Effects of adipose-derived cell supplementation on tendon-bone healing in a rat model of chronic rotator cuff tear with suprascapular nerve injury.

OBJECTIVE: To investigate the effect of adipose-derived cells (ADCs) on tendon-bone healing in a rat model of chronic rotator cuff tear (RCT) with suprascapular nerve (SN) injury. METHODS: Adult rats underwent right shoulder surgery whereby the supraspinatus was detached, and SN injury was induced. ADCs were cultured from the animals' abdominal fat. At 6 weeks post-surgery, the animals underwent surgical tendon repair; the ADC (+ve) group (n = 18) received an ADC injection, and the ADC (-ve) group (n = 18) received a saline injection. Shoulders were harvested at 10, 14, and 18 weeks and underwent histological, fluorescent, and biomechanical analyses. RESULTS: In the ADC (+ve) group, a firm enthesis, including dense mature fibrocartilage and well-aligned cells, were observed in the bone-tendon junction and fatty infiltration was less than in the ADC (-ve) group. Mean maximum stress and linear stiffness was greater in the ADC (+ve) compared with the ADC (-ve) group at 18 weeks. CONCLUSION: ADC supplementation showed a positive effect on tendon-bone healing in a rat model of chronic RCT with accompanying SN injury. Therefore, ADC injection may possibly accelerate recovery in massive RCT injuries.

Postoperative Rotation Deformity of Head-Neck Fragments in Unstable Intertrochanteric Fractures Fixed with Intramedullary Nails.

BACKGROUND: Our purpose was to quantify the postoperative rotation deformity (RD) after osteosynthesis of unstable intertrochanteric fractures (ITFx) using 3D-CT / image processing software, and to clarify the clinical meaning of RD. METHODS: Forty-six consecutive patients with unstable intertrochanteric fractures were enrolled in this study. All were fixed with Gamma 3 Trochanteric nail and RC Lag Screw® (Stryker). We performed 3D-CT evaluations for the rotational deformity of head-neck fragments, the medial cortex support (MCS) between main fragments and bone healing at 3 months postoperatively. RESULTS: The RD was significantly larger in the patients without the MCS (5.1 ± 4.0°, N = 9) than those with the MCS (2.4 ± 2.6°, N = 37) (P = 0.006*). Delayed healing (N=3) was observed in patients without the MCS, and the association between RD and delayed healing was significant (P = 0.003*, cut-off value 6.4°, sensitivity 100% and specificity 90.7%, AUC 0.91). CONCLUSIONS: This study proposed a novel method of measuring postoperative RD. Lack of MCS may lead to RD and consequent delayed healing in unstable ITFx fixed with intramedullary nails.

Does physiotherapy after rotator cuff repair require supervision by a physical therapist?: a meta-analysis.

BACKGROUND: A supervised physiotherapy program (SPP) is a standard regimen after surgical rotator cuff repair (RCR); however, the effect of a home-based exercise program (HEP), as an alternative, on postoperative functional recovery remains unclear. Therefore, the purpose of this meta-analysis was to compare the functional effects of SPP and HEP after RCR. METHODS: We searched electronic databases including Central, Medline, and Embase in April 2022. The primary outcomes included the Constant score, American Shoulder and Elbow Surgeons score, University of California Los Angeles shoulder score, and pain score. Secondary outcomes included range of motion, muscle strength, retear rate, and patient satisfaction rate. A meta-analysis using random-effects models was performed on the pooled results to determine the significance. RESULTS: The initial database search yielded 848 records, five of which met our criteria. Variables at 3 months after surgery were successfully analyzed, including the Constant score (mean difference, -8.51 points; 95% confidence interval [CI], -32.72 to 15.69; P=0.49) and pain score (mean difference, 0.02 cm; 95% CI, -2.29 to 2.33; P=0.99). There were no significant differences between the SPP and HEP. Other variables were not analyzed owing to the lack of data. CONCLUSIONS: Our data showed no significant differences between SSP and HEP with regard to the Constant and pain scores at 3 months after RCR. These results suggest that HEP may be an alternative regimen after RCR. Level of evidence: I.

