conventionally performed THR was not performed as this is a subset of revision for all-causes and wide confidence intervals were already observed for that analysis. It is also important to mention this NJR analysis study is of an observational study design which has inherent limitations. Nonetheless, this is the most feasible study design to answer this research question requiring use of a large data set due to revision being a rare outcome.Declaration of Interest(b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Survivorship and risk factors for revision of metal-on-metal hip resurfacing.

Metal-on-metal hip resurfacing (MoM-HR) has seen decreased usage due to safety and longevity concerns. Joint registries have highlighted the risks in females, smaller hips, and hip dysplasia. This study aimed to identify if reported risk factors are linked to revision in a long-term follow-up of MoM-HR performed by a non-designer surgeon. A retrospective review of consecutive MoM hip arthroplasties (MoM-HRAs) using Birmingham Hip Resurfacing was conducted. Data on procedure side, indication, implant sizes and orientation, highest blood cobalt and chromium ion concentrations, and all-cause revision were collected from local and UK National Joint Registry records. A total of 243 hips (205 patients (163 male, 80 female; mean age at surgery 55.3 years (range 25.7 to 75.3)) with MoM-HRA performed between April 2003 and October 2020 were included. Mean follow-up was 11.2 years (range 0.3 to 17.8). Osteoarthritis was the most common indication (93.8%), and 13 hips (5.3%; 7M:6F) showed dysplasia (lateral centre-edge angle < 25°). Acetabular cups were implanted at a median of 45.4° abduction (interquartile range 41.9° - 48.3°) and stems neutral or valgus to the native neck-shaft angle. In all, 11 hips (4.5%; one male, ten females) in ten patients underwent revision surgery at a mean of 7.4 years (range 2.8 to 14.2), giving a cumulative survival rate of 94.8% (95% confidence interval (CI) 91.6% to 98.0%) at ten years, and 93.4% (95% CI 89.3% to 97.6%) at 17 years. For aseptic revision, male survivorship was 100% at 17 years, and 89.6% (95% CI 83.1% to 96.7%) at ten and 17 years for females. Increased metal ion levels were implicated in 50% of female revisions, with the remaining being revised for unexplained pain or avascular necrosis. The Birmingham MoM-HR showed 100% survivorship in males, exceeding the National Institute for Health and Care Excellence '5% at ten years' threshold. Female sex and small component sizes are independent risk factors. Dysplasia alone is not a contraindication to resurfacing.

Survival of revision ankle arthroplasty.

The number of revision total ankle arthroplasties (TAAs) which are undertaken is increasing. Few studies have reported the survival after this procedure. The primary aim of this study was to analyze the survival of revision ankle arthroplasties using large datasets. Secondary aims were to summarize the demographics of the patients, the indications for revision TAA, further operations, and predictors of survival. The study combined data from the National Joint Registry and NHS Digital to report the survival of revision TAA. We have previously reported the failure rates and risk factors for failure after TAA, and the outcome of fusion after a failed TAA, using the same methodology. Survival was assessed using life tables and Kaplan Meier graphs. Cox proportional hazards regression models were fitted to compare failure rates. A total of 228 patients underwent revision TAA. The mean follow-up was 2.6 years (SD 2.0). The mean time between the initial procedure and revision was 2.3 years (SD 1.8). The most commonly used implant was the Inbone which was used in 81 patients. A total of 29 (12.7%) failed; nine (3.9%) patients underwent a further revision, 19 (8.3%) underwent a fusion, and one (0.4%) had an amputation. The rate of survival was 95.4% (95% confidence interval (CI) 91.6 to 97.5) at one year, 87.7% (95% CI 81.9 to 91.7; n = 124) at three years and 77.5% (95% CI 66.9 to 85.0; n = 57) at five years. Revision-specific implants had a better survival than when primary implants were used at revision. A total of 50 patients (21.9%) had further surgery; 19 (8.3%) underwent reoperation in the first 12 months. Cox regression models were prepared. In crude analysis the only significant risk factors for failure were the use of cement (hazard ratio (HR) 3.02 (95% CI 1.13 to 8.09)) and the time since the primary procedure (HR 0.67 (95% CI 0.47 to 0.97)). No risk factors for failure were identified in multivariable Cox regression modelling. Revision TAAs have good medium term survival and low rates of further surgery. New modular revision implants appear to have improved the survival compared with the use of traditional primary implants at revision.