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This Article Full Text Full Text (PDF) All Versions of this Article: 36/6/1150    most recent 0363546508314404v2 0363546508314404v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Request Reprints Google Scholar Articles by Van de Velde, S. K. Articles by Li, G. PubMed PubMed Citation Articles by Van de Velde, S. K. Articles by Li, G. Related Collections Reconstruction Biomechanics Kinematics and kinetics Knee Patella

The Effect of Anterior Cruciate Ligament Deficiency and Reconstruction on the Patellofemoral Joint

Samuel K. Van de Velde, MD^*, Thomas J. Gill, MD^*, Louis E. DeFrate, ScD^*,, Ramprasad Papannagari, MS^* and Guoan Li, PhD^,

From the ^* Bioengineering Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, and Orthopaedic Research Laboratories, Duke University Medical Center, Durham, North Carolina

Address correspondence to Guoan Li, PhD, Bioengineering Laboratory, Massachusetts General Hospital/Harvard Medical School, 55 Fruit St, GRJ 1215, Boston, MA 02114 (e-mail: gli1{at}partners.org).

Background: Little is known about the effect of anterior cruciate ligament deficiency and reconstruction on the patellofemoral joint.

Hypothesis: Anterior cruciate ligament deficiency changes the patellofemoral joint biomechanics. Reconstruction of the ligament does not restore the altered patellofemoral joint function.

Study Design: Controlled laboratory study.

Methods: Eight patients with an acute anterior cruciate ligament injury in 1 knee and the contralateral side intact were included in the study. Magnetic resonance and dual-orthogonal fluoroscopic imaging techniques were used to compare the patellofemoral joint function during a single-leg lunge between the intact, the anterior cruciate ligament–injured, and the anterior cruciate ligament–reconstructed knee. Data on the patellar tendon apparent elongation and orientation, patellar tracking, and patellofemoral cartilage contact location were collected preoperatively and at 6 months after reconstruction.

Results: Anterior cruciate ligament deficiency caused a significant apparent elongation and change in orientation of the patellar tendon. It decreased the flexion and increased the valgus rotation and tilt of the patella. Anterior cruciate ligament injury caused a proximal and lateral shift in patellofemoral cartilage contact location. Anterior cruciate ligament reconstruction reduced the abnormal apparent elongation but not the orientation of the patellar tendon, and it restored the patellar flexion and proximal shift in contact. The abnormal patellar rotation, tilt, and lateral shift in cartilage contact persisted after reconstruction.

Conclusion: The altered function of the patellar tendon in anterior cruciate ligament deficiency resulted in an altered patellar tracking and patellofemoral cartilage contact. Persistent changes in patellofemoral joint function after anterior cruciate ligament reconstruction imply that reconstruction of the anterior cruciate ligament does not restore the normal function of the patellofemoral joint.

Clinical Relevance: The abnormal kinematics of the patellofemoral joint might predispose the patellofemoral cartilage to degenerative changes associated with anterior cruciate ligament deficiency, even if the ligament is reconstructed in a way that restores anteroposterior knee laxity.

Key Words: anterior cruciate ligament (ACL) • patellar tracking • patellofemoral joint • knee kinematics • anterior cruciate ligament (ACL) reconstruction