Summary

Based on the histopathological and biomechanical results in our controlled experimental study, it has been shown that the patellar tendon autograft applied in superior capsular reconstruction surgery is as successful as the tensor fascia lata autograft.

Abstract

Patients with irreparable rotator cuff tears today constitute one of the challenging patient groups encountered in the outpatient clinic for shoulder surgeons.Superior capsular reconstruction (SCR), defined by Mihata in 2012, is a surgical procedure to restore shoulder stability in irreparable rotator cuff tears. According to the common view in the literature, the most important reason for graft rupture, which is the most important complication of SCR surgery, is insufficient integration of the graft to the bone attachment sites. There are studies in the literature on appropriate graft selection. Dermal allografts, synthetic grafts and fascia lata autografts can be used. Patellar tendon graft (PT) is one of the most commonly used grafts in anterior cruciate ligament reconstruction surgery. Our aim of the study is to compare PT autograft and Fascia lata autograft (FL) histopathologically and biomechanically in SCR surgery. Our hypothesis is that PT graft is as effective a graft choice as FL. Our study is the first in the literature to show that the patellar tendon is an option that can be applied in SCR surgery. Method: Twelve rabbits with irreparable retracted rotator cuff tears in both shoulders and 4 rabbits without surgical intervention were included in the study as a control group.First, a 1*1 cm rotator cuff defect was created on both shoulders of 12 rabbits. Six weeks after the first surgery, the SCR procedure was applied to the right shoulders of 12 rabbits with TFL taken from the same side and to the left shoulder with PT autograft taken from the same side. No surgical intervention was applied to 4 rabbits in the control group.Following sacrification after 6 weeks of follow-up, all shoulders were investigated for histopathological (4 control, 4 TFL-4 PT) recovery and tested for biomechanical (4 control, 8 TFL, 8 PT) evaluation. Watkins scoring for macroscopic recovery and H-SCORE scoring for immunohistochemical evaluation were used. Results: In the histopathological evaluation, the PT group showed higher cellularity (p=0.02), vascularity (p=0.01), collagen continuity (p=0.14), and total Watkins score (p=0.001) compared to the TFL group. Immunohistochemical analysis of tissues for CD31 showed that PT had significantly higher reactivity compared to other groups (P=0.014). Immunohistochemical analysis of tissues for collagen types showed that PT tendons had significantly higher reactivity to collagen type I and type III than other groups (P=0.019 and 0.015). In the biomechanical evaluation, although the mean tensile strength (138.13 ± 19.38) in the PT group was higher than the mean tensile strength (136.56 ± 23.34) in the TFL group, no statistical difference was found (p>0.05). Conclusion: Based on the histopathological and biomechanical results in our controlled experimental study, it has been shown that the PT autograft applied in SCR surgery is as successful as the TFL autograft. The SCR treatment method with PT was described in the literature for the first time in a controlled study.