Aims

Thromboprophylaxis following Total Hip Replacement (THR) surgery remains controversial, balancing VTE prevention against wound leakage and subsequent deep infection.

We analysed the 90 day cause of death post THR in our institution after the implementation of new thromboprophylactic policy of low dose aspirin for low risk patients, as part of a multimodal regime. Those at high risk were anticoagulated.

This study utilized data from the NJR dataset on all Corail/Pinnacle total hip replacements (THR) to determine (a) the level of unit variation of the Corail/Pinnacle 36mm Metal On Metal THR within England and Wales; (b) patient, implant and surgeon factors that may be associated with higher revision rates; (c) Account for the influence of the MHRA announcement in 2010.

The national Revision Rate (RR) for the Corail / Pinnacle MOM THR was 10.77% (OR:1.46; CI:1.17–1.81). This was significantly greater than other articulation combinations (MOP 1.72%, COP 1.36%, COC 2.19%).

The 2010 MHRA announcement did not increase rate of revision (X²=1649.63, df=13, p<.001).

Patient factors associated with significantly increased revision rates included, female gender (OR 1.38 (CI 1.17–1.63, p<.001) and younger age OR 0.99 (CI 0.98–0.99), p<.001). Implant factor analysis demonstrated an inverse relationship between cup size and revision. As head length increased RR increased – highest risk of revision +12.5 (OR 1.69 (CI 1.12–2.55), p=0.13). Coxa vara, high offset stems had a higher risk of revision compared to standard offset stems (OR:1.41 (CI 1.15–1.74; p<.001). As stem size increased risk of revision decreased (OR 0.89 (CI 0.85–0.93); p<.001). Surgeon grade did not influence RR.

There was significant variation in RR between hospitals with 7 units (7/61 excluding low volume centres, <50 implants) identified as having significant higher rates of revision. However, for each of these units there was a greater proportion of higher risk patients (female, cup size 50–54, stem type).

This study has provided insight into unit variation, risk factors and the long term outcome of the Corail/Pinnacle 36mm MOMTHR. Future aims are to use these results to develop a risk stratified algorithm for the long term follow of these patients to minimize patient inconvenience and excess use of limited NHS resources.

Ceramic on ceramic (CoC) bearings in total hip arthroplasty (THA) are commonly used but concerns exist regarding ceramic fracture. This study aims to report the risk of revision for fracture of modern CoC bearings and identify factors that might influence this risk, using data from the National Joint Registry.

We analysed data on 111,681 primary CoC THA's and 182 linked revisions for bearing fracture recorded in the National Joint Registry of England, Wales, Northern Ireland and the Isle of Man (NJR). We used implant codes to identify ceramic bearing composition and generated Kaplan-Meier estimates for implant survivorship. Logistic regression analyses were performed for implant size and patient specific variables to determine any associated risks for revision.

99.8% of bearings were CeramTec Biolox® products. Revisions for fracture were linked to 7 of 79,442 (0.009%) Biolox® Delta heads, 38 of 31,982 (0.119%) Biolox® Forte heads, 101 of 80,170 (0.126%) Biolox® Delta liners and 35 of 31,258 (0.112%) Biolox® Forte liners. Regression analysis of implant size revealed smaller heads had significantly higher odds of fracture (χ2=68.0, p<0.0001). The highest fracture risk were observed in the 28mm Biolox® Forte subgroup (0.382%). There were no fractures in the 40mm head group for either ceramic type. Liner thickness was not predictive of fracture (p=0.67). BMI was independently associated with revision for both head fractures (OR 1.09 per unit increase, p=0.031) and liner fractures (OR 1.06 per unit increase, p=0.006).

We report the largest registry study of CoC bearing fractures to date. Modern CoC bearing fractures are rare events. Fourth generation ceramic heads are around 10 times less likely to fracture than third generation heads, but liner fracture risk remains similar between these generations.

Aim

To assess the incidence of fatal pulmonary embolism (PE) following elective total knee replacement (TKR) with a standardised multi-modal prophylaxis regime in a large teaching DGH over a 10 year period.

