We have investigated the errors in the identification of the transepicondylar axis and the anteroposterior axis between a minimally-invasive and a conventional approach in four fresh-frozen cadaver knees. The errors in aligning the femoral prosthesis were compared with the reference transepicondylar axis as established by CT.

The error in the identification of the transepicondylar axis was significantly higher in the minimal approach (4.5° of internal rotation, sd 4) than in the conventional approach (3° of internal rotation, sd 4; p < 0.001). The errors in identifying the anteroposterior axis in the two approaches were 0° (sd 5) and 1.8° (sd 5) of internal rotation, respectively (p < 0.001).

We report the mid-term results of femoral impaction grafting which was used in 53 patients during the second stage of a two-stage revision for an infected total hip replacement. We reviewed all cases performed between 1989 and 1998. All patients underwent a Girdlestone excision arthroplasty, received local and systemic antibiotics and subsequently underwent reconstruction, using femoral impaction grafting.

Four patients had further infection (7.5%), and four died within 24 months of surgery. One patient underwent revision of the stem for a fracture below its tip at ten months. This left 44 patients with a mean follow-up of 53 months (24 to 122). All had improved clinical scores and a satisfactory radiological outcome.

We describe a method of intertrochanteric osteotomy with posterior rotation of the femoral head and neck. We analysed 45 hips in 44 children and adolescents aged from six to 18 years with residual dysplasia after conservative (35) and operative (10) treatment of developmental dysplasia of the hip complicated by avascular necrosis of the femoral head. In ten, femoral osteotomy was combined with a variety of pelvic procedures.

Thirty-seven hips (36 patients) were available for follow-up at a mean of 4 years 5 months (2 to 15 years). Excellent results were obtained in nine, good in 17, fair in seven and poor in four.

Aims

The optimal treatment for independent patients with a displaced intracapsular fracture of the hip remains controversial. The recognised alternatives are hemiarthroplasty and total hip arthroplasty. At present there is no established standard of care, with both types of arthroplasty being used in many centres.

It has been shown that raised intracapsular pressure causes avascular necrosis of the femoral head in experimental animals, but the relevance of this to clinical fractures of the femoral neck is controversial. We have studied 19 patients with intracapsular fractures of the femoral neck by pressure measurement and by ultrasonography to demonstrate capsular distension. The intra-articular pressure in Garden Grade I and II fractures averaged 66.4 mmHg with a maximum of 145 mmHg. In 10 Garden Grade III and IV fractures the average pressure was 28 mmHg with a maximum of 65 mmHg. Most of the recorded intracapsular pressures were high enough to have caused possible vascular embarrassment, and it is suggested that early decompression of the haemarthrosis should be considered.

A clinical, radiological and histopathological study of femoral heads from 125 patients with fracture of the neck of the femur and from 30 cadavers was carried out to identify various risk factors. The findings showed that the Singh index was unreliable as a radiological indicator of the bone content of the femoral heads; that the bone content of the femoral head in patients sustaining a fracture of the femoral neck did not differ from that of the controls; that osteomalacia was not found in any of the heads examined; and that the distribution of trabecular microfractures did not support the hypothesis that fracture of the neck was the result of progressive fatigue. It was concluded that the single most important factor leading to fracture in this Australian population was injury caused by falls and that such injury was frequently associated with other disease processes.

A boy aged fourteen trapped and tore at its origin a branch of the terminal part of the superficial femoral artery over a cancellous exostosis during extension of the knee from the position of full flexion. Three months later an expanding false aneurysm necessitated arteriography, after which suture of the tear gave a successful result.

Fracture of the neck of the femur after resurfacing arthroplasty usually leads to failure and conversion to a total hip replacement. We describe an intracapsular fracture of the femoral neck sustained after hip resurfacing which was treated by cannulated screws, resulting in union and retention of the resurfacing implant. The result at follow-up three years later was very satisfactory with a Harris hip score of 99.

1. A series of 142 fractures of the trochanteric region treated by fixation with Vitallium nail-plates of the original McLaughlin pattern is described. The hospital mortality was 9 per cent. Disruption of the nail-plate junction occurred in 8 per cent of cases. This confirms McLaughlin and Garcia's (1955) view that this pattern of nail-plate should no longer be used.

