Multi-tissue epigenetic analysis of the osteoarthritis susceptibility locus mapping to the plectin gene PLEC.

OBJECTIVE: In cartilage, the osteoarthritis (OA) associated single nucleotide polymorphism (SNP) rs11780978 correlates with differential expression of PLEC, and with differential methylation of PLEC CpG dinucleotides, forming eQTLs and mQTLs respectively. This implies that methylation links chondrocyte genotype and phenotype, thus driving the functional effect of this genetic risk signal. PLEC encodes plectin, a cytoskeletal protein that enables tissues to respond to mechanical forces. We sought to assess whether these PLEC functional effects were cartilage specific. METHOD: Cartilage, fat pad, synovium and peripheral blood were collected from patients undergoing arthroplasty. PLEC CpGs were analysed for mQTLs and allelic expression imbalance (AEI) was performed to test for eQTLs. Plectin was knocked down in a mesenchymal stem cell (MSC) line using CRISPR/Cas9 and cells phenotyped by RNA-sequencing. RESULTS: mQTLs were discovered in fat pad, synovium and blood. Their effects were however stronger in the joint tissues and of comparable effect between these tissues. We observed AEI in synovium in the same direction as for cartilage and correlations between methylation and PLEC expression. Knocking-down plectin impacted on pathways reported to have a role in OA, including Wnt signalling, glycosaminoglycan biosynthesis and immune regulation. CONCLUSIONS: Synovium is also a target of the rs11780978 OA association functionally operating on PLEC. In fat pad, mQTLs were identified but these did not correlate with PLEC expression, suggesting the functional effect is not joint-wide. Our study highlights interplay between genetic risk, DNA methylation and gene expression in OA, and reveals clear differences between tissues from the same diseased joint.

Identification of long non-coding RNAs expressed in knee and hip osteoarthritic cartilage.

OBJECTIVE: Long intergenic non-coding RNAs (lincRNAs) are emerging as key regulators in gene expression; however, little is known about the lincRNA expression changes that occur in osteoarthritis (OA). Here we aimed to define a transcriptome of lncRNAs in OA cartilage, specifically comparing the lincRNA transcriptome of knee and hip cartilage. METHOD: RNA-seq was performed on nucleic acid extracted from hip cartilage from patients undergoing joint replacement surgery because of either OA (n = 10) or because of a neck of femur fracture (NOF; n = 6). After transcript alignment, counts were performed using Salmon and differential expression for ENSEMBL lincRNAs determined using DESeq2. Hip RNA-seq lincRNA expression was compared to a knee dataset (ArrayExpress; E-MTAB-4304). ChIP-seq data from ENCODE was used to determine whether lincRNAs were associated with promoters (plncRNA) or unidirectional enhancer-like regulatory elements (elncRNAs). RESULTS: Our analysis of the hip transcriptome identified 1692 expressed Transcripts Per Million (TPM ≥1) Ensembl lincRNAs, of which 198 were significantly (FDR ≤0.05) differentially expressed in OA vs normal (NOF) cartilage. Similar analysis of knee cartilage transcriptome identified 648 Emsembl lincRNAs with 93 significantly (FDR ≤0.05) differentially expressed in intact vs damaged cartilage. In total, 1834 lincRNAs were expressed in both hip and knee cartilage, with a highly significant correlation in expression between the two cartilages. CONCLUSION: This is the first study to use RNA-seq to map and compare the lincRNA transcriptomes of hip and knee cartilage. We propose that lincRNAs expressed selectively in cartilage, or showing differential expression in OA, will play a role in cartilage homoeostasis.

Increased symptoms of stiffness 1 year after total knee arthroplasty are associated with a worse functional outcome and lower rate of patient satisfaction.

