Biological augmentation reduces failure rates but does not improve functional outcomes after acute patellar tendon repair.

INTRODUCTION/

OBJECTIVES

Acute patellar tendon rupture (PTR) is a rare but disabling injury, and repair failure remains a major concern despite advances in surgical techniques. Biological augmentation has been proposed to reinforce repair, but its clinical benefits remain uncertain. The aim of this study was to compare functional outcomes between isolated repair and biological augmentation for acute PTR and to assess differences in failure and complication rates at a minimum follow-up of two years.

METHODS

This retrospective study included 39 knees treated surgically for acute PTR between 2015 and 2023 ​at a single center. Patients were divided into two groups based on surgical technique: isolated repair or repair with biological augmentation using autograft or allograft tissue. Functional outcomes were assessed using Kujala and Lysholm scores. Patellar height was evaluated on standardized lateral radiographs using the Caton-Deschamps index (CDI) and Insall-Salvati index (ISI). Postoperative complications and surgical failures were recorded. Patients with surgical failure were excluded from the functional and radiological analyses.

RESULTS

The final cohort consisted of 36 patients (39 knees) with a follow-up rate of 82%. The mean follow-up duration was 62.4 ​± ​26.2 months (range: 24-110). Kujala and Lysholm scores were comparable between groups, with no statistically significant differences (Kujala score: 92.9 ​± ​7.9 vs. 93.8 ​± ​9.8, p ​= ​0.636; Lysholm score: 93.8 ​± ​5.7 vs. 93.5 ​± ​13.5, p ​= ​0.053). Patellar height was statistically significantly greater in the isolated repair group (CDI: 1.01 ​± ​0.23 vs. 0.86 ​± ​0.10, p ​= ​0.045; ISI: 1.17 ​± ​0.21 vs. 0.98 ​± ​0.17, p ​= ​0.020). All surgical failures occurred in the isolated repair group (5/23, 21.7%), while no failures occurred in the augmentation group (p ​= ​0.046). Postoperative complications were infrequent and similar between groups.

CONCLUSION

At a minimum of two years' follow-up, biological augmentation did not improve functional outcomes compared with isolated repair but was associated with a lower rate of surgical failure and significantly lower patellar height, without an increased risk of complications. These results suggest that biological augmentation may be preferred over isolated repair when the primary goal is to reduce failure rates.

LEVEL OF EVIDENCE: this was a level III, retrospective cohort study.