We present the clinical results and survivorship
of consecutive 100 Birmingham Hip Resurfacings in 90 patients at
a minimum follow-up of ten years. All procedures were carried out
by an independent surgeon who commenced a prospective study in 1998.
Patients were assessed clinically using the Western Ontario and
McMaster Universities osteoarthritis index, Short-Form 36, Harris
hip score and University of California, Los Angeles activity score. Radiological
analysis was performed by an independent observer and blood metal
ion levels concentrations were measured at ten years post-operatively
in 62 patients. The median acetabular component inclination was
46.2° (34° to 59°) and anteversion 11.0° (0° to 30°). The median
chromium concentration in the unilateral group was 1.74 (0.41 to
15.23) and for the bilateral group was 2.98 (1.57 to 18.01). The
equivalent values for cobalt were 1.67 (0.54 to 20.4) and 1.88 (1.38
to 19.32). In total there were eight failures giving an overall survival
at ten years of 92% (95% confidence interval (CI) 86.7 to 97.3).
BHR in male patients had an improved survivorship of 94.6% (95%
CI 89.4 to 100) compared with females at 84.6% (95% CI 70.7 to 98.5),
but this did not reach statistical significance (p = 0.119). Four
of the nine BHRs with a bearing diameter of 42 mm failed. The overall results were consistent with data produced from other
centres in that the clinical outcome of large male patients was
extremely encouraging, whereas the survival of the smaller joints
was less satisfactory.
We examined prospectively collected data from 6782 consecutive hip fractures and identified 327 fractures in 315 women aged ≤65 years. We report on their demographic characteristics, treatment and outcome and compare them with a cohort of 4810 hip fractures in 4542 women aged >
65 years. The first significant increase in age-related incidence of hip fracture was at 45, rather than 50, which is when screening by the osteoporosis service starts in most health areas. Hip fractures in younger women are sustained by a population at risk as a result of underlying disease. Mortality of younger women with hip fracture was 46 times the background mortality of the female population. Smoking had a strong influence on the relative risk of ‘early’ (≤ 65 years of age) fracture. Lag screw fixation was the most common method of operative treatment. General complication rates were low, as were re-operation rates for cemented prostheses. Kaplan-Meier implant survivorship of displaced intracapsular fractures treated by reduction and lag screw fixation was 71% (95% confidence interval 56 to 81) at five years. The best form of treatment remains controversial.
Gender-specific total knee replacement has generated much interest recently. We reviewed 1970 Sigma knees implanted in 920 women and 592 men with a mean age of 69.7 years. At a mean follow-up of 7.3 years (minimum, five years), we found minimal differences in the outcome between genders. At the final follow-up, men had a higher overall Knee Society score and more osteolysis (3.8% vs 1.1%). However, there were no significant differences between men and women in terms of complications or improvements in knee function, pain score or range of movement. The estimated ten-year survivorship was 97% in women and 98% in men (p = 0.96). We concluded that there was little difference in outcome between the genders treated by a modern unisex design of total knee replacement in this large multicentre study.
We describe the results of a randomised, prospective study of 200 ankle replacements carried out between March 2000 and July 2003 at a single centre to compare the Buechel-Pappas (BP) and the Scandinavian Total Ankle Replacement (STAR) implant with a minimum follow-up of 36 months. The two prostheses were similar in design consisting of three components with a meniscal polyethylene bearing which was highly congruent on its planar tibial surface and on its curved talar surface. However, the designs were markedly different with respect to the geometry of the articular surface of the talus and its overall shape. A total of 16 ankles (18%) was revised, of which 12 were from the BP group and four of the STAR group. The six-year survivorship of the BP design was 79% (95% confidence interval (CI) 63.4 to 88.5 and of the STAR 95% (95% CI 87.2 to 98.1). The difference did not reach statistical significance (p = 0.09). However, varus or valgus deformity before surgery did have a significant effect) (p = 0.02) on survivorship in both groups, with the likelihood of revision being directly proportional to the size of the angular deformity. Our findings support previous studies which suggested that total ankle replacement should be undertaken with extreme caution in the presence of marked varus or valgus deformity.
