The December 2012 Hip & Pelvis Roundup³⁶⁰ looks at: swimming against the tide with resurfacing; hip impingement surgery; the relationship between obesity and co-morbidities and joint replacement infection; cemented hips; cross-linked polyethylene notching; whether cement is necessary in oncological arthroplasty; and how total hip replacement may result in weight gain.

There has been an in increase in the availability of effective biological agents for the treatment of rheumatoid arthritis as well as a shift towards early diagnosis and management of the inflammatory process. This article explores the impact this may have on the place of orthopaedic surgery in the management of patients with rheumatoid arthritis.

Cite this article: Bone Joint J 2014;96-B:1287–9

Many different designs of total hip arthroplasty (THA) with varying performance and cost are available. The identification of those which are the most cost-effective could allow significant cost-savings. We used an established Markov model to examine the cost effectiveness of five frequently used categories of THA which differed according to bearing surface and mode of fixation, using data from the National Joint Registry for England and Wales. Kaplan–Meier analyses of rates of revision for men and women were modelled with parametric distributions. Costs of devices were provided by the NHS Supply Chain and associated costs were taken from existing studies. Lifetime costs, lifetime quality-adjusted-life-years (QALYs) and the probability of a device being cost effective at a willingness to pay £20 000/QALY were included in the models.

The differences in QALYs between different categories of implant were extremely small (<  0.0039 QALYs for men or women over the patient’s lifetime) and differences in cost were also marginal (£2500 to £3000 in the same time period). As a result, the probability of any particular device being the most cost effective was very sensitive to small, plausible changes in quality of life estimates and cost.

Our results suggest that available evidence does not support recommending a particular device on cost effectiveness grounds alone. We would recommend that the choice of prosthesis should be determined by the rate of revision, local costs and the preferences of the surgeon and patient.

Cite this article: Bone Joint J 2015;97-B:449–57.

Following the recall of modular neck hip stems in July 2012, research into femoral modularity will intensify over the next few years. This review aims to provide surgeons with an up-to-date summary of the clinically relevant evidence. The development of femoral modularity, and a classification system, is described. The theoretical rationale for modularity is summarised and the clinical outcomes are explored. The review also examines the clinically relevant problems reported following the use of femoral stems with a modular neck.

Joint replacement registries in the United Kingdom and Australia have provided data on the failure rates of modular devices but cannot identify the mechanism of failure. This information is needed to determine whether modular neck femoral stems will be used in the future, and how we should monitor patients who already have them implanted.

Cite this article: Bone Joint J 2013;95-B:1011–21.

This study demonstrates a significant correlation between the American Knee Society (AKS) Clinical Rating System and the Oxford Knee Score (OKS) and provides a validated prediction tool to estimate score conversion.

A total of 1022 patients were prospectively clinically assessed five years after TKR and completed AKS assessments and an OKS questionnaire. Multivariate regression analysis demonstrated significant correlations between OKS and the AKS knee and function scores but a stronger correlation (r = 0.68, p < 0.001) when using the sum of the AKS knee and function scores. Addition of body mass index and age (other statistically significant predictors of OKS) to the algorithm did not significantly increase the predictive value.

The simple regression model was used to predict the OKS in a group of 236 patients who were clinically assessed nine to ten years after TKR using the AKS system. The predicted OKS was compared with actual OKS in the second group. Intra-class correlation demonstrated excellent reliability (r = 0.81, 95% confidence intervals 0.75 to 0.85) for the combined knee and function score when used to predict OKS.

Our findings will facilitate comparison of outcome data from studies and registries using either the OKS or the AKS scores and may also be of value for those undertaking meta-analyses and systematic reviews.

Cite this article: Bone Joint J 2015;97-B:503–9.

There is little evidence on the cost effectiveness of different brands of hip prostheses. We compared lifetime cost effectiveness of frequently used brands within types of prosthesis including cemented (Exeter V40 Contemporary, Exeter V40 Duration and Exeter V40 Elite Plus Ogee), cementless (Corail Pinnacle, Accolade Trident, and Taperloc Exceed) and hybrid (Exeter V40 Trilogy, Exeter V40 Trident, and CPT Trilogy). We used data from three linked English national databases to estimate the lifetime risk of revision, quality-adjusted life years (QALYs) and cost.

For women with osteoarthritis aged 70 years, the Exeter V40 Elite Plus Ogee had the lowest risk of revision (5.9% revision risk, 9.0 QALYs) and the CPT Trilogy had the highest QALYs (10.9% revision risk, 9.3 QALYs). Compared with the Corail Pinnacle (9.3% revision risk, 9.22 QALYs), the most commonly used brand, and assuming a willingness-to-pay of £20 000 per QALY gain, the CPT Trilogy is most cost effective, with an incremental net monetary benefit of £876. Differences in cost effectiveness between the hybrid CPT Trilogy and Exeter V40 Trident and the cementless Corail Pinnacle and Taperloc Exceed were small, and a cautious interpretation is required, given the limitations of the available information.

