Aims

Metal-on-metal total hip replacements (MoM THRs) are frequently revised. However, there is a paucity of data on clinical outcomes following revision surgery in this cohort. We report on outcomes from the largest consecutive series of revisions from MoM THRs and consider pre-revision factors which were prognostic for functional outcome.

Introduction

The prevalence of adverse reactions to metal debris (ARMD) associated with metal on metal (MoM) hip arthroplasty has been reported to be as high as 69%. Such findings promoted the development of metal-artefact reducing sequence (MARS)-magnetic resonance imaging (MRI) classifications, with the aim of stratifying soft lesions by severity of disease. The Modified Oxford Classification is a straightforward system that has been shown to correlate with disease progression.

Introduction

The prevalence of adverse reactions to metal debris around metal-on-metal (MOM) hip replacements has been reported to range from 7 to 69%. Little has been published on MRI scans with conventional total hip bearing surfaces. This study aimed to establish the prevalence of soft tissue lesions associated with metal-on-polyethylene (MOP) and ceramic-on-ceramic (COC) bearings, compared to MOM prostheses.

Critics of Unicompartmental knee replacement (UKR) highlight poor survivorship in national joint registries and argue that revision to Total Knee Replacement (TKR) is technically difficult with inferior function and survivorship compared to primary TKR.

We prospectively reviewed outcomes of UKRs in our institution undergoing early revision to a TKR, comparing conventional revisions to those performed using computer navigation. 20 cases were identified, 7 conventional and 13 navigated. 13 were male and 7 female, mean age at primary UKR was 63.6 years (range: 47–81).

Mean follow up time after revision was 5.2 years (2–9.5). Mean surgical time was 152 mins in conventional revisions and 163 mins for navigated. 43% of conventional cases required revision stems or augments, compared to 15% of conventional cases. Mean Oxford Knee Scores for revised knees were 32.8 in the conventional group and 34.64 in the navigated group, compared to 30.02 in the national joint registry. This compares to a mean Oxford score of 37.16 for primary TKRs in the registry. One of the conventional revisions required a further revision of the tibial component for loosening. This equates to a 95% suvivorship at mean 5 year follow up, or 1.10 revisions per 100 component years. Joint registry data had 1.97 revisions per 100 component years for UKR to TKR revisions, and 0.48 for primary TKRs.

Our results are significantly improved compared to other published series of UKR revisions to TKRs. Only one other series has reported outcomes of these revisions using navigation. Despite small numbers, our results suggest that navigation makes revisions of UKRs more straightforward with similar surgical times. Fewer revision components were required with navigation and functional scores were marginally improved.

The Fixion expandable nailing system provides an intramedullary fracture fixation solution without the need for locking screws. Proponents of this system have demonstrated shorter surgery times with rapid fracture healing, but several centres have reported suboptimal results with loss of fixation. This is the largest comparative series to be reported to date.

We compared outcomes between 50 consecutive diaphyseal tibial fractures treated with a Fixion device at our institution to an age, sex and fracture configuration matched series of 57 fractures at a neighbouring hospital treated with a conventional interlocked intramedullary nail. Minimum follow up time was 2 years.

Operating time was significantly reduced in the Fixion group (mean 61 minutes, range 20–99) compared to the interlocked group (88 minutes, 52–93), p< 0.00001. The union rate was no different between the Fixion group (93.9%) and the interlocked group (96.5%), p=0.527. Time to clinical and radiological union was significantly faster in the Fixion group (median 85 days, range 42–243) compared to the interlocked group (119, 70–362), p< 0.0001. The overall reoperation rate was lower in the Fixion series (24.5% vs 38.6%, p=0.121), although the majority of reoperations in the interlocked group were more minor, for screw removal. 3 Fixion nails were revised for fixation failure and 2 manipulations were required for rotational deformities after falls; all of these patients were non-compliant with post-operative instructions. There were no fixation failures in the interlocked group. 3 fractures were noted to propagate during inflation of Fixion nails.

