Objectives. All-suture anchors are increasingly used in rotator cuff repair procedures. Potential benefits include decreased bone damage. However, there is limited published evidence for the relative strength of fixation for all-suture anchors compared with traditional anchors. Materials and Methods. A total of four commercially available all-suture anchors, the ‘Y-Knot’ (ConMed), Q-FIX (Smith & Nephew), ICONIX (Stryker) and JuggerKnot (Zimmer Biomet) and a traditional anchor control TWINFIX Ultra PK Suture Anchor (Smith & Nephew) were tested in cadaveric human humeral head rotator cuff repair models (n = 24). This construct underwent cyclic loading applied by a mechanical testing rig (Zwick/Roell). Ultimate load to failure, gap formation at 50, 100, 150 and 200 cycles, and failure mechanism were recorded. Significance was set at p < 0.05. Results. Overall, mean maximum tensile strength values were significantly higher for the traditional anchor (181.0 N, standard error (. se). 17.6) compared with the all-suture anchors (mean 133.1 N . se. 16.7) (p = 0.04). The JuggerKnot anchor had greatest displacement at 50, 100 and 150 cycles, and at failure, reaching statistical significance over the control at 100 and 150 cycles (22.6 mm . se. 2.5 versus 12.5 mm . se. 0.3; and 29.6 mm . se. 4.8 versus 17.0 mm . se. 0.7). Every all-suture anchor tested showed substantial (> 5 mm) displacement between 50 and 100 cycles (6.2 to 14.3). All-suture anchors predominantly failed due to anchor pull-out (95% versus 25% of traditional anchors), whereas a higher proportion of traditional anchors failed secondary to suture breakage. Conclusion. We demonstrate decreased failure load, increased total displacement, and variable failure mechanisms in all-suture anchors, compared with traditional anchors designed for rotator cuff repair. These findings will aid the surgeon’s choice of implant, in the context of the clinical scenario. Cite this article: N. S. Nagra, N. Zargar, R. D. J. Smith, A. J. Carr. Mechanical properties of all-suture anchors for rotator cuff repair. Bone Joint Res 2017;6:82–89. DOI: 10.1302/2046-3758.62.BJR-2016-0225.R1

Aims. Many biomechanical studies have shown that the weakest biomechanical point of a rotator cuff repair is the suture-tendon interface at the medial row. We developed a novel double rip-stop (DRS) technique to enhance the strength at the medial row for rotator cuff repair. The objective of this study was to evaluate the biomechanical properties of the DRS technique with the conventional suture-bridge (SB) technique and to evaluate the biomechanical performance of the DRS technique with medial row knots. Methods. A total of 24 fresh-frozen porcine shoulders were used. The infraspinatus tendons were sharply dissected and randomly repaired by one of three techniques: SB repair (SB group), DRS repair (DRS group), and DRS with medial row knots repair (DRSK group). Specimens were tested to failure. In addition, 3 mm gap formation was measured and ultimate failure load, stiffness, and failure modes were recorded. Results. The mean load to create a 3 mm gap formation in the DRSK and DRS groups was significantly higher than in the SB group. The DRSK group had the highest load to failure with a mean ultimate failure load of 395.0 N (SD 56.8) compared to the SB and DRS groups, which recorded 147.1 N (SD 34.3) and 285.9 N (SD 89.8), respectively (p < 0.001 for both). The DRS group showed a significantly higher mean failure load than the SB group (p = 0.006). Both the DRS and DRSK groups showed significantly higher mean stiffness than the SB group. Conclusion. The biomechanical properties of the DRS technique were significantly improved compared to the SB technique. The DRS technique with medial row knots showed superior biomechanical performance than the DRS technique alone

