Aims. The aims were to assess whether joint-specific outcome after total knee arthroplasty (TKA) was influenced by implant design over a 12-year follow-up period, and whether patient-related factors were associated with loss to follow-up and mortality risk. Methods. Long-term follow-up of a randomized controlled trial was undertaken. A total of 212 patients were allocated a Triathlon or a Kinemax TKA. Patients were assessed preoperatively, and one, three, eight, and 12 years postoperatively using the Oxford Knee Score (OKS). Reasons for patient lost to follow-up, mortality, and revision were recorded. Results. A total of 94 patients completed 12-year functional follow-up (62 females, mean age 66 years (43 to 82) at index surgery). There was a clinically significantly greater improvement in the OKS at one year (mean difference (MD) 3.0 (95% CI 0.4 to 5.7); p = 0.027) and three years (MD 4.7 (95% CI 1.9 to 7.5); p = 0.001) for the Triathlon group, but no differences were observed at eight (p = 0.331) or 12 years’ (p = 0.181) follow-up. When assessing the OKS in the patients surviving to 12 years, the Triathlon group had a clinically significantly greater improvement in the OKS (marginal mean 3.8 (95% CI 0.2 to 7.4); p = 0.040). Loss to functional follow-up (53%, n = 109/204) was independently associated with older age (p = 0.001). Patient mortality was the major reason (56.4%, n = 62/110) for loss to follow-up. Older age (p < 0.001) and worse preoperative OKS (p = 0.043) were independently associated with increased mortality risk. An age at time of surgery of ≥ 72 years was 75% sensitive and 74% specific for predicting mortality with an area under the curve of 78.1% (95% CI 70.9 to 85.3; p < 0.001). Conclusion. The Triathlon TKA was associated with clinically meaningful greater improvement in knee-specific outcome when compared to the Kinemax TKA. Loss to follow-up at 12 years was a limitation, and studies planning longer-term functional assessment could limit their cohort to patients aged under 72 years. Cite this article: Bone Jt Open 2024;5(10):911–919

Aims. The primary aim of this study was to assess whether the postoperative Oxford Knee Score (OKS) demonstrated a ceiling effect at one and/or two years after total knee arthroplasty (TKA). The secondary aim was to identify preoperative independent predictors for patients that achieved a ceiling score after TKA. Methods. A retrospective cohort of 5,857 patients undergoing a primary TKA were identified from an established arthroplasty database. Patient demographics, body mass index (BMI), OKS, and EuroQoL five-dimension (EQ-5D) general health scores were collected preoperatively and at one and two years postoperatively. Logistic regression analysis was used to identify independent preoperative predictors of patients achieving postoperative ceiling scores. Receiver operating characteristic curve was used to identify a preoperative OKS that predicted a postoperative ceiling score. Results. The ceiling effect was 4.6% (n = 272) at one year which increased significantly (odds ratio (OR) 40.3, 95% confidence interval (CI) 30.4 to 53.3; p < 0.001) to 6.2% (n = 363) at two years, when defined as those with a maximal score of 48 points. However, when the ceiling effect was defined as an OKS of 44 points or more, this increased to 26.3% (n = 1,540) at one year and further to 29.8% (n = 1,748) at two years (OR 21.6, 95% CI 18.7 to 25.1; p < 0.001). A preoperative OKS of 23 or more and 22 or more were predictive of achieving a postoperative ceiling OKS at one and two years when defined as a maximal score or a score of 44 or more, respectively. Conclusion. The postoperative OKS demonstrated a small ceiling effect when defined by a maximal score, but when defined by a postoperative OKS of 44 or more the ceiling effect was moderate and failed to meet standards. The preoperative OKS was an independent predictor of achieving a ceiling score. Cite this article: Bone Joint J 2020;102-B(11):1519–1526