PURPOSE: Symptoms of stiffness after total knee arthroplasty (TKA) cause significant morbidity, but there is limited data to facilitate identification of those most at risk after surgery. Stratifying risk can aid earlier directed treatment options. METHODS: A retrospective cohort consisting of 2589 patients undergoing a primary TKA was identified from an established arthroplasty database. Patient demographics, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and short form (SF) 12 scores were collected pre-operatively and 1 year post-operatively. In addition, patient satisfaction was assessed for 1 year. Patients with a worse WOMAC stiffness score in 1 year were defined as the "increased" stiffness group and the other cohort as the non-stiffness group. RESULTS: At 1 year after surgery 129 (5%) patients had a significant increase in their stiffness symptoms (20%, 95% confidence interval (CI) 17.9-22.0, p < 0.001), and had significantly (all p < 0.001) less of an improvement in their pain, function and total WOMAC scores, and SF-12 scores compared to the non-stiffness group (n = 2460). Patient satisfaction was significantly lower (odds ratio (OR) 0.178, CI 0.121 to 0.262, p < 0.001) for the increased stiffness group. Logistic regression analysis identified male gender (OR 1.66, p = 0.02), lung disease (OR 2.06, p = 0.002), diabetes (OR 1.82, p = 0.02), back pain (OR 1.81, p = 0.005), and a pre-operative stiffness score of 44 or more (OR 5.79, p < 0.001) were significantly predictive of increased stiffness. CONCLUSION: Patients with increased symptoms of stiffness after TKA have a worse functional outcome and a lower rate of patient satisfaction, and patients at risk of being in this group should be informed pre-operatively. LEVEL OF EVIDENCE: Retrospective prognostic study, Level III.

Patient age of less than 55 years is not an independent predictor of functional improvement or satisfaction after total knee arthroplasty.

INTRODUCTION: Management of the young patient with end-stage osteoarthritis of the knee is difficult, with surgical options of osteotomy, partial or total knee arthroplasty (TKA). The primary aim of this study was to assess whether age of less than 55 years was an independent predictor of functional outcome and satisfaction after total knee arthroplasty (TKA). The secondary aims were to identify pre-operative differences in patient demographics, comorbidity and function between patients less than 55 years old compared to those 55 years old and over. MATERIALS AND METHODS: A retrospective cohort consisting of 2589 patients undergoing a primary TKA was identified from an established arthroplasty database. Patient demographics, comorbidity, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Short Form (SF) 12 scores were collected pre-operatively and 1 year post-operatively. In addition, patient satisfaction was assessed at 1 year. Regression analysis was used to identify independent pre-operative predictors of change in the WOMAC and SF-12 scores, and patient satisfaction. RESULTS: Patients less than 55 years old were significantly less likely to be satisfied with the overall outcome of their TKA (OR 0.4, p = 0.001). After adjusting for confounding variables age group was not an independent predictor of overall satisfaction with overall outcome (OR 0.71, p = 0.16). Independent predictors of an increased risk of dissatisfaction with the overall outcome at 1 year were depression (OR 0.58, p = 0.008) and worse pre-operative SF-12 MCS (p = 0.04). CONCLUSION: Age of less than 55 years is not an independent predictor of functional outcome or rate of patient satisfaction after TKA. However, depression and poor mental health are significantly more prevalent in patients less than 55 years old and were independently associated with a lower satisfaction rate.

Patient-reported factors influencing return to work after joint replacement.

BACKGROUND: An increasing number of patients in the working population are undergoing total hip and knee replacement for osteoarthritis and the timing and success of return to work (RTW) is becoming increasingly important as a measure of success for these patients. There is limited understanding of the patient variables that determine the ability to RTW. AIMS: To explore the factors influencing RTW following hip and knee replacement from the patient's perspective. METHODS: A cross-sectional population-based postal survey carried out with patients of working age after hip and knee replacement surgery in a UK teaching hospital. Free text comments were collected regarding the experiences of patients returning to work following hip and knee replacement. Qualitative thematic analysis was undertaken to identify the factors influencing RTW from the patient's perspective. RESULTS: From the patients' perspective three key factors were identified that influenced RTW. Patients reported an improved physical and psychological performance at work after surgery in comparison to pre-operative functioning, although there was a lack of informed advice regarding RTW after surgery. Workplace support and adaptation of the job role enhanced the experience of RTW. CONCLUSIONS: Return to work is influenced by a combination of patient, clinician and occupational factors. The relationship between each of these needs to be explored in greater depth through further qualitative work to gain a wider understanding of the variables influencing patients' RTW following hip and knee replacement.