Our primary objective was to compare healing rates in patients undergoing arthroscopic rotator cuff repair for degenerative tears, with and without bone channeling. Our secondary objectives were to compare disease-specific quality of life and patient reported outcomes as measured by the Western Ontario Rotator Cuff Index (WORC), American Shoulder and Elbow Surgeons (ASES) score and Constant score between groups. Patients undergoing arthroscopic rotator cuff repair at three sites were randomized to receive either bone channeling augmentation or standard repair. Healing rates were determined by ultrasound at 6 and 24 months post operatively. WORC, ASES, and Constant scores were compared between groups at baseline and at 3, 6, 12 and 24 months post operatively. One hundred sixty-eight patients were recruited and randomized between 2013 to 2018. Statistically significant improvements occurred in both groups from pre-operative to all time points in all clinical outcome scores (p < 0 .0001). Intention to treat analysis revealed no statistical differences in healing rates between the two interventions at 24 months post-operative. No differences were observed in WORC, ASES or Constant scores at any time-point. This trial did not demonstrate superiority of intra-operative bone channeling in rotator cuff repair surgery at 24 months post-operative. Healing rates and patient-reported function and quality of life measures were similar between groups

Tears of the rotator cuff tendons are a very common entity. Despite recent advances in arthroscopic rotator cuff repair, the re-tear rate remains high. Thus, new methods to improve healing rates following rotator cuff repair must be sought. The purpose of this prospective randomized double-blind controlled study is to compare the functional outcomes and healing rates of an adjuvant pre-operative bone microfracture technique prior to arthroscopic cuff repair. Patients undergoing arthroscopic rotator cuff repair were randomized to receive either a percutaneous bone microfracture of the supraspinatus footprint or a “soft tissue needling” technique, in which the pin was passed through the peripheral edges of the rotator cuff, five-seven days prior to index surgery, under ultrasound guidance. Follow-ups were completed at 3, 6, 12 and 24 months post-operatively. Healing status was determined by ultrasound at 6 and 24 months. The primary objective was to compare the WORC score at 24 months. Secondary objectives included the healing status via ultrasound, the Constant, and the ASES scores. A sample size calculation determined that 90 patients provided 80% power to detect a statistical difference between groups. Baseline demographic data did not differ between groups. No statistical differences were detected in the WORC outcome at any time points (p=0.47, baseline, p=0.60, 3 months, p=0.79, 6 months, p=0.50, 12 months, p=0.54, 24 months). Healing rates did not differ between groups (P=0.34) and no differences were observed in the ASES or Constant Scores at all time-points. Statistically significant improvements occurred in both groups from baseline to all time points in all clinical outcome scores (p < 0 .0001). No statistically significant differences in primary or secondary outcomes were identified between pre-operative bone microfracture and soft tissue needling techniques prior to arthroscopic rotator cuff repair. This study does not support pre-operative microfracture as a adjuvant technique prior to arthroscopic cuff repair

Aims. It has been established that mechanical stimulation benefits tendon-bone (T-B) healing, and macrophage phenotype can be regulated by mechanical cues; moreover, the interaction between macrophages and mesenchymal stem cells (MSCs) plays a fundamental role in tissue repair. This study aimed to investigate the role of macrophage-mediated MSC chondrogenesis in load-induced T-B healing in depth. Methods. C57BL/6 mice rotator cuff (RC) repair model was established to explore the effects of mechanical stimulation on macrophage polarization, transforming growth factor (TGF)-β1 generation, and MSC chondrogenesis within T-B enthesis by immunofluorescence and enzyme-linked immunosorbent assay (ELISA). Macrophage depletion was performed by clodronate liposomes, and T-B healing quality was evaluated by histology and biomechanics. In vitro, bone marrow-derived macrophages (BMDMs) were stretched with CELLOAD-300 load system and macrophage polarization was identified by flow cytometry and quantitative real-time polymerase chain reaction (qRT-PCR). MSC chondrogenic differentiation was measured by histochemical analysis and qRT-PCR. ELISA and qRT-PCR were performed to screen the candidate molecules that mediated the pro-chondrogenic function of mechanical stimulated BMDMs. Results. Mechanical stimulation promoted macrophage M2 polarization in vivo and in vitro. The conditioned media from mechanically stimulated BMDMs (MS-CM) enhanced MSC chondrogenic differentiation, and mechanically stimulated BMDMs generated more TGF-β1. Further, neutralizing TGF-β1 in MS-CM can attenuate its pro-chondrogenic effect. In vivo, mechanical stimulation promoted TGF-β1 generation, MSC chondrogenesis, and T-B healing, which were abolished following macrophage depletion. Conclusion. Macrophages subjected to appropriate mechanical stimulation could polarize toward the M2 phenotype and secrete TGF-β1 to promote MSC chondrogenesis, which subsequently augments T-B healing. Cite this article: Bone Joint Res 2023;12(3):219–230

