Posterolateral structures of the knee in posterior cruciate ligament deficiency.
BACKGROUND
In vitro data suggest that injury to the posterior cruciate ligament stresses the posterolateral structures of the knee, placing them at greater risk of secondary injury. However, it is not known how isolated posterior cruciate ligament deficiency affects these soft tissue stabilizers of the knee joint in vivo.


OBJECTIVE
Posterior cruciate ligament deficiency will alter the apparent length patterns of the lateral collateral ligament (LCL) and popliteus.


METHODS
Controlled laboratory study.


METHODS
The apparent length changes in the lateral collateral ligament and popliteus muscle-tendon unit during weightbearing knee flexion were studied in 14 patients with isolated, unilateral posterior cruciate ligament deficiency using magnetic resonance imaging, dual-orthogonal fluoroscopy, and 3-dimensional modeling. Data of the injured and uninjured contralateral sides were compared.


RESULTS
Posterior cruciate ligament deficiency caused significant increases in the apparent length of both posterolateral structures (P < .05). The differences between injured and uninjured contralateral side were greatest at 120 degrees of knee flexion in the lateral collateral ligament (48.2 +/- 6.1 mm and 51.6 +/- 6.1 mm, respectively) and at 30 degrees of knee flexion in the popliteus (101.2 +/- 9.3 mm and 110.4 +/- 10.2 mm, respectively).


CONCLUSIONS
Deficiency of the posterior cruciate ligament alters the length patterns of posterolateral structures in vivo and might place them at greater risk of secondary injury.


CONCLUSIONS
Reestablishment of normal kinematics after posterior cruciate ligament injury is critical for restoring normal function of posterolateral structures of the knee.
Kozanek
Michal
M
Bioengineering Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA.
Fu
Eric C
EC
Van de Velde
Samuel K
SK
Gill
Thomas J
TJ
Li
Guoan
G
D000293:Adolescent; D000328:Adult; D005260:Female; D005471:Fluoroscopy; D006801:Humans; D021621:Imaging, Three-Dimensional; D007593:Joint Instability / Q000503:physiopathology*; D007718:Knee Injuries / Q000503:physiopathology*; D007719:Knee Joint / Q000033:anatomy & histology; D008279:Magnetic Resonance Imaging; D008297:Male; D016119:Posterior Cruciate Ligament / Q000293:injuries* / Q000503:physiopathology; D017695:Soft Tissue Injuries / Q000503:physiopathology*