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.

Aims

The primary aim of this study is to assess the survival of the uncemented hydroxyapatite (HA) coated Trident II acetabular component as part of a hybrid total hip arthroplasty (THA) using a cemented Exeter stem. The secondary aims are to assess the complications, joint-specific function, health-related quality of life, and radiological signs of loosening of the acetabular component.

In this RCT the primary aim was to assess whether a short (125mm) Exeter V40 stem offered an equivalent hip specific function compared to the standard (150mm) stem when used for cemented total hip arthroplasty (THA). Secondary aims were to evaluate health-related quality of life (HRQoL), patient satisfaction, stem height and alignment, radiographic loosening, and complications between the two stems.

A prospective multicentre double-blind randomised control trial was conducted. During a 15-month period, 220 patients undergoing THA were randomised to either a standard (n=110) or short (n=110) stem Exeter. There were no significant (p≥0.065) differences in preoperative variables between the groups. Functional outcomes and radiographic assessment were undertaken at 1- and 2-years.

There were no differences (p=0.428) in hip specific function according to the Oxford hip score at 1-year (primary endpoint) or at 2-years (p=0.767) between the groups. The short stem group had greater varus angulation (0.9 degrees, p=0.003) when compared to the standard group and were more likely (odds ratio 2.42, p=0.002) to have varus stem alignment beyond one standard deviation from the mean. There were no significant (p≥0.083) differences in the Forgotten joint scores, EuroQol-5-Dimension, EuroQol-VAS, Short form 12, patient satisfaction, complications, stem height or radiolucent zones at 1 or 2-years between the groups.

The Exeter short stem offers equivalent hip specific function, HRQoL, patient satisfaction, and limb length when compared to the standard stem at 2-years post-operation. However, the short stem was associated with a greater rate of varus malalignment which may influence future implant survival.

Aims

The primary aim of this study was to compare the hip-specific functional outcome of robotic assisted total hip arthroplasty (rTHA) with manual total hip arthroplasty (mTHA) in patients with osteoarthritis (OA). Secondary aims were to compare general health improvement, patient satisfaction, and radiological component position and restoration of leg length between rTHA and mTHA.

Aims

There are comparatively few randomized studies evaluating knee arthroplasty prostheses, and fewer still that report longer-term functional outcomes. The aim of this study was to evaluate mid-term outcomes of an existing implant trial cohort to document changing patient function over time following total knee arthroplasty using longitudinal analytical techniques and to determine whether implant design chosen at time of surgery influenced these outcomes.

The optimal approach for total hip arthroplasty (THA) remains controversial. We present the results of the Direct Superior Approach (DSA), an improved variation of the posterior approach with high levels of stability, patient-reported functional outcomes, and satisfaction.

This is a single-surgeon prospective series. All patients undergoing THA between 2010 and 2015 via the DSA were included. Complication data was collected by interrogation of the Scottish Arthroplasty Project national joint registry. Pre and one-year post-operative Oxford Hip Score (OHS), Euroqol-5D (EQ-5D), and patient satisfaction questionnaires were collected.

659 patients received a THA via the DSA during the study period. Average age was 61.8 years (range 16.4–93.3). Analysis of registry data revealed no cases of dislocation, 5 cases of venous thromboembolism (0.75%), and 5 cases of deep infection (0.75%). 586 patients (88.9%) underwent their surgery in the National Health Service, and post-operative outcomes were available for 337 of these patients (57.5% follow-up) at one year. Average improvement in OHS and EQ-5D was 20 (range −14 – 48) and 0.39 (−0.697–1.2) respectively. 311 patients (92.3%) were satisfied.

This description of the DSA is accessible to all surgeons, confers excellent stability with no dislocations, and is associated with excellent post-operative functional outcomes and patient satisfaction.

The aims of the study were primarily to establish the overall success of debridement, antibiotics and implant retention (DAIR) in the management of infected total hip replacements (THRs) and secondarily to identify risk factors for failure.

Using a standardised and recognised study protocol (“Meta-analysis of observational studies in epidemiology (MOOSE) guidelines) a systematic review and meta-analysis of the literature was performed. The primary outcome measure of interest was treatment success. The search strategy and inclusion criteria plus quality assessment yielded 39 articles eligible for analysis.