Effect of suprascapular nerve injury on muscle and regenerated enthesis in a rat rotator cuff tear model.

BACKGROUND: Massive rotator cuff tears (RCTs) are complicated by muscle atrophy, fibrosis, and intramuscular fatty degeneration, which are associated with postoperative tendon-to-bone healing failure and poor clinical outcomes. We evaluated muscle and enthesis changes in large tears with or without suprascapular nerve (SN) injury in a rat model. METHODS: Sixty-two adult Sprague-Dawley rats were divided into SN injury (+) and SN injury (-) groups (n=31 each), comprising tendon (supraspinatus [SSP]/infraspinatus [ISP]) and nerve resection and tendon resection only cases, respectively. Muscle weight measurement, histological evaluation, and biomechanical testing were performed 4, 8, and 12 weeks postoperatively. Ultrastructural analysis with block face imaging was performed 8 weeks postoperatively. RESULTS: SSP/ISP muscles in the SN injury (+) group appeared atrophic, with increased fatty tissue and decreased muscle weight, compared to those in the control and SN injury (-) groups. Immunoreactivity was only positive in the SN injury (+) group. Myofibril arrangement irregularity and mitochondrial swelling severity, along with number of fatty cells, were higher in the SN injury (+) group than in the SN injury (-) group. The bone-tendon junction enthesis was firm in the SN injury (-) group; this was atrophic and thinner in the SN injury (+) group, with decreased cell density and immature fibrocartilage. Mechanically, the tendon-bone insertion was significantly weaker in the SN injury (+) group than in the control and SN injury (+) groups. CONCLUSIONS: In clinical settings, SN injury may cause severe fatty changes and inhibition of postoperative tendon healing in large RCTs. Level of evidence: Basic research, controlled laboratory study.

Targeting FoxO transcription factors with HDAC inhibitors for the treatment of osteoarthritis.

OBJECTIVES: Osteoarthritis (OA) features ageing-related defects in cellular homeostasis mechanisms in articular cartilage. These defects are associated with suppression of forkhead box O (FoxO) transcription factors. FoxO1 or FoxO3 deficient mice show early onset OA while FoxO1 protects against oxidative stress in chondrocytes and promotes expression of autophagy genes and the essential joint lubricant proteoglycan 4 (PRG4). The objective of this study was to identify small molecules that can increase FoxO1 expression. METHODS: We constructed a reporter cell line with FoxO1 promoter sequences and performed high-throughput screening (HTS) of the Repurposing, Focused Rescue and Accelerated Medchem (ReFRAME) library . Hits from the HTS were validated and function was assessed in human chondrocytes, meniscus cells and synoviocytes and following administration to mice. The most promising hit, the histone deacetylase inhibitor (HDACI) panobinostat was tested in a murine OA model. RESULTS: Among the top hits were HDACI and testing in human chondrocytes, meniscus cells and synoviocytes showed that panobinostat was the most promising compound as it increased the expression of autophagy genes and PRG4 while suppressing the basal and IL-1ß induced expression of inflammatory mediators and extracellular matrix degrading enzymes. Intraperitoneal administration of panobinostat also suppressed the expression of mediators of OA pathogenesis induced by intra-articular injection of IL-1ß. In a murine OA model, panobinostat reduced the severity of histological changes in cartilage, synovium and subchondral bone and improved pain behaviours. CONCLUSION: Panobinostat has a clinically relevant activity profile and is a candidate for OA symptom and structure modification.

The clinical outcomes of infraspinatus rotational transfer for irreparable posterosuperior rotator cuff tears: a preliminary report.