Controversy exists regarding the optimal technique for arthroscopic rotator cuff repair. No previous comparative trials have reported on the long-term follow-up of single and double row fixation in arthroscopic cuff repair. The purpose of this study was to compare the long-term functional outcomes of single-row and double-row suture techniques for repair of the rotator cuff 10-years post-operatively. Ninety patients undergoing arthroscopic rotator cuff repair were randomized to receive either single-row or double-row repair. The primary objective was to compare the Western Ontario Rotator Cuff Index (WORC) score 10-years post-operatively. Secondary objectives included comparison of the Constant, and American Shoulder and Elbow Surgeons (ASES) scores and supraspinatus strength between groups. Out of 90 patients originally randomized, 57 returned for the long-term 10-year follow-up. Baseline demographic data did not differ between groups. The WORC score was not significantly different between groups at long-term follow-up (p=0.13). No statistical differences were observed between groups for the Constant (p=0.51), ASES (p=0.48) scores, or strength scores (p=0.93). A significant improvement was observed between pre-operative and the final 10-year follow-up. There were no differences observed in all outcomes between two and 10-years post-operatively. No statistically significant differences in functional or quality of life outcomes were identified between single-row and double-row fixation techniques at long-term follow-up

The indication for rotator cuff repair in elderly patients is controversial. Methods. Consecutive patients over the age of 70 years, under the care of a single surgeon, receiving an arthroscopic rotator cuff repair were reviewed. Predominantly, a single row repair was performed using one (34 cases) or two (30) 5mm Fastin, double-loaded anchors. Double-row repair was performed in four cases. Subacromial decompression and treatment of biceps pathology were performed as necessary. Data were collected from medical records, digital radiology archives and during clinic appointments. Pain, motion, strength and function were quantified with the Constant-Murley Shoulder Outcome Score, administered pre operatively and at 1-year post operatively. Ultrasound scans were performed at one year to document integrity of the repair. Results. Sixty-nine arthroscopic cuff repairs were identified in 68 patients. The mean age was 77 years (70–86). The median ASA grade was 2 (79%). The dominant side was operated on in 68% of cases. A range of tear sizes were operated on (5 small, 17 moderate, 29 large and 18 massive). The tendons involved in the tear also varied (supraspinatus 12, supra and infraspinatus 53, supraspinatus and subscapularis 2, supraspinatus infraspinatus and subscapularis 2). Re-rupture occurred in 20 cases (29%). The mean Constant score increased from 23 (95% CI 19–26) to 59 (54–64) (P< 0.001). Where the repair remained sound, Constant score improved 42 points (95%CI 36–48). If the cuff re-ruptured, constant score also increased on average 12 points (95% CI 2–21). Re-rupture rate was highest for massive cuff repairs: ten out of eighteen (56%). Conclusion. Arthroscopic rotator cuff repair in the elderly is a successful procedure. Approximately seven out of ten repairs remained intact after one year. Even where re-rupture occurs, a significant improvement in the Constant score was found

Objectives

The aim of this study was to determine whether there is any significant difference in temporal measurements of pain, function and rates of re-tear for arthroscopic rotator cuff repair (RCR) patients compared with those patients undergoing open RCR.

Development of a novel technique of arthroscopic rotator cuff repair which adapts the proven strong open technique using the Arthrex Post (low profile screw) into an arthroscopic technique by using the Arthrex Biotenodesis screw technique. The theoretical advantages of this technique are the ability to use stronger suture material, with a simple, tolerant, knotless and adaptable technique

Prior to use of this technique on patients we required laboratory confirmation of its benefit over present techniques. We have previous experience with laboratory testing at Exeter University using a MONSANTO TEN-SIOMETER for the previous Arthrex Post system. A similar experimental model was used for this study comparing two methods of fixation:

standard arthroscopic technique with Corkscrew anchor to decorticated footprint area on fresh frozen porcine humerus.