Understanding the patient-reported factors determining time taken to return to work after hip and knee arthroplasty.

PURPOSE: The key factors underscoring safe and early return to work after hip (THA) or knee (TKA) arthroplasty are poorly defined. The aim of this study was to evaluate the effect of patient-reported variables upon time taken to return to work after THA or TKA in a working population. METHODS: Questionnaires asking about employment history, education, general health and experiences of returning to work after THA and TKA were administered by post and at outpatients' clinic. RESULTS: One hundred and two from 272 eligible patients, of whom 52 had undergone THA and 50 TKA, were recruited sequentially. In total, 83 patients were employed pre-operatively and 80 returned to work at median 12 (2-64) weeks. Those in more manual occupations (p = 0.001) without pre-operative sick leave due to their hip or knee arthritis (p = 0.016) and a higher level of qualification (p = 0.041) returned to employment significantly quicker than the rest of the cohort. THA patients report a greater improvement in terms of performance at work (63 vs 44 %, p = 0.007) and job prospects (50 vs 36 %, p = 0.046) as compared with patients after TKA. CONCLUSIONS: Patients with pre-operative sick leave, basic or no qualifications and more physically demanding occupations take longer to return to work. Operating patients before their arthritis forces them to become unemployed would improve their chances to return to work. Hip arthroplasty patients have a greater perceived benefit in terms of performance at work and job prospect. A more tailored return to work time predictions to allow a faster return to work and avoid frustration. LEVEL OF EVIDENCE: IV.

Isolated popliteus tendon injury does not lead to abnormal laxity in posterior-stabilised total knee arthroplasty.

PURPOSE: The popliteus tendon is crucial to postero-lateral stability and prone to iatrogenic injury intra-operatively. Its role in the stability of the replaced knee remains contentious. The aim of this study was to use computer navigation to quantify the effect of popliteus sectioning on the 'envelope of laxity' (EoL) offered by a posterior-stabilised (PS) total knee arthroplasty (TKA) and compare with that of the native knee. METHODS: Loaded cadaveric legs were mounted on a purpose built rig. EoL was measured in 3 degrees of freedom using computer navigation. Knees were subjectively stressed in varus/valgus, internal/external rotation and anterior draw. This was performed preoperatively, during TKA and after sectioning of the popliteus tendon. Real-time data were recorded at 0°, 30°, 60° and 90° of flexion as the operating surgeon stressed the knee in 3 degrees of freedom to its subjective endpoint. Mixed-effect modelling was used to quantify the effects of intervention on degree of laxity. RESULTS: In all conditions, there was an increase in laxity with knee flexion. Insertion of a PS TKA resulted in increased constraint, particularly in rotation. Sectioning of the popliteus did not result in a significant increase in knee laxity to 90º of knee flexion. However, at deeper flexion angles, tendon sectioning overcame the constraints of the implant resulting in a significant increase in rotatory and varus/valgus laxity towards the native condition. CONCLUSION: These findings support the view that certain current designs of PS knee replacement can constrain the knee in flexion in the absence of postero-lateral deficiency. For this implant, isolated sectioning of the popliteus tendon did not substantially generate abnormal knee laxity.

Factors influencing return to work after hip and knee replacement.

BACKGROUND: Return to employment is one of the key goals of joint replacement surgery in the working-age population. There is limited quantitative and qualitative research focusing on return to work after hip and knee replacement. It remains unclear why certain groups of patients are not able to achieve sufficient functional improvement to allow productive return to work while others can. Very little is known about the individual patient and employer perspectives in this regard. AIMS: To review current evidence for the factors influencing employment outcomes in patients undergoing hip and knee replacement. METHODS: Original articles and reviews in Medline, Embase and PsycINFO from 1987 to 2013 were included in the analysis. RESULTS: Age, patient motivation, employment before surgery and type of job were found to be important factors in determining return to work following hip and knee replacement. CONCLUSIONS: There is a need for further qualitative work on how and why these factors influence employment outcomes.

No difference in patellar tracking between symmetrical and asymmetrical femoral component designs in TKA.

