Intrasynovial autograft for reconstruction of chronic large rotator cuff tears in a rabbit model: biomechanical, computed tomography, and histological results.

BACKGROUND: Rotator cuff (RC) tears are a common cause of shoulder dysfunction and pain, posing significant challenges for orthopedic surgeons. Grafts have been proposed as a solution to augment or bridge torn tendons, but optimal clinical outcomes are not always achieved due to poor graft integration, suboptimal mechanical properties, and immunological reactions. The aim of this study was to investigate the biomechanical, CT and histological results of RC reconstruction using an intrasynovial tendon autograft, in a chronic large tear subscapularis rabbit model. METHODS: Twenty-six adult male Zealand white rabbits were used in this study. Large defects in the subscapularis tendons were produced bilaterally in 20 rabbits. After 6 weeks, secondary procedures were performed to the right shoulder of the rabbits, which were reconstructed with an intrasynovial interposition autograft (graft group). The left shoulder did not undergo any further treatment (defect group). The specimens were randomly divided into two equal time groups and underwent biomechanical testing, CT analysis, and histological evaluation at 6, and 12 weeks after reconstruction. In addition, 6 rabbits that were not operated, were used as a control group. RESULTS: At 12 weeks post-repair, the graft group exhibited a significant increase in ultimate failure load compared to the defect group (p < 0.05). Furthermore, the 12-week graft group demonstrated comparable stiffness to that of the control group. CT analysis indicated no significant progression of intramuscular fat accumulation in both graft groups, in contrast to the 12-week defect group when compared to the control group. Finally, histological evaluation revealed a gradual integration of the graft with the host tissue at 12 weeks. CONCLUSION: Our study suggests that intrasynovial flexor tendon autografts hold promise as an effective interposition graft for the reconstruction of chronic large RC tears, as they improve the biomechanical and biological properties of the repaired tendon. Nonetheless, further investigations in preclinical large animal models are warranted to validate and extrapolate these findings to human studies.

Investigation of the pressure value while performing biceps tenodesis for superior capsuler reconstruction.

BACKGROUND: To compare the histopathological results of biceps tenodesis (BT) performed with normal, low, and high pressures for superior capsule reconstruction (SCR) in rabbits with massive rotator cuff tears. MATERIALS AND METHODS: Thirty rabbits were divided into three groups. Rabbits 1-10 underwent SCR with BT at the same pressure (Group 1), value measured in the groove; 50% lower (Group 2); 50% higher (Group 3). After the 4-week follow-up, shoulder were en-bloc excised and histopathological evaluation was performed with modified Bonar's scale. Results were compared between the groups, statistically. RESULTS: Extracellular matrix were significantly lower in group 2 compared to the other groups (p < 0.05). Cellularity levels were significantly lower in group 2 compared to the other groups (p < 0.05). Group 2 had no difference between the sides (p > 0.05). Group 2 had lower vascularity levels compared to the other groups (p = 0.01). DICSUSSION: When the biceps tendon was in the bicipital groove and in a more mobile state with lower pressure exposure. BT performed with a tension that creates less pressure than the biceps in the groove is more successful in SCR.

Arthroscopic cuff repair: footprint remnant preserving versus debriding rotator cuff repair of transtendinous rotator cuff tears with remnant cuff.