Initial results show a significant advantage of the biotenodesis technique with failure at over 1,000 N compared to 113N for a 2cm bone tunnel and 180N–600N for anchors. This shows promise for use in patients.

Purpose

Controversy exists regarding the optimal technique for arthroscopic rotator cuff repair. The purpose of this multicentre randomized double-blind controlled study was to compare the functional outcomes and healing rates of double-row suture techniques with single row repair.

Re-rupture rates after rotator cuff repair remain high because of inadequate biological healing at the tendon-bone interface. Single-growth factor therapies to augment healing at the enthesis have so far yielded inconsistent results. An emerging approach is to combine multiple growth factors over a spatiotemporal distribution that mimics normal healing. We propose a novel combination treatment of insulin-like growth factor 1 (IGF-1), transforming growth factor β1 (TGF-β1) and parathyroid hormone (PTH) incorporated into a controlled-release tyraminated poly-vinyl-alcohol hydrogel to improve healing after rotator cuff repair. We aimed to evaluate this growth factor treatment in a rat chronic rotator cuff tear model. A total of 30 male Sprague-Dawley rats underwent unilateral supraspinatus tenotomy. Delayed rotator cuff repairs were then performed after 3 weeks, to allow tendon degeneration that resembles the human clinical scenario. Animals were randomly assigned to: [1] a control group with repair alone; or [2] a treatment group in which the hydrogel was applied at the repair site. All animals were euthanized 12 weeks after rotator cuff surgery and the explanted shoulders were analyzed for biomechanical strength and histological quality of healing at the repair site. In the treatment group had significantly higher stress at failure (73% improvement, P=0.003) and Young's modulus (56% improvement, P=0.028) compared to the control group. Histological assessment revealed improved healing with significantly higher overall histological scores (10.1 of 15 vs 6.55 of 15, P=0.032), and lower inflammation and vascularity. This novel combination growth factor treatment improved the quality of healing and strength of the repaired enthesis in a chronic rotator cuff tear model. Further optimization and tailoring of the growth factors hydrogel is required prior to consideration for clinical use in the treatment of rotator cuff tears. This novel treatment approach holds promise for improving biological healing of this clinically challenging problem

It is undetermined which factors predict return to work following arthroscopic rotator cuff repair. We aimed to identify which factors predicted return to work at any level, and return to pre-injury levels of work 6 months post-arthroscopic rotator cuff repair. Multiple logistic regression analysis of prospectively collected demographic, pre-injury, preoperative, and intraoperative data from 1502 consecutive primary arthroscopic rotator cuff repairs, performed by a single surgeon, was performed to identify independent predictors of return to work, and return to pre-injury levels of work respectively, 6 months post-surgery. Six months post-rotator cuff repair, 76% of patients returned to work (RTW), and 40% returned to pre-injury levels of work (Full-RTW). RTW at 6 months was likely if patients were still working after their injuries, but prior to surgery (Wald statistic [W]=55, p<0.0001), were stronger in internal rotation preoperatively (W=8, p=0.004), had full-thickness tears (W=9, p=0.002), and were female (W=5, p=0.030). Patients who achieved Full-RTW were likely to have worked less strenuously pre-injury (W=173, p<0.0001), worked more strenuously post-injury but pre-surgery (W=22, p<0.0001), had greater behind-the-back lift-off strength preoperatively (W=8, p=0.004), and had less passive external rotation range of motion preoperatively (W=5, p=0.034). Patients who were still working post-injury, but pre-surgery were 1.6-times more likely to RTW than patients who were not (p<0.0001). Patients who nominated their pre-injury level of work as “light” were 11-times more likely to achieve Full-RTW than those who nominated “strenuous” (p<0.0001). Six months post-rotator cuff repair, a higher patient-rated post-injury, but pre-surgery level of work was the strongest predictor of RTW. A lower patient-rated pre-injury level of work was the strongest predictor of Full-RTW. Greater preoperative subscapularis strength independently predicted both RTW, and Full-RTW