BACKGROUND: This study aimed to examine the preliminary clinical results of the infraspinatus rotational transfer procedure for irreparable posterosuperior rotator cuff tears. METHODS: This study included 34 patients (mean age, 68.4 years). Their mean tear width and length measurements were 50.9 mm and 50.6 mm, respectively. The functional outcomes, including physician-determined and patient-reported scores, were evaluated before and at 1 year after surgery. The structural outcomes determined using the magnetic resonance imaging examination results were also assessed. RESULTS: The clinical scores significantly improved after surgery compared with the scores before surgery: the Constant-Murley score (53.3±21.1 to 76.8±10.5), University of California at Los Angeles Shoulder score (15.6±3.6 to 27.8±6.7), American Shoulder and Elbow Surgeons Shoulder score (51.8±18.3 to 89.1±13.5), and WORC score (925.0±436.8 to 480.3±373.2) (all p<0.001). Postoperative re-tears were noted in two patients (5.9%). CONCLUSIONS: One year postoperatively, the patient's clinical scores significantly improved, with a re-tear rate of 5.9%.

Posterior decentering of the humeral head in patients with arthroscopic rotator cuff repair.

BACKGROUND: In some patients with rotator cuff tear (RCT), the axial view of magnetic resonance imaging (MRI) shows subtle posterior decentering (PD) of the humeral head from the glenoid fossa. This is considered to result from a loss of centralization that is typically produced by rotator cuff function. There are few reports on PD in RCT despite the common occurrence of posterior subluxation in degenerative joint disease. In this study, we investigated the effect of PD in arthroscopic rotator cuff repair (ARCR). METHODS: We conducted a retrospective study of consecutive patients who underwent ARCR at our institute and were followed-up for at least 1 year. PD was identified as a 2-mm posterior shift of the humeral head relative to the glenoid fossa in the axial MRI view preoperatively. The tear size and fatty degeneration (FD, Goutallier classification) were also evaluated using preoperative MRI. Retears were evaluated through MRI at 1 year postoperatively. RESULTS: We included 135 shoulders in this study. Ten instances of PD (including seven retears) were observed preoperatively. Fifteen retears (three and 12 retears in the small/medium and large/massive tear groups, respectively) were observed postoperatively. PD was significantly correlated with tear size, FD, and retear occurrence (p<0.01 each). The odds ratio for PD in retears was 34.1, which was greater than that for tear size ≥3 cm and FD grade ≥3. CONCLUSIONS: We concluded that large tear size and FD contribute to the occurrence of PD. Furthermore, PD could be a predictor of retear after ARCR.

Clinical outcomes in patients with retear after arthroscopic rotator cuff repair: A meta-analysis.

BACKGROUND: Rotator cuff retear is a major concern after arthroscopic rotator cuff repair (ARCR); however, the effects of retear remain unclear. Therefore, the purpose of this study was to assess the clinical outcomes of postoperative retear and intact tendons after ARCR. METHODS: We searched PubMed, Cochrane Library, Scopus, and PEDro databases for studies performed from January 2000 to June 2020. Clinical outcomes included the Constant score, American Shoulder and Elbow Surgeons (ASES) score, University of California Los Angeles shoulder (UCLA) score, pain score, range of motion, and muscle strength. Meta-analysis using random-effects models was performed on the pooled results to determine significance. RESULTS: The initial database search yielded 3141 records. After removal of duplicates, 26 of which met the inclusion criteria. Patients in the retear group had significantly lower Constant score [- 8.51 points (95% CI, - 10.29 to - 6.73); P < 0.001], ASES score [- 12.53 points (95% CI, - 16.27 to - 8.79); P < 0.001], UCLA score [- 3.77 points (95% CI, - 4.72 to - 2.82); P < 0.001], and significantly higher pain score [0.56 cm (95% CI, 0.10 to 1.01); P = 0.02] than the intact group. In addition, the retear group had significantly lower flexion [- 10.46° (95% CI, - 19.86 to - 1.07); P = 0.03], abduction [- 14.84° (95% CI, - 28.55 to - 1.14); P = 0.03], and external rotation [- 7.22° (95% CI, - 13.71 to - 0.74); P = 0.03] range of motion, and flexion [- 1.65 kg·f (95% CI, - 2.29 to - 1.01); P < 0.001], abduction [- 1.87 kg·f (95% CI, - 3.02 to - 0.72); P = 0.001], and external rotation [- 1.66 kg·f (95% CI, - 3.25 to - 0.07); P = 0.04] muscle strength. CONCLUSION: Our results suggest that retear after ARCR leads to poor clinical outcomes after surgery.