Aims. To estimate the measurement properties for the Oxford Knee Score (OKS) in patients undergoing revision knee arthroplasty (responsiveness, minimal detectable change (MDC-90), minimal important change (MIC), minimal important difference (MID), internal consistency, construct validity, and interpretability). Methods. Secondary data analysis was performed for 10,727 patients undergoing revision knee arthroplasty between 2013 to 2019 using a UK national patient-reported outcome measure (PROM) dataset. Outcome data were collected before revision and at six months postoperatively, using the OKS and EuroQol five-dimension score (EQ-5D). Measurement properties were assessed according to COnsensus-based Standards for the selection of health status Measurement Instruments (COSMIN) guidelines. Results. A total of 9,219 patients had complete outcome data. Mean preoperative OKS was 16.7 points (SD 8.1), mean postoperative OKS 29.1 (SD 11.4), and mean change in OKS + 12.5 (SD 10.7). Median preoperative EQ-5D index was 0.260 (interquartile range (IQR) 0.055 to 0.691), median postoperative EQ-5D index 0.691 (IQR 0.516 to 0.796), and median change in EQ-5D index + 0.240 (IQR 0.000 to 0.567). Internal consistency was good with Cronbach’s α 0.88 (baseline) and 0.94 (post-revision). Construct validity found a high correlation of OKS total score with EQ-5D index (r = 0.76 (baseline), r = 0.83 (post-revision), p < 0.001). The OKS was responsive with standardized effect size (SES) 1.54 (95% confidence interval (CI) 1.51 to 1.57), compared to SES 0.83 (0.81 to 0.86) for the EQ-5D index. The MIC for the OKS was 7.5 points (95% CI 5.5 to 8.5) based on the optimal cut-off with specificity 0.72, sensitivity 0.60, and area under the curve 0.66. The MID for the OKS was 5.2 points. The MDC-90 was 3.9 points. The OKS did not demonstrate significant floor or ceiling effects. Conclusion. This study found that the OKS was a useful and valid instrument for assessment of outcome following revision knee arthroplasty. The OKS was responsive to change and demonstrated good measurement properties. Cite this article: Bone Joint J 2021;103-B(4):627–634

Risk of revision following total knee replacement is relatively high in patients under 55 years of age, but little is reported regarding non-revision outcomes. This study aims to identify predictors of dissatisfaction following TKR in patients younger than 55 years of age. We assessed 177 TKRs (157 consecutive patients) from 2008 to 2013. Data was collected on age, sex, implant, indication, BMI, social deprivation, range of motion, and prior knee surgery in addition to Oxford Knee Score (OKS) and SF-12 score. Postoperative data included knee range of motion, complications, and OKS, SF-12 score and satisfaction measures at one year. Overall, 24.9% of patients (44/177) were unsure or dissatisfied with their TKR. Significant predictors of dissatisfaction on univariable analysis (p<0.05) included: Kellgren-Lawrence grade 1/2 osteoarthritis; indication; poor preoperative OKS; postoperative complications; and poor improvements in OKS and pain component score (PCS) of the SF-12. Odds ratios for dissatisfaction by indication compared to primary OA: OA with previous meniscectomy 2.86; OA in multiply operated knee 2.94; OA with other knee surgery 1.7; OA with BMI>40kgm-2 2; OA post-fracture 3.3; and inflammatory arthropathy 0.23. Multivariable analysis showed poor preoperative OKS, poor improvement in OKS and postoperative stiffness, particularly flexion of <90°, independently predicted dissatisfaction (p<0.005). Patients coming to TKR when under 55 years of age differ from the ‘average’ arthroplasty population, often having complex knee histories and indications for surgery, and an elevated risk of dissatisfaction

Purpose. Various alignment philosophies for total knee arthroplasty (TKA) have been described, all striving to achieve excellent long-term implant survival and good functional outcomes. In recent years, in search of higher functionality and patient satisfaction, a shift towards more patient-specific alignment is seen. Robotics is the perfect technology to tailor alignment. The purpose of this study was to describe ‘inverse kinematic alignment’ (iKA) technique, and to compare clinical outcomes of patients that underwent robotic-assisted TKA performed by iKA versus adjusted mechanical alignment (aMA). Methods. The authors analysed the records of a consecutive series of patients that received robotic assisted TKA with iKA (n=40) and with aMA (n=40). Oxford Knee Score (OKS) and satisfaction on a visual analogue scale (VAS) were collected at a follow-up of 12 months. Clinical outcomes were assessed according to patient acceptable symptom state (PASS) thresholds, and uni- and multivariable linear regression analyses were performed to determine associations of OKS and satisfaction with 6 variables (age, sex, body mass index (BMI), preoperative hip knee ankle (HKA) angle, preoperative OKS, alignment technique). Results. The iKA and aMA techniques yielded comparable outcome scores (p=0.069), with OKS respectively 44.6±3.5 and 42.2±6.3. VAS Satisfaction was better (p=0.012) with iKA (9.2±0.8) compared to aMA (8.5±1.3). The number of patients that achieved OKS and satisfaction PASS thresholds was significantly higher (p=0.049 and p=0.003, respectively) using iKA (98% and 80%) compared to aMA (85% and 48%). Knees with preoperative varus deformity, achieved significantly (p=0.025) better OKS using iKA (45.4±2.0) compared to aMA (41.4±6.8). Multivariable analyses confirmed better OKS (β=3.1; p=0.007) and satisfaction (β=0.73; p=0.005) with iKA. Conclusions. The results of this study suggest that iKA and aMA grant comparable clinical outcomes at 12-months follow-up, though a greater proportion of knees operated by iKA achieved the PASS thresholds for OKS and satisfaction. Notably. in knees with preoperative varus deformity, iKA yielded significantly better OKS and satisfaction than aMA

