Aims. This study examined windswept deformity (WSD) of the knee, comparing prevalence and contributing factors in healthy and osteoarthritic (OA) cohorts. Methods. A case-control radiological study was undertaken comparing 500 healthy knees (250 adults) with a consecutive sample of 710 OA knees (355 adults) undergoing bilateral total knee arthroplasty. The mechanical hip-knee-ankle angle (mHKA), medial proximal tibial angle (MPTA), and lateral distal femoral angle (LDFA) were determined for each knee, and the arithmetic hip-knee-ankle angle (aHKA), joint line obliquity, and Coronal Plane Alignment of the Knee (CPAK) types were calculated. WSD was defined as a varus mHKA of < -2° in one limb and a valgus mHKA of > 2° in the contralateral limb. The primary outcome was the proportional difference in WSD prevalence between healthy and OA groups. Secondary outcomes were the proportional difference in WSD prevalence between constitutional varus and valgus CPAK types, and to explore associations between predefined variables and WSD within the OA group. Results. WSD was more prevalent in the OA group compared to the healthy group (7.9% vs 0.4%; p < 0.001, relative risk (RR) 19.8). There was a significant difference in means and variance between the mHKA of the healthy and OA groups (mean -1.3° (SD 2.3°) vs mean -3.8°(SD 6.6°) respectively; p < 0.001). No significant differences existed in MPTA and LDFA between the groups, with a minimal difference in aHKA (mean -0.9° healthy vs -0.5° OA; p < 0.001). Backwards logistic regression identified meniscectomy, rheumatoid arthritis, and osteotomy as predictors of WSD (odds ratio (OR) 4.1 (95% CI 1.7 to 10.0), p = 0.002; OR 11.9 (95% CI 1.3 to 89.3); p = 0.016; OR 41.6 (95% CI 5.4 to 432.9), p ≤ 0.001, respectively). Conclusion. This study found a 20-fold greater prevalence of WSD in OA populations. The development of WSD is associated with meniscectomy, rheumatoid arthritis, and osteotomy. These findings support WSD being mostly an acquired condition following skeletal maturity. Cite this article: Bone Jt Open 2024;5(10):879–885

Aims. The aim of this study was to describe the prevalence and patterns of neuropathic pain over one year in a cohort of patients with chronic post-surgical pain at three months following total knee arthroplasty (TKA). Methods. Between 2016 and 2019, 363 patients with troublesome pain, defined as a score of ≤ 14 on the Oxford Knee Score pain subscale, three months after TKA from eight UK NHS hospitals, were recruited into the Support and Treatment After Replacement (STAR) clinical trial. Self-reported neuropathic pain and postoperative pain was assessed at three, nine, and 15 months after surgery using the painDETECT and Douleur Neuropathique 4 (DN4) questionnaires collected by postal survey. Results. Symptoms of neuropathic pain were common among patients reporting chronic pain at three months post-TKA, with half reporting neuropathic pain on painDETECT (191/363; 53%) and 74% (267/359) on DN4. Of those with neuropathic pain at three months, half continued to have symptoms over the next 12 months (148/262; 56%), one-quarter had improved (67/262; 26%), and for one-tenth their neuropathic symptoms fluctuated over time (24/262; 9%). However, a subgroup of participants reported new, late onset neuropathic symptoms (23/262; 9%). Prevalence of neuropathic symptoms was similar between the screening tools when the lower cut-off painDETECT score (≥ 13) was applied. Overall, mean neuropathic pain scores improved between three and 15 months after TKA. Conclusion. Neuropathic pain is common in patients with chronic pain at three months after TKA. Although neuropathic symptoms improved over time, up to half continued to report painful neuropathic symptoms at 15 months after TKA. Postoperative care should include screening, assessment, and treatment of neuropathic pain in patients with early chronic postoperative pain after TKA. Cite this article: Bone Joint J 2024;106-B(6):582–588