Neurotropin protects rotator cuff tendon cells from lidocaine-induced cell death.

BACKGROUND: Local anesthetics often are used in rotator cuff tears as therapeutic tools, although some cases have reported that they have detrimental effects. Neurotropin (NTP) is used widely in Japan as a treatment for various chronic pain conditions and is shown to have protective effects on cartilage and nerve cells. In this study, we investigated the protective effect of NTP against lidocaine-induced cytotoxicity. METHODS: Tenocytes from rotator cuff tendons were incubated with lidocaine, NTP, lidocaine with NTP, and a control medium. Cell viability was evaluated using the WST-8 assay. Cell apoptosis was detected via annexin V staining using flow cytometry. The expression of BCL-2 and cytochrome c, which are involved in the intrinsic mitochondrial pathway of apoptosis, was evaluated via Western blotting and immunohistochemical staining. RESULTS: In the cell viability assay, lidocaine decreased cell viability in a dose-dependent manner, and NTP did not affect cell viability. Moreover, NTP significantly inhibited the cytotoxic effect of lidocaine. The flow cytometry analysis showed that lidocaine significantly induced apoptosis in tenocytes, and NTP considerably inhibited this lidocaine-induced apoptosis. Western blotting experiments showed that lidocaine decreased the protein expression of BCL-2, and that NTP conserved the expression of BCL-2, even when used with lidocaine. Immunohistochemical staining for cytochrome c showed that 0.1% lidocaine increased cytochrome c-positive cells, and NTP suppressed lidocaine-induced cytochrome c expression. CONCLUSIONS: NTP suppresses lidocaine-induced apoptosis of tenocytes by inhibiting the mitochondrial apoptotic pathway. Intra-articular/ bursal injection of NTP with lidocaine could protect tenocytes in rotator cuff tendons against lidocaine-induced apoptosis.

Incidence of Re-Dislocation/Instability After Arthroscopic Bankart Repair: Analysis via Telephone Interviews.

INTRODUCTION: Current advances in arthroscopic surgery have led to good outcomes for arthroscopic Bankart repair (ABR) for recurrent anterior shoulder dislocation. However, recent studies have reported recurrence rates of 4%-19% after ABR. In our survey conducted from February 2002 to December 2010, the post-ABR re-dislocation rate was 8.8%. In 2011, we began performing the ABR with open Bristow (B) procedure or Remplissage (R) procedure in patients with large glenoid or humeral head bone defects and in patients who play collision sports. Therefore, the present study is the second series evaluating the incidence of re-dislocation and instability after recurrent anterior shoulder dislocation. METHOD: Surgery was performed for 84 cases of shoulder instability from January 2011 to August 2017. After excluding 7 open surgeries, 6 reoperations, and 2 patients with multidirectional instability, telephone interviews were conducted with 69 patients. The average follow-up duration was 46.9 months (range, 13-92 months). RESULT: ABR alone was performed 61 patients; the B procedure was added for 3 patients, and the R procedure was added for 5 patients. Telephone interviews were conducted with 61 patients. There were no cases of re-dislocation or reoperation. Four patients who underwent only ABR experienced postoperative instability, but not to the extent that their daily lives were affected. CONCLUSION: This study showed that the addition of R or B technique to ABR for recurrent anterior shoulder dislocation resulted in a 0% re-dislocation rate.

Functional and Structural Outcomes After Retears of Arthroscopically Repaired Large and Massive Rotator Cuff Tears.

