Aims. To explore the novel molecular mechanisms of histone deacetylase 4 (HDAC4) in chondrocytes via RNA sequencing (RNA-seq) analysis. Methods. Empty adenovirus (EP) and a HDAC4 overexpression adenovirus were transfected into cultured human chondrocytes. The cell survival rate was examined by real-time cell analysis (RTCA) and EdU and flow cytometry assays. Cell biofunction was detected by Western blotting. The expression profiles of messenger RNAs (mRNAs) in the EP and HDAC4 transfection groups were assessed using whole-transcriptome sequencing (RNA-seq). Volcano plot, Gene Ontology, and pathway analyses were performed to identify differentially expressed genes (DEGs). For verification of the results, the A289E/S246/467/632 A sites of HDAC4 were mutated to enhance the function of HDAC4 by increasing HDAC4 expression in the nucleus. RNA-seq was performed to identify the molecular mechanism of HDAC4 in chondrocytes. Finally, the top ten DEGs associated with ribosomes were verified by quantitative polymerase chain reaction (QPCR) in chondrocytes, and the top gene was verified both in vitro and in vivo. Results. HDAC4 markedly improved the survival rate and biofunction of chondrocytes. RNA-seq analysis of the EP and HDAC4 groups showed that HDAC4 induced 2,668 significant gene expression changes in chondrocytes (1,483 genes upregulated and 1,185 genes downregulated, p < 0.05), and ribosomes exhibited especially large increases. The results were confirmed by RNA-seq of the EP versus mutated HDAC4 groups and the validations in vitro and in vivo. Conclusion. The enhanced ribosome pathway plays a key role in the mechanism by which HDAC4 improves the survival rate and biofunction of chondrocytes. Cite this article: Bone Joint Res 2023;12(7):433–446

Abstract. Introduction. Medial fix bearing unicompartmental knee replacement (UKR) designs are consider safe and effective implants with many registries data and big cohort series showing excellent survivorship and clinical outcome comparable to that reported for the most expensive and surgically challenging medial UKR mobile bearing designs. However, whether all polyethylene tibial components (all-poly) provided comparable results to metal-backed modular components during medial fix bearing UKR remains unclear. There have been previous suggestions that all-poly tibia UKR implants might show unacceptable higher rates of early failure due to tibial component early loosening especially in high body max index (BMI) patients. This study aims to find out the short and long-term survival rate of all-poly tibia UKR and its relationship with implant thickness and patient demographics including sex, age, ASA and BMI. Material and Methods. we present the results of a series of 388 medial fixed bearing all-polly tibia UKR done in our institution by a single surgeon between 2007–2019. Results. We found out excellent implant survival with this all-poly tibia UKR design with 5 years survival rate: 96.42%, 7 years survival rate: 95.33%, and 10 years survival rate: 91.87%. Only 1.28% had early revision within 2 years. Conclusion. Fixed bearing medial all-poly tibia UKR shows excellent survivor rate at 2, 5, 7 and 10 years follow up and the survival rate is not related with sex, age, BMI, ASA grade or implant thickness. Contrary to the popular belief, we found out that only 1.71% of all implants was revised due to implant loosening

To assess the clinical features, development of metastases, and survival rate of patients with local recurrence after the resection of osteosarcoma in a large series. Five hundred and thirty (530) patients with high-grade osteosarcoma were treated between 1989 and 1998. Fifty-four patients (10%) developed local recurrence after resection and adjuvant chemotherapy. There were 38 men and 16 women with a mean age of 19 years (range 6–50). The mean follow up was 39 months (range 7–120 months). Forty-three patients (79%) had clear resection margins microscopically, while in 8 patients (15%) microscopic tumour was found at the resection margin, and contaminated excision was performed in 3 patients. Histological response was category 1 in 24% of the patients, and category 2 in 76%. Clinical features, treatment, and prognosis were analyzed. Survival rates were examined using Kaplan-Meier Analysis. The average interval between the first resection and local recurrence was 15 months (range 2–109 months). Forty-one patients (76%) had local recurrence in deep soft tissue, 7 in bone, and 6 in subcutaneous tissue. Twenty-six patients (49%) had lung metastasis at the time of local recurrence, while 21 patients (38%) developed it later. Thirty patients (57%) were treated with resection of the recurrent lesion and 18 (32%) were treated with amputation. 1-, 3-, and 5-year survival rates after local recurrence were 0.57, 0.38, and 0.22 respectively. 87% of patients with local recurrence developed metastases either concurrently or at a later date. Immediate amputation did achieve local tumor control. However, the survival rate was not statistically higher. 87% of the local recurrence arose in soft tissue. Therefore, careful attention should be paid to secure the wide margin around biopsy tract, muscle insertion to the affected bone, and neurovascular bundle at the time of initial resection