BACKGROUND: In transtendinous full thickness rotator cuff tears (FTRCT) with remnant cuff, conventionally, cuff remnant of the greater tuberosity (GT) is debrided for better tendon to bone healing. However, larger cuff defect caused overtension on the repaired tendon. The purpose of this study was to compare the clinical outcomes and tendon integrity between remnant preserving and remnant debriding cuff repairs in the transtendinous FTRCT with remnant cuff. METHODS: From March, 2012 to October, 2017, a total of 127 patients who had the transtendinous FTRCT with remnant cuff were enrolled in this study. Rotator cuff tears were repaired arthroscopically, with patients divided into two groups: group I (n = 63), where rotator cuff remnants were preserved during the repair, and group II (n = 64), where the remnants were debrided during the repair. Clinical outcomes were assessed at the last follow-up (minimum 2 years) using the UCLA score, ASES score, SST score, Constant Shoulder score, and range of motion (ROM). The analysis of structural integrity and tendon quality was performed using the Sugaya classification on postoperative MRI scans at 8 months after surgery. RESULTS: At the final follow-up, UCLA, ASES, SST, and CS scores significantly improved from preoperative values to postoperative (all p < 0.05): UCLA (I: 19.6 ± 6.0 to 31.7 ± 3.2, II: 18.0 ± 5.7 to 31.5 ± 3.2), ASES (I: 54.3 ± 10.7 to 86.5 ± 12.5, II: 18.0 ± 5.7 to 85.8 ± 12.4), SST (I: 5.6 ± 2.8 to 10.2 ± 2.0, II: 5.0 ± 2.9 to 10.1 ± 2.5), CS (I: 74.0 ± 17.2 to 87.8 ± 9.7, II: 62.0 ± 19.2 to 88.3 ± 6.2). However, there were no significant differences between the two groups (p > 0.05). Also, remnant preserving cuff repair yielded significantly better tendon quality on postoperative MRI (p < 0.05). The incidence of re-tear (Sugaya's Type IV and V) was not significantly different between the two groups (I:17% vs. II:19%; p = 0.053). CONCLUSIONS: Remnant preserving rotator cuff repairs, which facilitate tendon-to-tendon healing, are superior in terms of tendon quality and are the preferred option for transtendinous FTRCT. TRIAL REGISTRATION: Retrospectively registered.

Role of Critical Shoulder Angle in Degenerative Type Rotator Cuff Tears: A Turkish Cohort Study.

BACKGROUND This retrospective study investigated the association between the critical shoulder angle (CSA) and the development of full-thickness rotator cuff tears (FTRCTs) in the Turkish population. The CSA is an imaging parameter that quantifies the relationship between the inclination of the glenoid and the lateral extension of the acromion in the coronal plane. The CSA is an anatomical measurement, and higher CSA values have been associated with an increased incidence of FTRCTs. However, there is a lack of data on CSA regarding the Turkish population. MATERIAL AND METHODS In this study, CSA measurements were recorded in 2 groups: 50 patients with FTRCT who had arthroscopic repair (group 1) and 50 age- and sex-matched individuals with no FTRCT detected by magnetic resonance imaging (group 2). Sex, age, affected side, dominant side, and smoking status were recorded for each patient. The CSA measurements of the affected sides were performed on true anterior-posterior view radiographs. RESULTS The results showed a statistically significant difference between the mean CSA values of group 1 (37.48°) and group 2 (33.53°), P<0.001. CSA values of 36 and above had a sensitivity of 73.58%, specificity of 74.47%, positive predictive value of 75%, and negative predictive value of 74.47% for detecting FTRCT. CONCLUSIONS CSA measurement on radiographs is a useful diagnostic tool in the Turkish population, and an above-average CSA value is associated with a significantly increased incidence of degenerative-type FTRCT.

The subacromial bursa modulates tendon healing after rotator cuff injury in rats.

Rotator cuff injuries result in more than 500,000 surgeries annually in the United States, many of which fail. These surgeries typically involve repair of the injured tendon and removal of the subacromial bursa, a synovial-like tissue that sits between the rotator cuff and the acromion. The subacromial bursa has been implicated in rotator cuff pathogenesis and healing. Using proteomic profiling of bursa samples from nine patients with rotator cuff injury, we show that the bursa responds to injury in the underlying tendon. In a rat model of supraspinatus tenotomy, we evaluated the bursa's effect on the injured supraspinatus tendon, the uninjured infraspinatus tendon, and the underlying humeral head. The bursa protected the intact infraspinatus tendon adjacent to the injured supraspinatus tendon by maintaining its mechanical properties and protected the underlying humeral head by maintaining bone morphometry. The bursa promoted an inflammatory response in injured rat tendon, initiating expression of genes associated with wound healing, including Cox2 and Il6. These results were confirmed in rat bursa organ cultures. To evaluate the potential of the bursa as a therapeutic target, polymer microspheres loaded with dexamethasone were delivered to the intact bursae of rats after tenotomy. Dexamethasone released from the bursa reduced Il1b expression in injured rat supraspinatus tendon, suggesting that the bursa could be used for drug delivery to reduce inflammation in the healing tendon. Our findings indicate that the subacromial bursa contributes to healing in underlying tissues of the shoulder joint, suggesting that its removal during rotator cuff surgery should be reconsidered.