Abstract. Introduction. Total knee replacement (TKR) is a successful operation for many patients, however 15–20% of patients experience chronic post-surgical pain (CPSP). Many will experience neuropathic characteristics. We describe the prevalence and patterns of neuropathic pain in a cohort of patients with CPSP three months after TKR. Methodology. Between 2016–2019, 363 patients with troublesome pain, ≤14 on Oxford Knee score pain subscale, at three months after TKR from eight NHS hospitals were recruited into the Support and Treatment After Replacement (STAR) trial. Self-reported neuropathic pain was assessed at three, nine and fifteen months after surgery using painDETECT and Douleur Neuropathique 4 (DN4). Results. At three months post-operative, 53% reported neuropathic pain on painDETECT and 74% on DN4. Half (56%) remained in neuropathic pain over the twelve-month follow-up period, 26% reported improvement, and 9% reported new neuropathic symtpoms or fluctuated in and out of neuropathic pain (9%). Overall mean neuropathic pain scores improved between three and 15 months after TKR. When the painDETECT cut-off score of ≥13(ambiguous/possible) was used, DN4 and painDETECT measures showed similar prevalence rates at each timepoint. Conclusion. Neuropathic pain is common among patients with CPSP at three months after TKR. Although symptoms improved over time, one quarter to one half of our cohort continued to report symptoms at fifteen months. We propose a painDETECT cutoff score of ≥13 be used to identify neuropathic features in the TKR population. Postoperative care should include identification, assessment, and treatment of neuropathic pain in patients with CPSP after TKR

Abstract. Introduction. Anxiety and depression are risk factors for poor outcome following knee replacement surgery. The aim of this study was to investigate the prevalence of anxiety and depression before and after primary (pKR) and revision knee replacement (rKR). Methodology. Retrospective cohort study. 315,720 pKR and 12,727 rKR recruited from the NHS Patient Reported Outcome Measures (PROMs) programme from 2013–2021. Anxiety and depression were defined using: (i) Survey question: “Have you been told by a doctor that you have depression? Yes/No”; (ii) EQ-5D anxiety/depression domain. Rates of EQ-5D anxiety/depression were investigated at baseline and at 6-months following surgery. The prevalence of depression was investigated by patient age and gender. Results. Overall, 28,434/315,720 (9.0%) pKR and 1,536/12,727 (12.0%) rKR reported pre-operative depression. For all age groups, depression was more common in female than male patients. Prevalence of depression reduced with age (<60 years: 16.8% pKR, 22.7% rKR; 80+ years: 5.3% pKR, 5.2% rKR). Depression was most prevalent in female patients, under 60 years undergoing rKR (25.6%). Pre-operation, 109,000/303,998 (35.9%) pKR and 5,433/12,216 rKR (44.5%) reported moderate or extreme EQ-5D anxiety/depression. Post-operation, 65,351/308,914 (21.2%) pKR and 4,176/12,409 rKR (33.7%) reported moderate or extreme EQ-5D anxiety/depression. Conclusion. Anxiety and depression were prevalent in patients undergoing knee replacement surgery. Patients undergoing revision procedures, female patients and younger patients had the highest rates of depression. Large improvements in anxiety/depression were observed at early follow-up after pKR and rKR

Introduction. Periprosthetic joint infection (PJI) is a devastating complication after total joint arthroplasty. Patients undergoing revision for PJI may experience considerable psychological distress and symptoms of depression, both of which are linked to poor post-operative outcomes. We therefore aim to identify the prevalence of depressive symptoms in patients prior to treatment for PJI. Methods. All patients between September 2008 – October 2018 undergoing single or 2-stage revision for PJI with minimum 1-year follow-up were retrospectively reviewed at a single institution. The 2-stage (n=37) and single stage (n=39) patients that met inclusion criteria were matched based off age (+/−5), gender and BMI (+/−5) to patients undergoing aseptic revisions. Based on prior literature, patients were considered to have depressive symptoms if their VR-12 mental component score (MCS) was below 42. Using Student's t-tests, outcomes evaluated included pre-operative and 1-year post-operative VR-12 MCS and physical component scores (PCS). Results. Compared to matched controls, there was a significant difference in pre-operative depressive symptoms in patients undergoing 2-stage revision (40.5% vs 10.8%, p = 0.003) but not 1 year post-operatively (21.6% vs 10.8%, p = 0.2). Among single stage patients, there was no difference pre-operatively (20.5% vs 12.8%, p = 0.36) or 1 year post-operatively (15.3% vs 15.3%, p=1.0). PCS were significantly lower in 2-stage patients pre-operatively (31.6 vs 36.0, p=0.05) but not post-operatively (40.0 vs 39.7, p=0.89). In single stage patients there was no difference in PCS both pre-operatively (34.8 vs 34.0, p=0.78) or post-operatively (38.6 vs 39.4, p=0.79). Conclusion. In addition to lower pre-operative function, patients undergoing 2-stage revision for PJI have a four times higher prevalence of pre-operative depressive symptoms compared to patients undergoing aseptic revision. Orthopedic surgeon awareness and screening of 2-stage patients pre-operatively with referral for potential treatment of depression if needed may help improve early outcomes post-operatively

