All patients with a MOM THR implanted at our unit were recalled for clinical examination, Oxford hip score, radiographs, MARS MRI and cobalt/chromium ion levels. Patients were sub-classified, determining further follow up: a regular screening programme or referral to a revision arthroplasty surgeon.

We identified 299 MOM THR's. 59 patients reported a recent deterioration in symptoms. 67 had an abnormal x-ray. 232 hips underwent MARS MRI: 66 showed mild MOM disease, 31 moderate MOM disease, 17 severe MOM disease. 117 had a substantial fluid collection around the hip. Serum cobalt/chromium ions were raised in 135 patients. 46 had one or both above 7 ppb. 148 THR's were referred to a revision surgeon. 21 have been revised and 14 are awaiting revision.

In total 64 hips have been revised. 13 were histologically proven ALVAL, 19 had clinical findings of ALVAL (not histologically confirmed), and 1 non-specific reaction to metal wear. 53 asymptomatic patients had evidence of soft tissue reaction on MRI and/or rising metal ions.

Our screening programme identified asymptomatic patients with evidence of a suspicious reaction to their MOM THR. We recommend all patients with a MOM THR are fully screened for ARMD regardless of symptoms and metal ion levels.

Background:

Higher than expected revision rates have been observed in large bearing metal-on-metal total hip replacements. We have introduced a metal on metal hip screening clinic at our unit and report the results.

Urinary catheterisation may be associated with a risk of infection in hip and knee arthroplasty, however post-operative urinary retention can be distressing for the patient. This study investigates the factors that might predict the need for post-operative catheterisation.

A prospective blinded study of 128 consecutive patients undergoing lower limb arthroplasty was carried out. Data obtained included sex, age, joint (hip or knee), prostate score (IPSS), previous urinary retention, co-morbidities and residual bladder volume after attempted complete voiding measured using an ultrasound bladder scanner. Anaesthetic type and requirement for urinary catheterisation postoperatively were recorded. Predictive risk factors were identified using binary logistic regression, and expressed as odds ratios (OR) and 95% confidence intervals (CI).

The mean age was 69.5 years. There were 56 males and 72 females. 38 patients (30%) required post-operative catheterisation. Logistic regression identified the following predictive risk factors: bladder scan volume per ml increase (OR 1.006; CI 1.000–1.012); male sex (OR 5.51; CI 2.01–15.16); previous catheter (OR 4.26; CI 1.53–11.82); spinal/epidural/combined spinal epidural anaesthesia (OR 6.78; CI 1.75–26.32); moderate IPSS score (OR 5.15; CI 1.73–15.37); severe IPSS score (OR 3.53; CI 0.605–20.54). Our model specificity is 91%, positive predictor value 71% and negative predictor value 82%.

Introduction

Urinary catheterisation can cause bacteraemia and therefore may be associated with a risk of infection in hip and knee arthroplasty. However postoperative urinary retention can be distressing for the patient. This study investigates the factors that might predict the need for postoperative catheterisation in order to help develop a protocol to decide who should be electively catheterised.