Clinical and cost-effectiveness of individualised (early) patient-directed rehabilitation versus standard rehabilitation after surgical repair of the rotator cuff of the shoulder: protocol for a multicentre, randomised controlled trial with integrated Quintet Recruitment Intervention (RaCeR 2).

INTRODUCTION: Despite the high number of operations and surgical advancement, rehabilitation after rotator cuff repair has not progressed for over 20 years. The traditional cautious approach might be contributing to suboptimal outcomes. Our aim is to assess whether individualised (early) patient-directed rehabilitation results in less shoulder pain and disability at 12 weeks after surgical repair of full-thickness tears of the rotator cuff compared with current standard (delayed) rehabilitation. METHODS AND ANALYSIS: The rehabilitation after rotator cuff repair (RaCeR 2) study is a pragmatic multicentre, open-label, randomised controlled trial with internal pilot phase. It has a parallel group design with 1:1 allocation ratio, full health economic evaluation and quintet recruitment intervention. Adults awaiting arthroscopic surgical repair of a full-thickness tear are eligible to participate. On completion of surgery, 638 participants will be randomised. The intervention (individualised early patient-directed rehabilitation) includes advice to the patient to remove their sling as soon as they feel able, gradually begin using their arm as they feel able and a specific exercise programme. Sling removal and movement is progressed by the patient over time according to agreed goals and within their own pain and tolerance. The comparator (standard rehabilitation) includes advice to the patient to wear the sling for at least 4 weeks and only to remove while eating, washing, dressing or performing specific exercises. Progression is according to specific timeframes rather than as the patient feels able. The primary outcome measure is the Shoulder Pain and Disability Index total score at 12-week postrandomisation. The trial timeline is 56 months in total, from September 2022. TRIAL REGISTRATION NUMBER: ISRCTN11499185.

The rat as a novel model for chronic rotator cuff injuries.

Chronic rotator cuff injuries (CRCIs) still present a great challenge for orthopaedics surgeons. Many new therapeutic strategies are developed to facilitate repair and improve the healing process. However, there is no reliable animal model for chronic rotator cuff injury research. To present a new valuable rat model for future chronic rotator cuff injuries (CRCIs) repair studies, and describe the changes of CRCIs on the perspectives of histology, behavior and MRI. Sixty male Wistar rats were enrolled and underwent surgery of the left shoulder joint for persistent subacromial impingement. They were randomly divided into experimental group (n = 30, a 3D printed PEEK implant shuttled into the lower surface of the acromion) and sham operation group (n = 30, insert the same implant, but remove it immediately). Analyses of histology, behavior, MRI and inflammatory pain-related genes expression profiles were performed to evaluate the changes of CRCIs. After 2-weeks running, the rats in the experimental group exhibited compensatory gait patterns to protect the injured forelimb from loading after 2-weeks running. After 8-weeks running, the rats in the experimental group showed obvious CRCIs pathological changes: (1) acromion bone hyperplasia and thickening of the cortical bone; (2) supraspinatus muscle tendon of the humeral head: the bursal-side tendon was torn and layered with disordered structure, forming obvious gaps; the humeral-side tendon is partially broken, and has a neatly arranged collagen. Partial fat infiltration is found. The coronal T2-weighted images showed that abnormal tendon-to-bone junctions of the supraspinatus tendon. The signal intensity and continuity were destroyed with contracted tendon. At the nighttime, compared with the sham operation group, the expression level of IL-1ß and COX-2 increased significantly (P = 0063, 0.0005) in the experimental group. The expression of COX-2 in experimental group is up-regulated about 1.5 times than that of daytime (P = 0.0011), but the expression of IL-1ß, TNF-a, and NGF are all down-regulated (P = 0.0146, 0.0232, 0.0161). This novel rat model of chronic rotator cuff injuries has the similar characteristics with that of human shoulders. And it supplies a cost-effective, reliable animal model for advanced tissue engineered strategies and future therapeutic strategies.

