Femoral nerve block is a reliable and effective method of providing anaesthesia and analgesia in the peri-operative period but there remains a small but serious risk of neurological complication. We aimed to determine incidence and outcome of neurological complications following femoral nerve block in patients who had major knee surgery.

During the period January 2003 to August 2008, medical records of all patients undergoing knee surgery by Dr Myles Coolican and Dr David Parker, who had been administered femoral block for peri-operative analgesia, were evaluated.

Patients with a neurological complication were invited take part in the study. A detailed physical examination including sensory responses, motor response and reflexes in both limbs was performed by an independent orthopaedic surgeon. Subjective outcome and pain specific questionnaires as well as clinical measurements were also collected.

Out of 1393 patients administered with femoral nerve block anaesthesia during this period, 28 subjects (M:F= 5:23) were identified on the basis of persistent symptoms (more than three months) of femoral nerve dysfunction. All the patients had sensory dysfunction in the autonomous zone of femoral nerve sensory distribution. The incidence of neurological complications was 2.01%. One patient was deceased of unrelated causes and five patients declined to participate in the study. 14 patients out of the 22 have been examined so far. Nine cases had a one shot nerve block and five had continuous peripheral nerve block catheter. Areas of hypoesthesia/anaesthesia involving femoral nerve distribution occurred in 7 subjects and hyperaesthesia/paresthesia occurred in four. One subject had a combination of hypoesthesia and hyperesthesia in different areas of the femoral nerve distribution. Three subjects had bilateral symptoms following bilateral simultaneous nerve blocks. Dysesthesias in the affected dermatomes were found in seven cases and paresthesias were found in eight cases. Douleur Neuropathique en 4 questions (DN4) score of ï³ 4 was found in all the patients (average value: 5.55). The average scores for tingling, pins and needles and burning sensation (in a scale from 0 to 10) are 3.8, 3.1 and 2.9 respectively.

The incidence of persistent neurological complication after femoral nerve block in our series is much higher compared to the reported incidence in the contemporary literature (Auroy Y. et al. Major complications of regional anesthesia in France: Anesthesiology 2002; 97:1274 80). The symptoms significantly influence the quality of life in the affected cases and question the value of the femoral nerve block in knee surgery.

Transtrochanteric rotational osteotomy (TRO) is a controversial procedure with reported inconsistent results. We reviewed 50 patients (60 hips) who underwent this procedure for extensive osteonecrosis of the femoral head, focusing on varization to determine its effectiveness as a head-preserving procedure in young adults. The mean age of the patients was 28 years (range, 18–46 years). Using the Ficat-Arlet classification, 40 hips had Stage II and 20 hips had Stage III involvement. According to the classification system of Shimizu et al., the extent of the lesions were Grade C in 54 hips and Grade B in six hips; the location of the lesions were Grade c in 56 hips and Grade b in four hips. Minimum follow-up was 18 months (mean, 84 months; range, 18–156 months). The mean preoperative Harris hip score was 44.7 points (range, 32–62 points) which improved to an average postoperative score of 80.1 points (range, 44–100 points) at the latest follow-up. Forty-four hips showed no radiographic evidence of progression of collapse. Ten hips showed progressive collapse, seven hips showed progressive varus deformity, three hips had stress fractures of the femoral neck, and one hip had infection. We believe TRO with varization is worth attempting for extensive osteonecrosis of the femoral head in young adults, although failures and complications are not uncommon.