Anterior cruciate ligament injury. Results after reconstruction in terms of function, postoperative pain and kinematics

Abstract

The aim of this study was to evaluate the functional and objective outcome after anterior cruciate ligament reconstruction using bone-patellar tendon-bone grafts. Other main objectives were to evaluate postoperative pain, pain reduction and knee kinematics after anterior cruciate ligament injury and reconstruction.In a prospective study, 112 patients were operated on using anterior cruciate ligament reconstruction with bone patellar-tendon bone-tendon grafts. The patients were followed for four to seven years (median 66 months). The results after suture of the patellar tendon and bone grafting of the patellar defect were studied in 60 patients for two years. Pain relief using morphine, local anaesthetic and an external cooling system was evaluated and the plasma concentrations of morphine and morphine metabolites (morphine-3-glucuronide and morphine-6-glucuronide) were measured. The kinematics after anterior cruciate ligament rupture and reconstruction were evaluated using radiostereometric analysis during continuous knee movement from 55 degrees of flexion to full extension. Anterior knee laxity was evaluated using both the radiostereometric technique and the KT-1000 laxitymeter. The clinical results after anterior cruciate ligament reconstruction were excellent or good in the majority of patients in terms of the Lysholm score, Tegner activity level, IKDC evaluation system and one-leg-hop quotient. The anterior knee laxity evaluated using the KT-1000 laxitymeter had improved significantly at the four- to seven-year follow-up compared with preoperatively. However, a quarter of the patients underwent additional surgery during the follow-up period due to meniscal injuries, cartilage injuries and hardware-related problems. Suturing the patellar tendon and bone grafting the defect in the patella produced no benefits. The external cooling system was useful in relieving postoperative pain, more so if combined with intra-articular morphine and local anaesthetic. Morphine appeared to have a direct effect on receptors in the knee, as there were low concentrations of morphine and morphine metabolites in the plasma, indicating a peripheral action. The kinematics of the knee were significantly different from those of the normal knee. There was less rotation of the tibia during extension and the tibia was more posteriorly displaced during the entire movement from 55 degrees of extension to full flexion. The lateral femoral condyle showed less anterior displacement in the injured knee during extension. These abnormal kinematics might be one of the reasons for meniscal injuries, as well as cartilage injuries and osteoarthrosis, after anterior cruciate ligament injury. Reconstruction of the anterior cruciate ligament resulted in improved functional scores and reduced anterior knee laxity but did not affect the kinematics of the knee.