Background: Valgus-producing open-wedge high tibial osteotomy is an established treatment for varus malalignment and medial osteoarthritis, with reproducible results in the frontal plane. However, an undesirable but often accepted increase in posterior tibial slope and decrease in patellar height are still routinely seen.
Purpose: To evaluate the influence of valgus open-wedge high tibial osteotomy on posterior tibial slope and patellar height when special techniques are used to minimize unwanted changes.
Study Design: Case series; Level of evidence, 4.
Methods: Twenty-five patients, 3 women and 22 men (mean age, 40.2 years), underwent valgus open-wedge high tibial osteotomy. Several technical steps were taken to prevent an increase in posterior tibial slope during the osteotomy. To minimize patellar height changes, the tibial tuberosity was left on either the proximal or distal fragment, depending on the desired patellofemoral effect. The medial and lateral posterior slope was measured using the proximal posterior cortex as a reference; the patellar height was assessed with the Caton-Deschamps Index and compared on preoperative and postoperative radiographs.
Results: No significant posterior tibial slope changes were observed. Patellar height increased with both types of tibial tuberosity osteotomy. With the proximal osteotomy, the Caton-Deschamps Index increased from 0.95 to 0.97; with the distal osteotomy, it increased from 0.89 to 0.95. The change was not significant with either osteotomy. The posterior tibial slope did not change on the medial side, measuring 4.2 preoperatively and postoperatively. The lateral slope decreased from 5.4 to 5.1. There was no correlation between the correction in the coronal plane and the changes in the sagittal plane.
Conclusion: Open-wedge high tibial osteotomy can be performed without significant changes in patellar height or posterior tibial slope if specific intraoperative methods are used to prevent their occurrence. Analysis and control of sagittal changes in valgus open-wedge high tibial osteotomy should reduce the incidence of unwanted changes in patellar height and posterior tibial slope.
Background
The actual in vivo tibiofemoral and patellofemoral kinematics of the posterior cruciate ligament (PCL)-reconstructed knee joint are unknown.
Hypothesis
Current single-bundle PCL reconstruction is unable to correct the abnormal tibiofemoral and patellofemoral kinematics caused by rupture of the ligament.
Study Design
Controlled laboratory study/case series; Level of evidence, 4.
Methods
Seven patients with an isolated PCL injury in 1 knee and the contralateral side intact were included in the study. Magnetic resonance and dual fluoroscopic imaging techniques were used to compare the tibiofemoral and patellofemoral kinematics between the intact contralateral (control group), PCL-deficient, and PCL-reconstructed knee during physiologic loading with a single-legged lunge. Data were collected preoperatively and 2 years after single-bundle reconstruction.
Results
The PCL reconstruction reduced the abnormal posterior tibial translation in PCL-deficient knees to levels not significantly different from those of the intact knee. Posterior cruciate ligament deficiency resulted in an increased lateral tibial translation between 75° and 120° of flexion, and reconstruction was unable to restore these values to normal. No differences were detected among the groups in varus-valgus and internal-external rotation. The PCL reconstruction reduced the increased patellar flexion of PCL-deficient knees between 90° and 120° of knee flexion and the lateral shift at 120°. The abnormal patellar rotation and tilt seen in PCL deficiency at flexion angles of 75° and greater persisted after reconstruction.
Conclusion
Single-bundle PCL reconstruction was successful in restoring normal anteroposterior translation of the tibia, as well as the patellar flexion and shift. However, single-bundle PCL reconstruction was unable to achieve the same success in mediolateral translation of the tibia or in the patellar rotation and tilt.
Clinical Relevance
The persistent abnormal mediolateral translation of the tibia, as well as decreased patellar rotation and tilt, provide a possible explanation for the development of cartilage degeneration after reconstruction of an isolated PCL injury.