Due to well-known complications of metal-on-metal hip resurfacing arthroplasty the indication for this procedure has significantly decreased over the past years. As a high number of patients is currently living with resurfacing implants, however, there is a clear need for information about the longterm results and especially about the rate of local as well as systemic adverse effects. We retrospectively reviewed our first 95 patients who had 100 consecutive BHR hip resurfacings performed from 1998–2001. Median age at surgery was 52 years (range, 28–69 years); 49% were men. After a mean follow-up period of 16.1 years (range 15.2 – 17.6 years) we assessed survival rate (revision for any reason as endpoint), radiographic changes and patient-related outcome in patients who had not undergone revision. In addition we measured whole blood concentrations of cobalt at follow-up. 17% of our patients in the original cohort were lost to follow-up. In the remaining patients the 16-year survivorship was 80.1%. The overall survival rate was slightly higher in males (80.6%) than in females (77.1%). The WOMAC overall score showed a median value of 91.7 points (range 35.4 – 100). Median whole blood ion levels were 1.9 µg/L for cobalt (0.6 – 140.2 µg/L), 14.9% of patients showed elevated levels. The number of patients with relevant radiographic signs of local adverse reactions to metal debris was relatively low. In contrast to earlier reports and very few other longterm studies our results show an unsatisfactory performance of resurfacing. In particular the outcome of male patients deteriorated between 10 and 16 years of follow-up. Although only a small number of patients shows relevant elevation of metal-ion levels, the clinical relevance has still to be determined

The topic of this study was to research the survival rate of ATLAS hip prosthesis (acetabular cup) performed by one operating surgeon only and with a minimum of 10 years follow up. Material and method: The ATLAS cup was hemispheric, in titanium alloy TA6V4, with a thin layer (2.5mm). It had a large central orifice as well as a radial slot allowing a certain elasticity enabling a pressfit impaction. Between January 1989 and December 1995, 297 ATLAS were implanted in the Clinique Saint André of Reims, 171 ATLAS II non hydroxyapatite coated and 126 ATLAS III hydroxyapatite coated. There were 176 women (59,2%) and 121 men (40,8%). The average age was 66 (20 to 94). Each patient was contacted by phone to find out if the prosthesis was still in place or whether a new operation had been performed. For the deceased patients, the family or the usual doctor were contacted by phone to answer the question with a maximum of details. The non-parametric survival rates were performed using the actuarial method according to Kaplan-Meier. The results were given with a reliability rate of 95%. The PRISM program was used. RESULTS: On the 1st of January 2006, out of the 297 patients present at the start, 38 patients (12,8%) could not be contacted, 70 patients (23,5%) had died, 35 were reviewed and 120 answered the phone inquiry. 32 patients had undergone a revision: 23 due to the cup: there were 15 cases of wear of the polyethylene, 4 osteolysis, 3 cases of recurring dislocation and a secondary tilt of the cup, 5 cases of acetabular and femoral revision for 4 femoral loosening (change of cup by principal) and 4 cases of revision of the femoral components only. The survival rate of the global series of 297 ATLAS (coated and non coated with hydroxyapatite) taking into consideration only the revisions due to the acetabular cup (wear of polyethylene, wrong position) was evaluated at 90% after 10 years and 85,5% after 15 years. The results were better for the ATLAS III coated in hydroxyapatite: 92,3% after 10 years and 88,4% after 14 years, which confirms the advantages of this surface treatment. In this series, the revision rate for wear of the polyethylene was less important (3%). With a maximum of 17 years follow up no mobilisation of the insert in the cup had been observed and no metallosis. Conclusion: The survival rate of the global series of 297 ATLAS (coated and non coated with hydroxyapatite), taking into consideration only the revisions due to the cup (wear of the polyethylene, wrong position) was of 90% after 10 years and 85,5% after 15 years. The rate was higher for the ATLAS III coated with hydroxyapatite: 92,3% after 10 years and 88,4 % after 14 years, which confirmed the advantages of this surface treatment

