The exact alignment of the femoral component is crucial for the success of hip resurfacing arthroplasty. This prospective study was performed to find whether the imageless computer-assisted navigation surgery can improve the accuracy during hip resurfacing arthroplasty by comparing the alignment of the femoral component implanted with navigation system and conventional-mechanical guided system.

Forty patients were randomly allocated into 2 groups for resurfacing hip arthroplasty using Birmingham hip resurfacing system. In the conventional group, femoral component positioning was assisted by mechanical alignment guides. In the navigation group, it was assisted by an imageless computer-assisted surgical system of Vectorvision^® (BrainLAB, Germany). We measured the difference between the preoperative plan of femoral component’s position and postoperative results on radiographs in the 2 groups

In the conventional group, a median difference of the stem alignment was 5.4° (range, 0.2°–10.9°) and a median difference of the stem anteversion was 2.6° (range, 0°–6.5°). In the navigated group, a median difference of the stem alignment was 2.3° (range, 0.2°–4.9°) and a median difference of the stem anteversion was 1° (range, 0°–3.6°). These differences between the 2 groups were statistically significant (P< 0.05).

In resurfacing arthroplasty with a hip navigation, the procedure showed a good performance and reliability. It is achieved with greater precision with a navigation system than a mechanical alignment system.

The aim of this study is to analyse the mid to long term results of cementless total hip arthroplasty (THA) performed in hemophilic coxarthrosis. Twenty-seven consecutive cementless THAs (23 patients) were performed at our institute for hemophilic coxarthrosis between June 1995 and June 2003. All these patients were followed up regularly for minimum 5 years and were included in this study. The average age at the time of surgery was 36 years (± 8.1) (range, 24–52 years). All the patients had hemophilia A. Twelve patients (52%) had more than 1 joint affected by hemophilic arthropathy. The mean follow-up period was 92 months (± 31.4) (range, 60–156 months). For clinical assessment we evaluated Harris hip score, range of motion, amount of transfusion and factor replacement, perioperative bleeding and the problems associated with the use of coagulation factors. For radiographic assessment, we evaluated the stability and fixation of components, various bone responses around the implants and complications such as loosening and osteolysis.

The average Harris hip score improved from 60.7 (± 19.3) (range, 30–89) before surgery to 95.9 (± 3) (range, 90–100) at the latest follow-up. The hip range of motion increased in all planes of motion after the operation. The mean factor VIII requirement per THA was 37 500 units (± 18 500) (range, 19 000–90 000 units). During surgery and post operative period mean 1.5 units (± 1.5) (range, 0–5 units) of packed cells and 0.5 units (± 1.4) (range, 0–5 units) of fresh frozen plasma was required. There was episode of re-bleeding in 4 cases. In one of them, severe osteolysis around pelvis and femoral stem was noted due to pseudotumor. Radiographically, except 1 loosened cup, the fixation was stable in all cases at the latest follow-up. Heterotopic ossification was noted in 2 hips. Osteolysis was noted in 4 femurs and 5 acetabulae. In 1 case of severe osteolysis around the stem, morsellised bone graft was performed at 144 months after the index operation. One case of pseudotumor was waiting for surgery. One loosened cup was revised to a cemented cup.

Unlike worrisome results of cemented THA, meticulously performed cementless THA for moderate or severe hemophilic arthropathy is safe and greatly effective in reducing pain, increasing the range of motion and improving the walking ability. However, special attention must be paid to the possible complications associated with re-bleeding such as pseudotumor around the hip. To obtain the best results multidisciplinary team comprising of pediatrician, hematologist, rehabilitation therapist and orthopaedic surgeon should be needed.