Journal Logo

D18E FREE COMMUNICATION/SLIDE SPORTS INJURY AND CARE

PERMANENT TIBIAL SUBLUXATION IN ANTERIOR CRUCIATE LIGAMENT (ACL)INJURED KNEES

Pandarinath, R1; Rahusen, F T.1; Almekinders, L C. FACSM1

Author Information
Medicine & Science in Sports & Exercise: May 2002 - Volume 34 - Issue 5 - p S134
  • Free

Previous studies on the degree instability of the tibiofemoral joint following ACL rupture and reconstruction have focused on the total amount of excess translation of the tibia. Little is known about the exact relation of this tibial translation and the position of the femur.

PURPOSE:

to accurately define the tibio-femoral relationship through stress radiography in human knees following ACL rupture and after ACL reconstruction.

METHODS:

a previously described stress-radiographic technique was used to evaluate tibial position relative to femur with a anterior-directed force and subsequently a posterior-directed force. Total tibial translation was also calculated from these measurements. In addition, KT-1000 measurements and Lysholm scores were obtained. Three groups were studied. Group 1 consisted of patients with untreated ACL ruptures, Group 2 consisted of patients with clinically successful ACL reconstruction and Group 3 were controls with normal knees.

RESULTS:

Stress radiography data showed that the mean total tibial translation was 9.6 mm in Group 1 (P < 0.001) compared to 6.0 mm in group 2 and 4.3 mmm in Group 3. Within Group 1, patients with radiographic signs of osteoarthritis were more stable with a total tibial excursion of 6.3 mm. Part of the improved stability in Group 2 and arthritic knees in Group 1, was not the result of decreased anterior tibial translation. It was actually associated with a permanent, fixed anterior subluxation of the tibia. A posterior-directed stress did not reduce the tibia to the anatomic position relative to the femur (Group 1 with arthritis 9.9 mm and Group 2 3.2 mm short of full reduction, p < 0.01).

CONCLUSION:

ACL rupture eventually leads to osteoarthritis in many knees. This is associated with a irreducible tibial subluxation along with a decrease in instability. Similarly, some permanent tibial subluxation was found in ACL reconstructed knees. This may explain why stable, reconstructed knees still may develop osteoarthritis in spite of improved stability.

©2002The American College of Sports Medicine