Sciatic Nerve Palsy (SNP) is a recognised complication in Primary Total Hip Replacement after a transtrochanteric or a posterior approach (5). It is considered to be caused by direct trauma to the nerve during surgery. In our unit this complication was rare with an incidence of < 0.2% over the past ten years. However we know describe six cases of sciatic nerve palsy occurring in 355 consecutive primary THRs (incidence 1.60%) performed in our unit from June 2000 to June 2001. Each of these sciatic nerve palsies we believe was due to postoperative haematoma in the region of the sciatic nerve.

To our knowledge there are only five reported cases in the literature of sciatic nerve palsy secondary to postoperative haematoma (1). (Each of the six patients who developed SNP was receiving prophylactic anticoagulation).

Cases recognized early and drained promptly showed earlier and more complete recovery. Those in whom diagnosis was delayed and were therefore managed expectantly showed no or poor recovery. More than usual pain the buttock, significant swelling in the buttock region and sciatic nerve tenderness associated with signs of sciatic nerve irritation may suggest the presence of haematoma in the region of the sciatic nerve. It is therefore of prime importance to be vigilant for the signs and symptoms of sciatic nerve palsy in the early post operative period because if recognized and treated early the potential injury to the sciatic nerve may be reversible.

Aim: To assess the blood loss in patients undergoing total knee arthroplasty and to determine the effects of surgical technique, duration of surgery and use of tourniquet. To look at the value of patient factors including gender, age, weight, pre-operative haemoglobin as predictive factors for future transfusion. We assessed the complications of wound healing, regaining the range of motion and thromboembolic effects.

Patients and Methods: A prospective review of 150 patients undergoing knee arthroplasty, with a minimum follow-up of 2 years (2–8 years). We divided the patients into three groups (n=50). Group A had no tourniquet applied and haemostasis secured before skin closure, Group B had tourniquet released after cementation to secure haemostasis before skin closure and Group C had tourniquet applied until after the skin closure.

Patients were matched for age, gender, pathology, weight, implant type, pre operative haemoglobin and senior operator in all three groups. We assessed intra-operative and total blood loss, transfusions requirements, postoperative wound complication, regaining of the range of motion, incidence of systemic effects of tourniquet and duration of hospital stay. We also looked at the effects of NSAIDS on blood loss and compared the validity of various factors reported in the literature to be predictive of future transfusion after the surgery. Statistical analysis used were, student’s t-test, univariate and multivariate analysis and regression statistical analysis.

Results: Group A had maximum blood loss (mean 1374 mls.) followed by Group B (mean 774 mls.) The mean blood loss of Group C was 550 mls (p< 0.001, 95% confidence interval range of 527843 mls). Statistically the duration of operation was the most important factor in minimising the blood loss (p< . 0001 R₂ =0.68). The association of pre operative haemoglobin and weight as predictors of future transfusions statistically did not show a strong relationship (R2 = 0.17, R₂ = 0.13 respectively). Statistically no significant difference was found in wound complications, hospital stay, post operative pain and regaining the range of motion in three groups (R₂ 0.58). Patients on NSAIDS did not loose more bloods than patients not on NSAIDS.

Conclusions: The use of tourniquet until after the skin closure is statistically the best method for reducing blood loss in total knee arthroplasty. It does not cause significant wound problems and does not significantly affect the regaining of range of motion. Furthermore the usage of NSAIDS does not cause excessive postoperative bleeding.