PURPOSE: Poor knee extension function after total knee arthroplasty (TKA) is associated with factors including articular geometry and alignment. Femoral trochlear geometry has evolved from symmetrical to become more prominent proximal-laterally, with the groove aligned proximal-lateral to distal-medial. This study in vitro tested the hypothesis that a modern asymmetrical prosthesis would restore patellar tracking and stability to more natural behaviour than an older symmetrical prosthesis. METHODS: Six knees had their patellar tracking measured optically during active knee extension. Medial-lateral force versus displacement stability was measured at fixed angles of knee flexion. The measurements were repeated after inserting each of the symmetrical and asymmetrical TKAs. RESULTS: Significant differences of patellar lateral displacement stability, compared to normal, were not found at any angle of knee flexion. The patella tracked medial-laterally within 2.5 mm of the natural path with both TKAs. However, for both TKAs near knee extension, the patella was tilted laterally by approximately 6° and was also flexed approximately 8° more than in the natural knee. CONCLUSION: The hypothesis was not supported: The more anatomical component design did not provide more anatomical patellar kinematics and stability.

Can we define envelope of laxity during navigated knee arthroplasty?

PURPOSE: Functional outcomes after knee arthroplasty (TKA) remain poor. The ability to restore the soft tissue envelope intraoperatively may improve such outcomes. The aim of this study was to extend the scope of computer navigation as a tool to quantifying the envelope of laxity during subjective stress testing preoperatively and to quantify the effects of knee replacement and how it changes as a result of ligamentous failure. METHODS: Loaded cadaveric legs were mounted on a purpose-built rig. Envelope of laxity was measured in 3 degrees of freedom using computer navigation. Knees were subjectively stressed in varus/valgus, internal/external rotation and anterior draw. This was performed preoperatively, during TKA and after sequential sectioning of ligaments. Real-time data were recorded at 0°, 30°, 60° and 90° of flexion. Mixed effect modelling was used to quantify the effects of intervention on degree of laxity. RESULTS: In all cases, there was an increase in laxity with increasing flexion or ligament sectioning. Operator and movement cycle had no effect. Insertion of a TKA showed increased stability within the joint, especially in internal/external rotation and anterior drawer. Once the PCL and popliteus were cut, the implant only maintained some rotatory stability; thereafter, the soft tissue envelope failed. CONCLUSIONS: This work has shown a novel way by which computer navigation can be used to analyse soft tissue behaviour during TKA beyond the coronal plane and throughout range of motion. Despite subjective stress testing, our results show reproducible patterns of soft tissue behaviour-in particular a wide range of mid-flexion excursion. It also quantifies the limits within which a cruciate-retaining TKR can maintain knee stability. This functionality may guide the surgeon in identifying and/or preventing soft tissue imbalances intra-operatively, improving functional results.

Analysis of sequential cytokine release after ACL reconstruction.

PURPOSE: Rupture of the anterior cruciate ligament is common and may necessitate surgical reconstruction. Surgical reconstruction aims to restore normal kinematics and biology within the knee. The acute phase response after surgical reconstruction remains poorly defined but may influence graft integration through modulation of host tissue remodelling. METHODS: The very early host production of key cytokines after surgery was studied. A consecutive series of 14 patients undergoing reconstructive surgery were studied per-operatively, 1 and 6 h after surgery, examining the hypothesis that the acute phase response would be non-specific but consistent between individuals, demonstrating increases of pro-inflammatory cytokines. RESULTS: A consistent increased release of monocyte-driven, non-specific, IL-1 and IL-6 release but not T cell-derived IL-2 was found. Perhaps, more interestingly, very early high concentrations of secondary growth factors PDGF and TGF-ß suggestive of an anabolic response were found. CONCLUSION: These data support the contention that an anabolic response starts earlier than previously thought within the surgically reconstructed knee.

The effect of femoral component rotation on the kinematics of the tibiofemoral and patellofemoral joints after total knee arthroplasty.