Rotator cuff repair has excellent clinical outcomes but continues to be a challenge when it comes to large and massive tears as well as revision procedures. Reported symptomatic retear rates are still too high to be acceptable. The purpose of the present study was to evaluate the effectiveness of a combination of augmentation techniques consisting of microfractures of the greater tuberosity, extracellular matrix (ECM) patch graft and subsequent platelet concentrate (PC) subacromial injections in revision rotator cuff repair. The study was designed as a retrospective comparative study on prospectively collected data from a consecutive cohort of patients. All patients who underwent arthroscopic revision rotator cuff repair for symptomatic failure of previous posterosuperior rotator cuff repair were considered eligible for the study. Symptomatic failure had been diagnosed according to clinical examination and confirmed by magnetic resonance imaging (MRI). Structural integrity had been assessed on MRI and classified according to Sugaya classification. Only patients affected by stage IV-V were considered eligible. Tear reparability was confirmed during arthroscopy. Only patients with a minimum 2 years follow-up were included. Patients were divided in two groups. In group 1 (control group) a standard arthroscopic revision and microfractures of the greater tuberosity were performed; in group 2 (experimental group), microfractures of the greater tuberosity and a ECM patch graft were used to enhance tendon repair, followed by postoperative PC injections. Minimum follow-up was 12 months. Primary outcome was the Constant-Murley score (CMS) normalized for age and gender. Subjective outcome was assessed with the Disabilities of the Arm, Shoulder and Hand (DASH) score in its short version (Quick-DASH). Tendon integrity was assessed with MRI at 6 months after surgery. Comparison between groups for all discrete variables at baseline and at follow-up was carried out with the Student's t-test for normally distributed data, otherwise Mann-Whitney U-test was used. Within-group differences (baseline vs follow-up) for discrete variables were analyzed by paired t-test, or by Wilcoxon signed-rank test in case of data with non-normal distribution. Differences for categorical variables were assessed by chi-squared test. Significance was considered for p values < 0.05. Forty patients were included in the study (20 patients for each group). The mean follow-up was 13 ± 1.6 months. No patients were lost at the follow up. Comparison between groups did not show significant differences for baseline characteristics. At follow-up, mean CMS was 80.7 ± 16.6 points in group 1 and 91.5 ± 11.5 points in group 2 (p= 0.022). Mean DASH score was 28.6 ± 21.6 points in group 1 and 20.1 ± 17.4 points in group 2 (p= 0.178). Post-operative MRI showed 6 healed shoulders in Group 1 and 16 healed shoulders in Group 2 (p<0.004). No postoperative complications were reported in both groups. The combination of microfractures of the greater tuberosity, ECM patch graft, and subsequent PC subacromial injections is an effective strategy in improving tendon healing rate

Tendons mainly consist of collagen in order to withstand high tensile forces. Compared to other, high turnover tissues, cellularity and vascularity in tendons are low. Thus, the natural healing process of tendons takes long and can be problematic. In case of injury to the enthesis, the special transition from tendon over cartilage to bone is replaced by a fibrous scar tissue, which remains an unsolved problem in rotator cuff repair. To improve tendon healing, many different approaches have been described using scaffolds, stem cells, cytokines, blood products, gene therapy and others. Despite promising in vitro and in vivo results, translation to patient care is challenging. In clinics however, tendon auto- or allografts remain still first choice to augment tendon healing if needed. Therefore, it is important to understand natural tendon properties and natural tendon healing first. Like in other tissues, senescence of tenocytes seems to play an important role for tendon degeneration which is interestingly not age depended. Our in vivo healing studies have shown improved and accelerated healing by adding collagen type I, which is now used in clinics, for example for augmentation of rotator cuff repair. Certain cytokines, cells and scaffolds may further improve tendon healing but are not yet used routinely, mainly due to missing clinical data, regulatory issues and costs. In conclusion, the correct diagnosis and correct first line treatment of tendon injuries are important to avoid the necessity to biologically augment tendon healing. However, strategies to improve and accelerate tendon healing are still desirable. New treatment opportunities may arise with further advances in tendon engineering in the future

