Tear patterns, surgical repair, and clinical outcomes of patellar tendon ruptures after anterior cruciate ligament reconstruction with a bone-patellar tendon-bone autograft.

BACKGROUND

Patellar tendon ruptures are rare after graft harvest for anterior cruciate ligament (ACL) reconstruction. Few reports are available in the literature.

PURPOSE: To report the common tear patterns and results of treatment with tendon repair and cable augmentation.

STUDY

DESIGN

Case series; Level of evidence, 4.

METHODS

All tendon ruptures were repaired to bone with suture anchors and augmented with a Dall-Miles cable, followed by an aggressive rehabilitation protocol. The tear location was recorded. Range of motion, strength, and subjective survey testing were conducted preoperatively and postoperatively.

RESULTS

Thirteen patellar tendon ruptures were found from our database of 5364 ACL reconstructions, for an incidence of 0.24%. Seven ruptures occurred from the patellar origin medially and the tibial attachment laterally in a Z-shaped pattern. Four were completely distal, and 2 were completely proximal ruptures. All patients exhibited early flexion loss, but 11 of 13 patients maintained full, terminal hyperextension throughout treatment. The mean postoperative side-to-side flexion deficit was 33° at 1 month, 6° at 3 months, and 3° at latest follow-up at a mean of 4.8 years after tendon repair (range, 1-16 years). By International Knee Documentation Committee (IKDC) criteria, 10 patients had normal flexion, and 3 were nearly normal at latest follow-up. Twelve patients had normal extension, and 1 had nearly normal extension at latest follow-up. Mean isokinetic quadriceps muscle strength was 68.7% of the other side at 3 months after repair and 100.0% at latest follow-up, occurring at a mean of 47.5 months (range, 12-120 months). At a mean of 2 years (range, 1-4 years) after repair, the mean modified Noyes subjective score was 89.8 ± 9.2.

CONCLUSION

Patellar tendon ruptures are rare after ACL graft harvest. These ruptures usually occur in either a proximal-medial and distal-lateral pattern or an entirely distal pattern, in contrast to the proximal-only tear pattern commonly observed in unharvested patellar tendons. Good objective and subjective results were achieved with repair of postoperative patellar tendon ruptures using suture anchors and Dall-Miles cable augmentation, followed by aggressive, immediate range of motion exercises.