Introduction

There is no established evidence to support the use of drains after total knee replacement; however 94% of orthopaedic surgeons in UK routinely use closed suction drains. Haematomas can form with or without using drains, presence of which in addition may provide portal for infection and may increase blood loss. Blood group and save is routinely performed for every patient undergoing total knee replacement, however actual cross match and transfusion is needed for a small percentage of patients.

Introduction

Acetabular bone deficiency presents one of the most challenging problems during revision hip arthroplasty. A variety of surgical options and techniques are available including impaction bone grafting. We present our medium to long-term experience of 68 consecutive hips in 64 patients who had acetabular revision using impacted cancellous bone grafting with bone cement with a mean follow up of 10.5 ±3.75) years (range 5.1 to 17.7 years).

Femoral impaction grafting with cancellous bone and cement is an important technique in reconstituting deficient bone stock in revision hip arthroplasty. We report the medium to long term results of 75 consecutive patients using a collarless, polished, tapered femoral stem with an average age of 68 (±11.4) years and a mean follow up of 10.5 (±2.4) years (range 6.3 to 14.1 years).

The median Endoklinik pre-operative bone defect score was 3 (IQR: 2–3) with a median subsidence at 1 year of 2mm (IQR: 1–3mm). At the most recent follow-up (mean 10.5±2.4 years), the median Harris Hip Score (HHS) was 80.6 (IQR: 67.6–88.9) and median subsidence 2mm (IQR: 1–4mm). Ten-year survivorship with any further femoral operation as an endpoint was 92%. Four prostheses required further revision.

Subsidence of the Exeter stem continued, albeit at a slower rate after the first year and was related to the Endoklinik pre-operative bone loss (p=0.037). The degree of subsidence at 1 year was a strong predictor of long term subsidence (p<0.001). Neither subsidence nor bone stock were related to long term outcome (HHS). There was a correlation between previous revision surgery and a poor Harris Hip Score (p=0.028) and those who had undergone previous revision surgery for infection had a higher risk of complications (p=0.048).

The good long term results of this technique commend its use in revision hip arthroplasty for patients with poor femoral bone stock.

Introduction/Background: Uncemented total hip arthrolpasty [THA] was developed to achieve biological fixation of the prosthesis through integration of components into the prepared bone, especially in young patients with higher functional demands and longer life expectancy. The aim of this study was to update the results of a prospectiv series of primary cementless total hip arthroplasties after a minimum of 10 years follow-up

Materials and Methods: We reviewed 201 consecutive uncemented Bi-contact [Aesculap, Tuttlingen, Germany] THA in 177 patients. Harris hip score was recorded pre-operatively and at most recent follow up. Radiological measurements of the acetabulum for migration and radiolucency with Charnley-Lee zones, femur for stem subsistence, calcar resorption, prosthesis-bone radiolucency in the Gruen zones and hypertrophic calcification were carried out. Using revision as an end point, the cumulative survival of the prosthesis was noted. Survival analysis was performed using Kaplan-Meier curves and constructing life tables.

Results: 122 THR with a mean follow-up of 12.9 years were available for follow-up. 62 patients were dead and 17 patients were lost for follow-up. The mean age at surgery was 66.6 years (range 39–88).12 acetabula and 1 femur were revised in 11 patients due to any cause and 3 patients had indications for revision. The cumulative survival of the prosthesis with revision due to any cause was 95.42% at 10 years and 93.57% at 12 years. With revision due to aseptic loosening as an end-point, the cumulative survival was 97.8% at 10 years and 95.9% at 12 years. Comparison of worst-case curves using Log-rank test was statistically significant (p=0.0005).

Conclusion: Our series shows excellent stem results (without HA coating) with no revisions due to aseptic loosening. All stems were stable. Cup survivals were comparable to the other uncemented THA and cemented THA.

