We investigated the blood flow to the femoral head during and after Resurfacing Arthroplasty of the hip.

In a previous study, we recorded the intra-operative blood flow in 12 patients who had a posterior approach to the hip and 12 who had a trochanteric flip approach. Using a LASER Doppler flowmeter, we found a 40% drop in blood flow in the posterior group and an 11% drop in the trochanteric flip group (p<0.001). The aim of this current study was to find out whether the intra-operative fall in blood flow persists during the post-operative period.

We therefore conducted a Single Positron Emission Tomography (SPECT) scan on 14 of the same group of patients. The proximal femur was divided into four regions of interest. These were the mid-shaft, proximal shaft, inter-trochanteric and head-neck regions. The data was analysed for bone activity and comparisons made between the two groups for each region of the femur. We found that the bone activity in the mid-shaft, upper-shaft, and head-neck regions was the same eleven months after the surgery irrespective of the approach to the hip. However there was higher activity in the trochanteric flip group in the inter-trochanteric region.

We conclude that the intra-operative deficit in blood flow to the head-neck region of the hip associated with the posterior approach does not seem to persist in the late post-operative period. We believe the reason for increased bone activity in inter-trochanteric region to be due to the healing of the trochanteric flip osteotomy.

Metal on metal hip resurfacing is increasing in popularity for the young, active patient. We present the results of a consecutive series from a single surgeon over a ten year period; 295 hip resurfacings (McMinn and Cormet; Corin, Cirencester, UK) with a minimum follow up of 2 years and a mean follow up of 4 years. There were 173 males with a mean age of 53.4 years and 121 females with a mean age of 50.3 years. Forty-six patients underwent bilateral resurfacings. All resurfacings were performed through a posterior approach.

The aetiology in this group was primary OA in 75.9%, inflammatory arthritis in 6.1%, DDH in 6.1%, AVN in 4.7%, trauma in 4.7%, Perthes in 1.7% and SUFE in 0.7%. Patients were reviewed clinically and radiographically on an annual basis. Follow-up was available on 93% of patients. 94.2% of hips have survived and the mean Harris Hip Score is 87.5. Females had a higher failure rate (10.7%) than males (2.3%). There was no clear trend between patient age and failure rate. The highest failure rate (33.3%) was seen in patients with DDH whilst only 4.5% of patients with OA failed. One patient with AVN failed but no failures occurred in patients with inflammatory arthritis, trauma, Perthes or SUFE. Failures occurred due to cup loosening (2.0%), neck fractures (1.7%), head loosening (1.0%), head collapse (0.3%), infection (0.3%) and pain (0.3%). The five patients who suffered neck fractures were symptomatic within 3 months of surgery.

We remain cautiously optimistic about the medium term results of hip resurfacing. Careful patient selection is important and caution should be taken in females and patients with DDH

We used a laser Doppler flow-meter with high energy (20 m W) laser (Moor Instruments Ltd. Milwey, UK) to measure the blood flow to the femoral head during resurfacing arthroplasty.

Twenty-four hips were studied; 12 underwent a posterior approach and twelve a Ganz's trochanteric flip osteotomy. The approach was determined according to surgeon preference. Three patients were excluded, The exclusion criteria were previous hip surgery, history of hip fracture and avascular necrosis (AVN). All patients had the hybrid implant with cemented femoral component.

During surgery a 2.0mm drill bit was passed via the lateral femoral cortex to the superior part of the head neck junction. The position was confirmed using fluoroscopy. The measurements were taken during five stages of the operation: when the fascia lata was opened (baseline), at the end of soft tissue dissection, following dislocation of the hip, after relocation back into the socket, after inserting the implants prior to closing the soft tissues and, finally, at the end of soft tissue closure.

The results were analysed and the values were normalised to a percentage of the baseline value. We found a mean drop of 38.6 % in the blood flow during the posterior approach and a drop of 10.34% with the trochanteric flip approach. The significant drop occured between the baseline (1st stage) and the end of the soft-tissue dissection (2nd stage). In both groups the blood flow remained relatively constant afterwards.

Our study shows that there is a highly significant drop in blood flow (p<0.001) during the posterior approach compared with the trochanteric flip approach.

Management of periprosthetic femoral fractures above a Total Knee Arthroplasty remains a challenge. The different treatment options available include casting for undisplaced fractures, ORIF for a displaced fracture with a well-fixed implant or revision arthroplasty for a very distal fracture and for a fracture with a loose implant.

We describe our experience in treating a very distal displaced supracondylar fracture above a well-fixed femoral component in a 68-year-old woman who was recently diagnosed with breast carcinoma and awaiting mastectomy. There was no evidence of metastatic disease. The knee replacement was done 4 years before and the patient did not have any symptoms in the knee prior to the fall. Conventional ORIF with IM nailing or plate osteosynthesis was not possible due to the very distal site of the fracture.

We used a custom modified 95 degree angled blade plate in which a slot was cut in the middle of the blade halfway along its length to accommodate the pegs of the femoral component in the distal fragment. The fracture was reduced and fixed with the angled blade plate restoring length, alignment, and providing coronal stability. The patient had a satisfactory union at 3 months without deformity giving a good range of pain free movement in the knee.

DCS and 95 degree angled blade plate have been used in the past with mixed results. The lag screw or the blade has to be inserted more proximally to avoid the femoral component and so the distal fixation is often sub optimal. In our case modification of the blade allowed more distal placement providing optimal fixation and avoiding complex revision surgery.