PURPOSE: Complications after total knee arthroplasty (TKA) often involve the patellofemoral joint, and problems with patellar maltracking or lateral instability have sometimes been addressed by external rotation of the femoral component. This work sought to measure the changes of knee kinematics caused by TKA and then to optimise the restoration of both the patellofemoral and tibiofemoral joint kinematics, by variation of femoral component internal-external rotation. METHODS: The kinematics of the patella and tibia were measured in eight cadaveric knees during active extension motion. This was repeated with the knee intact, with a Genesis II TKA in the standard position (3° of external rotation) and with the femoral component at ±5° rotation from there. RESULTS: Both patellar and tibial motions were significantly different from normal with the standard TKA rotation, with 3° tibial abduction at 90° flexion and reversal of the screw-home from 5° external rotation to 6° internal rotation. The patella was shifted medially 6 mm in flexion and tilted 7° more laterally near extension. Femoral rotation to address one abnormality caused increased abnormality in other degrees of freedom. Internal and then external rotation of 5° caused tibial abduction and then adduction of 5° at 90° flexion. These femoral rotations also caused increased patellar lateral tilt of 4° with femoral external rotation and decreased tilt by 4° with internal rotation. Thus, correction of tibial abduction in flexion, by external rotation of the femoral component, worsened the patellar lateral tilt near extension. CONCLUSIONS: It was concluded that femoral rotation alone could not restore all aspects of both patellar and tibial kinematics to normal with this specific implant. The clinical relevance of this is that it appears to be inadvisable to reposition the femoral component, in an attempt to improve patellar tracking, if that repositioning may then cause abnormal tibiofemoral kinematics. Further, the pattern of patellar tracking, with the type of TKA used in this study, could not be adjusted to normal by femoral component rotation.

Sex does not clinically influence the functional outcome of total knee arthroplasty but females have a lower rate of satisfaction with pain relief.

BACKGROUND: The aims were to assess whether sex had a clinically significant independent influence on the outcome of total knee arthroplasty (TKA) according to the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, Short Form (SF-) 12 scores and patient satisfaction at 1 year. METHODS: A retrospective cohort of 3510 primary TKA were identified. Patient demographics, comorbidities, WOMAC and SF-12 scores were collected preoperatively and 1 year postoperatively. Patient satisfaction were assessed at 1 year. RESULTS: There were 1584 males and 1926 females. The preoperative WOMAC and SF-12 scores were significantly (p < 0.001) worse in females but were not greater than the minimal clinically important difference (MCID). When adjustments had been made for confounding differences, females showed a significantly greater improvement in their function (1.5 points, p = 0.03) and total (1.5 points, p = 0.03) WOMAC scores compared to males, but these were not greater than the MCID. When adjustments had been made for confounding differences, females were less likely to be satisfied with their pain relief (p = 0.03) relative to males. CONCLUSION: Sex does not clinically influence the knee specific outcome (WOMAC) or overall generic (SF-12) health 1 year after TKA. However, satisfaction with pain relief after TKA was significantly less likely in female patients. LEVEL OF EVIDENCE II: Prognostic retrospective cohort study.

The epidemiology of ankle injuries occurring in English Football Association academies.

OBJECTIVE: To ascertain the epidemiology of ankle injuries in elite youth football. DESIGN: Retrospective analysis of prospectively collected injury data from English Football Association (FA) academies. SETTING: Forty-one FA football academies, between 1998 and 2006. PARTICIPANTS: For the complete seasons studied, a total of 14 776 players was registered from U9 to the U16 age category, a mean of 2463 players per year. All ankle injuries of sufficient severity to miss 48 h or more of training were studied, 2563 injuries in total. MAIN OUTCOME MEASURE: The incidence and burden of ankle injuries in this population and factors associated with injury. RESULTS: There was a mean incidence of one ankle injury per player per year, and a mean of 20 training days and two matches were missed per ankle injury. Increased injury rates were seen in older players, in competition and later in each half of match time. Peaks in injury were observed early in the season and after the winter break. In competition, more injuries were associated with a contact situation than in training. Eighty-eight injuries (3.4%) required a lay-off of 3 months or more and in 18 (0.7%) cases the player failed to return to training. In total, 52 290 training days and 5182 match appearances were lost through ankle injury. The majority of injuries were sprains, but more severe injuries occurred accounted for 3.9% of the total. CONCLUSIONS: Ankle injuries are common in young football players and are often severe, with prolonged loss of training time. This has potential far-reaching implications, both on and off the field.