The proportion of success from the literature following DAIR in the management of infected THRs is improving over time – the pooled mean proportion of success is 84.5% in studies from 2011–15. There was improved success with early debridement (75.7%) compared with delayed debridement (48.1%) (p=0.006).

The reported outcomes following DAIR appear to be improving with time. One of the most influential determinants of outcome is timing of debridement from onset of symptoms.

Surgeons should have a low threshold for investigating deep infection when presented with an acutely symptomatic THR and be aware of the updated reported outcomes associated with DAIR when considering management options.

Arthroscopic procedures are increasingly performed for femoroacetabular impingement (FAI). The Non-Arthroplasty Hip Register (NAHR) collects data including the iHOT12 and EQ5D. However there is currently little evidence of its usefulness in assessing hip arthroscopy outcomes. This study aims to assess minimum 1-year outcomes of hip arthroscopy for FAI using the minimum data set (MDS) of the NAHR by comparing these to a patient satisfaction questionnaire.

Pre-operative scores for 78 consecutive hips in 76 patients (43F/33M, mean age at surgery 31.76±10.02 years) undergoing hip arthroscopy for FAI at our institution between February 2013-June 2015 were entered into the NAHR. Insufficient post-operative data was available from the registry. Therefore we collected iHOT12, EQ5D and satisfaction data by postal survey.

Preoperative mean iHOT-12 score was 32.67±14.23, median EQ5D Index score 0.653 (IQR 0.277) and median EQ5D Visual Analogue Scale 70 (IQR 25). Postoperative scores were available for 56 cases (55 patients, 71.8%) at median 18.9 months (IQR 13.77). There was a significant postoperative improvement in self-reported outcome as measured by iHOT-12 (mean improvement 35.7 points, p<0.001) and EQ5DIndex scores (median improvement 0.127, p=0.001). 24 patients were very satisfied, 19 satisfied, 6 neutral, 4 dissatisfied and 1 very dissatisfied. Satisfied patients exhibited greater improvement in iHOT-12 (mean 41.64±19.29 vs 2.8±24.08, p<0.001) and EQ5D index scores (p=0.013) but no difference in EQ5D VAS (p=0.15). Improvement in iHOT12 correlated with improvement in EQ5DIndex (r=0.676, p<0.001) and EQ5DVAS(r=0.552, p<0.001).

Hip arthroscopy for FAI yielded significant improvements in iHOT-12 and EQ5D index scores and 80% of responders were satisfied/very satisfied at a minimum one year postop. iHOT12 and EQ5DIndex correlated with patient satisfaction and improvements in iHOT12 correlated with improvements in general quality of life. Our findings suggest that the MDS of the NAHR is useful for assessing the outcome in these patients.

Physical outcome following total knee arthroplasty is variable. Satellite cells are undifferentiated myogenic precursors considered to be muscle stem cells. We hypothesised that; the recovery of muscle strength and physical function following knee arthroplasty would be influenced by the underlying number of muscle satellite cells.

16 patients provided a distal quadriceps muscle biopsy at time of surgery. Satellite cells were identified with a primary mouse antibody for Pax7 – a cytoplasmic protein marker, and the myonuclei with DAPI. Positive cells were identified on the basis of immunofluorescent staining in association with nuclear material, and confirmed by position under the basal lamina. Patient function was assessed using a validated physical assessment protocol, the Aggregated Locomotor Function (ALF) score, muscle strength assessed using the leg extensor power-rig, and clinical outcome assessed with the Oxford Knee Score (OKS) pre-operatively and at 1 year post operatively.

Muscle satellite cell content varied amongst the patient group (Positive Staining Index 3.1 to 11.4). Satellite cell content at time of surgery correlated with change in outcomes between pre-operative and 1 year assessments in all assessed parameters (ALF, r = 0.31; muscle power, r = 49; OKS, r = 0.33). Regression analysis employing a forward stepwise selection technique employed satellite cell volume in models of pre-operative to 1 year change for all outcome parameters. Physical function (satellite cell content, patient age and pre-operative ALF score) adjusted R2 = 0.92; Muscle power (pre-operative power and satellite cell content) adjusted R2 = 0.38; Clinical outcome (pre-operative OKS and satellite cell content) adjusted R2 = 0.28.

