Novel Augmentation Technique for Patellar Tendon Repair Improves Strength and Decreases Gap Formation: A Cadaveric Study

Abstract

Background Patellar tendon ruptures commonly are repaired using transosseous patellar drill tunnels with modified-Krackow sutures in the patellar tendon. This simple suture technique has been associated with failure rates and poor clinical outcomes in a modest proportion of patients. Failure of this repair technique can result from gap formation during loading or a single catastrophic event. Several augmentation techniques have been described to improve the integrity of the repair, but standardized biomechanical evaluation of repair strength among different techniques is lacking. Questions/purposes The purpose of this study was to describe a novel figure-of-eight suture technique to augment traditional fixation and evaluate its biomechanical performance. We hypothesized that the augmentation technique would (1) reduce gap formation during cyclic loading and (2) increase the maximum load to failure. Methods Ten pairs (two male, eight female) of freshfrozen cadaveric knees free of overt disorders or patellar tendon damage were used (average donor age, 76 years; range, 65-87 years). For each pair, one specimen underwent the standard transosseous tunnel suture repair with a modified-Krackow suture technique and the second underwent the standard repair with our experimental augmentation method. Nine pairs were suitable for testing. Each specimen underwent cyclic loading while continuously measuring gap formation across the repair. At the completion of cyclic loading, load to failure testing was performed. Results A difference in gap formation and mean load to failure was seen in favor of the augmentation technique. At 250 cycles, a 68% increase in gap formation was seen for the control group (control: 5.96 ± 0.86 mm [95% CI, 5.30-6.62 mm]; augmentation: 3.55 ± 0.56 mm [95% CI, 3.12-3.98 mm]; p = 0.02). The mean load to failure was 13% greater in the augmentation group (control: 899.57 ± 96.94 N [95% CI, 825.06-974.09 N]; augmentation: 1030 augmentation: .70 ± 122.41 N [95% CI, 936.61-1124; p = 0.01). Conclusions This biomechanical study showed improved performance of a novel augmentation technique compared with the standard repair, in terms of reduced gap formation during cyclic loading and increased maximum load to failure. Clinical Relevance Decreased gap formation and higher load to failure may improve healing potential and minimize failure risk. This study shows a potential biomechanical advantage of the augmentation technique, providing support for future clinical investigations comparing this

High-Strength Suture Tape Augmentation Improves Cyclic Gap Formation in Transosseous Patellar Tendon Repair: A Biomechanical Study

“…Our results are consistent with those of previous studies that have shown significantly improved gap formation with other augmentation strategies for inferior pole patellar tendon repair. 3 , 5 , 7 At 250 cycles, Ravalin et al. 3 reported significantly greater gap formation with the standard Krackow transosseous technique (7.3 ± 0.5 mm) compared with augmentation with either Ethibond suture (4.9 ± 0.5 mm) or 2.0 Dall-Miles cables (3.5 ± 0.8 mm).…”

“… 2 Several strategies for augmentation of this technique have been studied, including the use of cerclage wires, figure-8 suture, and hamstring autograft. 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 These augmented techniques have demonstrated superior biomechanical properties compared with the Krackow transosseous technique alone, which may facilitate advanced biomechanical stability to support accelerated rehabilitation protocols. 3 , 4 , 5 , 6 , 7 , 8…”

Patellar Tendon Excision and Repair for Residual Patella Alta after Prior Failed Patellar Tendon Repair: Surgical Decision Making and Outcome

“…For these reasons, primary repair utilizing nonabsorbable sutures to treat this patient's acute patellar tendon injury was decided to be utilized. An important factor taken into consideration was the potential for gap formation with which was previously demonstrated in biomechanical studies of this procedure choice [ 17 , 18 ]. However, it was ultimately decided that the potential benefits outweighed the risks for this procedure in comparison to the other techniques for patellar tendon repair.…”

Patellar Tendon Repair With Ipsilateral Semitendinosus Autograft Augmentation

“… 13 Biological augmentation of primary repair is believed to decrease strain across the repair site and reduce the risk of rerupture. 7 Mihalko et al. 14 performed a matched-pair cadaveric analysis in which primary suture repair was compared with suture repair with hamstring augmentation.…”

“…Several authors have proposed augmentation strategies in an effort to decrease strain across the repair site, allow early knee motion, and reduce the risk of rerupture. 7 Various augmentation techniques have been described including both nonbiological (cerclage wire, synthetic tape, or nonabsorbable suture) and biological (allograft or autograft) augmentation strategies, but the optimal treatment method remains controversial. 8 , 9 , 10 , 11 , 12 We present a technique for primary patellar tendon repair with bidirectional fixation using transosseous tunnels, suture anchor fixation, and ipsilateral hamstring autograft augmentation in a distal patellar pole socket ( Table 1 , Table 2 , Table 3 ).…”