In cementless Total Hip Arthroplasty (THA), some discussion persist in different continents, weather straight double tapered stems providing proximal metaphyseal fixation are preferable to more diaphyseal cylindrical fixation designs. With the objective of studying the grade of loosening of a straight double tapered stem and its survival rate, the authors analysed 257 THA with implanted Spotorno stems, followed up for a maximum of over 18 years (221 months), with an average of 110±57 months. The age of patients was 62±10 years in average, ranging from 18 to 86. Demographic data is analysed including, sex, height, weight and BMI. Main diagnosis was Primary Degenerative Osteoarthritis in 56% and Avascular Necrosis in 13% of all patients. Other diagnosis occurrence is presented, as well as the affected side, type of cup, head and stem size distributions. Clinical and functional evaluation of the THA showed Very Good and Good patient satisfaction grading in 78% of the cases and the average Harris Hip Score was 87, ranging from 49 to 98. In the Radiological evaluation, stem positioning, migration, osteolysis and distribution of radiolucent lines are quantified and described. 79 patients included in this study with 84 THA, died or were lost after a minimum of five years of complete clinical and radiological follow up. The most significant early and late complications of THA are presented and commented. THA requiring revision of the cup or stem for any cause, were 1 severe deep infection (0.4%), 4 cups loosened and migrated but not requiring revision of the stems (1.6%), 1 femoral osteolysis and loosening (0.4%) and 2 late traumatic femoral fractures (0.8%). From these, considering stem survival alone, a total of four stems (1.6%) underwent femoral revision as previously described, one due to infection, one due to loosening and two due to femoral fractures. Kaplan-Meyer cumulative survival analyses of the THA show a Spotorno stem survival rate of 98.4% at 18 years, with a confidence interval of 95%. In the experience of the authors, the Spotorno double tapered straight stem provides excellent clinical results, with high survival rate at longterm evaluation. The design of the stem allows for immediate progressive weight bearing without significant migration or thigh pain. Femoral proximal osteolysis or radiolucent lines are almost always associated with wear or loosening of the cup, that very often allow for revision of the cup without the need for revision of the stem

We have been using a Charnley type hip prosthesis with an alumina ceramic head. Three sizes of alumina head, 28, 26 and 22mm, were employed and the Ortron 90 Charnley total hip prosthesis was used at the same period. The objective of this study was to compare the survival rate and the wear rate of those four groups. There were 90, 62, 322 and 88 hips in 28, 26, 22mm alumina head and 0rtron 90 head group. Average age at operation was 49.5, 57.8, 58.0 and 60.6, respectively. A 28 mm prosthesis was indicated for relatively young patients. The mean duration of follow-up was 156, 97, 49 and 110 months, respectively. Twenty patients were chosen at random for each of four groups and the linear wear as seen on X-ray film was measured every two years with a computer and scanner. Results: The average linear wear rate (mm/yr) was 0.179 for the 28mm, 0.112 for the 26mm, 0.115 for the 22mm alumina head and 0.075 for the Ortron 90 head. The difference between the 28mm group and the other three groups was analyzed statistically. The Kaplan-Meier survivorship analysis, with revision for aseptic loosening as the endpoint, showed the survival rate of the 28mm group appeared to be inferior to that of the other three groups. Discussion: Our study showed that the wear rate of the 28mm alumina group was highest because low grade alumina was used. In addition, the polyethylene socket used for the 28mm group was thinner than that for the other groups. No clinical superiority of ceramics to metal in terms of polyethylene wear can be shown in this study. A randomized prospective study should be carried out to determine whether an alumina ceramic head is clinically superior to a metallic head in terms of polyethylene wear