Aims. The aim of our study was to determine the prevalence of total knee arthroplasty in different ethnic groups and compare pre-operative and post-operative function using the Oxford Knee Score (OKS). Background. King's College Hospital serves one of the most ethnically diverse areas of the UK. The prevalence of TKR differs between different ethnic and demographic groups. Methods. Data was collected prospectively on 150 consecutive patients undergoing total knee arthroplasty. Oxford Knee Scores were recorded pre-operatively, and then post-operatively at 6 weeks, 3 months, 6 months, 12 months and 24 months. The ethnic data was obtained from the patient's clinical notes. Results. The mean preoperative OKS was 18 (maximum 48) across all ethnic groups and improved to 37 post-operatively. The white ethnic groups made up 66.89% of all our TKR patients, whilst making up 64.32% of the local population. There is a significant difference between the pre-operative functional score between black and white ethnic groups (14 vs 18.6, p = 0.007). At 12 months the functional outcome is not significantly different (36.73 vs 36.90, p>0.05). Conclusions. We have presented the ethnicity breakdown of our TKR population. The White patients represent the largest group utilising TKR services. We found that patients of Black ethnicity were the second largest group using our service but they present with a significantly lower preoperative functional knee scores compared to white patients. Both groups benefit similarly after surgery. This implies Black ethnic groups seek help later and with more disability. The availability and benefits of TKR in the treatment of knee osteoarthritis should be promoted amongst the Black community

PURPOSE OF STUDY. Periprosthetic fractures after total knee arthroplasty is a potentially serious and challenging complication and the incidence is continuously rising. The purpose of this study was to analyse the prevalence and analyse effectiveness of the various treatment methods for management of periprosthetic fracture of the distal femur after total knee arthroplasty, and to determine the clinical and radiographic results of patients following surgical treatment of these injuries. METHODS. We reviewed all patients with periprosthetic fractures after total knee arthroplasty treated surgically between 2003 and 2008 from the prospective hospital database. Medical and radiographic records were reviewed for patient characteristics, fracture characteristics, implant details, healing, and complications. Antero-posterior and lateral radiographs were reviewed at the time of admission, post-operatively and at follow up visits. Fractures were classified according to the Lewis and Rorabeck, Orthopaedic Trauma Association and the methods of Su and DeWal. RESULTS. 26 patients (average age= 77.6) had operative management for displaced fractures. Mechanical fall was the commonest mode of injury at a mean of 4.66 years post primary replacement. Locking plates was the commonest method of fixation for stable implant and displaced fractures [Lewis & Rorabeck type 2] and 2 patients had distal femoral replacements for unstable implants. Successful fracture healing within 6 months occurred in all but one patient. Full weight bearing mobilisation was achieved at 3 months in 94% and patients with distal femoral replacements achieved quickest recovery. CONCLUSIONS. Compared to the current literature, we had a satisfactory outcome in following individualised treatment of periprosthetic fractures after knee joint replacement. Periprosthetic femoral fractures around the knee commonly constitute a challenging problem and require an adequate analysis of fracture etiology and distal femoral replacement achieves satisfactory results in fractures with unstable implants

