We carried out metal artefact-reduction MRI, three-dimensional CT measurement of the position of the component and inductively-coupled plasma mass spectrometry analysis of cobalt and chromium levels in whole blood on 26 patients with unexplained pain following metal-on-metal resurfacing arthroplasty.

MRI showed periprosthetic lesions around 16 hips, with 14 collections of fluid and two soft-tissue masses. The lesions were seen in both men and women and in symptomatic and asymptomatic hips. Using three-dimensional CT, the median inclination of the acetabular component was found to be 55° and its positioning was outside the Lewinnek safe zone in 13 of 16 cases. Using inductively-coupled plasma mass spectrometry, the levels of blood metal ions tended to be higher in painful compared with well-functioning metal-on-metal hips.

These three clinically useful investigations can help to determine the cause of failure of the implant, predict the need for future revision and aid the choice of revision prostheses.

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.

Cervical spinal disc replacement is used in the management of degenerative cervical disc disease in an attempt to preserve cervical spinal movement and to prevent adjacent disc overload and subsequent degeneration. A large number of patients have undergone cervical spinal disc replacement, but the effectiveness of these implants is still uncertain. In most instances, degenerative change at adjacent levels represents the physiological progression of the natural history of the arthritic disc, and is unrelated to the surgeon. Complications of cervical disc replacement include loss of movement from periprosthetic ankylosis and ossification, neurological deficit, loosening and failure of the device, and worsening of any cervical kyphosis. Strict selection criteria and adherence to scientific evidence are necessary. Only prospective, randomised clinical trials with long-term follow-up will establish any real advantage of cervical spinal disc replacement over fusion.

The incidence of deep-vein thrombosis and the need for thromboprophylaxis following isolated trauma below the knee is uncertain. We have investigated this with a prospective randomised double-blind controlled trial using low molecular weight heparin with saline injection as placebo in patients aged between 18 and 75 years who had sustained an isolated fracture below the knee which required operative fixation. All patients had surgery within 48 hours of injury and were randomised to receive either the placebo or low molecular weight heparin for 14 days, after which they underwent bilateral lower limb venography, interpreted by three independent radiologists. Further follow-up was undertaken at two, six, eight and 12 weeks.

A total of 238 patients fulfilled all the inclusion criteria, with 127 in the low molecular weight heparin group and 111 in the placebo group, all of whom underwent bilateral venography. There was no statistically significant difference in the incidence of deep-vein thrombosis between those patients treated with low molecular weight heparin or the placebo (p = 0.22). The number of deep-vein thromboses in the two groups was 11 (8.7%) and 14 (12.6%), respectively. Age and the type of fracture were significantly associated with the rate of deep-vein thrombosis (p = 0.001 and p = 0.009, respectively) but gender, comorbidities and the body mass index were not.

The overall incidence of deep-vein thrombosis in this series was 11%. There was no clinical or statistical significant reduction in the incidence of deep-vein thrombosis with the use of thromboprophylaxis. However, we accept that owing to a cessation of funding, recruitment to this trial had to be ended prior to establishing the necessary sample size. Our results cannot, therefore, categorically exclude the possibility that low molecular weight heparin treatment could be beneficial. We recommend a further multicentre trial be undertaken to resolve this matter.

More than a million hip replacements are carried out each year worldwide, and the number of other artificial joints inserted is also rising, so that infections associated with arthroplasties have become more common. However, there is a paucity of literature on infections due to haematogenous seeding following dental procedures. We reviewed the published literature to establish the current knowledge on this problem and to determine the evidence for routine antibiotic prophylaxis prior to a dental procedure.

We found that antimicrobial prophylaxis before dental interventions in patients with artificial joints lacks evidence-based information and thus cannot be universally recommended.