We evaluated the rates of survival and cause of revision of seven different brands of cemented primary total knee replacement (TKR) in the Norwegian Arthroplasty Register during the years 1994 to 2009. Revision for any cause, including resurfacing of the patella, was the primary endpoint. Specific causes of revision were secondary outcomes. Three posterior cruciate-retaining (PCR) fixed modular-bearing TKRs, two fixed non-modular bearing PCR TKRs and two mobile-bearing posterior cruciate-sacrificing TKRs were investigated in a total of 17 782 primary TKRs. The median follow-up for the implants ranged from 1.8 to 6.9 years. Kaplan-Meier 10-year survival ranged from 89.5% to 95.3%. Cox’s relative risk (RR) was calculated relative to the fixed modular-bearing Profix knee (the most frequently used TKR in Norway), and ranged from 1.1 to 2.6. The risk of revision for aseptic tibial loosening was higher in the mobile-bearing LCS Classic (RR 6.8 (95% confidence interval (CI) 3.8 to 12.1)), the LCS Complete (RR 7.7 (95% CI 4.1 to 14.4)), the fixed modular-bearing Duracon (RR 4.5 (95% CI 1.8 to 11.1)) and the fixed non-modular bearing AGC Universal TKR (RR 2.5 (95% CI 1.3 to 5.1)), compared with the Profix. These implants (except AGC Universal) also had an increased risk of revision for femoral loosening (RR 2.3 (95% CI 1.1 to 4.8), RR 3.7 (95% CI 1.6 to 8.9), and RR 3.4 (95% CI 1.1 to 11.0), respectively). These results suggest that aseptic loosening is related to design in TKR. Cite this article: Bone Joint J 2013;95-B:636–42

Aims. The benefit of a dual-mobility acetabular component (DMC) for primary total hip arthroplasties (THAs) is controversial. This study aimed to compare the dislocation and complication rates when using a DMC compared to single-mobility (SM) acetabular component in primary elective THA using data collected at a single centre, and compare the revision rates and survival outcomes in these two groups. Methods. Between 2010 and 2019, 2,075 primary THAs using either a cementless DM or SM acetabular component were included. Indications for DMC were patients aged older than 70 years or with high risk of dislocation. All other patients received a SM acetabular component. Exclusion criteria were cemented implants, patients treated for femoral neck fracture, and follow-up of less than one year. In total, 1,940 THAs were analyzed: 1,149 DMC (59.2%) and 791 SM (40.8%). The mean age was 73 years (SD 9.2) in the DMC group and 57 years (SD 12) in the SM group. Complications and revisions have been analyzed retrospectively. Results. The mean follow-up was 41.9 months (SD 14; 12 to 134). There were significantly fewer dislocations in the DMC group (n = 2; 0.17%) compared to the SM group (n = 8; 1%) (p = 0.019). The femoral head size did not influence the dislocation rate in the SM group (p = 0.702). The overall complication rate in the DMC group was 5.1% (n = 59) and in the SM group was 6.7% (n = 53); these were not statistically different (p = 0.214). No specific complications were attributed to the use of DMCs. In the DMC group, 18 THAs (1.6%) were revised versus 15 THAs in the SM group (1.9%) (p = 0.709). There was no statistical difference for any cause of revisions in both groups. The acetabular component aseptic revision-free survival rates at five years were 98% in the DMC group and 97.3% in the SM group (p = 0.780). Conclusion. The use of a monobloc DMC had a lower risk of dislocation in a high-risk population than SM component in a low-risk population at the mid-term follow-up. There was no significant risk of component-specific complications or revisions with DMCs in this large cohort. Cite this article: Bone Joint J 2024;106-B(3 Supple A):81–88

As the surgical indications for total knee replacement (TKR) expand to include younger, heavier and more active patients, knowledge of the effect of these demographic variables on the outcome and survival of the implant is increasingly important.