Aims. The purpose of this study is to determine an individual’s age-specific prevalence of total knee arthroplasty (TKA) after cruciate ligament surgery, and to identify clinical and genetic risk factors associated with undergoing TKA. Methods. This study was a retrospective case-control study using the UK Biobank to identify individuals reporting a history of cruciate ligament surgery. Data from verbal history and procedural codes recorded through the NHS were used to identify instances of TKA. Patient clinical and genetic data were used to identify risk factors for progression from cruciate ligament surgery to TKA. Individuals without a history of cruciate ligament reconstruction were used for comparison. Results. A total of 2,576 individuals with a history of cruciate ligament surgery were identified, with 290 (11.25%) undergoing TKA. In patients with prior cruciate ligament surgery, prevalence of TKA was 0.75% at age 45 years, 9.10% at age 65 years, and 20.43% at age 80 years. Patients with prior cruciate ligament surgery were 4.6 times more likely to have undergone TKA by age 55 years than individuals without prior cruciate ligament surgery. In the cruciate ligament surgery cohort, BMI > 30 kg/m. 2. (odds ratio (OR) 4.01 (95% confidence interval (CI) 2.74 to 5.87)), a job that always involved heavy manual or physical labour (OR 2.72 (95% CI 1.57 to 4.71)), or a job that always involved walking and standing (OR 2.58 (95% CI 1.58 to 4.20)) were associated with greater TKA odds. No single-nucleotide polymorphism (SNP) was associated with risk of TKA following cruciate ligament surgery. Conclusion. Patients with a history of prior cruciate ligament surgery have substantially higher risk of TKA and undergo arthroplasty at a relatively younger age than individuals without a history of prior cruciate ligament surgery. Physically demanding work and obesity were associated with higher odds of TKA after cruciate ligament surgery, but no SNP was associated with risk of TKA. Cite this article: Bone Joint J 2024;106-B(3):249–255

Abstract. Introduction. The aims of our systematic review were to assess the Nickel sensitising potential of total knee arthroplasty (TKA), explore the relationship between Nickel hypersensitivity and clinical outcomes, and evaluate the utility of skin patch testing pre- and/or post-operatively. Methodology. A literature search was performed through EMBASE, Medline and PubMed databases. Articles were screened independently by two investigators. Levels of Evidence were assessed using Oxford CEBM criteria and quality was assessed using MINORS and Cochrane risk-of-bias tools. Results. Twenty studies met the eligibility criteria, reporting on 1354 TKAs. Prevalence of Nickel hypersensitivity ranged from 0% to 87.5%. Only one study which compared prevalence of hypersensitivity in the same patient group before and after surgery noted newly positive patch test reactions in 4.1%. Three studies reported lower prevalence of hypersensitivity in post-operative patients compared to pre-operative patients. Seven studies suggested hypersensitivity might cause complications; six studies did not support any relationship. Seven studies recommended pre-operative patch testing in patients with history of metal allergy; nine studies concluded testing may be valuable post-operatively. Conclusions. Patients undergoing TKA do not seem to be at increased risk of developing Nickel hypersensitivity, and there is conflicting evidence that patients with established hypersensitivity are more likely to experience adverse clinical outcomes. The evidence suggests performing patch testing pre-operatively in patients with history of metal allergy to aid selection of the most appropriate prosthesis, and post-operatively once common causes of implant failure have been excluded, since implant removal or revision with hypoallergenic implants may alleviate symptoms

Abstract. Introduction. The prevalence of recurrent infection following two-stage exchange arthroplasty following failure of a total knee arthroplasty (TKA) has been reported to be 10% to 25%. There is limited literature available on repeat two stage revisions for TKA infection with only small cohorts and variable success rates. Methodology. A retrospective cohort study investigating the outcome of two stage revision arthroplasty for treatment of TKA infection was conducted with the aim of identifying factors linked to recurrence of infection. A consecutive cohort of all microbiology intra-operative periprosthetic knee samples from a single revision arthroplasty centre between January 2010 and December 2016 was identified. The final cohort consisted of 658 samples taken during 64 patients undergoing two stage revision knee surgery for infection. Patient demographics, medical and orthopaedic history data including post-operative outcomes and subsequent treatment was obtained from the electronic records system and medical notes. Results. 65.6% of the cohort (N=42) had successful eradication of their infection. For the twenty-two patients that had failure of their two stage revision, twenty patients had samples available from further surgical intervention. Sixteen patients (80%) had different organisms isolated when they had repeat surgical samples taken when compared to their first stage samples. Overall, for subsequent treatments there was a success rate of 75% if the same organism was identified and 62.5% if there were new isolated organisms. Conclusion. These findings may have implications for the treatment strategies chosen for re-infection after two stage TKA revisions if new causative organisms are isolated