Acellular porcine Achilles tendon patch encapsulating tendon-derived stem cells for rotator cuff repair in a rabbit model.

Currently, the predominant method for repairing rotator cuff involves surgical suture techniques, but the failure rate remains notably high. Failure of the rotator cuff insertion to provide adequate biomechanics during early healing is considered a major cause of failure. Addressing this problem, biological augmentation emerges as a promising strategy for enhancing the biomechanical properties during early stages. Tendon-derived stem cells (TDSCs), which facilitate the differentiation of repair-supportive cells, hold the potential to improve the efficacy of patch application. The study aims to assess the behavior of TDSCs in acellular porcine Achilles tendon (APAT) patches and to explore the capacity of the APAT patch encapsulating TDSCs in promoting both tendon-to-bone healing and biomechanical enhancements in a rabbit rotator cuff repair model. Transmission electron microscopy (TEM) analyses validated the complete cellular clearance of native cells from APAT patches, with uniform distribution of TDSCs. Immunofluorescence staining confirmed successful TDSCs attachment, while population doubling time (PDT) underscored increased TDSCs proliferation on APAT patches. Quantitative polymerase chain reaction (qPCR) demonstrated upregulation of tenocyte and osteocyte related genes in TDSCS cultured within the patches. In the subsequent in vivo experiment, fifty-four rabbits were used to create rotator cuff injury models and randomly assigned to a control group, an APAT patch group, and an APAT patch with TDSCs group. Histological analysis showed that the APAT patch with TDSCs group had significantly enhanced tendon-to-bone healing and a distinctly organized tendon-fibrocartilage-bone structure, as compared to the APAT patch group. In addition, the biomechanical properties of the APAT patch with TDSCs group were significantly improved. In conclusion, APAT patches promote TDSC proliferation and stimulate tenogenic and osteogenic differentiation. APAT patches encapsulating TDSCs have shown considerable potential in promoting tendon-to-bone healing of rotator cuff injuries, indicating that their use in rotator cuff repair surgery is clinically meaningful.

[Early effectiveness of arthroscopic tri-anchor double-pulley suture-bridge repair of medium-size supraspinatus tendon tears].

Objective: To explore the early effectiveness of arthroscopic tri-anchor double-pulley suture-bridge in treatment of medium-size supraspinatus tendon tears. Methods: Between December 2020 and January 2023, 40 patients with medium-size supraspinatus tendon tears were treated with arthroscopic tri-anchor double-pulley suture-bridge. There were 18 males and 22 females, with an average age of 62.6 years (mean, 45-73 years). Among them, 17 patients had trauma history. The main clinical symptom was shoulder pain with hug resistance test (+). The interval from symptom onset to operation was 10.7 months on average (range, 3-36 months). Visual analogue scale (VAS) score, University of California Los Angeles (UCLA) score, American Shoulder and Elbow Surgeons (ASES) score, and shoulder range of motion (ROM) of forward flexion, abduction, and external rotation were used to evaluate shoulder function. MRI was performed to assess the structural integrity and tension of reattached tendon. Patient satisfactions were calculated at last follow-up. Results: All incisions healed by first intention, no complications such as incision infection or nerve injury occurred. All patients were followed up 12-37 months (mean, 18.2 months). At 12 months after operation, VAS score, UCLA score, and ASES score significantly improved when compared with the preoperative scores ( P<0.05). At 3 and 12 months after operation, the ROM of external rotation significantly improved when compared with preoperative one ( P<0.05), and further improved at 12 months after operation ( P<0.05). However, the ROMs of abduction and forward flexion did not improve at 3 months after operation when compared with those before operation ( P>0.05), but significantly improved at 12 months after operation ( P<0.05). Twenty-six patients underwent MRI at 3-6 months, of which 23 patients possessed intact structural integrity, good tendon tension, and tendon healing; 3 patients underwent tendon re-tear. The self-rated satisfaction rate was 92.5% at last follow-up. Conclusion: Arthroscopic tri-anchor double-pulley suture-bridge in treatment of medium-size supraspinatus tendon tears can maximize the tendon-bone contact area, obtain satisfied early effectiveness with high satisfaction rate and low incidence of tendon re-tear. However, the function of abduction is limited at 3 months after operation, and patients need to adhere to rehabilitation training to further improve the joint activity.

