HIP International

Today's THR systems have been developed in conjunction with feedback from clinical practice, i.e. by evolution. In the 70s and 80s ceramic stems, monolithic cups, monoblock components, and skirted heads were used. Today, modular hip systems are offered, designed for ceramic heads, which articulate against ceramic or PE cups. The surgeon has the option of choosing a combination suitable to the specific situation. About 70 cups with ceramic inserts have been developed. More than 200,000 ceramic inserts have been used since the mid 80s.

The article discusses which combinations of head and cup inserts have been approved by government agencies and which combinations are not recommended

The influence of regional size on the precision error in the evaluation of bone mineral changes along femoral components in uncemented THA's was studied methodologically using Dual Energy X-ray Absorptiometry (DEXA) and with a review of the literature. A significant negative relation between region size and precision error was found in experimental studies and the precision error was shown to vary with type of DEXA scanner when reviewing the literature. When using Gruen's zones we found that the precision was best at the tip and poorest in the proximal regions. Guidelines based upon calculations of the approximate percentage changes necessary in a single individual to be statistically significant in a longitudinal study with 95% probability were made for three different types of DEXA scanners.

We report the radionuclide bone scan appearances following hemiarthroplasty of the hip in 15 asymptomatic, active patients at a mean of 14 months following surgery. All patients had a normal clinical examination, white cell count and erythrocyte sedimentation rates.

Tracer activity was graded. Minimal tracer activity especially along the lateral stem and acetabulum were consistent findings. We conclude that this should be regarded as normal in this situation.

Femoral varus, derotation and shortening osteotomy is part of the surgical treatment of hip subluxation and dislocation in children with cerebral palsy. In such cases, a post-operative neck-shaft angle of 110–120° is desirable as well as 0–15° anteversion. Standard techniques of planning a femoral osteotomy require accurate knowledge of proximal femoral deformity, but in cerebral palsy this may be difficult to measure owing to excessive anteversion and difficulties with positioning for radiographs.

We have developed and used a method that does not rely on preoperative radiographic measurements or the use of the femoral diaphysis for reference. Our method is focused on achieving the desired postoperative neck-shaft and anteversion angles mentioned above. The centre of the femoral neck is used as a reference and the chisel for a blade plate is applied 20–30° varus to this neutral axis. Osteotomy cuts are then made parallel to the chisel and perpendicular to the femoral shaft. The chisel is replaced with a 90° blade plate and the osteotomy is reduced, derotated and fixed to the femoral shaft. The final neck-shaft angle is therefore 90° plus 20–30°, ie the desirable 110–120°. This position is achieved without knowledge of the angle of the wedge of bone removed by the osteotomy.

This technique has been performed in 16 hips in 10 patients with cerebral palsy during one year. The final neck shaft angle fell within the desired range in 12 hips (75%). We have found this technique to be a simple and reliable means of achieving correction in patients in whom accurate preoperative estimate of the femoral neck shaft angle is not possible.

There are many factors affecting the outcome of major hip surgery. One postulated factor is the patient's peri-operative nutritional status. Several papers have confirmed the benefits of dietary supplements for malnourished patients. Despite this, there are currently no guidelines as to how best to assess nutrition in orthopaedic patients.

The aim of this study was to find a simple diagnostic test that accurately reflects nutritional status in patients undergoing major hip surgery. Twentyfive patients with fracture neck of femur and 25 total hip replacement patients were assessed. Nutritional risk assessment scores, body mass index (BMI), anthropometric and biochemical tests were applied. The different indices were correlated. Length of hospital stay was used as a measure of morbidity.

The correlations between the individual indices of nutritional status were disappointingly low. The only significant correlations for the Total Hip Arthroplasty group were BMI to triceps skinfold thickness (r_s=0.769, 95%CI: 0.505 to 0.900, p=0.0001) and BMI to skeletal muscle mass (r_s=0.501,95%CI: 0.092 to 0.766, p=0.018). The assessment of BMI is in practice very difficult in patients with fractures of the neck of the femur. There were no statistically significant correlations between any of the nutritional indices measured and postoperative morbidity.

This study was unable to accurately assess nutritional status in patients undergoing major hip surgery. A simple nutritional assessment that can be used on a busy orthopaedic ward has not been identified.

The Authors report a case of postoperative bleeding after total hip replacement revision, successfully stopped by the use of selective arterial embolization. Physiopathology and treatment of postoperative bleeding after total hip arthroplasty are discussed.

The Charnley-Hastings hip prosthesis is a hybrid bipolar hemiarthroplasty derived from a Hastings acetabular component and a Charnley stem. This report documents a presentation in which the acetabular component rotated in a medial fashion, resulting in an intra-acetabular dislocation of the Charnley femoral component.