Abstract. Introduction. Higher than expected rates of tibial loosening with the ATTUNE® total knee arthroplasty (TKA) implant has been reported. Component loosening can be associated with the development of radiolucency lines (RLL) and our study aim was to systematically assess the reported rates of these. Methodology. A systematic search was undertaken using the Cochrane methodology in four online databases. Identified studies were assessed and screened against predetermined inclusion criteria. Meta-analysis was conducted using a random-effects model. Results. Nine studies (n=2,727 TKAs) from 6,590 titles met the inclusion criteria: 1 Randomised Controlled Trial (n=74), 1 prospective cohort (n=200), 4 retrospective cohort (n=1,639), and 3 case-series (n=814). All used the 2013 ATTUNE® design. In meta-analysis: 8 studies (n=1,440 ATTUNE TKAs) reported an overall prevalence of 11% (95%CI: 6.4-18.3%) for medial tibia RLL; 7 studies (n=940) a 12.3% (95%CI: 4.0-32%) rate of any tibia RLL.; 5 studies (n=736) femoral RLL in 11% (95%CI: 7.2-106.5%) and 7 studies (n=896) any RLL in 20.7% (95%CI: 13.4-30.6%). Meta-analysis of 4 studies (n=1,036) comparing the ATTUNE® with another implant (PFC Sigma®, LCS®, or PERSONA®) showed a higher risk of medial tibia RLL (OR: 2.538; 95%CI: 1.397-4.611, P=0.002) and any RLL (OR: 2.725; 95%CI: 1.302-5.703, P=0.008) in the ATTUNE® group. Conclusions. The 2013 ATTUNE® TKA system is associated with high rates of radiolucency around the tibial and femoral components. Comparative studies suggesting these rates are more than double those of other systems. Radiolucency may be a herald of component loosening, therefore, close surveillance of this implant is recommended

Aims. This study compares the PFC total knee arthroplasty (TKA) system in a prospective randomized control trial (RCT) of the mobile-bearing rotating-platform (RP) TKA against the fixed-bearing (FB) TKA. This is the largest RCT with the longest follow-up where cruciate-retaining PFC total knee arthroplasties are compared in a non-bilateral TKA study. Patients and Methods. A total of 167 patients (190 knees with 23 bilateral cases), were recruited prospectively and randomly assigned, with 91 knees receiving the RP and 99 knees receiving FB. The mean age was 65.5 years (48 to 82), the mean body mass index (BMI) was 29.7 kg/m. 2. (20 to 52) and 73 patients were female. The Knee Society Score (KSS), Knee Society Functional Score (KSFS), Oxford Knee Score (OKS), Western Ontario and McMaster Universities Arthritis Index (WOMAC), and 12-Item Short-Form Health Survey Physical and Mental Component Scores (SF-12 PCS, SF-12 MCS) were gathered and recorded preoperatively, at five-years’ follow-up, and at ten years’ follow-up. Additionally, Knee Injury and Osteoarthritis Outcome Scores (KOOS) were collected at five- and ten-year follow-ups. The prevalence of radiolucent lines (RL) on radiographs and implant survival were recorded at five- and ten-year follow-ups. Results. At the ten-year follow-up, the RP group (n = 39) had a statistically significant superior score in the OKS (p = 0.001), WOMAC (p = 0.023), SF-12 PCS (p = 0.019), KOOS Activities of Daily Living (ADL) (p = 0.010), and KOOS Sport and Recreation (Sport/Rec) (p = 0.006) compared with the FB group (n = 46). The OKS, SF-12 PCS, and KOOS Sport/Rec at ten years had mean scores above the minimal clinically important difference (MCID) threshold. There was no significant difference in prevalence of radiolucency between groups at five-years’ follow-up (p = 0.449), nor at ten-years’ follow-up (p = 0.08). Implant survival rate at 14 years postoperative was 95.2 (95% CI 90.7 to 99.8) and 94.7 (95% CI 86.8 to 100.0) for the RP and FB TKAs, respectively. Conclusion. At ten-year follow-up, the mobile-bearing knee joint arthroplasty had statistically and clinically relevant superior OKS, SF-12 PCS, and KOOS (Sport/Rec) than the fixed-bearing platform. No difference was seen in prevalence of radiolucent lines. There was a greater than 94% implant survival rate for both cohorts at 14 years. Cite this article: Bone Joint J 2018;100-B:1336–44