However, it is unlikely that cemented brands are among the most cost effective. Similar patterns of results were observed for men and other ages. The gain in quality of life after total hip arthroplasty, rather than the risk of revision, was the main driver of cost effectiveness.

Cite this article: Bone Joint J 2015;97-B:762–70.

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.

In this study we randomised 140 patients who were due to undergo primary total knee arthroplasty (TKA) to have the procedure performed using either patient-specific cutting guides (PSCG) or conventional instrumentation (CI).

The primary outcome measure was the mechanical axis, as measured at three months on a standing long-leg radiograph by the hip–knee–ankle (HKA) angle. This was undertaken by an independent observer who was blinded to the instrumentation. Secondary outcome measures were component positioning, operating time, Knee Society and Oxford knee scores, blood loss and length of hospital stay.

A total of 126 patients (67 in the CI group and 59 in the PSCG group) had complete clinical and radiological data. There were 88 females and 52 males with a mean age of 69.3 years (47 to 84) and a mean BMI of 28.6 kg/m² (20.2 to 40.8). The mean HKA angle was 178.9° (172.5 to 183.4) in the CI group and 178.2° (172.4 to 183.4) in the PSCG group (p = 0.34). Outliers were identified in 22 of 67 knees (32.8%) in the CI group and 19 of 59 knees (32.2%) in the PSCG group (p = 0.99). There was no significant difference in the clinical results (p = 0.95 and 0.59, respectively). Operating time, blood loss and length of hospital stay were not significantly reduced (p = 0.09, 0.58 and 0.50, respectively) when using PSCG.

The use of PSCG in primary TKA did not reduce the proportion of outliers as measured by post-operative coronal alignment.

Cite this article: Bone Joint J 2015;97-B:56–63.

Despite a lack of long-term follow-up, there is an increasing trend towards using femoral heads of large diameter in total hip replacement (THR), partly because of the perceived advantage of lower rates of dislocation. However, increasing the size of the femoral head is not the only way to reduce the rate of dislocation; optimal alignment of the components and repair of the posterior capsule could achieve a similar effect.

In this prospective study of 512 cemented unilateral THRs (Male:Female 230:282) performed between 2004 and 2011, we aimed to determine the rate of dislocation in patients who received a 22 mm head on a 9/10 Morse taper through a posterior approach with capsular repair and using the transverse acetabular ligament (TAL) as a guide for the alignment of the acetabular component. The mean age of the patients at operation was 67 years (35 to 89). The mean follow-up was 2.8 years (0.5 to 6.6). Pre- and post-operative assessment included Oxford hip, Short Form-12 and modified University of California Los Angeles and Merle D’Aubigne scores. The angles of inclination and anteversion of the acetabular components were measured using radiological software. There were four dislocations (0.78%), all of which were anterior.

In conclusion, THR with a 22 mm diameter head performed through a posterior approach with capsular repair and using the TAL as a guide for the alignment of the acetabular component was associated with a low rate of dislocation.

Cite this article: Bone Joint J 2014;96-B:1202–6.

The October 2014 Knee Roundup³⁶⁰ looks at: microfracture equivalent to OATS; examination better than MRI in predicting hamstrings re-injury; a second view on return to play with hamstrings injuries; dislocation risks in the Oxford Unicompartmental Knee; what about the tibia?; getting on top of lateral facet pain post TKR; readmission in TKR; patient-specific instrumentation; treating infrapatellar saphenous neuralgia; and arthroscopy in the middle-aged.

We report the five year outcomes of a two-stage approach for infected total hip replacement. This is a single-surgeon experience at a tertiary centre where the more straightforward cases are treated using single-stage exchange. This study highlights the vital role of the multidisciplinary team in managing these cases.

A total of 125 patients (51 male, 74 female) with a mean age of 68 years (42 to 78) were reviewed prospectively. Functional status was assessed using the Harris hip score (HHS). The mean HHS improved from 38 (6 to 78.5) pre-operatively to 81.2 (33 to 98) post-operatively. Staphylococcus species were isolated in 85 patients (68%).

The rate of control of infection was 96% at five years. In all, 19 patients died during the period of the study. This represented a one year mortality of 0.8% and an overall mortality of 15.2% at five years. No patients were lost to follow-up.

We report excellent control of infection in a series of complex patients and infections using a two-stage revision protocol supported by a multidisciplinary approach. The reason for the high rate of mortality in these patients is not known.