A total of 11 patients (12 knees) with stable lesions of osteochondritis dissecans of the knee underwent arthroscopic fixation of the fragments using polylactide bioabsorbable pins. The site of the lesion was the medial femoral condyle in ten knees and the lateral femoral condyle in two. The mean age of the patients was 14.8 years (12 to 16). At a mean follow-up of 32.4 months (13 to 38 months) all fragments had MRI evidence of union. One patient developed early transient synovitis, which resolved with non-steroidal anti-inflammatory medication. All patients returned to sporting activities within eight months of operation and did not require a period of immobilisation.

Locognosia, the ability to localise touch, is one aspect of tactile spatial discrimination which relies on the integrity of peripheral end-organs as well as the somatosensory representation of the surface of the body in the brain. The test presented here is a standardised assessment which uses a protocol for testing locognosia in the zones of the hand supplied by the median and/or ulnar nerves.

The test-retest reliability and discriminant validity were investigated in 39 patients with injuries to the median or ulnar nerve. Intraclass correlation coefficients were used to calculate the test-retest reliability. Discriminant validity was assessed by comparing the injured with the unaffected hand.

Excellent test-retest reliability was demonstrated for the injuries to the median (intraclass correlation coefficient 0.924, 95% confidence interval 0.848 to 1.00) and the ulnar nerves (intraclass correlation coefficient 0.859, 95% confidence interval 0.693 to 1.00). The magnitude of the difference in scores between affected and unaffected hands showed good discriminant validity. For injuries to the median nerve the mean difference was 11.1 points (1 to 33; sd 7.4), which was statistically significant (p < 0.0001, paired t-test) and for those of the ulnar nerve it was 4.75 points (1 to 13.5; sd 3.16), which was also statistically significant (paired t-test, p < 0.0001).

The locognosia test has excellent test-retest reliability, is a valid test of tactile spatial discrimination and should be included in the evaluation of outcome after injury to peripheral nerves.

We studied 70 consecutive patients with adolescent idiopathic scoliosis who underwent corrective surgery. They were divided into two groups. In the study group of 38 patients one or more modern blood-conservation measures was used peri-operatively. The 32 patients in the control group did not have these measures. Both groups were similar in regard to age, body-weight, the number of levels fused and the type of surgery.

Only two patients in the study group were transfused with homologous blood and these transfusions were ‘off-protocol’. Wastage of autologous pre-donated units was minimal (6 of 83 units). By contrast, all patients in the control group were transfused with homologous blood. In the study group there was a significant decrease (p = 0.005) in the estimated blood loss when all the blood-conservation methods were used.

The use of blood-conservation measures, the lowering of the haemoglobin trigger for transfusion and the education of the entire team involved in the care of the patient can prevent the need for homologous blood transfusion in patients undergoing surgery for adolescent idiopathic scoliosis.

Ciprofloxacin hydrochloride-loaded microspheres were prepared by a spray-drying method using pectin and chitosan. The effects of different polymers and drug ratios were investigated.

The most appropriate carriers were selected by in vitro testing. A rat methicillin-resistant Staphylococcus aureus osteomyelitis model was used to evaluate the effects of the loaded microspheres.

The drug was released rapidly from the pectin carrier but this was more sustained in the chitosan formulation.

Chitosan microspheres loaded with ciprofloxacin hydrochloride were more effective for the treatment of osteomyelitis than equivalent intramuscular antibiotics.

We undertook a prospective, randomised study in order to evaluate the efficacy of clamping the drains after intra-articular injection of saline with 1:500 000 adrenaline compared with post-operative blood salvage in reducing blood loss in 212 total knee arthroplasties. The mean post-operative drained blood volume after drain clamping was 352.1 ml compared to 662.3 ml after blood salvage (p < 0.0001). Allogenic blood transfusion was needed in one patient in the drain group and for three in the blood salvage group. Drain clamping with intra-articular injection of saline with adrenaline is more effective than post-operative autologous blood transfusion in reducing blood loss during total knee arthroplasty.