Muscle satellite cell content influences recovery of muscle power and physical function following total knee arthroplasty. Importantly it is also associated with change in clinical scores; suggesting it to be a biomarker for patient outcomes.

Total knee arthroplasty (TKA) is an established and successful procedure. However, the design of prostheses continues to be modified in an attempt to optimise the functional outcome of the patient.

The aim of this study was to determine if patient outcome after TKA was influenced by the design of the prosthesis used.

A total of 212 patients (mean age 69; 43 to 92; 131 female (62%), 81 male (32%)) were enrolled in a single centre double-blind trial and randomised to receive either a Kinemax (group 1) or a Triathlon (group 2) TKA.

Patients were assessed pre-operatively, at six weeks, six months, one year and three years after surgery. The outcome assessments used were the Oxford Knee Score; range of movement; pain numerical rating scales; lower limb power output; timed functional assessment battery and a satisfaction survey. Data were assessed incorporating change over all assessment time points, using repeated measures analysis of variance longitudinal mixed models. Implant group 2 showed a significantly greater range of movement (p = 0.009), greater lower limb power output (p = 0.026) and reduced report of ‘worst daily pain’ (p = 0.003) over the three years of follow-up. Differences in Oxford Knee Score (p = 0.09), report of ‘average daily pain’ (p = 0.57) and timed functional performance tasks (p = 0.23) did not reach statistical significance. Satisfaction with outcome was significantly better in group 2 (p = 0.001).

These results suggest that patient outcome after TKA can be influenced by the prosthesis used.

Cite this article: Bone Joint J 2015;97-B:64–70.

Summary Statement

Service industry metrics (the net promoter score) are being introduced as a measure of UK healthcare satisfaction. Lower limb arthroplasty, as a ‘service’, scores comparably with the most successful commercial organisations.

Summary Statement

Using current analysis/methodology, new implant technology is unlikely to demonstrate a large enough change in patient function to impact on the cost-effectiveness of the procedure.

Satisfaction with care is important to both patients and to those who pay for it. The Net Promoter Score (NPS), widely used in the service industries, has been introduced into the NHS as the ‘friends and family test’; an overarching measure of patient satisfaction. It assesses the likelihood of the patient recommending the healthcare received to another, and is seen as a discriminator of healthcare performance. We prospectively assessed 6186 individuals undergoing primary lower limb joint replacement at a single university hospital to determine the Net Promoter Score for joint replacements and to evaluate which factors contributed to the response.

Achieving pain relief (odds ratio (OR) 2.13, confidence interval (CI) 1.83 to 2.49), the meeting of pre-operative expectation (OR 2.57, CI 2.24 to 2.97), and the hospital experience (OR 2.33, CI 2.03 to 2.68) are the domains that explain whether a patient would recommend joint replacement services. These three factors, combined with the type of surgery undertaken (OR 2.31, CI 1.68 to 3.17), drove a predictive model that was able to explain 95% of the variation in the patient’s recommendation response. Though intuitively similar, this ‘recommendation’ metric was found to be materially different to satisfaction responses. The difference between THR (NPS 71) and TKR (NPS 49) suggests that no overarching score for a department should be used without an adjustment for case mix. However, the Net Promoter Score does measure a further important dimension to our existing metrics: the patient experience of healthcare delivery.

Cite this article: Bone Joint J 2014;96-B:622–8.

Objectives

Lower limb muscle power is thought to influence outcome following total knee replacement (TKR). Post-operative deficits in muscle strength are commonly reported, although not explained. We hypothesised that post-operative recovery of lower limb muscle power would be influenced by the number of satellite cells in the quadriceps muscle at time of surgery.

INTRODUCTION

This study investigates the relationship between direct measurement of outcome and patient report of that outcome via the OKS. The stability of this relationship over time following surgery is also assessed.

Introduction

Many prosthetic design changes have been introduced in attempt to improve outcomes following TKA; however there is no consensus as to whether these changes confer benefits to patients. This study aimed to assess whether patients treated with a modern implant design had an enhanced patient outcome compared to a traditional model in a double blind randomised controlled trial.