Cite this article: Bone Joint J 2014;96-B:1312–18

With the established success of the National Joint Registry and the emergence of a range of new national initiatives for the capture of electronic data in the National Health Service, orthopaedic surgery in the United Kingdom has found itself thrust to the forefront of an information revolution. In this review we consider the benefits and threats that this revolution poses, and how orthopaedic surgeons should marshal their resources to ensure that this is a force for good.

We have compared the time to recovery of isokinetic quadriceps strength after total knee replacement (TKR) using three different lengths of incision in the quadriceps. We prospectively randomised 60 patients into one of the three groups according to the length of incision in the quadriceps above the upper border of the patella (2 cm, 4 cm or 6 cm). The strength of the knees was measured pre-operatively and every month post-operatively until the peak quadriceps torque returned to its pre-operative level.

There was no significant difference in the mean operating time, blood loss, hospital stay, alignment or pre-operative isokinetic quadriceps strength between the three groups. Using the Kaplan–Meier method, group A had a similar mean recovery time to group B (2.0 ± 0.2 vs 2.5 ± 0.2 months, p = 0.176). Group C required a significantly longer recovery time (3.4 ± 0.3 months) than the other groups (p < 0.03). However, there were no significant differences in the mean Oxford knee scores one year post-operatively between the groups.

We conclude that an incision of up to 4 cm in the quadriceps does not delay the recovery of its isokinetic strength after TKR.

Cite this article: Bone Joint J 2014;96-B:902–6.

Recently the National Patient Safety Agency in the United Kingdom published a report entitled “Mitigating surgical risk in patients undergoing hip arthroplasty for fractures of the proximal femur”. A total of 26 deaths had been reported to them when cement was used at hemiarthroplasty between October 2003 and October 2008. This paper considers the evidence for using cement fixation of a hemiarthroplasty in the treatment of hip fractures.

We compared revision and mortality rates of 4668 patients undergoing primary total hip and knee replacement between 1989 and 2007 at a University Hospital in New Zealand. The mean age at the time of surgery was 69 years (16 to 100). A total of 1175 patients (25%) had died at follow-up at a mean of ten years post-operatively. The mean age of those who died within ten years of surgery was 74.4 years (29 to 97) at time of surgery. No change in comorbidity score or age of the patients receiving joint replacement was noted during the study period. No association of revision or death could be proven with higher comorbidity scoring, grade of surgeon, or patient gender.

We found that patients younger than 50 years at the time of surgery have a greater chance of requiring a revision than of dying, those around 58 years of age have a 50:50 chance of needing a revision, and in those older than 62 years the prosthesis will normally outlast the patient. Patients over 77 years old have a greater than 90% chance of dying than requiring a revision whereas those around 47 years are on average twice as likely to require a revision than die. This information can be used to rationalise the need for long-term surveillance and during the informed consent process.

We aimed to determine whether cemented hemiarthroplasty is associated with a higher post-operative mortality and rate of re-operation when compared with uncemented hemiarthroplasty. Data on 19 669 patients, who were treated with a hemiarthroplasty following a fracture of the hip in a nine-year period from 2002 to 2011, were extracted from NHS Scotland’s acute admission database (Scottish Morbidity Record, SMR01). We investigated the rate of mortality at day 0, 1, 7, 30, 120 and one-year post-operatively using 12 case-mix variables to determine the independent effect of the method of fixation. At day 0, those with a cemented hemiarthroplasty had a higher rate of mortality (p < 0.001) compared with those with an uncemented hemiarthroplasty, equivalent to one extra death per 424 procedures. By day one this had become one extra death per 338 procedures. Increasing age and the five-year co-morbidity score were noted as independent risk factors. By day seven, the cumulative rate of mortality was less for cemented hemiarthroplasty though this did not reach significance until day 120. The rate of re-operation was significantly higher for uncemented hemiarthroplasty. Despite adjusting for 12 confounding variables, these only accounted for 15% of the observed variability.

The debate about the choice of the method of fixation for a hemiarthroplasty with respect to the rate of mortality or the risk of re-operation may be largely superfluous. Our results suggest that uncemented hemiarthroplasties may have a role to play in elderly patients with significant co-morbid disease.

Cite this article: Bone Joint J 2014;96-B:1185–91.

There is a North Atlantic divide, with cementless femoral stems being used more frequently in the USA and cemented stems being used more frequently in many countries in Europe. This is primarily because different cemented stems have been used on different sides of the Atlantic and the results of the cemented stems in the US have often been poor, whereas the results of the stems used in Europe have been good. In the National registers in Europe, cemented stems have tended to achieve better results than cementless.

Cite this article: Bone Joint J 2013;95-B, Supple A:51–2.