One-stage versus two-stage bilateral unicompartmental knee replacement: a comparison of immediate post-operative complications.

We retrospectively studied the major complications occurring after one- and two-stage bilateral unicompartmental knee replacements (UKR). Between 1999 and 2008, 911 patients underwent 1150 UKRs through a minimally invasive approach in our unit. Of these, 159 patients (318 UKRs) had one-stage and 80 patients (160 UKRs) had two-stage bilateral UKRs. The bilateral UKR groups were comparable in age and American Society of Anaesthesiology grade, but more women were in the two-stage group (p = 0.019). Mechanical thromboprophylaxis was used in all cases. Major complications were recorded as death, pulmonary embolus, proximal deep-vein thrombosis and adverse cardiac events within 30 days of surgery. No statistical differences between the groups were found regarding the operating surgeon, the tourniquet time or minor complications except for distal deep-vein thrombosis. The anaesthetic times were longer for the two-stage group (p = 0.0001). Major complications were seen in 13 patients (8.2%) with one-stage operations but none were encountered in the two-stage group (p = 0.005). Distal deep-vein thrombosis was more frequent in the two-stage group (p = 0.036). Because of the significantly higher risk of major complications associated with one-stage bilateral UKR we advocate caution before undertaking such a procedure.

Comparison of expected vs. actual tunnel position in anterior cruciate ligament reconstruction.

In a prospective blinded non-randomised cohort study, 32 patients were assessed following anterior cruciate ligament reconstruction using autograft middle-third bone-patellar tendon-bone, over a period of 10 months. Two experienced surgeons performed the procedures, one using an arthroscopically assisted technique (16 patients) and the other by mini-arthrotomy (16 patients). A comparison was made between the positions of the tunnels as perceived by the surgeon intra-operatively with the actual position as shown on the post-operative X-ray. An independent blinded observer made the latter assessment. Actual vs. expected tunnel placement was analysed using the coefficient of correlation. The anteroposterior femoral tunnel position indicated perfect correlation (R(2)=1.00, P=0), and on the lateral view showed good correlation (R(2)=0.55, P=0.005). However, the tibial tunnel position anteroposteriorly showed poor correlation (R(2)=0.14, P=0.22), and on the lateral view no correlation (R(2)=0.07, P=0.36). The ideal tibial tunnel position is controversial, and in this study, two tibial tunnels were just anterior to the acceptable position and one was posterior. Altogether these three, and one other, were in very different positions to that expected by the surgeon. Surgeons may consider that before drilling the tibial tunnel, intra-operative confirmation of the guide-wire position would be helpful.

Intra-operative tibial plateau fracture during unicompartmental knee replacement: a case report.

Periprosthetic fracture is a recognised complication of joint replacement. Intra-operative fractures of the tibia during total knee replacement have been reported and classified, but there have been no reports in patients undergoing unicompartmental knee replacement. We report a case of intra-operative fracture of the medial tibial plateau during impaction of the tibial component of an Oxford unicompartmental knee replacement. This occurred following a small breach in the posterior tibial cortex during preparation of the tibial plateau for the implant. We therefore advise caution during this stage of the procedure, especially in patients who may already be at risk of intra-operative fracture.

An alternative to fixation of displaced fractures of the anterior intercondylar eminence in children.

Fractures of the anterior intercondylar eminence in children are relatively uncommon. There is considerable debate as to the best treatment of displaced fractures, but most methods described in the literature involve an open procedure combined with some form of fixation. Using human anatomical dissections, we have shown that the transverse meniscal ligament can become incarcerated within the fracture and act as a block to reduction. We describe an arthroscopic technique which requires no fixation device and report the results of its use in eight displaced fractures. This method gives reliable results and offers the advantage of less potential morbidity.