End-stage osteoarthritis is characterised by pain and reduced physical function, for which total knee arthroplasty (TKA) is recognised to be a highly effective treatment. Most implants are multi radius in design, though modern kinematic theory suggests a single flexion/extension axis is located in the femur. A recently launched TKA implant (Triathlon, Stryker US), is based on this theory, adopting a single radius of curvature femoral component. It is hypothesised that this design allows better function, and specifically, that it results in enhanced efficiency of the quadriceps group through a longer patello-femoral moment arm.

Change in power output was compared between single and multi radius implants as part of a larger ongoing randomised controlled trial to benchmark the new implant. Power output was assessed using a Leg Extensor Power Rig, well validated for use with this population, pre-operatively and at 6, 26 and 52 weeks post-operatively in 101 Triathlon and 82 Kinemax implants. All patients were diagnosed with osteoarthritis, and drawn from a single centre. Output was reported as maximal wattage (W) generated in a single leg extension, and expressed as a proportion of the contralateral limb power output to act as an internal control.

The results are shown in the table below. Two-way repeated measures ANOVA demonstrated a significant effect of TKA on the quadriceps power output, F = 249.09, p = <0.001 and also a significant interaction of the implant group on the output F = 11.33, p = 0.001. Independent samples t-tests of between group differences at the four assessment periods highlighted greater improvement in the single radius TKA group at all post-operative assessments (p <0.03), see table.

The theoretical enhanced quadriceps efficiency conferred by single radius design was found in this study. Power output was significantly greater at all post-operative assessments in the single radius compared to the multi radius group. This difference was particularly relevant at early 6 week and 1 year assessment. Lower limb power output is known to link positively to functional ability. The results support the hypothesis that TKAs with a single radius design have enhanced recovery and better function.

Introduction

Recovery of muscle strength following Total Knee Replacement (TKR) is variable, and can affect the resultant function of the patient. Satellite cells are undifferentiated myogenic precursors considered to be muscle stem cells that lie quiescently around the muscle fibre. These cells repair damaged fibres and have the potential to generate new muscle fibres. Therefore, theoretically, they could be associated with the variation in muscle recovery following surgery. We hypothesised that the recovery of muscle strength following knee replacement in a given patient would be influenced by the underlying number of satellite cells in that patient.

Aim

To investigate the incidence, types and trends in diagnosis of venous thromboembolic events (VTE) in patients undergoing total knee arthroplasty (TKA) over a ten-year period.

Introduction: Patient-reported outcome and satisfaction scores have become increasingly important in evaluating successful surgery. There is continued enthusiasm for metal-on-metal resurfacing of the hip, particularly as an alternative to total hip replacement (THR) in young, active patients with osteoarthritis. However, although mid-term survivorship data is promising, it remains unclear whether patient-reported outcomes following resurfacing match those following THR.

Patients and Methods: This case-matched control study compared patient-reported outcome and satisfaction data following hip resurfacing and total hip arthroplasty. Thirty-three consecutive patients selected for hip resurfacing were compared with 99 patients undergoing cemented total hip replacement (THR), matched for age, sex and pathology. Participants completed a Short-Form 12 Health Survey (SF-12) and Oxford Hip Score (OHS) questionnaire pre-operatively and 6 months post operatively, with an additional patient satisfaction questionnaire.

Results: There was no difference in length of hospital stay. Both groups reported improved outcome scores, with mean OHS improvements of 19.5 (95% CI: 17.0–22.1), and 20.6 (95% CI: 18.6–22.5) following resurfacing and THR respectively. There were similar improvements in SF-12 PCS of 14.2 (95% CI: 9.5 to 14.2) and 15.2 (95% CI: 13.2 to 18.2) for the resurfacing and THR groups respectively. The improvement in outcome scores did not differ between the two groups on multivariate regression analysis (P=0.509 for OHS, P=0.629 for SF-12 PCS). Both groups reported high levels of satisfaction, which tended to be better in patients undergoing hip resurfacing (97.0% vs 92.9%), with resurfacing patients reporting better pain relief (P=0.022) and better heavy lifting (P=0.038) at 6 months.

Discussion: This study shows that the short-term patient-centred outcome scores for hip resurfacing are at least as good as for conventional hip replacement, with slightly higher levels of satisfaction.