Aims. It has been hypothesized that a unicompartmental knee arthroplasty (UKA) is more likely to be revised than a total knee arthroplasty (TKA) because conversion surgery to a primary TKA is a less complicated procedure. The purpose of this study was to determine if there is a lower threshold for revising a UKA compared with TKA based on Oxford Knee Scores (OKSs) and range of movement (ROM) at the time of revision. Methods. We retrospectively reviewed 619 aseptic revision cases performed between December 1998 and October 2018. This included 138 UKAs that underwent conversion to TKA and 481 initial TKA revisions. Age, body mass index (BMI), time in situ, OKS, and ROM were available for all patients. Results. There were no differences between the two groups based on demographics or time to revision. The top reasons for aseptic TKA revision were loosening in 212 (44%), instability in 88 (18%), and wear in 69 (14%). UKA revision diagnoses were primarily for loosening in 50 (36%), progression of osteoarthritis (OA) in 50 (36%), and wear in 17 (12%). Out of a maximum 48 points, the mean OKS of the UKAs before revision was 23 (SD 9.3), which was significantly higher than the TKAs at 19.2 (SD 9.8; p < 0.001). UKA patients scored statistically better on nine of the 12 individual OKS questions. The UKA cases also had a larger pre-revision mean ROM (114°, SD 14.3°) than TKAs (98°, SD 25°) ; p < 0.001). Conclusion. At revision, the mean UKA OKSs and ROM were significantly better than those of TKA cases. This study suggests that at our institution there is a difference in preoperative OKS between UKA and TKA at the time of revision, demonstrating a revision bias. Cite this article: Bone Joint J 2020;102-B(6 Supple A):91–95

There is a lack of evidence surrounding selective patella resurfacing, but patella cartilage loss at time of total knee arthroplasty (TKA) is often used as an indication in those who perform it. This study compares the outcomes of TKA without patella resurfacing in patients with and without patella cartilage loss (PFOA). Prospective case control study of 209 consecutive patients undergoing cruciate retaining single radius TKA without patella resurfacing for KL≥3 osteoarthritis. The presence and location of full thickness patella cartilage loss was documented intra-operatively at TKA, identifying n=108 cases with PFOA (mean age 70±9.7, mean BMI 31±6.2, 72 (67%) female) Vs n=101 controls without PFOA (age 68±9.2, BMI31±5.6, 52 (51%) female). Primary outcome measure was improvement in the Oxford Knee Score (OKS) at one year. There were more females in the PFOA group (67% Vs 51%, p=0.037), but no other preoperative differences. There was no difference in preoperative OKS between patients with patella cartilage loss (20.6±7.9) and those without (21.0±7.2, p=0.720). There was no difference in OKS improvement following TKA without patella resurfacing between those with full thickness patella cartilage loss (14.2±9.8) and those without (15.4±9.5, p=0.365). Facet involvement (number and location) did not affect OKSs. No differences were found in the individual OKS questions between groups (p>0.05). There was no difference in one-year OKS or improvements therein between patients with and without full thickness patella cartilage loss treated with single radius cruciate retaining TKA without patella resurfacing, questioning its use an indication for selective patella resurfacing

Aims

The metabolic equivalent of task (MET) score examines patient performance in relation to energy expenditure before and after knee arthroplasty. This study assesses its use in a knee arthroplasty population in comparison with the widely used Oxford Knee Score (OKS) and EuroQol five-dimension index (EQ-5D), which are reported to be limited by ceiling effects.