Modern metal-on-metal hip resurfacing has been widely performed in the United Kingdom for over a decade. However, the literature reports conflicting views of the benefits: excellent medium- to long-term results with some brands in specific subgroups, but high failure rates and local soft-tissue reactions in others. The National Joint Registry for England and Wales (NJR) has collected data on all hip resurfacings performed since 2003. This retrospective cohort study recorded survival time to revision from a resurfacing procedure, exploring risk factors independently associated with failure. All patients with a primary diagnosis of osteoarthritis who underwent resurfacing between 2003 and 2010 were included in the analyses. Cox’s proportional hazard models were used to analyse the extent to which the risk of revision was related to patient, surgeon and implant covariates.

A total of 27 971 hip resurfacings were performed during the study period, of which 1003 (3.59%) underwent revision surgery. In the final adjusted model, we found that women were at greater risk of revision than men (hazard ratio (HR) = 1.30, p = 0.007), but the risk of revision was independent of age. Of the implant-specific predictors, five brands had a significantly greater risk of revision than the Birmingham Hip Resurfacing (BHR) (ASR: HR = 2.82, p < 0.001, Conserve: HR = 2.03, p < 0.001, Cormet: HR = 1.43, p = 0.001, Durom: HR = 1.67, p < 0.001, Recap: HR = 1.58, p = 0.007). Smaller femoral head components were also significantly more likely to require revision (≤ 44 mm: HR = 2.14, p < 0.001, 45 to 47 mm: HR = 1.48, p = 0.001) than medium or large heads, as were operations performed by low-volume surgeons (HR = 1.36, p <  0.001). Once these influences had been removed, in 4873 male patients < 60 years old undergoing resurfacing with a BHR, the five-year estimated risk of revision was 1.59%.

In summary, after adjustment for a range of covariates we found that there were significant differences in the rate of failure between brands and component sizes. Younger male patients had good five-year implant survival when the BHR was used.

Blood metal ions have been widely used to investigate metal-on-metal hip replacements, but their ability to discriminate between well-functioning and failed hips is not known. The Medicines and Healthcare products Regulatory Agency (MHRA) has suggested a cut-off level of 7 parts per billion (ppb).

We performed a pair-matched, case-control study to investigate the sensitivity and specificity of blood metal ion levels for diagnosing failure in 176 patients with a unilateral metal-on-metal hip replacement. We recruited 88 cases with a pre-revision, unexplained failed hip and an equal number of matching controls with a well-functioning hip. We investigated the 7 ppb cut-off level for the maximum of cobalt or chromium and determined optimal mathematical cut-off levels from receiver-operating characteristic curves.

The 7 ppb cut-off level for the maximum of cobalt or chromium had a specificity of 89% and sensitivity 52% for detecting a pre-operative unexplained failed metal on metal hip replacement. The optimal cut-off level for the maximum of cobalt or chromium was 4.97 ppb and had sensitivity 63% and specificity 86%.

Blood metal ions had good discriminant ability to separate failed from well-functioning hip replacements. The MHRA cut-off level of 7 ppb provides a specific test but has poor sensitivity.

Bone preservation and physiological distribution of forces on the proximal femur are key elements in introducing a successful uncemented total hip replacement. In order to achieve this, in the mid 1990s, we developed an ultra short proximal loading custom-made component with a lateral flare, a high femoral neck osteotomy and without a diaphyseal stem.

We report the outcome of 129 custom-made hydroxyapatite-coated uncemented short femoral components inserted into 109 patients between June 1995 and May 2004. The mean age of the patients was 51 years (21 to 71) and the mean follow-up was eight years (4.9 to 14.1). Bone behaviour around the implant was studied on the post-operative radiographs. The mean Harris hip score improved from 44 (8 to 66) pre-operatively to 95 (76 to 100) at final follow-up. The Western Ontario MacMaster University Osteoarthritis index was 93 of 100 at final review. None of the patients reported thigh pain. A total of five hips were revised, three for polyethylene liner exchange and two for complete revision of the acetabular component. No femoral components were revised. The radiological changes in the proximal femur were generally good, as evidenced by spot welds both on the medial and lateral aspects of the femur. No component migrated. The presence of a lateral flare and use of a high osteotomy of the femoral neck provided good clinical and radiological results. The absence of a diaphyseal portion of the stem did not impair stability.