Arthroscopic Medialization Partial Repair with Biologic Interposition Tuberoplasty for Large to Massive Irreparable Rotator Cuff Tear.

An irreparable rotator cuff tear is a challenging condition to treat, and various treatment modalities are being introduced. Medialization in the partial repair method has the limitation of exposing the tuberosity, while tension-free biologic interposition tuberoplasty using acellular dermal matrix has the limitation of exposing the humeral head. The authors believe that by combining these two techniques, it is possible to complement each other's limitations. Therefore, they propose a surgical method that combines medialization and biologic interposition tuberoplasty for addressing these constraints.

Cell-Based Therapies for Rotator Cuff Injuries: An Updated Review of the Literature.

This review focuses on non-surgical treatment options for rotator cuff injuries and highlights the potential of mesenchymal stem cells (MSCs) as a potential regenerative approach. MSCs, sourced from various tissues like bone marrow and adipose tissue, exhibit promising mechanisms in vitro, influencing tendon-related gene expression and microenvironment modulation. Animal studies support this, showcasing MSCs' ability to reduce inflammation, improve tissue remodeling, and enhance repaired tendon strength. Human trials, while varied and limited, suggest that MSCs might lower retear rates and enhance post-repair outcomes, but randomized controlled trials yield mixed results, emphasizing the necessity for standardized investigations. Ultimately, while cell-based therapies demonstrate an excellent safety profile, more rigorous clinical trials are necessary to determine their efficacy in improving patient outcomes and achieving lasting structural changes in rotator cuff injuries.

Up to date diagnosis and treatment of massive irreparable cuff tears: Results of the survey of the U45 ESSKA Committee.

PURPOSE: Irreparable rotator cuff tears are disabling and can severely affect daily life activities, especially when young and active patients are involved. The definition is still debated, and they can have several clinical presentations. The treatment depends on the clinical presentation and the patient's age. METHODS: The survey was developed by the ESSKA U45 Committee and was uploaded on the ESSKA website. Fifty-seven questionnaires were returned. Several aspects of the diagnosis and treatment of massive irreparable cuff tears were investigated. Moreover, treatment options for specific clinical scenarios were given for posterior-superior and anterior-superior cuff tears in young and old patients. RESULTS: Fatty degeneration of the muscles was the most common criterion to define an irreparable tear (59.7%). In young patients with external rotation with the arm at side lag, partial repair of the cuff was the most common option (41.8%); in case of external rotation with the arm at side + external rotation at 90° of abduction lag without pseudoparalysis, the most common option was partial repair of the cuff + latissimus dorsi or lower trapezius transfer (39.3%), and in case of external rotation with the arm at side + external rotation at 90° of abduction lag with pseudoparalysis, partial repair of the cuff + latissimus dorsi or lower trapezius transfer was still the most common option (25.5%). The same scenarios in old patients yielded the following results: reverse prosthesis (49.1%), reverse prosthesis (44.6%) and reverse prosthesis ± latissimus dorsi or lower trapezius transfer (44.6%), respectively. CONCLUSIONS: The present survey clearly confirms that biological options (partial cuff repairs and tendon transfers) are the reference in the case of young patients with deficient cuffs (both posterior and anterior). Reverse shoulder prosthesis is the most common treatment option in old patients in all clinical scenarios. LEVEL OF EVIDENCE: Level IV.

Studying Edema Formation After Release of the Infraspinatus Muscle as an Experimental Model of Rotator Cuff Lesions in Sheep: A Histological Analysis.