Aims. The purpose of this study was to assess total knee arthroplasty (TKA) volume and rates of early complications in morbidly obese patients over the last decade, where the introduction of quality models influencing perioperative care pathways occurred. Methods. Patients undergoing TKA between 2011 to 2018 were identified in the American College of Surgeons National Surgical Quality Improvement Program database. Patients were stratified by BMI < 40 kg/m. 2. and ≥ 40 kg/m. 2. and evaluated by the number of cases per year. The 30-day rates of any complication, wound complications, readmissions, and reoperation were assessed. Trends in these endpoints over the study period were compared between groups using odds ratios (ORs) and multivariate analyses. Results. In total, 314,695 patients underwent TKA and 46,362 (15%) had BMI ≥ 40 kg/m. 2. The prevalence of morbid obesity among TKA patients did not change greatly, ranging between 14% and 16%. Reoperation rate decreased from 1.16% to 0.96% (odds ratio (OR) 0.81 (95% confidence interval (CI) 0.66 to 0.99)) for patients with BMI < 40 kg/m. 2. , as did rates of readmission (4.46% to 2.87%; OR 0.61 (0.55 to 0.69)). Patients with BMI ≥ 40 kg/m. 2. also had fewer readmissions over the study period (4.87% to 3.34%; OR 0.64 (0.49 to 0.83)); however, the rate of reoperation did not change (1.37% to 1.41%; OR 0.99 (0.62 to 1.56)). Significant improvements were not observed for infective complications over time for either group; patients with BMI ≥ 40 kg/m. 2. had increased risk of both deep infection and wound complications compared to non-morbidly obese patients. Rate of any complication decreased for all patients. Conclusion. The proportion of TKAs in morbidly obese patients has not significantly changed over the past decade. Although readmission rates improved for all patients, reductions in reoperation in non-morbidly obese patients were not experienced by the morbidly obese, resulting in a widening of the complication gap between these cohorts. Care improvements have not lowered the differential risk of infective complications in the morbidly obese. Cite this article: Bone Joint J 2021;103-B(6 Supple A):38–44

Introduction. There is little published evidence regarding cannabis or cannabinoid use among orthopedic patients, yet there is increasing public attention on its possible role in treating various medical conditions including pain. California passed legislation legalizing cannabis for medical treatment in 2003 and recreational use in 2018. All patients undergoing total joint arthroplasty (TJA) at our institution are screened preoperatively with a urine toxicology (UTox) screen. Though a positive test for other substances triggers surgery cancellation, a positive screen for cannabis and/or opiates does not impact whether surgery is performed. We sought to quantify the prevalence of cannabinoid and opioid use among patients with chronic pain from end-stage hip and knee osteoarthritis who underwent arthroplasty at our institution in 2012 and 2017. Methods. Institutional Review Board approval was obtained. A retrospective chart review was performed for all patients with severe arthritis who underwent total hip and knee arthroplasty (THA and TKA) at our institution during the calendar years 2012 and 2017. Patients were excluded if TJA was performed for acute trauma or if no pre-operative UTox screen was obtained. The UTox screen was used to determine preoperative cannabis and opioid use. Chi-squared testing was performed, and significance was defined as p<=0.05. Results. In the two years studied, 546 of 560 primary TJA surgeries (98%) had a pre-operative UTox screen performed. These 546 operations in 525 patients were reviewed (359 TKAs and 187 THAs). Comparing 2012 to 2017, the prevalence of preoperative cannabis use increased from 9% to 15% (p =.05) while the prevalence of opioid use decreased from 24% to 17% (p=.04). The proportion of patients who tested positive for both cannabis and opioids was low (3%) and did not change between 2012 and 2017 (p=.50). With the numbers available, patients who were using cannabis were no more or less likely to be taking opioids than non-cannabis users (p=.24). Discussion and Conclusion. To our knowledge, this is the first study to identify the prevalence and trends of cannabis use in patients undergoing TJA. At our institution, cannabis use increased more than 60% while opioid use decreased about 30% over a 5-year interval. Whether these findings are related remains unclear. Future directions will include studying postoperative opioid requirements, disposition, complications, and readmissions in TJA patients who use cannabis

