Heterotopic ossification after surface replacement arthroplasty and total hip arthroplasty: a randomized study.

With a randomized clinical trial, we compared the incidence and severity of heterotopic ossification in cohorts of patients who have undergone either surface replacement arthroplasty or total hip arthroplasty at a minimum follow-up of 1 year. Surface replacement arthroplasty group had a significantly higher rate of severe heterotopic ossification (Brooker grades 3-4) than the total hip arthroplasty group, 12.6% (13/103) vs 2.1% (2/97) respectively (P = .02). Grade 4 heterotopic ossification was observed (4.9%, 5/103) exclusively in the surface replacement arthroplasty group. Patients with severe heterotopic ossification had significantly inferior functional outcome scores. Surgeons offering surface replacement must be aware of this risk and use meticulous surgical technique and consider routine prophylaxis against heterotopic ossification.

The effects of different tensioning strategies on knee laxity and graft tension after double-bundle anterior cruciate ligament reconstruction.

BACKGROUND: Double-bundle anterior cruciate ligament reconstruction replicates the 2 functional bundles of the native ligament, the posterolateral and the anteromedial, to control anteroposterior and rotational laxity. HYPOTHESIS: Double-bundle anterior cruciate ligament reconstruction laxity should be affected by the way grafts are tensioned. STUDY DESIGN: Controlled laboratory study. METHODS: Fourteen intact cadaveric knees were instrumented in a 6 degree of freedom rig, and kinematics throughout flexion-extension were recorded with an electromagnetic system under a 90-N anterior force or a 5-N.m internal rotation torque. Anteromedial and posterolateral bundle bovine extensor tendon grafts were fixed to load cells on the tibia, and tension was adjusted to match the intact knee anteroposterior laxity with 3 different protocols: (1) anteromedial bundle first and then posterolateral bundle at 90 degrees and 20 degrees of flexion, respectively; (2) posterolateral bundle first and then anteromedial bundle at 20 degrees and 90 degrees of flexion, respectively; and (3) both bundles together at 20 degrees of flexion. Finally, a single-bundle graft positioned at 10 o'clock was tensioned at 20 degrees of flexion. RESULTS: Lower graft tensions were required to match intact knee laxity in double-bundle anterior cruciate ligament reconstruction. Tension patterns with knee flexion were independent from the tensioning protocol. Protocols 1 and 2 overconstrained anteroposterior laxity, whereas protocol 3 matched intact knee anteroposterior laxity throughout the range of motion. The single-bundle reconstructions had excess anteroposterior laxity in flexion. Rotations were better restored with double-bundle protocols 2 and 3. CONCLUSION: Knee laxity after double-bundle anterior cruciate ligament reconstruction is affected by the sequence in which the grafts are tensioned. CLINICAL RELEVANCE: Double-bundle anterior cruciate ligament reconstruction ensures better laxity restoration than does single bundle when both bundles are fixed together.

Timing of tourniquet release in knee arthroplasty. Meta-analysis of randomized, controlled trials.

BACKGROUND: Some surgeons release the tourniquet before closing the wound to secure hemostasis during knee arthroplasty. We examined whether early tourniquet release could reduce the perioperative blood loss and whether not releasing the tourniquet until after wound closure would increase the risk of early postoperative complications. METHODS: We searched electronic databases and reference lists of relevant articles, retrieved all of the published randomized controlled trials designed to address these issues, and performed a meta-analysis. RESULTS: Eleven studies involving a total of 872 patients and 893 primary knee arthroplasties were analyzed systematically. The studies showed considerable clinical and methodological diversity. Early release of the tourniquet increased the total measured blood loss (weighted mean difference = 228.7 mL; 95% confidence interval = 168.3 to 289.1; p < 0.00001). Early release also increased blood loss as calculated on the basis of the maximum decrease in hemoglobin concentration (weighted mean difference = 320.7 mL; 95% confidence interval = 204.3 to 437.1; p < 0.00001). The rate of reoperations due to postoperative complications was 3.1% (nine of 290) in the group with late tourniquet release compared with 0.3% (one of 290) in the group with early tourniquet release; the risk difference was 3% (95% confidence interval, 0.1% to 5%), which was significant (p = 0.04). CONCLUSIONS: Early tourniquet release for hemostasis increases the blood loss associated with primary knee arthroplasty. However, tourniquet release after wound closure can increase the risk of early postoperative complications requiring another operation. Well-conducted large studies are needed to further explore the risk of early postoperative complications associated with late tourniquet release in knee arthroplasty. LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions to Authors for a complete description of levels of evidence.