BACKGROUND: Most studies have shown acceptable clinical results in patients with large or massive tears treated by arthroscopic rotator cuff repair (ARCR); however, the effects of retears after surgery in these patients remain unknown. PURPOSE: To evaluate functional and structural outcomes after retears of large and massive rotator cuff tears treated by ARCR. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A total of 196 consecutive patients with large to massive rotator cuff tears underwent physical examination and magnetic resonance imaging before and after ARCR at 6, 12, and 24 months. Of these, 9 patients were lost at 6 months after surgery. Therefore, 187 patients were followed up for 24 months after surgery; 148 patients showed no postsurgical ruptures. Consequently, the remaining 39 patients with postsurgical ruptures were included in this study (mean age at surgery, 64.2 ± 8.7 years). Functional outcome measures comprised the University of California, Los Angeles (UCLA) and Japanese Orthopaedic Association (JOA) scores. Structural outcome measures consisted of the global fatty degeneration index (GFDI), mediolateral tear size, and residual tendon attachment area as evaluated by our own scoring system. RESULTS: The mean UCLA and JOA scores significantly improved from 16.3 ± 3.9 and 63.2 ± 10.7 preoperatively to 27.9 ± 5.5 (P < .0001) and 84.5 ± 9.4 (P < .0001) at final follow-up, respectively. The mean mediolateral tear size (P = .03, .02, and .02, respectively) and residual tendon attachment area (P = .04, .03, and .04, respectively) significantly improved from preoperatively to 6, 12, and 24 months postoperatively. The correlation analysis between the functional and structural variables confirmed significant associations between the residual tendon attachment area, the JOA and UCLA scores at 24 months postoperatively, and the preoperative GFDI (r = -0.81 to 0.78). CONCLUSION: The residual tendon attachment area after a retear was significantly larger at 24 months after surgery than before surgery. In addition, significant associations were confirmed between preoperative fatty degeneration, the residual tendon attachment area, and functional outcomes after a retear. These results may explain why functional outcomes significantly improved even after retears in this series.

Midterm Functional and Structural Outcomes of Large/Massive Cuff Tears Treated by Arthroscopic Partial Repair.

BACKGROUND: Previous studies have shown good clinical outcomes in patients with irreparable large or massive rotator cuff tears treated using arthroscopic partial repair (APR); however, few studies have evaluated both functional and structural outcomes in these patients. PURPOSE: To evaluate both functional and structural outcomes in patients with large or massive rotator cuff tears treated using APR. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Between March 2009 and November 2016, a total of 30 patients underwent APR because of the irreparability of their large or massive rotator cuff tears during surgery. Of these patients, 24 completed the minimum 24-month follow-up (mean, 61.8 ± 27.1 months; range, 24-112 months) and were included in this study. Functional outcome measures included the Japanese Orthopaedic Association (JOA) and University of California Los Angeles (UCLA) scores and the visual analog scale for pain. Structural outcome measures comprised preoperative fatty degeneration, mediolateral tear size, residual tendon attachment area, and glenohumeral (GH) arthritic changes evaluated on magnetic resonance imaging scans or plain radiographs before and after surgery. Functional and structural outcomes were evaluated preoperatively, at 3 months postoperatively, and at the final follow-up. RESULTS: The JOA scores for all patients significantly improved from 67.9 ± 11.3 preoperatively to 85.4 ± 15.6 postoperatively (P < .0001). Similarly, the UCLA scores significantly improved from 15.8 ± 4.20 preoperatively to 29 ± 6.69 at final follow-up postoperatively (P < .0001). The mediolateral tear size were significantly decreased at 3 months postoperatively (P < .001) and at the final follow-up (P < .001). Compared with preoperative scores, the novel score evaluating the residual tendon attachment area improved from 3.08 ± 0.46 to 3.54 ± 0.41 (P < .001) after surgery overall, although it significantly deteriorated from 3 months postoperatively to the final follow-up. GH osteoarthritis progressed in 6 patients (25%). Patients who developed osteoarthritis had lower JOA and UCLA scores than did those who did not (JOA, P = .010; UCLA, P = .037). CONCLUSION: In irreparable large or massive rotator cuff tears treated using APR, functional outcome improved after surgery. Although the residual tendon attachment area improved, functional outcome after APR corresponded to the GH alterations at the midterm follow-up. Longer-term follow-up is needed to further elucidate the effect of APR on clinical outcomes in these patients.

Clinical outcome in patients with hand lesions associated with complex regional pain syndrome after arthroscopic rotator cuff repair.