Surgical dislocation of the hip in the treatment of acetabular fractures allows the femoral head to be safely displaced from the acetabulum. This permits full intra-articular acetabular and femoral inspection for the evaluation and potential treatment of cartilage lesions of the labrum and femoral head, reduction of the fracture under direct vision and avoidance of intra-articular penetration with hardware. We report 60 patients with selected types of acetabular fracture who were treated using this approach. Six were lost to follow-up and the remaining 54 were available for clinical and radiological review at a mean follow-up of 4.4 years (2 to 9). Substantial damage to the intra-articular cartilage was found in the anteromedial portion of the femoral head and the posterosuperior aspect of the acetabulum. Labral lesions were predominantly seen in the posterior acetabular area. Anatomical reduction was achieved in 50 hips (93%) which was considerably higher than that seen in previous reports. There were no cases of avascular necrosis. Four patients subsequently required total hip replacement. Good or excellent results were achieved in 44 hips (81.5%). The cumulative eight-year survivorship was 89.0% (95% confidence interval 84.5 to 94.1). Significant predictors of poor outcome were involvement of the acetabular dome and lesions of the femoral cartilage greater than grade 2. The functional mid-term results were better than those of previous reports. Surgical dislocation of the hip allows accurate reduction and a predictable mid-term outcome in the management of these difficult injuries without the risk of the development of avascular necrosis.
There are theoretical and practical advantages to modular rather than monoblock designs of prostheses for shoulder arthroplasty, but there are no reported studies which specifically compare the clinical and radiological results of their use. We have compared the results of unconstrained total shoulder arthroplasty for osteoarthritis using both types of implant. The monoblock design was used between 1992 and 1995 and the modular design after 1995. Both had cemented all-polyethylene glenoids, the monoblock with matched and the modular with mismatched radii of curvature. There were 34 consecutive shoulders in each group with a mean follow-up of 6.1 years in the first and 5.2 years in the second. There were no significant differences in improvement of pain scores, active elevation, external rotation, internal rotation, patient satisfaction, or the Neer ratings between the two groups. Two of 28 glenoid components in the first group and six of 30 in the second met the criteria for being radiologically at risk for loosening (p = 0.25). There were no significant differences in clinical outcome or radiological changes between the first- and second-generation designs of implant for shoulder arthroplasty.
We reviewed retrospectively the results in 211 consecutive patients who had undergone limb salvage for bone neoplasia with endoprosthetic reconstruction of the proximal femur (96), distal femur (78), proximal tibia (30) and total femur (7). Their mean age was 50 years (11 to 86) and the mean follow-up period was 37.3 months (1 to 204). A total of 35 (16.6%) prostheses failed. Overall, implant survival was 78% (95% confidence interval (CI) 0.29 to 0.54) at five years, 60% (95% CI 0.93 to 2.35) at ten years and 60% (95% CI 1.27 to 3.88) at 15 years. Survivorship of the limb was 97.6% (95% CI 1.73 to 3.35) at ten years. The gender, age, diagnosis and location of the tumour were not prognostic variables for failure. Modular endoprosthetic replacement in the lower limb is a durable long-term reconstructive option, with the implants generally outlasting the patient.
Although the importance of sound statistical principles in the design and analysis of data has gained prominence in recent years, biostatistics, the application of statistics to the analysis of biological and medical data, is still a subject which is poorly understood and often mishandled. This review introduces, in the context of orthopaedic research, the terminology and the principles involved in simple data analysis, and outlines areas of medical statistics that have gained prominence in recent years. It also lists and provides an insight into some of the more common errors that occur in published orthopaedic journals and which are frequently encountered at the review stage in papers submitted to the