Between November 1986 and September 1990, 402 patients underwent 562 primary cemented cruciate-retaining TKRs carried out by a single surgical team. The overall results showed a survival of 96.8% at 14 years with 1.44% lost to follow-up. Evaluating the demographics of these patients showed that certain groups fared significantly less well. The best results were seen in non-obese women with osteoarthritis who were over 60 years of age in whom there was ten-year survival of 99.4%. The worst results were in obese men with osteoarthritis who were less than 60 years of age in whom there was a ten-year survival of 35.7%. Caution should be exercised when considering TKR on a patient with this combination of poor risk factors.

By identifying demographic factors at the time of consultation the surgeon is better able to predict the survival of the TKR. This information is important when considering the best options for treatment of a patient and in providing accurate information during preoperative counselling.

Introduction: The ten-year survivorship of Oxford Unicompartmental Knee Arthroplasty (OUKA) has ranged from 98% in the hands of the developers to only 82–90% in reports from independent centers and national registries. This study was performed to investigate the effects of surgeon training and correct patient selection on the expected outcome of this procedure.

Methods: We created a computer-simulated joint registry consisting of 20 surgeons who performed OUKA on 1,000 patients. Mathematical models of the patient and surgeon populations and corresponding hazard functions were formulated using data from the Swedish and Australian joint registries. The long-term survivorship of UKA was assumed to average 94% at 10 years and was modeled as the product of hazard functions quantifying risk factors under the surgeon’s control, risk factors presented by the patient, and the inherent revision risk of the procedure. We performed four simulations looking at the effect of surgeon training by pairing surgeons and patients based on surgeon experience and patient risk factors.

Results: When experienced surgeons (> 40 cases) performed OUKA on low risk patients (bottom quintile), the revision rate dropped from 6.0% to 4.5%. The same surgeons had a revision rate of 7.5% when assigned to the highest risk patient group (top quintile). Conversely, when the least experienced surgeons (< 10 cases) selected the least fit patients, the revision rate increased from 6% to 8.25%. However, when these surgeons were assigned to the lowest risk group, only 5.25% of patients were revised. Taken simultaneously, these results indicate that the overall revision rate of this procedure can vary between 4.5% to 8.25%, depending upon the experience of the surgeon and the patients selected.

Conclusions:

Mathematical models of patients and surgeons can be built using joint registry data. These models can then be used in a computer simulation yielding results comparable to what has been reported in the literature.

Aims

The use of high tibial osteotomy (HTO) to delay total knee arthroplasty (TKA) in young patients with osteoarthritis (OA) and constitutional deformity remains debated. The aim of this study was to compare the long-term outcomes of TKA after HTO compared to TKA without HTO, using the time from the index OA surgery as reference (HTO for the study group, TKA for the control group).

Aims. The aim of this study was to investigate the distribution of phenotypes in Asian patients with end-stage osteoarthritis (OA) and assess whether the phenotype affected the clinical outcome and survival of mechanically aligned total knee arthroplasty (TKA). We also compared the survival of the group in which the phenotype unintentionally remained unchanged with those in which it was corrected to neutral. Methods. The study involved 945 TKAs, which were performed in 641 patients with primary OA, between January 2000 and January 2009. These were classified into 12 phenotypes based on the combined assessment of four categories of the arithmetic hip-knee-ankle angle and three categories of actual joint line obliquity. The rates of survival were analyzed using Kaplan-Meier methods and the log-rank test. The Hospital for Special Surgery score and survival of each phenotype were compared with those of the reference phenotype with neutral alignment and a parallel joint line. We also compared long-term survival between the unchanged phenotype group and the corrected to neutral alignment-parallel joint line group in patients with Type IV-b (mild to moderate varus alignment-parallel joint line) phenotype. Results. The most common phenotype was Type I-b (mild to moderate varus alignment-medial joint line; 27.1% (n = 256)), followed by Type IV-b (23.2%; n = 219). There was no significant difference in the clinical outcomes and long-term survival between the groups. In Type IV-b phenotypes, the neutrally corrected group showed higher 15-year survival compared with the unchanged-phenotype group (94.9% (95% confidence interval (CI) 92.0 to 97.8) vs 74.2% (95% CI 98.0 to 100); p = 0.020). Conclusion. Constitutional varus was confirmed in more than half of these patients. Mechanically aligned TKA can achieve consistent clinical outcomes and long-term survival, regardless of the patient’s phenotype. The neutrally corrected group had better long-term survival compared with the unchanged phenotype group. Cite this article: Bone Joint J 2024;106-B(5):460–467

