Summary

Of all risk factors Retraction,Infraspinatus atrophy,Acromion humeral Interval and the global fatty degeneration index were identified as independent risk factors using multivariate regression analysis. There is post operative progression of fatty degeneration (GFDI) with preserved occupancy ratio in healed cuff repair, where as in retear group there is deterioration of GFDI and muscle atrophy.

Abstract

Background

Large and massive rotator cuff tears are defined as tears measuring 3-5 cm for large tears and greater than 5 cm for massive cuff tear. From the reported literature the retear rate after Arthroscopic rotator cuff repair (ARCR) is 10%-48.4% and the retear rate after arthroscopic repair of massive rotator cuff injuries is as high as 94%. The aim of the study is to identify the independent risk factors for retear using multiple regression analysis.

Methods

A retrospective comparative cohort study. 92 patients who underwent arthroscopic knotted double row cuff repair were included in the study Group A: Healed (n=70) and Group B: Retear (n=22). The MRI was taken at 12 months after surgery to assess for healing and functional scores viz ASES Constant Scores were taken at the final follow up. The pre operative parameters tear size, tear retraction, global fatty degeneration index (GFDI), teres minor atrophy, critical shoulder angle, Acromial Index, Acromio Humeral Interval and Occupancy ratio were compared between two groups. Univariate and Multivariate regression analysis was performed for identification of independent risk factors for retear.

Results

The mean follow up period is 26.4 months. The retear rate was around 23% (22 out of 92) among which 17 cases (72%) has Sugaya type V and 5 cases (23%) were noted to have Sugaya type IV. Pre-operative radiological parameters like tear size (p = 0.158), critical shoulder angle (p = 0.093) and Acromial index (p = 0.211) were similar in both groups and didn’t influence retear rates. Statistically significant differences were observed in other radiological measurements like Acromio-humeral interval (p = 0.001), pre-operative retraction (p =0.001), teres minor atrophy (p = 0.046), occupancy ratio (p < 0.001), and Global fatty degeneration index (p < 0.001) thus influencing the retear rates. On multiple regression analysis Retraction, Infraspinatus atrophy, Acromio Humerus Interval and Global Fatty Degeneration Index were identified as independent risk factors.

Conclusion

Of all the risk factors Retraction, Infraspinatus atrophy, Acromion humeral Interval and the global fatty degeneration index were identified as independent risk factors using multivariate regression analysis. There is post operative progression of fatty degeneration (GFDI) with preserved occupancy ratio in healed cuff repair, where as in retear group there is deterioration of fatty degeneration and muscle atrophy post operatively.


Level of study: III (Retrospective comparative cohort)