The effect of overstuffing the patellofemoral joint on the extensor retinaculum of the knee.

Overstuffing the patellofemoral compartment during TKR leads to complications such as maltracking and wear, predisposing to early failure. However, there is no data describing how the patellar construct thickness affects the retinacula. This study instrumented cadaveric knees that had a Genesis II (Smith & Nephew, Memphis, TN, USA) TKR in situ. Sutures were passed along the medial patellofemoral ligament (MPFL) and the deep transverse fibre band of the lateral retinaculum, from the ilio-tibial band (ITB) to the patella. These sutures were attached to displacement transducers. Length changes in the retinacula were measured during knee flexion-extension against the actions of 175 N quadriceps and 30 N ITB tensions. This was done with the natural patellar thickness, then repeated with the patella 2 mm thinner, 2 mm thicker and 4 mm thicker (overstuffed). Each thickness change caused a significant overall slackening or stretching of the MPFL (P < 0.0001 by ANOVA), with 2.3 mm mean stretching (P < 0.001 all angles of knee flexion by post-testing) at 4 mm thicker. The ITB-patellar band was not slackened (P = 0.491) or stretched (P = 0.346) significantly by 2 mm thickness changes. 4 mm thickening stretched the lateral retinaculum 1.1 mm (P = 0.0108). Patellar thickness affected the MPFL more than the lateral retinaculum. This difference reflected the mobile attachment of the lateral retinaculum to the ITB, whereas the MPFL was stretched directly between bony attachments. 2 mm overstuffing did not stretch the retinacula sufficiently to cause mechanical effects.

Predicting range of movement after knee replacement: the importance of posterior condylar offset and tibial slope.

We have attempted to quantify the influence of clinical, radiological and prosthetic design factors upon flexion following knee replacement. Our study examined the outcome following 101 knee replacements performed in two prospective randomized trials using similar cruciate retaining implants. Multivariate analyses, after adjusting for age, sex, diagnosis and the type of prosthesis revealed that the only significant correlates for range of movement at 12 months were the difference in posterior condylar offset ratio (p < 0.001), tibial slope (p < 0.001) and preoperative range of movement (p = 0.025). We found a moderate correlation between 12-month range of movement and posterior tibial slope (R = 0.58) and the difference of post femoral condylar offset (i.e, post-operative minus preoperative posterior condylar offset, R = 0.65). Posterior condylar offset had the greatest impact upon final range of movement highlighting this as an important consideration for the operating surgeon at pre-operative templating when choosing both the design and size of the femoral component.

Meaningful changes in the Short Form 12 physical and mental summary scores after total knee arthroplasty.

BACKGROUND: The aim of this study was to identify minimal clinically important difference (MCID), minimal important change (MIC) and minimal detectable change (MDC) for the Short Form (SF-) 12 physical and mental component summary (PCS, MCS) scores after total knee arthroplasty (TKA) using an anchor based methodology. METHODS: During a 10-year period, 2589 TKA were performed. SF-12 PCS and MCS scores were recorded preoperatively and at one year postoperatively. At one year, patients were asked "How much did the knee replacement surgery improve the quality of your life?" Their response was recorded as: a great improvement, moderate improvement, little improvement, no improvement at all, or the quality of my life is worse. Patients recording a little (n = 211) and no (n = 115) were used to calculate the MCID and the MIC. The MDC90 was calculated using distribution based methods for the whole cohort. RESULTS: The MCID was 1.8 (p = 0.04) for the PCS and 1.5 (p = 0.33) for the MCS score. The MIC was 2.7 (p = 0.04) for the PCS and -1.4 (p = 0.17) for the MCS score. The MDC90 was 8.9 for the PCS and 13.8 for the MCS score. CONCLUSION: The MCID for the PCS can be used to compare the outcomes between groups, and the MIC can be used to ensure that a clinical difference has been observed for a cohort of patients. The values for the MDC90 can be used to assess whether or not an individual patient has experienced a change.

Cemented Exeter total hip arthroplasty with a 32 mm head on highly crosslinked polyethylene: Does age influence functional outcome, satisfaction, activity, stem migration, and periprosthetic bone mineral density?