2. Despite this, satisfactory functional results were achieved in 78 per cent of the survivors.

3. The new Model V McLaughlin nail-plate is described, and the stresses in nail-plates are considered. On theoretical grounds and laboratory tests the weakness at the nail-plate junction has been eliminated in the new model, and the strength of the appliance as a whole compares favourably with other types of nail-plate. Full clinical trial is therefore justified, and seventy-one patients have so far been operated on, with satisfactory early results.

4. Marked stiffness of the hip joint greatly increases angulatory and rotational stresses on the nail-plate, and a high incidence of disruption is to be expected in these cases.

In a prospective, randomised study we have compared the pertrochanteric external fixator (PF) with the sliding hip screw (SHS) in 100 consecutive patients who were allocated randomly to the two methods of treatment. Details of the patients and the patterns of fracture were similar in both groups. Follow-up was for six months.

Use of the PF was associated with significantly less blood loss, a shorter operating time, reduced postoperative pain, shorter hospitalisation (p < 0.001), earlier mobilisation (p < 0.001) and a reduced rate of mechanical complications (p < 0.01). Superficial infection was significantly more common with the PF (p < 0.01), but without long-term adverse consequences. There were no differences in the healing of the fracture, mortality or final functional outcome. Our results indicate that the external fixator is an effective and safe device for treating pertrochanteric fractures and should be considered as a useful alternative to conventional fixation with the sliding hip screw.

We aimed to evaluate the precision and longitudinal sensitivity of measurement of bone mineral density (BMD) in the pelvis and to determine the effect of bone cement on the measurement of BMD in femoral regions of interest (ROI) after total hip arthroplasty (THA).

A series of 29 patients had duplicate dual-energy x-ray absorptiometry (DXA) scans of the hip within 13 months of THA. Pelvic analyses using 3- and 4-ROI models gave a coefficient of variation (CV) of 2.5% to 3.6% and of 2.5% to 4.8%, respectively. Repeat scans in 17 subjects one year later showed a significant change in BMD in three regions using the 4-ROI model, compared with change in only one region with the 3-ROI model (p < 0.05).

Manual exclusion of cement from femoral ROIs increased the net CV from 1.6% to 3.6% (p = 0.001), and decreased the measured BMD by 20% (t = 12.1, p < 0.001). Studies of two cement phantoms in vitro showed a small downward drift in bone cement BMD giving a measurement error of less than 0.03 g/cm²/year associated with inclusion of cement in femoral ROIs.

Changes in pelvic periprosthetic BMD are best detected using a 4-ROI model. Analysis of femoral ROI is more precise without exclusion of cement although an awareness of its effect on the measurement of the BMD is needed.

Rotational deformity following intramedullary nailing may cause symptoms and require surgical correction by osteotomy. Reamed, locked intramedullary nailing may be performed, but concern about cortical blood supply and potential pulmonary dysfunction from reaming have led many surgeons to limit this and use smaller diameter nails. Slotted nails are commonly used but are less stiff in torsion than the newer unslotted nails, particularly at the lower diameters.

We report two cased of recurrent femoral rotational deformity after using statically interlocked slotted intramedullary nails to correct existing femoral rotational deformities. These patients show that small diameter statically interlocked femoral nails with diminished bone-nail contact must be stiff enough in rotation to avoid potential recurrence.

Nonunion of intertrochanteric fractures is uncommon but its effects are disabling. We describe a modification of the medial displacement and valgus osteotomy of Dimon and Hughston (1967) which we used in seven fractures, six of which united within 16 weeks. Postoperatively, hip function was good. The method provides good initial stability, a source of cancellous bone graft, good postoperative hip abductor function and reliable healing of the nonunion without the need for intraoperative imaging.

1. Arrest of growth at one proximal tibial epiphysis of young rabbits was obtained by stapling.

2. Radiopaque markers allowed the subsequent growth of both proximal and distal epiphyses of the experimental and contralateral tibiae and of both lower femoral epiphyses to be followed radiographically.

3. The reduction in the normal deceleration of growth rate at the distal epiphysis found after epiphysiodesis of the proximal epiphysis was again observed.

4. This change in growth rate was not encountered in the distal femoral epiphysis lying adjacent to the stapled tibial epiphysis.

5. Removal of the staples after the change in growth rate had become established at the distal tibial epiphysis was followed by a return to an approximately normal growth rate by both proximal and distal epiphyses.

6. It is concluded that a direct relationship exists between the additional growth at the uninjured epiphysis and the deficiency in growth obtained at the stapled epiphysis, and that this change in growth rate is limited to the experimental tibia.