Biomechanics Versus Biology: The Effect of Rotator Cuff Repair Constructs on Healing and Outcomes

Return to Sport after Arthroscopic Rotator Cuff Repair of Full-Thickness Rotator Cuff Tears: A Systematic Review

OBJECTIVE

Perform a systematic literature review regarding return to sport (RTS) outcomes after arthroscopic rotator cuff repair (aRCR) for full-thickness rotator cuff tears (FTRCTs).

DATA SOURCES

Systematic review of all articles in PubMed, Medline, and Excerpta Medica Database (EMBASE) was conducted in April 2022 using a combination of keywords: "rotator cuff repair," "RCR," "complete," "full-thickness," "tear," "RCT," "injury," "shoulder," "arthroscopic," "return to sport," "RTS," "sport," "return to play," and "athlete." Cohorts were included from all articles reporting RTS after aRCR for FTRCTs. Studies that were non-English, failed to distinguish between partial and FTRCT outcomes, or treated FTRCTs by open RCR, mini-open RCR, debridement, or nonsurgical management were excluded. Abstracted data included study design, surgical techniques, concomitant procedures, demographics, FTRCT type and size, patient-reported outcomes, type of sport, competition level, time to return, and reasons for failing to RTS.

MAIN RESULTS

11 studies were reviewed, with inclusion of 463 patients (385 athletes; mean age 47.9). RTS varied considerably in rate and timing, with 50.0% to 100% of patients returning on average between 4.8 to 14 months. In addition, 31 patients returned to a higher level of sport, 107 returned to or near preinjury level, and 36 returned to a lower level of competition or failed to RTS entirely.

CONCLUSIONS

The ability for athletes to RTS after aRCR for FTRCTs is likely multifactorial, demonstrating high variability in return rates and time to RTS. Given the paucity of available literature, future studies are warranted to provide a more definitive consensus.

Pharmacologic Enhancement of Rotator Cuff Repair: A Narrative Review

INTRODUCTION

As rotator cuff repairs (RCRs) are among the most common procedures in upper extremity orthopedics, healing augmentation using pharmacologic enhancement of the repaired rotator cuff muscle is of particular interest.

OBJECTIVE

The purpose of this study is to review the current understanding of Matrix Metalloproteinases (MMPs), Doxycycline, Testosterone, Estrogen, Growth hormone/ IGF-1, Vitamin D, and Vitamin C as a means to mitigate deleterious effects and propagate factors that support healing following RCR.

METHODS

A review of English language articles in PubMed and Medline was conducted in December of 2020. All articles describing the current understanding of the aforementioned therapies were reviewed. Studies were excluded if they were non-English or reported incomplete results.

RESULTS

Matrix metalloproteinases (MMP's) are fundamental to the healing process after rotator cuff tears through a delicate balance of various proteases that can be modulated by doxycycline through inhibition. While testosterone has shown to induce replication and differentiation of the tendon stem-cells, estrogen agonists have been shown to decrease inflammation and muscle atrophy. Though growth hormone being associated with elevated collagen synthesis and decreased anoxic damage when present, clinical studies have shown inconclusive and adverse effects on rotator cuff healing. Patients with Vitamin D deficiency have shown to have increased fatty infiltration in rotator cuff muscle while Vitamin C functions as an antioxidant that increases collagen and fibroblast proliferation.

CONCLUSION

As manipulation of pharmacologic factors shows potential for enhancing healing following RCRs, future studies are needed to establish a viable augmentation strategy to improve patient outcomes.

The Effects Of Obesity On 1 Year Functional Outcomes Following Arthroscopic Rotator Cuff Tear Repair

Background

The purpose of our study was to examine the impact that an increased body mass index (BMI) has on arthroscopic rotator cuff repair (aRCR) outcomes.

Methods

We identified a sample of 313 patients who underwent aRCR at our institution from 2017 to 2020. Patients were classified into cohorts by BMI: normal BMI (<25), overweight (25-30), and obese (≥30). Patient-Reported Outcomes Measurement Information System (PROMIS) scores (Pain Interference, Pain Intensity, and Upper Extremity) and Clinical Global Impressions scale rating of pain and functional improvement after surgery were obtained at 1 year postoperatively. The significance of the BMI category as a predictor for outcomes was evaluated using multiple linear and multivariable logistic regressions. Receiver operating characteristic curve analysis with Youden’s J-statistic was used to determine optimal BMI cutoff for predicting likelihood of achieving minimum clinically important difference (MCID) and substantial clinical benefit (SCB) on the Clinical Global Impressions scales.

Results

Obesity was a significant predictor of reduced preoperative-to-postoperative improvement in the PROMIS Upper Extremity score (P = .04). However, BMI was not predictive of other preoperative-to-postoperative differences in outcome scores or the size and number of cuff tendons torn (P > .05). Optimal BMI cutoffs were determined for pain MCID (40.8), pain SCB (26.8), function MCID (27.4), and function SCB (26.8), but all cutoffs had low correct classification rates (≤13%).

Discussion and Conclusion

Obesity was not found to be an independent risk factor for increased rotator cuff tear size or tendon involvement but was nonetheless associated with worse upper extremity function and pain after aRCR.