Medium-term survivorship of the Oxford phase 3 unicompartmental knee replacement (UKR) has not yet been established in an Asian population. We prospectively evaluated the outcome of 400 phase 3 Oxford UKRs in 320 Korean patients with a mean age at the time of operation of 69 years (48 to 82). The mean follow-up was 5.2 years (1 to 10). Clinical and radiological assessment was carried out pre- and post-operatively. At five years, the mean Knee Society knee and functional scores had increased significantly from 56.2 (30 to 91) pre-operatively to 87.2 (59 to 98) (p = 0.034) and from 59.2 (30 to 93) to 88.3 (50 to 100) (p = 0.021), respectively. The Oxford knee score increased from a mean of 25.8 (12 to 39) pre-operatively to 39.8 (25 to 58) at five years (p = 0.038). The ten-year survival rate was 94% (95% confidence interval 90.1 to 98.0). A total of 14 UKRs (3.5%) required revision. The most common reason for revision was dislocation of the bearing in 12 (3%). Conversion to a total knee replacement was required in two patients who developed osteoarthritis of the lateral compartment.

This is the largest published series of UKR in Korean patients. It shows that the mid-term results after a minimally invasive Oxford phase 3 UKR can yield satisfactory clinical and functional results in this group of patients.

Aims. The objective of this study was to present the outcomes of rotational acetabular osteotomy (RAO) over a 30-year period for osteoarthritis (OA) secondary to dysplasia of the hip in pre- or early-stage OA. Methods. Between September 1987 and December 1994, we provided treatment to 47 patients (55 hips) with RAO for the management of pre- or early-stage OA due to developmental hip dysplasia. Of those, eight patients (11 hips) with pre-OA (follow-up rate 79%) and 27 patients (32 hips) with early-stage OA (follow-up rate 78%), totalling 35 patients (43 hips) (follow-up rate 78%), were available at a minimum of 28 years after surgery. Results. In the pre-OA group, the mean Merle d'Aubigné score improved significantly from 14.5 points (SD 0.7) preoperatively to 17.4 points at final follow-up (SD 1.2; p = 0.004) and in the early-stage group, the mean score did not improve significantly from 14.0 (SD 0.3) to 14.6 (SD 2.4; p = 0.280). Radiologically, the centre-edge angle, acetabular roof angle, and head lateralization index were significantly improved postoperatively in both groups. Radiological progression of OA was observed in two patients (two hips) in the pre-OA group and 17 patients (18 hips) in the early-stage group. Kaplan-Meier survival analysis, with radiological progression of OA as the primary outcome, projected a 30-year survival rate of 81.8% (95% confidence interval (CI) 0.59 to 1.00) for the pre-OA group and 42.2% (95% CI 0.244 to 0.600) for the early-stage group. In all cases, the overall survival rate stood at 51.5% (95% CI 0.365 to 0.674) over a 30-year period, and when the endpoint was conversion to total hip arthroplasty, the survival rate was 74.0% (95% CI 0.608 to 0.873). Conclusion. For younger patients with pre-OA, joint preservation of over 30 years can be expected after RAO. Cite this article: Bone Joint J 2024;106-B(5 Supple B):25–31