Aims

Treatment of end-stage anteromedial osteoarthritis (AMOA) of the knee is commonly approached using one of two surgical strategies: medial unicompartmental knee arthroplasty (UKA) or total knee arthroplasty (TKA). In this study we aim to investigate if there is any difference in outcome for patients undergoing UKA or TKA, when treated by high-volume surgeons, in high-volume centres, using two different clinical guidelines. The two strategies are ‘UKA whenever possible’ vs TKA for all patients with AMOA.

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The primary aim was to assess whether preoperative health-related quality of life (HRQoL) was associated with postoperative mortality following total hip arthroplasty (THA) and knee arthroplasty (KA). Secondary aims were to assess whether patient demographics/comorbidities and/or joint-specific function were associated with postoperative mortality.

Lateral meniscal failure and secondary valgus with lateral compartment arthrosis is quite common in the developed world. The varus knee is the common phenotype of the ‘jock’ of both genders, while the valgus knee is a common consequence of lateral meniscal tear, skiing or ‘catwalk’ life. Occurring more commonly in ‘flamingo’ phenotypes, lateral meniscal failure can be disabling, entirely preventing high heels being worn for instance. Indications. Lateral UKA is indicated for most valgus knees, and is substantially safer than TKA. ACL integrity is not essential in older people, as the patello-femoral mechanism is in line with the lateral compartment. Severe valgus with substantial bone loss is not a contraindication, if the deformity is simply angular. As long as there is not marked subluxation, fixed flexion deformity invariably corrects after notch osteophyte removal from femur and tibia. Combinations. Lateral UKA can be combined safely with PFJA: performed through a lateral approach, this is a safe and conservative procedure. ACL integrity is not essential – reconstruction can be undertaken simultaneously, if necessary. Combining lateral UKA with medial UKA is only rarely needed, and sometimes needs ACL reconstruction too. Adding a medial UKA in under 5 years usually results from overcorrection of the valgus. Mid Term Results, at a median of 7 years postop: Between 2005 to 2009, 64 knees in 58 patients had a lateral UKA using a device designed for the lateral compartment. This included 41 females and 17 males with a mean age of 71 years at the time of surgery (range 44–92). Thirty-nine patients underwent surgery on the right knee and 6 underwent bilateral procedures, of which four were performed under a single anesthetic. Primary lateral compartment osteoarthritis was the primary diagnosis in 63 cases with secondary osteoarthritis to a lateral tibial plateau fracture the indication in one patient. At 119 months follow up, the predicted cumulative survival was 0.97. With re-operation as an endpoint, 11% of patients within the study had undergone re-operation with a predicted cumulative survival of 0.81 at 119 months. This compares well with historic fixed bearing series. Preoperative OKS scores were available for 50 knees, scores were available for 63 knees at 9–48 months and 52 knees at 61–119 months post index operation. There was a significant improvement in the OKS between the preoperative scores (median 26 range 9–36) and early postoperative time points of 9–48 months, (median 42 range 23–48) (p<0.001). At the later postoperative time point of 61–119 months the score had been maintained (42 range 10–48). Conclusion. Lateral UKA is a small and safe procedure, with clinical outcomes that are equivalent to a medial UKA and are maintained at a median of 7 years postoperatively

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The aim of this study was to describe and compare joint-specific and generic health-related quality of life outcomes of the first versus second knee in patients undergoing staged bilateral total knee arthroplasty (BTKA) for osteoarthritis.

Aims

While residual fixed flexion deformity (FFD) in unicompartmental knee arthroplasty (UKA) has been associated with worse functional outcomes, limited evidence exists regarding FFD changes. The objective of this study was to quantify FFD changes in patients with medial unicompartmental knee arthritis undergoing UKA, and investigate any correlation with clinical outcomes.

Aims

Access to total knee arthroplasty (TKA) is sometimes restricted for patients with severe obesity (BMI ≥ 40 kg/m²). This study compares the cost per quality-adjusted life year (QALY) associated with TKA in patients with a BMI above and below 40 kg/m² to examine whether this is supported.