The purpose of this study is the evaluate the net promotor score of arthroscopic subacromial decompression and rotator cuff repair. The Friends and Family Test, a variant of the Net Promoter Score, was adapted for the National Health Service to evaluate overall patient satisfaction and how likely patients are to recommend an intervention. It ranges from −100 to 100. Positive scores indicate good performance. This study quantifies the scores in 71 patients at 1 year following arthroscopic sub acromial decompression and rotator cuff repair. All of the procedures were performed by 1 consultant shoulder specialist. The patient filled out a shoulder questionnaire pre-operatively, at 6 months and 1 year. The score was 72 for subacromial decompression (n = 32) and 85 for rotator cuff repair +/− decompression (n = 39). Oxford shoulder score was also taken and had a rise of 4.3 and 6.9 respectively. Our study indicates that these procedures are highly valued and are recommended by patients according to the Friends and Family Test. The results of the Friends and Family Test correlated well with postoperative functional improvement and satisfaction. We conclude from this study that a compound score based on the Friends and Family Test is a useful addition to traditional measures of patient satisfaction

The April 2015 Shoulder & Elbow Roundup. 360 . looks at: Distal clavicular resection not indicated in cuff repair?; Platelet-rich plasma in rotator cuff repair; Radial head geometry: time to change?; Heterotopic ossification in elbow trauma; Another look at heterotopic ossification in the humerus; Triceps on for total elbow arthroplasty?; Predicting outcomes in rotator cuff repair; Deltoid fatty infiltration and reverse shoulder arthroplasty

The February 2014 Shoulder & Elbow Roundup. 360 . looks at: whether arthroscopic acromioplasty is a cost-effective intervention; shockwave therapy in cuff tear; whether microfracture relieves short-term pain in cuff repair; the promising early results from L-PRF augmented cuff repairs; rehabilitation following cuff repair; supination strength following biceps tendon rupture; whether longer is better in humeral components; fatty degeneration in a rodent model; and the controversial acromioclavicular joint dislocation

Objectives. Platelet-rich fibrin matrix (PRFM) has been proved to enhance tenocyte proliferation but has mixed results when used during rotator cuff repair. The optimal PRFM preparation protocol should be determined before clinical application. To screen the best PRFM to each individual’s tenocytes effectively, small-diameter culture wells should be used to increase variables. The gelling effect of PRFM will occur when small-diameter culture wells are used. A co-culture device should be designed to avoid this effect. Methods. Tenocytes harvested during rotator cuff repair and blood from a healthy volunteer were used. Tenocytes were seeded in 96-, 24-, 12-, and six-well plates and co-culture devices. Appropriate volumes of PRFM, according to the surface area of each culture well, were treated with tenocytes for seven days. The co-culture device was designed to avoid the gelling effect that occurred in the small-diameter culture well. Cell proliferation was analyzed by water soluble tetrazolium-1 (WST-1) bioassay. Results. The relative quantification (condition/control) of WST-1 assay on day seven revealed a significant decrease in tenocyte proliferation in small-diameter culture wells (96 and 24 wells) due to the gelling effect. PRFM in large-diameter culture wells (12 and six wells) and co-culture systems induced a significant increase in tenocyte proliferation compared with the control group. The gelling effect of PRFM was avoided by the co-culture device. Conclusion. When PRFM and tenocytes are cultured in small-diameter culture wells, the gelling effect will occur and make screening of personalized best-fit PRFM difficult. This effect can be avoided with the co-culture device. Cite this article: C-H. Chiu, P. Chen, W-L. Yeh, A. C-Y. Chen, Y-S. Chan, K-Y. Hsu, K-F. Lei. The gelling effect of platelet-rich fibrin matrix when exposed to human tenocytes from the rotator cuff in small-diameter culture wells and the design of a co-culture device to overcome this phenomenon. Bone Joint Res 2019;8:216–223. DOI: 10.1302/2046-3758.85.BJR-2018-0258.R1