OBJECTIVES: Our primary aim was to describe migration of the Exeter stem with a 32 mm head on highly crosslinked polyethylene and whether this is influenced by age. Our secondary aims were to assess functional outcome, satisfaction, activity, and bone mineral density (BMD) according to age. PATIENTS AND METHODS: A prospective cohort study was conducted. Patients were recruited into three age groups: less than 65 years (n = 65), 65 to 74 years (n = 68), and 75 years and older (n = 67). There were 200 patients enrolled in the study, of whom 115 were female and 85 were male, with a mean age of 69.9 years (sd 9.5, 42 to 92). They were assessed preoperatively, and at three, 12 and, 24 months postoperatively. Stem migration was assessed using Einzel-Bild-Röntgen-Analyse (EBRA). Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Harris Hip Score (HHS), Hip Disability and Osteoarthritis Outcome Score (HOOS), EuroQol-5 domains questionnaire (EQ-5D), short form-36 questionnaire (SF-36,) and patient satisfaction were used to assess outcome. The Lower Extremity Activity Scale (LEAS), Timed Up and Go (TUG) test, and activPAL monitor (energy expelled, time lying/standing/walking and step count) were used to assess activity. The BMD was assessed in Gruen and Charnley zones. RESULTS: Mean varus/valgus tilt was -0.77° and axial subsidence was -1.20 mm. No significant difference was observed between age groups (p ⩾ 0.07). There was no difference according to age group for postoperative WOMAC (p ⩾ 0.11), HHS (p ⩾ 0.06), HOOS (p ⩾ 0.46), EQ-5D (p ⩾ 0.38), patient satisfaction (p ⩾ 0.05), or activPAL (p ⩾ 0.06). Patients 75 years and older had a worse SF-36 physical function (p = 0.01) and physical role (p = 0.03), LEAS score (p < 0.001), a shorter TUG (p = 0.01), and a lower BMD in Charnley zone 1 (p = 0.02). CONCLUSION: Exeter stem migration is within normal limits and is not influenced by age group. Functional outcome, patient satisfaction, activity level, and periprosthetic BMD are similar across all age groups.Cite this article: N. D. Clement, M. Bardgett, K. Merrie, S. Furtado, R. Bowman, D. J. Langton, D. J. Deehan, J. Holland. Cemented Exeter total hip arthroplasty with a 32 mm head on highly crosslinked polyethylene: Does age influence functional outcome, satisfaction, activity, stem migration, and periprosthetic bone mineral density? Bone Joint Res 2019;8:275-287. DOI: 10.1302/2046-3758.86.BJR-2018-0300.R1.

Which patients are satisfied with their overall outcome but dissatisfied with their return to recreational activities after total knee arthroplasty?

BACKGROUND: The primary aim of this study was to assess whether patients dissatisfied with both recreational activities and overall outcome were different to those dissatisfied with recreational activities but satisfied with their overall outcome one year after total knee arthroplasty (TKA). METHODS: A retrospective cohort consisting of 3324 primary TKA were identified from an established arthroplasty database. Patient demographics, comorbidities, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Short Form (SF) 12 scores were collected pre-operatively and one year post-operatively. Overall patient satisfaction and satisfaction with recreational activities were assessed at one year. RESULTS: The rate of patient satisfaction with recreational activities (n = 2672, 80.4%) was significantly (odds ratio (OR) 0.47, 95% confidence intervals (CI) 0.41 to 0.54, p < 0.001) lower than satisfaction with the overall outcome (n = 2982, 89.7%). When adjusting for confounding variables older age (OR 1.03, p = 0.008), increasing BMI (OR 1.05, p = 0.01) and absence of hypertension (OR 0.66, p = 0.02) were independent predictors of being dissatisfied with recreational activities in isolation. The one-year components and total WOMAC scores were significant (p < 0.001) predictors of satisfaction with recreational activities and were reliable with an area under the curve of ≥0.82 CONCLUSION: Patients of older age, higher BMI and without hypertension are more likely to be dissatisfied with recreational activities despite being satisfied with their overall outcome.