BACKGROUND: Muscle edema formation and inflammatory processes are early manifestations of acute rotator cuff lesions in sheep. Histological analysis of affected muscles revealed edema formation, inflammatory changes, and muscle tissue disruption in MRs. HYPOTHESIS: Edema contributes to inflammatory reactions and early muscle fiber degeneration before the onset of fatty infiltration. STUDY DESIGN: Controlled laboratory study. METHODS: Osteotomy of the greater tuberosity, including the insertion of the infraspinatus tendon, was performed on 14 sheep. These experimental animal models were divided into 2 groups: a nontrauma group with surgical muscle release alone (7 sheep) and a trauma group with standardized application of additional trauma to the musculotendinous unit (7 sheep). Excisional biopsy specimens of the infraspinatus muscle were taken at 0, 3, and 4 weeks. RESULTS: Edema formation was histologically demonstrated in both groups and peaked at 3 weeks. At 3 weeks, signs of muscle fiber degeneration were observed. At 4 weeks, ingrowth of loose alveolar and fibrotic tissue between fibers was detected. Fatty tissue was absent. The diameter of muscle fibers increased in both groups, albeit to a lesser degree in the trauma group, and practically normalized at 4 weeks. Immunohistology revealed an increase in macrophage types 1 and 2, as well as inflammatory mediators such as prostaglandin E2 and nuclear factor kappa-light-chain-enhancer of activated B cells. CONCLUSION: Early muscle edema and concomitant inflammation precede muscle fiber degeneration and fibrosis. Edema formation results from tendon release alone and is only slightly intensified by additional trauma. CLINICAL RELEVANCE: This study illustrates that early edema formation and inflammation elicit muscle fiber degeneration that precedes fatty infiltration. Should this phenomenon be applicable to human traumatic rotator cuff tears, then surgery should be performed as soon as possible, ideally within the first 21 days after injury.

Which is better? Early versus delayed rehabilitation after arthroscopic rotator cuff repair.

PURPOSE: This study aimed to compare the 5-year clinical and functional outcomes, including repaired tendon healing status, between early and delayed rehabilitation after arthroscopic rotator cuff repair METHODS: A total of 75 patients with rotator cuff tears (less than 5 cm) underwent arthroscopic repairs over a 60-month period. Participants were randomly assigned to early and delayed postoperative rehabilitation groups with distinct protocols. Clinical and functional outcome measures included Constant score, University of California at Los Angeles (UCLA) score, visual analogue scale for pain and isokinetic dynamometer test for muscle strength recovery. Clinical and functional scores were compared between baseline and 5 years postoperatively. Radiologic assessment via magnetic resonance imaging was performed at a minimum of 12 months postoperatively for evaluations of tendon integrity and recurrent tears. RESULTS: Baseline characteristics showed no statistically significant differences between groups. Both groups demonstrated equivalent improvement in range of motion and pain scores with no statistical differences. Clinical scores improved significantly in both groups by postoperative 12 months and plateaued. At the postoperative 5-year mark, the early group showed better improvement in the visual analogue scale and UCLA score, while the delayed group had superior Constant scores. Postoperative magnetic resonance imaging revealed six recurrent tears, two in the early group and four in the delayed group, with no statistical differences. Muscle strength recovery showed no differences between the two groups. CONCLUSION: Both the early and the delayed rehabilitation groups showed similar outcomes in postoperative range of motion, functional scores, muscle strength recovery and tendon healing in the short- and mid-term follow-ups. LEVEL OF EVIDENCE: Level III.

Effect of age and gender in rates of achieving minimal clinically important difference and patient-acceptable symptom state 2 years after arthroscopic superior capsular reconstruction.

