Pullout failure strength of the posterior horn of the medial meniscus with root ligament tear.
OBJECTIVE
To evaluate the reparability of the posterior horn of the medial meniscus with root ligament tear by measuring the actual pullout failure strength of a simple vertical suture of an arthroscopic subtotal meniscectomized posterior horn of the medial meniscus.


METHODS
From November 2009 to May 2010, nine posterior horns of the medial meniscus specimens were collected from arthroscopic subtotal meniscectomy performed as a treatment for root ligament rupture of the posterior horn of the medial meniscus. Simple vertical sutures were performed on the specimens, and pullout failure load was tested with a biaxial servohydraulic testing machine (Model 8874; Instron Corp., Norwood, MA, USA). The degree of degeneration, extrusion, and medial displacement of the medial meniscus were evaluated with magnetic resonance imaging (MRI). The Kellgren-Lawrence classification was used in standing plain radiography, and mechanical alignment was measured using orthoroentgenography. Tear morphology was classified into ligament proper type or meniscoligamentous junctional type according to the site of the torn root ligament of the posterior horn of the medial meniscus during arthroscopy.


RESULTS
The mean pullout failure strength of the posterior horn of the medial meniscus was 71.6 ± 23.2 N (range, 41.4-107.7 N). The degree of degeneration of the posterior horn of the medial meniscus on MRI showed statistically significant correlation with pullout failure strength and Kellgren-Lawrence classification. Pullout failure strength showed correlation with mechanical alignment and Kellgren-Lawrence classification (P < 0.05).


CONCLUSIONS
The measurement of pullout failure strength of the posterior horn of the medial meniscus with root ligament tear showed a degree of repairability. The degree of degeneration of the posterior horn of the medial meniscus on MRI showed a significant correlation with the pullout failure strength. The pullout failure strength was also not only correlated with the degree of degeneration of the posterior horn of the medial meniscus, but also with mechanical alignment and Kellgren-Lawrence classification, which represent bony degenerative change.
Department of Orthopaedic Surgery, Chungnam National University College of Medicine, 640 Daesa-dong, Jung-gu, Daejeon 301-721, Korea.
Young-Mo
YM
Kim
Yong-Bum
YB
Joo
D000328:Adult; D000368:Aged; D001182:Arthroscopy; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000175:diagnosis / Q000601:surgery*; D008023:Ligaments, Articular / Q000000981:diagnostic imaging / Q000293:injuries / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008592:Menisci, Tibial / Q000000981:diagnostic imaging / Q000601:surgery*; D008875:Middle Aged; D011859:Radiography; D012421:Rupture / Q000000981:diagnostic imaging / Q000601:surgery; D013314:Stress, Mechanical; D013536:Suture Techniques; D000070600:Tibial Meniscus Injuries; D016896:Treatment Outcome