The Fixion nail is faster to implant and allows more physiological loading of the fracture, with a faster union time. However, these advantages are offset by a reduction in construct stability. Our results have demonstrated a learning curve with a reduction in complications as our indications were narrowed, avoiding osteoporotic, multifragmentary, unstable fractures and non-compliant patients

Periprosthetic fractures around a cemented femoral stem present a challenge to the treating surgeon. We propose a technique whereby a well fixed cement mantle can be retained in cases with simple fractures that can be reduced anatomically. This technique is well established in femoral stem revision, but not in association with a fracture.

24 Vancouver type B periprosthetic femoral fractures were treated by reducing the fracture and cementing a revision stem into the pre-existing cement mantle, with or without supplementary fixation.

3 patients died in the first 6 months for reasons not related to surgery and one was too frail to attend follow up. The remaining 20 cases were followed up for a mean of 3.0 years. The median time to radiological and clinical union was 3.0 months (2–11). The median Modified Harris Hip Score was 76.9 (35–97) and there was no sign of loosening or subsidence of the revision stems within the old cement mantle in any case at most recent follow up. One patient had further surgery for a delayed union and there were 2 subsequent fractures distal to the original fracture site in patients with poor bone stock.

Our results support the use of the cement-in-cement stem revision technique in anatomically reducible peri-prosthetic fractures with a well preserved pre-existing cement mantle. It is particularly suitable for older patients.

Introduction: Ankle diastasis injury occurs in up to 20% of ankle fractures. Various techniques have been used to treat syndesmosis injuries, but controversy remains and outcome is variable. In light of some recent cases of substandard syndesmosis fixations requiring revision, an audit of our results was undertaken.

Method: Study type: Retrospective audit of radiographs and patient records

Data collection: patients were selected using an orthopaedic database search for operations coded as distal tib/fib ORIF or ankle ORIF.

Study period: 12 months, July 2008 to July 2009 (currently data has been analyzed on the first 6 months only, the remaining 6 months will follow)

Audit questions to be answered: How is ankle diastasis injury being managed? Are we reducing syndesmosis correctly? Should there be a revision to local policy?

Audit standard: Syndesmoses should be adequately reduced and fixation techniques employed should be in accordance with recommendations in standard Orthopaedic reference texts (Rockwood & Green, AO fixation manual 3)

Results: 76 ankle ORIFs in July to December 2008 inclusive. Out of these, 16 had diastasis fixation (21%). 2 of the patients had a syndesmosis width over 6 mm indicating an inadequate reduction of the syndesmosis 1. Both of these required revision surgery. In total 70% of the post operative x-rays showed inadequate syndesmosis fixation or reduction.

Discussion: The single most predictive indicator of a favourable function is accurate reduction of the syndesmosis 2. Substandard fixations are associated with poor long term outcomes. This raises the potential for litigation and the requirement for education and policy change. We have produced policy guidelines for theatre and circulated the information to all surgeons. A further audit will be carried out to assess the effectiveness of this in 6 months time. (The data will be available from this re-audit for presentation at the conference.)

20 Vancouver type B periprosthetic femoral fractures were treated in our unit by cementing a revision stem into the pre-existing cement mantle following fracture reduction. The technique was used in elderly, multiply co-morbid patients with the intention of reducing operative time and peri-operative complications.

3 patients died in the first 3 months from reasons not related to surgery, with no recorded evidence of fracture healing and were excluded from the study and 1 was too frail to attend follow up. The remaining 16 cases were followed up for a mean of 3 years. The mean time to radiological union was 5 months (range: 2–11) and the mean time to clinical union was 4.9 months (range: 2–17). The mean Modified Harris Hip Score in these patients was 66.5 (range: 35.2–97). One patient had further surgery for a delayed union and there was one failure of fixation. The mean hospital stay was 10.8 days and the mean time to fully weight bear 38.1 days.

This study suggests that there is a valid role for the use of the in-cement revision technique in Vancouver type B periprosthetic femoral fractures in a highly selected group of elderly patients unsuitable for lengthy reconstructive procedure