Short-stem total hip arthroplasty (THA) may have bone sparing properties, which could be advantageous in a younger population with high risk of future revision surgery. We used data from the AOANJRR, LROI and SAR to compare survival rates of primary THA, stems used in the first-time revision procedures as well as the overall survival of first-time revisions between a cohort of short-stem and standard-stem THA. Short-stem THAs (designed as a short stem with mainly metaphyseal fixation) between 2007 and 2021 were identified (n=16,258). A propensity score matched cohort (1:2) with standard THAs in each register was identified (n=32,515). The cohorts were merged into a research dataset. Overall survival at 12 years follow-up was calculated using Kaplan-Meier survival analyses. Stem revisions (short-stem THA n=239, standard-stem THA n=352) were identified. The type of revision stem was classified as standard (<160 mm) or long (>160 mm). The survival rate of all first-time revisions in the two groups was calculated using any type of revision as outcome. The 12 year- overall survival rate (all revisions, all causes) for primary short-stem THAs was 95.3% (CI 94.5–95.9%), which was comparable to 95.2% (CI 94.7–95.7%) for standard-stem THAs. In the short-stem THA group, a standard stem (<160 mm) was more often (59%) used in the first-time revision than in the standard-stem group (47%, p=0.004). The overall survival of the first-time revisions did not differ between cases primarily operated with a short or a standard stem. In our multi-national register study, the overall survival rate of short stems was similar to that of standard stems. In short stem revisions there was a higher likelihood of using a standard-length stem for the revision compared with first-time revisions of standard stems. This finding might indicate bone-sparing properties with short-stemmed THAs

Aims. Unicompartmental knee arthroplasty (UKA) is the preferred treatment for anterior medial knee osteoarthritis (OA) owing to the rapid postoperative recovery. However, the risk factors for UKA failure remain controversial. Methods. The clinical data of Oxford mobile-bearing UKAs performed between 2011 and 2017 with a minimum follow-up of five years were retrospectively analyzed. Demographic, surgical, and follow-up data were collected. The Cox proportional hazards model was used to identify the risk factors that contribute to UKA failure. Kaplan-Meier survival was used to compare the effect of the prosthesis position on UKA survival. Results. A total of 407 patients who underwent UKA were included in the study. The mean age of patients was 61.8 years, and the mean follow-up period of the patients was 91.7 months. The mean Knee Society Score (KSS) preoperatively and at the last follow-up were 64.2 and 89.7, respectively (p = 0.001). Overall, 28 patients (6.9%) with UKA underwent revision due to prosthesis loosening (16 patients), dislocation (eight patients), and persistent pain (four patients). Cox proportional hazards model analysis identified malposition of the prostheses as a high-risk factor for UKA failure (p = 0.007). Kaplan-Meier analysis revealed that the five-year survival rate of the group with malposition was 85.1%, which was significantly lower than that of the group with normal position (96.2%; p < 0.001). Conclusion. UKA constitutes an effective method for treating anteromedial knee OA, with an excellent five-year survival rate. Aseptic loosening caused by prosthesis malposition was identified as the main cause of UKA failure. Surgeons should pay close attention to prevent the potential occurrence of this problem. Cite this article: Bone Jt Open 2023;4(12):914–922

Aims. The aim of this study was to determine the clinical outcomes and factors contributing to failure of transposition osteotomy of the acetabulum (TOA), a type of spherical periacetabular osteotomy, for advanced osteoarthritis secondary to hip dysplasia. Methods. We reviewed patients with Tönnis grade 2 osteoarthritis secondary to hip dysplasia who underwent TOA between November 1998 and December 2019. Patient demographic details, osteotomy-related complications, and the modified Harris Hip Score (mHHS) were obtained via medical notes review. Radiological indicators of hip dysplasia were assessed using preoperative and postoperative radiographs. The cumulative probability of TOA failure (progression to Tönnis grade 3 or conversion to total hip arthroplasty) was estimated using the Kaplan-Meier product-limited method. A multivariate Cox proportional hazards model was used to identify predictors of failure. Results. This study included 127 patients (137 hips). Median follow-up period was ten years (IQR 6 to 15). The median mHHS improved from 59 (IQR 52 to 70) preoperatively to 90 (IQR 73 to 96) at the latest follow-up (p < 0.001). The survival rate was 90% (95% CI 82 to 95) at ten years, decreasing to 21% (95% CI 7 to 48) at 20 years. Fair joint congruity on preoperative hip abduction radiographs and a decreased postoperative anterior wall index (AWI) were identified as independent risk factors for failure. The survival rate for the 42 hips with good preoperative joint congruity and a postoperative AWI ≥ 0.30 was 100% at ten years, and remained at 83% (95% CI 38 to 98) at 20 years. Conclusion. Although the overall clinical outcomes of TOA in patients with advanced osteoarthritis are suboptimal, favourable results can be achieved in selected cases with good preoperative joint congruity and adequate postoperative anterior acetabular coverage. Cite this article: Bone Joint J 2024;106-B(8):783–791