PURPOSE: This study aimed to evaluate patient-reported outcome measures (PROMs) and the effects of gender and age on achieving clinically significant outcomes in patients undergoing arthroscopic superior capsular reconstruction (ASCR) with a minimum 2-year follow-up. METHODS: Patients undergoing ASCR for irreparable rotator cuff tear between 2013 and 2020 were reviewed. Preoperative and minimum 2-year postoperative PROMs were collected, including American Shoulder and Elbow Surgeons (ASES), Constant, single assessment numeric evaluation (SANE), and visual analog scale (VAS) scores. Minimal clinically important difference (MCID) and patient-acceptable symptomatic state (PASS) were calculated for each functional score and analyzed according to age and gender. The percentages of patients achieving MCID and PASS were recorded. RESULTS: The study included 83 patients, with a mean follow-up of 3.5 ± 1.4 years. Significant improvements were found in ASES, Constant, SANE, and VAS for all groups based on gender and age. Based on receiver-operating characteristic curves, all scores had acceptable areas under the curve for PASS. Values for PASS and MCID were 81.5 and 10.3 for ASES; 61.5 and 6.2 for Constant; 82.5 and 11.5 for SANE and 1.5 and 1.1 for VAS, respectively. Analysis of achieving MCID and PASS showed no difference between the groups in the majority of outcome measures. However, female patients achieved the SANE thresholds for PASS at significantly higher rates than male patients. Patients ≥65 years old achieved ASES and Constant thresholds for MCID at significantly higher rates than patients ˂65 years old. CONCLUSION: Most patients achieved MCID and PASS at a 2-year follow-up. Patients showed comparable rates of MCID and PASS achievement on most outcome tools based on age and gender. Female patients achieved PASS on SANE at significantly higher rates than male patients and older patients achieved MCID on ASES and Constant at higher rates than young patients. Thus, age is a stronger factor for achieving MCID than gender. LEVEL OF EVIDENCE: Level II.

Semi-Bone Tunnel Technique Using Double-Row Suture Bridge Combined With Platelet-Rich Plasma Hydrogel for Rotator Cuff Repair in a Rabbit Model.

BACKGROUND: The approach to managing the footprint area and reconstructing the tendon-bone interface (TBI) is critical for optimal healing. PURPOSE: To evaluate the outcomes of the semi-bone tunnel (SBT) technique using a double-row suture bridge combined with platelet-rich plasma (PRP) hydrogel for rotator cuff repair in a rabbit model. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 48 New Zealand White rabbits were divided into 4 groups. The supraspinatus tendons were severed at the footprint to create a rotator cuff tear model in the surgical groups. Rabbits were treated with the traditional onto-surface repair (control group), SBT technique (SBT group), and SBT technique combined with PRP hydrogel implantation (SBT+PRP group). The rabbits without surgery were the normal group. At 8 weeks after surgery, macroscopic observation, magnetic resonance imaging (MRI) and micro-computed tomography (µCT) examinations, histological evaluations, and biomechanical tests were performed to assess the curative effects of the given treatments. RESULTS: The MRI results showed that the repaired supraspinatus tendon presented a uniform signal, minimal inflammatory response, and the lowest signal-to-noise quotient value in the SBT+PRP group. The µCT results suggested that the SBT technique did not reduce the local bone mineral density in the TBI area compared with the onto-surface repair technique. The histological staining results showed that the regenerated TBI in the SBT+PRP group had a 4-layer structure similar to the natural tissue. The highest values for biomechanical properties were observed in the SBT+PRP group, and there was no significant difference between the SBT+PRP group and normal group. CONCLUSION: The SBT technique presented a better tendon-bone healing effect for rotator cuff tear in the rabbit model compared with the traditional onto-surface repair technique. The specimens in the SBT+PRP group had a similar TBI structure and biomechanical properties to the natural tissue. CLINICAL RELEVANCE: The SBT technique can be an alternative surgical approach for rotator cuff repair, especially for moderate to large tears and cases requiring scaffold implantation.

Functional recovery prediction during rehabilitation after rotator cuff tears by decision support system.

BACKGROUND: Today's rehabilitation decision-making still relies on conventional methods and different specific targeted rehabilitation protocols. Our study focuses on the decision support system for early rehabilitation after rotator cuff (RC) tears repair, where a multicriteria decision-making framework (MCDM) is applied for the prediction of successful functional recovery and selection of a rehabilitation protocol. OBJECTIVE: To identify factors that affect recovery outcomes and to develop a decision support system methodology for predicting functional recovery outcomes at early rehabilitation after RC repair. METHODS: Twelve rehabilitation experts were involved in the design, calibration, and evaluation of a rehabilitation protocol based on the proposed decision support system constructed using the MCDM framework. For the development of a decision support system, 20 patients after RC surgery undergoing outpatient rehabilitation were enrolled in a prospective cohort clinical trial. RESULTS: The MCDM framework (SWARA method) sensitively assesses different criteria and determines the corresponding criteria weights that were similar to criteria weights assessed subjectively by rehabilitation experts. The assignment of patients into the classes, according to the heuristic evaluation method based on expert opinion and the standard qualitative evaluation methods showed the validity of MCDM methods remain the best new alternative in predicting recovery during rehabilitation. CONCLUSIONS: The results of this paper show that sustainable rehabilitation is an area that is quite suitable for the use of MCDM. The most of rehabilitation protocols are based on traditional methods and approaches, but the sensitive results showed the validity of MCDM methods and remains the best new alternative in prediction recovery protocols during rehabilitation.