Aims. The primary aim of this study was to assess whether pain in the contralateral knee had a clinically significant influence on the outcome of total knee arthroplasty (TKA) according to the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score. Secondary aims were to: describe the prevalence of contralateral knee pain; identify if it clinically improves after TKA; and assess whether contralateral knee pain independently influences patient satisfaction with their TKA. Methods. A retrospective cohort of 3,178 primary TKA patients were identified from an arthroplasty database. Patient characteristics, comorbidities, and WOMAC scores were collected preoperatively and one year postoperatively for the index knee. In addition, WOMAC pain scores were also collected for the contralateral knee. Overall patient satisfaction was assessed at one year. Preoperative contralateral knee pain was defined according to the WOMAC score: minimal (> 78 points), mild (59 to 78), moderate (44 to 58), and severe (< 44). Multivariate regression analysis was used to adjust for confounding. Results. According to severity there were 1,425 patients (44.8%) with minimal, 710 (22.3%) with mild, 518 (16.3%) with moderate, and 525 (16.5%) with severe pain in the contralateral knee. Patients in the severe group had a greater clinically significant improvement in their functional WOMAC score (9.8 points; p < 0.001). Only patients in the moderate (22.9 points) and severe (37.8 points) groups had a clinically significant improvement in their contralateral knee pain (p < 0.001), but they were significantly less likely to be satisfied with their TKA (moderate: odds ratio (OR) 0.64, 95% confidence interval (CI) 0.4 to 0.92, p = 0.022; severe: OR 0.57, 95% CI 0.39 to 0.82, p = 0.002). Conclusion. Contralateral knee pain did not impair improvement in the WOMAC score after TKA, and patients with the most severe contralateral knee pain had a clinically significantly greater improvement in their functional outcome. More than half the patients presenting for TKA had mild-to-severe contralateral knee pain, most of whom had a clinically meaningful improvement but were significantly less likely to be satisfied with their TKA. Cite this article: Bone Joint J. 2020;102-B(1):125–131

Total knee replacement (TKR) is an effective method of treating end-stage arthritis of the knee. It is not, however, a procedure without risk due to a number of factors, one of which is diabetes mellitus. The purpose of this study was to estimate the general prevalence of diabetes in patients about to undergo primary TKR and to determine whether diabetes mellitus adversely affects the outcome. We conducted a systematic review and meta-analysis according to the Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines. The Odds Ratio (OR) and mean difference (MD) were used to represent the estimate of risk of a specific outcome. Our results showed the prevalence of diabetes mellitus among patients undergoing TKR was 12.2%. Patients with diabetes mellitus had an increased risk of deep infection (OR = 1.61, 95% confidence interval (CI), 1.38 to 1.88), deep vein thrombosis (in Asia, OR = 2.57, 95% CI, 1.58 to 4.20), periprosthetic fracture (OR = 1.89, 95% CI, 1.04 to 3.45), aseptic loosening (OR = 9.36, 95% CI, 4.63 to 18.90), and a poorer Knee Society function subscore (MD = -5.86, 95% CI, -10.27 to -1.46). Surgeons should advise patients specifically about these increased risks when obtaining informed consent and be meticulous about their peri-operative care. Cite this article: Bone Joint J 2014;96-B:1637–43

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.