BACKGROUND: Complex regional pain syndrome (CRPS)-related hand lesions are one of the complications following arthroscopic rotator cuff repair (ARCR). This study aimed to investigate the clinical outcomes of patients with CRPS-related hand lesions following ARCR. METHODS: Altogether, 103 patients with ARCR were included in this study (mean age, 63.6±8.2 years; 66 males and 37 females; follow-up period, preoperative to 12 months postoperative). Clinical assessment included the Japanese Orthopaedic Association (JOA) score, University of California, Los Angeles (UCLA) score, Constant score, 36-item short form health survey (SF-36) score, and Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) score from preoperative to 12 months postoperatively. The patients were either assigned to the CRPS group or non-CRPS group depending on CRPS diagnosis until the final follow-up, and clinical outcomes were then compared between the groups. RESULTS: Of 103 patients, 20 (19.4%) had CRPS-related hand lesions that developed entirely within 2 months postoperatively. Both groups showed significant improvement in JOA, UCLA, and Constant scores preoperatively to 12 months postoperatively (P<0.001). Comparisons between the two groups were not significantly different, except for SF-36 "general health perception" (P<0.05) at 12 months postoperatively. At final follow-up, three patients had residual CRPS-related hand lesions with limited range of motion and finger edema. CONCLUSIONS: CRPS-related hand lesions developed in 19.4% of patients following ARCR. Shoulder or upper-limb function improved in most cases at 12 months, with satisfactory SF-36 patient-based evaluation results. Patients with residual CRPS-related hand lesions at the last follow-up require long-term follow-up.

Saphenous Nerve Entrapment Neuropathy After Closed Tibial Fracture: A Case Report.

CASE: A 43-year-old man who underwent intramedullary nailing for a closed tibial fracture developed saphenous nerve entrapment neuropathy. He developed severe medial leg pain, which was worse on walking or standing, 2 years postoperatively. Surgical neurolysis resulted in complete pain relief and functional recovery of the limb without recurrence of symptoms. CONCLUSION: Clinicians should consider several etiologies in the diagnostic evaluation of a patient with chronic pain after limb trauma. If a patient complains of lower extremity pain after intramedullary fixation of closed fractures of the tibial shaft, the possibility of saphenous nerve entrapment neuropathy should be considered.

Combination of risk factors affecting retear after arthroscopic rotator cuff repair: a decision tree analysis.

BACKGROUND: Several risk factors for postoperative retear after arthroscopic rotator cuff repair (ARCR) have been cited in a large number of reports; various combinations of these seem to be present in the clinical setting. PURPOSE: Using a combination model for decision tree analysis, we aimed to investigate the combination of risk factors that affect postoperative retear the most. METHODS: A total of 286 patients who underwent magnetic resonance (MR) imaging at 6 months after surgery were included in this study. Based on the structural integrity of the MR images taken 6 months after surgery, the patients were divided into a healed group (intact tendon, 254 patients) and a retear group (ruptured tendon, 32 patients). Using univariate and decision tree analyses, we selected a combination of 11 risk factors that drastically affected postoperative retear. RESULTS: The mean age was 64.9 ± 7.1 years, and the mean symptom duration was 9.7 ± 11.6 months. The tear was small/medium in 177 patients and large/massive in 109 patients. The technique for surgical repair was single row in 42 patients, double row in 60 patients, and suture bridging in 216 patients. On univariate analysis, both groups had significant differences in the anteroposterior (AP) tear size (P < .0001), mediolateral tear size (P < .0001), hyperlipidemia (P = .0178), global fatty degeneration index (P < .0001), supraspinatus fatty degeneration stage (P < .0001), and critical shoulder angle (CSA) (P = .0015). All of these 5 risk factors, except for mediolateral tear size, were selected as candidates for the decision tree analysis. Eight combination patterns were determined to have prediction probabilities that ranged from 4.3% to 86.1%. In particular, the combination of an AP tear size of ≥40 mm, hyperlipidemia, and a CSA of ≥37° affected retear after ARCR the most. CONCLUSIONS: Decision tree analysis lead to the extraction of different retear factor combinations, which were divided into 5 retear groups. The worst combination was of AP tear size ≥40 mm, hyperlipidemia, and CSA ≥37°, and the prediction probability of this combination was 86.2%. Therefore, our data may offer a new index for the prediction of retear after ARCR.