Effect of Platelet-Rich Plasma Dosing for Healing after Arthroscopic Cuff Repair Compared with Surgery Alone: A Systematic Review and Meta-Analysis.

INTRODUCTION: Platelet-rich plasma (PRP) has been used for arthroscopic rotator cuff repairs (aRCR), but no studies have addressed the impact of platelet concentration. The primary aim was to evaluate whether the PRP cell concentration has an effect on tendon healing after aRCR compared with surgery alone. The secondary aim was to assess the functional and pain outcomes. MATERIALS AND METHODS: A systematic review was performed with searches in the MEDLINE (PubMed), Scopus, Web of Science, and Cochrane (Central) databases according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Metanalytic procedures were performed for randomized controlled trials (RCTs), and a subgroup analysis was used for studies with target (approximately 10 6 cells·µL -1 ) or below-target PRP cellular concentrations (app. 5 × 10 5 cells·µL -1 ) regarding the primary outcome of tendon healing. RESULTS: This review included 10 studies (8 RCTs) with 342 patients in the aRCR + PRP group and 344 patients with isolated aRCR. The risk of bias was low to intermediate (6/4, respectively). Meta-analysis of the RCT revealed that the aRCR + high-concentration PRP group had an approximately 3.9-fold higher chance of healing than the non-PRP group (odds ratio, 3.89; 95% confidence interval, 1.78-8.44; P = 0.0007). No significant difference in healing was found between the aRCR + low-concentration PRP and non-PRP groups (odds ratio, 2.21; 95% confidence interval, 0.66-7.45; P = 0.2). The Constant-Murley score and University of California Los Angeles scores were significantly improved in the aRCR + PRP groups with more than 12 months of follow-up, and no significant differences were found consistently for the American Shoulder and Elbow Society and visual analog scale scores. CONCLUSIONS: This study highlights that a PRP cell concentration close to the target (10 6 cells·µL -1 ) of patients with aRCR may improve their healing and functional outcomes and that dosing may be potentially useful in therapy.

The influence of rotator cuff tear type and weight bearing on shoulder biomechanics in an ex vivo simulator experiment.

Glenohumeral biomechanics after rotator cuff (RC) tears have not been fully elucidated. This study aimed to investigate the muscle compensatory mechanism in weight-bearing shoulders with RC tears and asses the induced pathomechanics (i.e., glenohumeral translation, joint instability, center of force (CoF), joint reaction force). An experimental, glenohumeral simulator with muscle-mimicking cable system was used to simulate 30° scaption motion. Eight fresh-frozen shoulders were prepared and mounted in the simulator. Specimen-specific scapular anthropometry was used to test six RC tear types, with intact RC serving as the control, and three weight-bearing loads, with the non-weight-bearing condition serving as the control. Glenohumeral translation was calculated using instantaneous helical axis. CoF, muscle forces, and joint reaction forces were measured using force sensors integrated into the simulator. Linear mixed effects models (RC tear type and weight-bearing) with random effects (specimen and sex) were used to assess differences in glenohumeral biomechanics. RC tears did not change the glenohumeral translation (p > 0.05) but shifted the CoF superiorly (p ≤ 0.005). Glenohumeral translation and joint reaction forces increased with increasing weight bearing (p < 0.001). RC and deltoid muscle forces increased with the presence of RC tears (p ≤ 0.046) and increased weight bearing (p ≤ 0.042). The synergistic muscles compensated for the torn RC tendons, and the glenohumeral translation remained comparable to that for the intact RC tendons. However, in RC tears, the more superior CoF was close to where glenoid erosion occurs in RC tear patients with secondary osteoarthritis. These findings underscore the importance of early detection and precise management of RC tears.