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The overall aim of this study was to determine the impact of deprivation with regard to quality of life, demographics, joint-specific function, attendances for unscheduled care, opioid and antidepressant use, having surgery elsewhere, and waiting times for surgery on patients awaiting total hip arthroplasty (THA) and total knee arthroplasty (TKA).

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The aims of this study were to assess mapping models to predict the three-level version of EuroQoL five-dimension utility index (EQ-5D-3L) from the Oxford Knee Score (OKS) and validate these before and after total knee arthroplasty (TKA).

Aims

To map literature on prognostic factors related to outcomes of revision total knee arthroplasty (rTKA), to identify extensively studied factors and to guide future research into what domains need further exploration.

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. To examine the clinical characteristics of patients undergoing knee arthroplasty with a pre-operative Oxford Knee Score >34 (‘good’/‘excellent’), and assess the appropriateness of surgical intervention for this group. Background. In the current cost-constrained health economy, justification of surgical intervention is increasingly sought. As a validated disease-specific outcome measure, the pre-operative Oxford Knee Score (OKS) has been suggested as a possible threshold measurement in knee arthroplasty. However, contrary to expectations, analysis of pre-operative OKS in the joint registry population demonstrates a normal distribution curve with a sub-group of high-scoring patients. This suggests that either the baseline OKS does not accurately define surgical threshold, or that patients with a high OKS are inappropriately having knee replacements. Methods. Retrospective case-note review of patients listed for primary Knee arthroplasty (n=1058), with a preoperative OKS >34 (n=44). Data was extracted, with analysis of referral criteria, clinical presentation, radiological changes (Kellgren-Lawrence), and content analysis of the appropriateness of knee arthroplasty. Age and gender differences were compared between OKS<34 and OKS>34 groups. Results. No significant difference was observed in age between groups. Gender distribution in the OKS>34 group was 2:1(M:F) compared with 1:1.3 (M:F) in the OKS<34 group. Once listed for surgery, 81.8% proceeded with arthroplasty, while 18.2% cancelled due to improvement in symptoms. A contralateral knee arthroplasty had been performed in 10(22.8%), and previous arthroscopy in 15(34.1%) cases. Advanced radiological changes were observed in 33(75.0%) cases. Based on available information, surgery was deemed appropriate in 54.5%, questionable 15.9%, and perhaps inappropriate in 4.5% cases (insufficient information for categorisation 25.0%). Conclusion. A small group of patients deemed appropriate for knee arthroplasty present with high pre-operative OKS. Pre-operative OKS appears insensitive to the individual factors involved in defining treatment allocation, and further assessment is required. Introduction of pre-operative threshold scores cannot be currently recommended for knee arthroplasty

Background: In a recent publication from the National Joint Registry it was suggested that prosthesis type influenced patient satisfaction at one year following knee arthroplasty. In this report Unicondylar Replacement (UKR) was associated with lower levels of patient satisfaction when compared to cemented TKR. The unicondylar group did however have a significantly lower Oxford Knee Score (OKS) than the TKR group and this occurred irrespective of patient age. A common perception is that UKR is only offered to patients with lesser disease, with a decreased clinical profile. This may explain their higher levels of dissatisfaction as the overall change in their OKS from pre to post operation would be relatively smaller than for TKR. Aim: We hypothesised that patients listed for UKR have less severe disease and therefore a lower preoperative OKS when compared to TKR. Methods: After sample size calculation we retrospectively analysed 76 patients who underwent either UKR or TKR under the care of a single surgeon. OKS was recorded at a dedicated pre-assessment clinic. The decision to offer UKR was based on clinical and radiological criteria as outlined by the Oxford group. Results: There were 38 patients in either group. The mean pre-operative OKS was 39.5 (26–56, SD 7.6) in the UKR group and 41.6 (31–51, SD 5.7) in the TKR group. There was no statistical difference between these two groups (p=0.18). Discussion: Patients listed for knee replacement have significant pain and functional impairment. In our population those suitable for UKR have similarly severe symptoms to those who do not meet the criteria for UKR and are only eligible for TKR. It remains unclear why patients undergoing UKR should be less satisfied when they have better post operative patient reported outcome scores. It emphasizes the need for careful patient selection and counselling in patient undergoing UKR