The routine administration of prophylactic antibiotics for dental interventions to prevent haematogenous spread of infections to prosthetic joints is a contentious issue. In this editorial we discuss the potentially harmful effects of this practice and propose an alternative solution.

We used a biodegradable mesh to convert an acetabular defect into a contained defect in six patients at total hip replacement. Their mean age was 61 years (46 to 69). The mean follow-up was 32 months (19 to 50). Before clinical use, the strength retention and hydrolytic in vitro degradation properties of the implants were studied in the laboratory over a two-year period. A successful clinical outcome was determined by the radiological findings and the Harris hip score.

All the patients had a satisfactory outcome and no mechanical failures or other complications were observed. No protrusion of any of the impacted grafts was observed beyond the mesh. According to our preliminary laboratory and clinical results the biodegradable mesh is suitable for augmenting uncontained acetabular defects in which the primary stability of the implanted acetabular component is provided by the host bone. In the case of defects of the acetabular floor this new application provides a safe method of preventing graft material from protruding excessively into the pelvis and the mesh seems to tolerate bone-impaction grafting in selected patients with primary and revision total hip replacement.

The dismal outcome of tuberculosis of the spine in the pre-antibiotic era has improved significantly because of the use of potent antitubercular drugs, modern diagnostic aids and advances in surgical management. MRI allows the diagnosis of a tuberculous lesion, with a sensitivity of 100% and specificity of 88%, well before deformity develops. Neurological deficit and deformity are the worst complications of spinal tuberculosis. Patients treated conservatively show an increase in deformity of about 15°. In children, a kyphosis continues to increase with growth even after the lesion has healed. Tuberculosis of the spine is a medical disease which is not primarily treated surgically, but operation is required to prevent and treat the complications. Panvertebral lesions, therapeutically refractory disease, severe kyphosis, a developing neurological deficit, lack of improvement or deterioration are indications for surgery. Patients who present with a kyphosis of 60° or more, or one which is likely to progress, require anterior decompression, posterior shortening, posterior instrumented stabilisation and anterior and posterior bone grafting in the active stage of the disease. Late-onset paraplegia is best prevented rather than treated. The awareness and suspicion of an atypical presentation of spinal tuberculosis should be high in order to obtain a good outcome. Therapeutically refractory cases of tuberculosis of the spine are increasing in association with the presence of HIV and multidrug-resistant tuberculosis.

The National Institute for Clinical Excellence (NICE) produces recommendations on appropriate treatment within the National Health Service (NHS) in England and Wales. The NICE guidelines on prophylaxis for venous thromboembolism in orthopaedic surgery recommend that all patients be offered a low molecular weight heparin (LMWH). The linked hospital episode statistics of 219 602 patients were examined to determine the rates of complications following lower limb arthroplasty for the 12-month periods prior to and following the publication of these guidelines. These were compared with data from the National Joint Registry (England and Wales) regarding the use of LMWH during the same periods. There was a significant increase in the reported use of LMWH (59.5% to 67.6%, p < 0.001) following the publication of the guidelines. However, the 90-day venous thromboembolism events actually increased slightly following total hip replacement (THR, 1.69% to 1.84%, p = 0.06) and remained unchanged following total knee replacement (TKR, 1.99% to 2.04%). Return to theatre in the first 30 days for infection did not show significant changes. There was an increase in the number of patients diagnosed with thrombocytopenia, which was significant following THR (0.11% to 0.16%, p = 0.04). The recommendations from NICE are based on predicted reductions in venous thromboembolism events, reducing morbidity, mortality and costs to the NHS.

The early results in orthopaedic patients do not support these predictions, but do show an increase in complications.