Clinical results of conservative management in patients with full-thickness rotator cuff tear: a meta-analysis.

BACKGROUND: Several systematic reviews have reported on the conservative treatment of full-thickness rotator cuff tears; however, clinical results of this treatment still remain determined. METHODS: PubMed, Cochrane Library, PEDro, and CINAHL databases were systematically searched for randomized clinical trials and observational studies. Two independent researchers reviewed a total of 2,981 articles, 28 of which met the criteria for inclusion in the study. Clinical outcome measures included Constant score, visual analog scale score for pain, range of motion, and short-form 36 questionnaires. The meta-analysis used a linear mixed model weighted with the variance of the estimate. RESULTS: The meta-analysis showed a significant improvement after surgery. Pain score is 26.2 mm (1 month) to 26.4 mm (3 months), and 24.8 mm (12 months) (P<0.05); active abduction: 153.2º (2 months), 159.0º (6 months), 168.1º (12 months) (P<0.05); Constant score: 67.8 points (2 months) to 77.2 points (12 months) (P<0.05); short-form 36 questionnaires "vitality" section: 57.0 points (6 months) to 70.0 points (12 months) (P<0.05). CONCLUSIONS: Our data confirmed the effectiveness of conservative treatment in patients with full-thickness rotator cuff tears 12 months post-intervention. The results suggest that conservative treatment for patients with full-thickness rotator cuff tears should be the first line of treatment before considering surgery.

Editorial Commentary: Revision Surgery After Symptomatic Failed Arthroscopic Rotator Cuff Repair: What Factors Affect Primary Surgery?

Anteroposterior tear length, hyperlipidemia, and muscle fatty degeneration lead to retear after arthroscopic rotator cuff repair and to subsequent revision surgery. The challenge is to develop methods to prevent these adverse effects after surgery.

Preoperative hyaluronic acid injection modulates postoperative functional outcome in patients undergoing arthroscopic rotator cuff repair.

BACKGROUND: Arthroscopic rotator cuff repair (ARCR) generally yields acceptable clinical results. Hyaluronic acid (HA), a high-molecular-weight polysaccharide, is present in the extracellular matrix of soft connective tissue and synovial fluid, and its injection is known to significantly improve pain and clinical outcomes after rotator cuff injury. Some studies have described the role of HA injections as conservative therapy for rotator cuff tears. Since the subacromial bursa is believed to be the main source of shoulder pain in rotator cuff tears, subacromial injection is frequently used before surgery; however, its relationship with the clinical outcome after surgery remains unclarified. Therefore, we aimed to examine effects of preoperative subacromial HA injection on postoperative clinical outcome in patients with ARCR. METHODS: Ninety-eight patients were divided into a HA injection group and a non-injection group. The functional outcome measured was the University of California, Los Angeles (UCLA) score. Univariate analysis was performed to obtain variables with p values less than 0.1; we then used propensity score analysis, adjusting for pre- and post-operative confounding factors. RESULTS: The UCLA scores of all patients significantly improved 1 year postoperatively (PO) (p < 0.05). Subacromial HA injections were performed in patients with worse preoperative function. Univariate analysis showed significantly greater improvements in the injection group than in the non-injection group in terms of preoperative UCLA score, trauma, diabetes mellitus, UCLA score 3 months PO, abduction strength 4 months PO, and internal rotation (IR) strength 6 and 12 months PO. Propensity score analysis demonstrated that UCLA scores 3 months PO and IR strength 12 months PO in the injection group were significantly greater than those in the non-injection group. There were no significant differences in postoperative re-tear rates between the groups. In sub-analysis of the injection group, propensity scores showed that concurrent use of local anesthetics did not affect the data, suggesting that HA was effective. CONCLUSION: Subacromial injection was administered to patients with worse function before ARCR. Propensity score analysis successfully demonstrated that functional outcome after surgery was improved in patients who were administered this injection compared with patients who were not administered this injection before surgery.

Usefulness of Shoulder36 in rotator cuff tears: Comparison with Simple Shoulder Test.

