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Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_II | Pages 296 - 296
1 May 2010
Davies H Motha J Porteous M August A
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We report the results of cementless total hip arthroplasty using the Bi-metric titanium femoral stem at a minimum follow up of 10 years and a mean of 12.2 years (range 10–17).

64 hips (43 male/21 female) were implanted consecutively into 54 patients between 1988 and 1995. The mean age at operation was 54.3 years (range 42–65). All patients had a Bi-metric uncemented stem (Biomet UK). The first 13 patients received a metal backed screw in acetabular cup (TTAP-ST, Biomet UK) with the remainder receiving metal backed pressfit cups (Universal, Biomet UK).

All patients were followed up annually and assessed using the Hip Society Score (HSS; max 40 points) to record pain, function and mobility. Survivorship was calculated using the Kaplan-Meier method.

57 hips were followed up for a minimum of ten years. There were 4 deaths (6 hips) before completion of follow up and 1 patient was lost to follow up.

Using revision for any reason as the end point of the study; survivorship for the total hips at 10 years was 89.5% (95% confidence interval: 78.1–96.1%) with a mean Hip Society Score of 34.9 (range 20–40) compared to 14.5 (range 8–24) pre-operatively (p< 0.01 student t test).

Survivorship for the femoral stem in isolation was 100% at 10 years (95% CI 93.7–100%) and there continues to be no revisions to date at a mean follow up of 12.2 years.

The screw fix cup performed poorly with 3 acetabular revisions (including 1 liner change) before the 10 year follow up, a failure rate of 23.1%. There has sub-sequently been a further 4 acetabular revisions.

Ten year survivorship for the pressfit cup is 93.5% (95% CI 82.0–98.8%) with 3 revisions (including 2 liner changes) at ten years. There has subsequently been one further acetabular revision and 9 further liner changes (29.5% failure rate).

There have been no recorded infections and no instances of thigh pain.

Radiographs at ten years showed all the femoral stems were stable with no evidence of migration. Two stems had small radiolucent lines at the bone-implant interface but no signs of loosening. One stem had an area of osteolysis in Gruen zone 7 but didn’t require revision. Rates of osteolysis were extremely low given the large amounts of particulate debris in the hip from the worn acetabular liners.

In conclusion, although neither cup has proved to be particularly successful the Bi-metric stem has performed well at 10 year follow up and continues to do so. This is inspite of the fact they were implanted into a young and active group of patients.


Orthopaedic Proceedings
Vol. 91-B, Issue SUPP_III | Pages 407 - 407
1 Sep 2009
Ollivere B Duckett S August A Porteous M
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Introduction: The Birmingham Hip resurfacing was commercially introduced in 1997 and early originating centre series show good functional outcomes. Concerns have been raised over the longevity, functional outcomes and metal ion release from the implants. There are no series of medium term results from an independent district general hospital reported in the literature. We present a prospective series of 100 patients with mean 5 year follow up from a district general hospital. Each patient underwent yearly clinical, hip scoring, and regular radiographic evaluation.

Radiographic analysis was undertaken using Harris’, Hodgkinson’s and Amstutz’s criteria, evaluation of component position, neck narrowing and migration using diagnostic PACS workstations with standardised scaled images.

Results: Between June 2001 and Feb 2004 100 Birmingham Hip replacements were performed by two consultant surgeons (MP, AA). Mean follow up is 61.2 months (range 38–76 months). Harris hip scores (fig 1) improved from 46 pre-operatively to 90 post-operatively and no significant change over the next five years. There were no revisions in this period. Obese patients (BMI> 30) had a significantly (p< 0.03) lower post operative functional score as compared normal patients. No other factors were significant for outcome.

Component position was satisfactory in 93% of cases. Radiographic analysis showed no cups, or stems were definitely loose. Radiolucent lines were present in 8/100 acetabular and 3/100 femoral components, osteolytic lesions were seen in three acetabular components. Mean neck narrowing was 9mm. No patients show any radiographic evidence of avascular necrosis.

Conclusion This independent series shows the results of the Birmingham hip resurfacing are reproducible and comparable to those reported in the originating centre. The Birmingham hip resurfacing gives excellent clinical results, and there is no early evidence of radiographic failure. The high rate of neck narrowing gives us cause for concern and we would recommend regular radiographic follow up.