Despite reverse total shoulder arthroplasty (RTSA) being primarily indicated for massive rotator cuff tears, it is often possible to repair portions of the infraspinatus and subscapularis of patients undergoing this procedure. However, there is disagreement regarding whether these tissues should be repaired, as their effects remain unclear. Therefore, we investigated the effects of rotator cuff repair and changes in humeral and glenosphere lateralisation (HLat & GLat) on deltoid and joint loading. Six shoulders were tested on an in-vitro muscle driven active motion simulator. Cuff tear arthropathy was simulated in each specimen, which was then implanted with a custom adjustable RTSA fitted with a six axis load sensor. We assessed the effects of 4 RTSA configurations (i.e. all combinations of 0&10mm of HLat & GLat) on deltoid force, joint load, and joint load angle during abduction with/out rotator cuff repair. Deltoid and joint loads recorded by the load cell are reported as a % of Body Weight (%BW). Repeated measures ANOVAs and pairwise comparisons were performed with p<0.05 indicating significance. Cuff repair interacted with HLat & GLat (p=0.005, Fig. 1) such that with no HLat, GLat increased deltoid force without cuff repair (8.1±2.1%BW, p=0.012) and this effect was significantly increased with cuff repair (12.8±3.2%BW, p=0.010). However, adding HLat mitigated this such that differences were not significant. HLat and GLat affected deltoid force regardless of cuff status (−2.5±0.7%BW, p=0.016 & +7.7±2.3%BW, p=0.016, respectively). Rotator cuff repair did significantly increase joint load (+11.9±2.1%BW, p=0.002), as did GLat (+13.3±1.5%BW, p<0.001). The increases in deltoid and joint load caused by rotator cuff repair confirm that it acts as an adductor following RTSA and increases deltoid work. Additionally, cuff repair's negative effects are exacerbated by GLat, which strengthens its adduction affect, while Hlat increases the deltoid's abduction effect thus mitigating the cuff's antagonistic effects. Cuff repair increases concavity compression within the joint; however, Hlat produces a similar effect by wrapping the deltoid around the greater tuberosity – which redirects its force – and does so without increasing the magnitude of muscle and joint loading. The long-term effects of increased joint loading due to rotator cuff repair are unknown, however, it can be postulated that it may increase implant wear, and the risk of deltoid fatigue. Therefore, RTSA implant designs which improve joint compression without increasing muscle and joint loading may be preferable to rotator cuff repair

The treatment of massive rotator cuff tears remains controversial. There is lack of studies comparing patient-reported outcomes (PROM) of arthroscopic massive rotator cuff repairs (RCR) against large, medium and small RCRs. Our study aims to report the PROM for arthroscopic massive RCR versus non-massive RCR. Patients undergoing an arthroscopic RCR under a single surgeon over a 5-year period were included. Demographic data were recorded. Pre-operative Quick-DASH and Oxford Shoulder Score (OSS) were prospectively collected pre-operatively and at final review (mean of 18 months post-operatively). The scores were compared to a matched cohort of patients who had large, medium or small RCRs. A post-hoc power analysis confirmed 98% power was achieved. 82 patients were included in the study. 42 (51%) patients underwent massive RCR. The mean age of patients undergoing massive RCR was 59.7 and 55% (n=23) were female. 21% of massive RCRs had biceps augmentation. Quick-DASH improved significantly from a mean of 46.1 pre-operatively to 15.6 at final follow-up for massive RCRs (p<0.001). OSS improved significantly from a mean of 26.9 pre-operatively to 41.4 at final follow up for massive RCRs (p<0.001). There was no significant difference in the final Quick-DASH and OSS scores for massive and non-massive RCRs (p=0.35 and p=0.45 respectively). No revision surgery was required within the minimum one year follow up timescale. Arthroscopic massive rotator cuff repairs have no functional difference to non-massive rotator cuff repairs in the short term follow up period and should be considered in appropriate patient groups