Biomechanical Analysis of Patellar Tendon Repair With Knotless Suture Anchor Tape Versus Transosseous Suture

Abstract

Background: Patellar tendon ruptures have routinely been repaired with transosseous suture tunnels. The use of knotless suture anchors for repair has been suggested as an alternative. Purpose: To compare the load to failure and gap formation of patellar tendon repair at the inferior pole of the patella with knotless suture anchor tape versus transosseous sutures. A secondary objective was to investigate whether either technique shows an association between bone density and load to failure. Study Design: Controlled laboratory study. Methods: A total of 20 human tibias with attached patellar and quadriceps tendons were sharply incised at the bone-tendon junction at the inferior pole of the patella. A total of 10 tendons were repaired using 2 knotless suture anchors in the inferior pole of the patella and a single suture tape with 2 core sutures. The other 10 tendons were repaired using No. 2 suture passed through 3 transosseous tunnels. A distracting force was then applied through the suture in the quadriceps tendon. Gap distance through load cycling at the repair site and maximum load at repair failure were then measured. Bone density was measured using computed tomography scanning. Results: No difference was found in the mean load to failure of knotless patellar tendon repair versus transosseous suture repair (367.6 ± 112.2 vs 433.9 ± 99 N, respectively; P = .12). After 250 cycles, the mean repair site gap distance was 0.85 ± 0.45 mm for the knotless patellar tendon repair versus 2.94 ± 2.03 mm for the transosseous suture repair ( P = .03). A small correlation, although not statistically significant, was found between bone density and load to failure for the knotless tape repair ( R 2 = 0.228; P = .66). No correlation was found between bone density and load to failure for the transosseous repair ( R 2 = 0.086; P = .83). Conclusion: Suture tape repair with knotless anchors for repair of patellar tendon rupture has comparable load to failure with less gap formation than transosseous suture repair. There is a small correlation between bone density and failure load for knotless anchor repair, which may benefit from further investigation. Clinical Relevance: Using knotless suture anchors for patellar tendon rupture repair would allow for a smaller incision, less dissection, and likely shorter operating time.

Patellar Stress Fracture After Suture Anchor Patellar Tendon Repair in an Active Duty Military Member

“…Suture anchor repair is a technique with potentially superior biomechanical properties and clinical outcomes relative to transosseous suture repair 7,9,10,14 . Because this technique becomes more common, surgeons should recognize the potential for patellar stress fracture.…”

“…Transosseous suture repair over a patellar bone bridge has historically been the gold standard for patellar tendon repair 2,3,6 . Newer techniques using suture anchors have recently gained favor after biomechanical studies demonstrated similar load to failure with less tendon gap formation at the repair site [7][8][9][10][11][12][13] . Clinical evaluation of suture anchor repair in a retrospective review has shown a decreased rate of rerupture relative to transosseous repair 14 .…”

Suture Anchor Repair With Fully Threaded Knotless Anchors for Quadriceps Tendon Rupture Resulted in Favorable Outcomes After 2 Years

“…In fact, a recent cadaveric study reported that there was no statistically significant difference in ultimate load to failure between suture anchor repair and reattaching the tendon through bone tunnels. 5,[18][19][20] A previous study reported that fully threaded knotless anchors showed the highest failure strengths among other types of suture anchors 6 . Furthermore, a case of suture anchor repair with fully threaded knotless has been reported in a technical note article as an effective method for QTR.…”

“…In fact, a recent cadaveric study reported that there was no statistically significant difference in ultimate load to failure between suture anchor repair and reattaching the tendon through bone tunnels. 5 , 18 , 19 , 20 …”

Comparison of Biomechanical Failure Loads Between Tape-Type and Conventional Sutures in Internal Knotless Anchor–Based Constructs

“… 2 , 16 , 24 Similar conclusions have been drawn from biomechanical studies on quadriceps, patellar, and Achilles tendon repair procedures using tape-type sutures. 12 , 25 , 26 , 32 Deranlot et al 7 compared the abrasive effects of conventional sutures and tape-type sutures and concluded that the variance in coating materials and shape resulted in distinct frictional properties. Despite the increasing prevalence of tape-type sutures, whether internal knotless anchors can consistently affix tape-type sutures has not been thoroughly investigated.…”