Background. Pseudotumor or high grade ALVAL (aseptic lymphocyte-dominated vasculitis-associated lesion) development around total hip replacements secondary to local metal debris generation – especially in the setting of metal-on-metal bearings – is a well-recognised histopathologic phenomenon. Recent work has suggested a strong genetic correlation with an individual's risk of such lesion development following metal exposure. Emerging data have highlighted a similar potential concern around total knee replacements (TKRs), particularly with increasing construct modularity. To date, the body-of-knowledge pertaining to TKR-associated ALVALs has largely been limited to individual case reports or small retrospective case series’, with no large-scale investigation looking at this potential complication. This study sought to establish the preliminary prevalence of pseudotumor or high grade ALVAL formation seen at the revision of primary TKRs and to establish the correlation between histologic ALVAL grade and patient-reported functional outcomes. Methods. Findings of 1263 consecutive patients undergoing revision knee surgery, at a high-volume referral center, were reviewed. 161 cases of active infection were excluded. Complete histopathology reports were subsequently available for 321 (29.1%) non-infective cases. Each case was independently histologically-classified using a previously validated scoring system reflecting ALVAL grade. Post-operative patient-reported outcomes measures (PROMs) were available for 134 patients (41.7%), allowing direct correlation between functional performance and the established histopathology results. Results. In total, 23 high grade lesions were identified, including 5 distinct pseudotumors, representing 7.2% (23/321) of the cohort. When compared by histologic grade, Jonkeere-Terpstra testing yielded P-values of 0.02 and 0.03 for the Oxford Knee Score and WOMAC datasets, respectively, suggesting a high correlation between ALVAL grade and functional knee scores. Conclusions. The results of this large histologic analysis suggest a prevalence of pseudotumor or high grade ALVAL development at revision TKR surgery of greater than 7%. This unexpectedly high result may contribute clinical insight into the previously under-appreciated significance of metal debris-related local tissue reactions around TKRs. The findings herein also demonstrate a strong near-linear inverse relationship between patient-reported clinical knee performance and the underlying histologic grade of local tissue reaction. Collectively, this information may provide some further understanding of a proportion of the widely quoted 15–20% of patients who remain dissatisfied with their TKR after surgery. This result has potential diagnostic and management implications for clinicians treating patients with underperforming in situ TKRs and should prompt consideration of an ALVAL secondary to local wear debris-generated metallosis in the differential diagnosis

Aims

The Coronal Plane Alignment of the Knee (CPAK) classification has been developed to predict individual variations in inherent knee alignment. The impact of preoperative and postoperative CPAK classification phenotype on the postoperative clinical outcomes of total knee arthroplasty (TKA) remains elusive. This study aimed to examine the effect of postoperative CPAK classification phenotypes (I to IX), and their pre- to postoperative changes on patient-reported outcome measures (PROMs).

In the absence of patellar resurfacing, we have previously shown that the use of electrocautery around the margin of the patella improved the one-year clinical outcome of total knee replacement (TKR). In this prospective randomised study we compared the mean 3.7 year (1.1 to 4.2) clinical outcomes of 300 TKRs performed with and without electrocautery of the patellar rim: this is an update of a previous report. The overall prevalence of anterior knee pain was 32% (95% confidence intervals [CI] 26 to 39), and 26% (95% CI 18 to 35) in the intervention group compared with 38% (95% CI 29 to 48) in the control group (chi-squared test; p = 0.06). The overall prevalence of anterior knee pain remained unchanged between the one-year and 3.7 year follow-up (chi-squared test; p = 0.12). The mean total Western Ontario McMasters Universities Osteoarthritis Indices and the American Knee Society knee and function scores at 3.7 years’ follow-up were similar in the intervention and control groups (repeated measures analysis of variance p = 0.43, p = 0.09 and p = 0.59, respectively). There were no complications. A total of ten patients (intervention group three, control group seven) required secondary patellar resurfacing after the first year. Our study suggests that the improved clinical outcome with electrocautery denervation compared with no electrocautery is not maintained at a mean of 3.7 years’ follow-up. Cite this article: Bone Joint J 2014;96-B:473–8