Effects of the type of meniscal lesion on knee function.

ABSTRACT

The relationship between the type of meniscal lesion (bucket-handle, flap or degenerative tears) and preoperative knee function (5.1 +/- 6.2 days before arthroscopic meniscectomy) was studied in 35 patients. Patients with bucket-handle tears (group B, n = 12) had large knee extension work deficits during maximal voluntary contractions at 30 degrees and 180 degrees/s (Kin-Com dynamometer). These work deficits were accompanied by proportional decreases in the prime mover or agonist-EMG levels (VM vastus medialis and/or VL vastus lateralis). These patients had smaller deficits during flexion movements at 30 degrees/s. Moreover, a larger number of negative clinical signs and symptoms (pain at rest and during tests, locking, thigh atrophy, extension and flexion movement deficits larger than 10 degrees) were found with an equal or a higher prevalence in group B than in the other groups. Patients with flap tears (group F, n = 15) had deficits in work and agonist-EMG activity (VM and VL) only during the extension tests. In contrast, patients with degenerative tears (group D, n = 8) had a work deficit and a concomitant decrease in the EMG level of the medial gastrocnemius (MG), only during the flexion test at 30 degrees/s. Comparable mean knee function scores, as measured by the Lysholm and Gillquist questionnaire [35], were obtained for the three groups of patients, suggesting that this measure was not sensitive enough to discern functional differences related to types of meniscal tears. The results of this study have demonstrated a link between the type of meniscal lesion and the consequent preoperative knee joint disability profile as defined by comparison with the sound leg. These results emphasize the need to consider meniscal lesion type and an individual's preoperative strength deficit when group comparisons of patients are made or the effects of therapy (arthroscopic surgery and rehabilitation) are evaluated.