Surgical Treatment of Knee Dislocations: 5 to 22 Year Results

Abstract

The purpose of this paper is to present the results of surgical treatment of knee dislocations with 5 to 22 year follow up in 44 patients in this retrospective case series. Inclusion criteria are a combined PCL ACL plus medial and or lateral side reconstruction in patients with 5 to 22 year follow up. The surgery was performed by one surgeon for all patients. The mean follow up was 9.8 years with a range of 5 to 22 years. The patient age at the time of surgery was 30.9 years, with an age range of 13 to 65 years. The diagnosis were 9 ACL PCL medial (20.5%), 22 ACL PCL lateral (50.0%), and 13 ACL PCL medial lateral (29.5%). Mechanisms of injury included 26 motor vehicle related (59.1%), 9 sports injuries (20.5%), 6 industrial/farming (13.6%), and 3 pedestrian automobile encounters (6.8%). Evaluation methods included KT 1000 arthrometer measurements, stress radiography, knee ligament rating scales, physical examination, and plain radiographs. The KT 1000 arthrometer mean side to side difference measured in millimeters are: PCL screen 1.9 mm, corrected posterior 2.4 mm, corrected anterior 0.8 mm, and the anterior displacement at 30 degrees of knee flexion 1.7 mm. The combined mean side to side difference measurement for all parameters was 1.7 mm. Stress radiographic measurements at 90 degrees of knee flexion to evaluate the PCL reconstruction revealed a mean 1.9 mm side to side difference. Mean Lysholm knee ligament score was 84.4/100. Mean Hospital for Special Surgery score was 82.8/100. Mean Tegner score was 4.1/9. 65.1% of patients returned to their pre-injury level of activity, and 92.8% of postoperative patients returned to their pre-injury level of activity or one Tegner grade lower level of function. Post reconstruction physical examination for the PCL revealed 97.8% of knees had symmetrical or less than grade one posterior drawer (43 of 44 knees). Post ACL reconstruction 39 knees had symmetrical Lachman test (86.6%) and 40 knees had symmetrical (negative) pivot shift (90.9%). Symmetrical varus was present in 41 knees (93.2%), and symmetrical valgus was present in 43 knees (97.7%). Axial rotation was symmetrical to the normal knee in 38 knees (86.4%) and tighter than the normal knee in 6 (13.6%). There were 10 of the 44 knees developed degenerative joint disease (22.7%), and 3 of the 44 knees required total knee replacement (6.8%). There was no loss of terminal extension in any of the knees, but the mean flexion loss was 12.5 degrees compared to the normal knee. Static stability is achieved and documented with KT 1000 arthrometer measurements (mean 1.7 mm side to side difference), and stress radiography (1.9 mm side to side difference), and these results do not deteriorate with time. Functional stability is achieved with 92.8% of patients returning to physically demanding work and/or recreational activities. Post traumatic degenerative joint disease occurs in 22.7% of the knees in this series, and the incidence increases as the time from injury increases.