Aims. Implant failure has become more common as the number of primary total ankle arthroplasties (TAAs) performed has increased. Although revision arthroplasty has gained attention for functional preservation, the long-term results remain unclear. This study aimed to assess the long-term outcomes of revision TAA using a mobile-bearing prosthesis in a considerably large cohort; the risk factors for failure were also determined. Methods. This single-centre retrospective cohort study included 116 patients (117 ankles) who underwent revision TAA for failed primary TAA between July 2000 and March 2010. Survival analysis and risk factor assessment were performed, and clinical performance and patient satisfaction were evaluated preoperatively and at last follow-up. Results. The mean duration from initial revision TAA to last follow-up was 15.0 years (SD 3.0; 11.2 to 20.5). The cumulative survival rates of the revised ankles were 81% (95% confidence interval (CI) 74% to 88%), 74% (65% to 82%), and 70% (61% to 79%) at five, ten, and 15 years, respectively. Comorbidities prior to primary TAA, aseptic loosening, instability, or grafting of cysts were found to be the most common risk factors for secondary revision. The median value for preoperative pain, as assessed using the visual analogue scale, declined from 6 (interquartile range (IQR) 5 to 8) to 2 (IQR 0 to 5) (p < 0.001) and the mean American Orthopaedic Foot and Ankle Society ankle-hindfoot score improved from 43 (SD 17) preoperatively to 70 (SD 20) (p < 0.001) at last follow-up. Conclusion. Revision TAA offers acceptable survival rates after 15 years; it therefore offers a valuable option for treatment of implant failure in carefully selected cases. Although patient-reported outcomes improve substantially, the degree of improvement reported following primary TAA is not achieved. Cite this article: Bone Joint J 2024;106-B(1):46–52

Aims. There are concerns regarding complications and longevity of total elbow arthroplasty (TEA) in young patients, and the few previous publications are mainly limited to reports on linked elbow devices. We investigated the clinical outcome of unlinked TEA for patients aged less than 50 years with rheumatoid arthritis (RA). Methods. We retrospectively reviewed the records of 26 elbows of 21 patients with RA who were aged less than 50 years who underwent primary TEA with an unlinked elbow prosthesis. The mean patient age was 46 years (35 to 49), and the mean follow-up period was 13.6 years (6 to 27). Outcome measures included pain, range of motion, Mayo Elbow Performance Score (MEPS), radiological evaluation for radiolucent line and loosening, complications, and revision surgery with or without implant removal. Results. The mean MEPS significantly improved from 47 (15 to 70) points preoperatively to 95 (70 to 100) points at final follow-up (p < 0.001). Complications were noted in six elbows (23%) in six patients, and of these, four with an ulnar neuropathy and one elbow with postoperative traumatic fracture required additional surgeries. There was no revision with implant removal, and there was no radiological evidence of loosening around the components. With any revision surgery as the endpoint, the survival rates up to 25 years were 78.1% (95% confidence interval 52.8 to 90.6) as determined by Kaplan-Meier analysis. Conclusion. The clinical outcome of primary unlinked TEA for young patients with RA was satisfactory and comparable with that for elderly patients. A favourable survival rate without implant removal might support the use of unlinked devices for young patients with this disease entity, with a caution of a relatively high complication rate regarding ulnar neuropathy. Level of Evidence: Therapeutic Level IV. Cite this article: Bone Jt Open 2023;4(1):19–26