BACKGROUND: In patients with rotator cuff tears, Shoulder36 (Sh36) was compared to the Simple Shoulder Test (SST) to determine a broader use of Sh36 worldwide. METHODS: Sh36, SST, "Constant score," and the Japanese Orthopaedic Association score (JOA) were used to evaluate 230 patients (male, 116; female, 114) during the first visit, analyzed by staff blinded to the study. Pearson's correlation coefficient was used for the statistical analysis. RESULTS: The correlation coefficient between the Constant score and each domain in Sh36 was as follows: r = 0.68 (vs. pain, p < 0.01); r = 0.69 (vs. range of motion, p < 0.01); r = 0.74 (vs. muscle strength, p < 0.01); r = 0.62 (vs. general health, p < 0.01); r = 0.66 (vs. ability of daily living, p < 0.01); and r = 0.65 (vs. ability for sports, p < 0.01). The correlation coefficient between the JOA and each domain in Sh36 was as follows: r = 0.76 (vs. pain, p < 0.01); r = 0.73 (vs. range of motion, p < 0.01); r = 0.78 (vs. muscle strength, p < 0.01); r = 0.68 (vs. general health, p < 0.01); r = 0.71 (vs. ability of daily living, p < 0.01); and r = 0.70 (vs. ability for sports, p < 0.01). The correlation coefficient between the SST and each domain in Sh36 was as follows: r = 0.73 (vs. pain, p < 0.01); r = 0.70 (vs. range of motion, p < 0.01); r = 0.75 (vs. muscle strength, p < 0.01); r = 0.67 (vs. general health, p < 0.01); r = 0.69 (vs. ability of daily living, p < 0.01); and r = 0.64 (vs. ability for sports, p < 0.01). CONCLUSION: A strong association exists between the SST and each domain in the Sh36, in patients with rotator cuff tears ( r = 0.64-0.73), suggesting the usefulness of Sh36 for patient-based scoring.

Effects of Estrogen-Deficient State on Rotator Cuff Healing.

BACKGROUND: Rotator cuff retears after surgical repair are a concern, despite advances in operative techniques, but few studies have investigated the effects of the estrogen-deficient state on tendon-to-bone healing at the repair site. PURPOSE: We evaluated the effect of the estrogen-deficient state on tendon-to-bone healing after rotator cuff repair in an ovariectomized rat model. STUDY DESIGN: Controlled laboratory study. METHODS: Female Sprague Dawley rats underwent detachment and immediate repair of the supraspinatus tendon. Surgery was performed in 24 rats at 4.5 weeks of age 17 weeks after ovariectomy (OVX group) and in 24 age-matched control rats without ovariectomy (control group). Animals were sacrificed at 2, 4, 8, and 12 weeks after surgery for biomechanical and histological evaluations of reattachment. Bone mineral density (BMD) at the insertion site and cancellous bone in the humeral head was assessed by micro-computed tomography. RESULTS: BMD was significantly lower both at the insertion site and in cancellous area in the OVX group than in the control group at weeks 2 to 12. Ultimate load to failure, ultimate stress, linear stiffness, and the Young modulus were significantly lower in the OVX group than in the control group at 2 and 4 weeks, but the difference was no longer significant at 8 and 12 weeks. At 2 and 4 weeks, relatively immature granulation tissue was observed in the OVX group compared with the control group. At 8 and 12 weeks after surgery, there were differences in the tendon-bone interface in the 2 groups: Direct insertion with well-established chondroid tissue was seen in the control group, and indirect insertion without chondroid tissue was seen in the OVX group. Consistently, the amount of chondroid tissue was greater and collagen organization was better in the control group than in the OVX group. Cells expressing cathepsin K were significantly more numerous both at the insertion site and in cancellous bone in the OVX group than in the control group. CONCLUSION: The estrogen-deficient state by ovariectomy, compared with control rats, led to decreased biomechanical properties and poor development of chondroid tissue that influenced the repair of the tendon insertion after surgery. CLINICAL RELEVANCE: Agents that modulate bone metabolism might improve tendon-to-bone healing in patients with an estrogen-deficient state, such as postmenopausal women who undergo rotator cuff surgery.