Introduction: Good intermediate term results have been reported using a hybrid primary total hip arthroplasty (uncemented acetabular component with cemented stem) for osteoarthritis. Concerns have been highlighted recently regarding osteolysis behind the acetabular component. We present our results using the uncemented Aesculap plasma cup with an Exeter cemented femoral stem.

Methods: Outcome of 142 primary hip replacements (124 patients) at Derby Royal Infirmary between 1992–1998 was assessed. Most cases had a 28mm articulation, either Orthinox or ceramic. There were 60 men and 64 women, of mean age 55 (range 33–71). Mean time to follow up was 8.65 years (Range 7–13 years). Radiographic assessment was made to assess wear, acetabular lysis and loosening of the components. A clinical assessment and case note review was also performed.

Results: Of 142 hips, 2 were lost to follow up and 4 patients (6 hips) had died (unrelated causes). Of these, 7 revisions were performed; 3 for osteolysis, and 1 each for infection, acetabular wear, recurrent dislocation and early cup aseptic loosening. 9 hips were identified to have asymptomatic osteolysis (6 acetabular and 2 femoral). Mean rate of linear wear was 0.2mm/year for all hips, but 0.4mm/year for those with osteolysis. No cups without supplementary screw fixation developed acetabular osteolysis.

Conclusions: Our data suggests that there is a significant rate of acetabular osteolysis at intermediate (10 year) follow up of this combination of primary hybrid total hip replacement, often in association with increased acetabular wear. This can be asymptomatic and may lead to the need for complex revision surgery in the future. The failure rate is however significantly lower than in other reported studies with the same basic implants, but differing bearing diameters. This study highlights the need for close radiographic follow up of these patients, and the issue of subtle differences in the articulating surface.

We reviewed 158 hip replacements performed using the Exeter® stem between 1992 and 1996. The operations were performed using third generation cementation and the majority using medium viscosity Simplex cement via a posterior approach. Per-operative complications [shaft fracture etc] were not seen.

Using stem revision as an endpoint, only one stem has been revised [0.6%] for aseptic loosening, and one for sepsis. Aseptic asymptomatic loosening was observed in a further 4 patients [2.5%]. Stem subsidence was seen in the majority [81%], but none greater than 3mm [mean 1.4mm]. Other complications were rare.

This medium term review confirms that the Exeter® stem is a prosthesis with excellent results. This is one of the first series published outside Exeter to confirm their reported results.

39 consecutive patients (40 hips) undergoing femoral impaction grafting were retrospectively reviewed to assess our mid-term results and analyse them for any factors that could influence outcome. 36 revisions were for aseptic loosening, 3 for infection and 1 following a periprosthetic fracture. Those hips revised for infection were revised in 2 stages. In 37 cases, the Exeter X-Change bone impaction technique was used, implanting an Exeter stem with Simplex cement through a posterior approach. A Charnley stem was implanted in the 3 others.

Each surviving patient was assessed using the Harris hip score, AP pelvis and lateral hip radiographs. Potential prognostic factors were analysed using the Spearman’s rank correlation test.

The patients were reviewed after a mean follow-up of 5 years. 1 patient didn’t wish to attend review but was asymptomatic. Complications included 4 intraoperative femoral fractures during cement removal, 2 postoperative femoral fractures, 2 dislocations, 1 femoral component fracture and 1 deep infection. There were 3 re-revisions and 1 Girdlestones procedure.

The median Harris hip score of those implants still in-situ was 78.5. Those patients who had previously undergone a revision had a significantly worse Harris hip score (p< 0.05). The patients age, reason for revision, preoperative bone loss, surgeon, simultaneous acetabular revision, simultaneous bone grafting to acetabulum, loose acetabular component on radiographs, femoral subsidence, presence of trabeculae in the graft, any radiolucency, a complete cement mantle and ectopic bone formation had no significant correlation to the Harris hip score.

In this series, previous revision was found to be the only significant risk factor for a poor Harris hip score after femoral impaction grafting. Postoperative radiographic changes in this group correlated poorly with function and could not predict outcome. Further study is required to assess other factors such as bone graft and soft tissue quality that may also predict outcome.