Hidehiro Nakamura

Risk factors for shoulder re-dislocation after arthroscopic Bankart repair

BackgroundRecent studies have shown effective clinical results after arthroscopic Bankart repair (ABR) but have shown several risk factors for re-dislocation after surgery. We evaluated whether patients are at a risk for re-dislocation during the first year after ABR, examined the recurrence rate after ABR, and sought to identify new risk factors.MethodsWe performed ABR using bioabsorbable suture anchors in 102 consecutive shoulders (100 patients) with traumatic anterior shoulder instability. Average patient age and follow-up period was 25.7 (range, 14–40) years and 67.5 (range, 24.5–120) months, respectively. We evaluated re-dislocation after ABR using patient telephone interviews (follow-up rate, 100%) and correlated re-dislocation with several risk factors.ResultsRe-dislocation after ABR occurred in nine shoulders (8.8%), of which seven sustained re-injuries within the first year with the arm elevated at 90° and externally rotated at 90°. Of the remaining 93 shoulders without re-dislocation, 8 had re-injury under the same conditions within the first year. Thus, re-injury within the first year was a risk for re-dislocation after ABR (P < 0.001, chi-squared test). Using multivariate analysis, large Hill-Sachs lesions (odds ratio, 6.77, 95% CI, 1.24–53.6) and <4 suture anchors (odds ratio, 9.86, 95% CI, 2.00–76.4) were significant risk factors for re-dislocation after ABR.ConclusionsThe recurrence rate after ABR is not associated with the time elapsed and that repair strategies should augment the large humeral bone defect and use >3 anchors during ABR.

Effects of corticosteroids and hyaluronic acid on torn rotator cuff tendons in vitro and in rats.

Corticosteroids (CS) or hyaluronic acid (HA) is used in subacromial injection for the conservative treatment of rotator cuff tears (RCT); this study addresses the question of how CS and HA affect the tendon tissue and fibroblasts in vitro and in rats. Cell proliferation assays were performed in human tendon fibroblasts from RCT. Rats underwent surgery to create RCT, and the surgical sites were injected with CS or HA. The rotator cuff tendons were subjected to biomechanical testing, microscopic and immunohistochemical analysis of proliferating cell nuclear antigen (PCNA), and ultrastructural analysis. Cell proliferation was significantly decreased with CS in vitro (pu2009<u20090.05). Maximal load of CS‐treated tendons was significantly decreased compared with that of HA‐treated tendons (pu2009<u20090.05), as well as PCNA+ cells at 2 weeks (pu2009<u20090.05). Ultrastructural observations of the CS‐treated rats detected apoptosis of tendon fibroblasts 24u2009h after surgery. Histological and biomechanical data 4 weeks after surgery were not significant among the three groups. Unlike HA, CS caused cell death, and inhibition of the proliferation of tendon fibroblasts, leading to a delay of tendon healing involved and a subsequent decrease of biomechanical strength at the surgical site.

Effects of lidocaine on torn rotator cuff tendons.

We determined lidocaines action on torn rotator cuff tendons in vitro and in vivo. For in vitro experiments, cell proliferation and viability assays were performed using tenocytes derived from human torn rotator cuff tendons. For in vivo experiments, acute rotator cuff tears were made on the supraspinatus tendons in the rats’ bilateral shoulders; before closure, lidocaine was injected into the shoulder and saline into the contralateral shoulder (control). After sacrifice, the specimens underwent biomechanical testing or histological analysis at 24u2009h and at 2, 4, and 8 weeks after surgery. The extent of collagen organization and apoptosis were semi‐quantitatively evaluated using collagen picrosirius red staining. Apoptosis was examined using TUNEL staining and electron microscopy. Cell proliferation decreased dose‐dependently. After exposure to 0.1% lidocaine for 24u2009h, cell viability decreased. Two and 4 weeks after surgery, the ultimate load to failure decreased more in the lidocaine group than in the control group, with significantly reduced stiffness in the lidocaine group 2 weeks after surgery. Collagen organization significantly decreased in the lidocaine group by 4 weeks after surgery but returned to baseline at 8 weeks. TUNEL staining detected numerous apoptotic tenocytes at the torn tendon edge exposed to lidocaine 24u2009h after surgery; electron microscopy confirmed the condensed cell nuclei. These changes were not observed in controls. Lidocaine caused cytotoxicity to tenocytes under both conditions, decreased biomechanical properties, and induced apoptosis and delay of collagen organization in this model. Subacromial lidocaine injections in patients with rotator cuff tears should be performed carefully.

Factors Affecting Clinical Outcome in Patients With Structural Failure After Arthroscopic Rotator Cuff Repair

PURPOSEn(1) To compare clinical outcomes between patients with large or massive rotator cuff tears who have healed cuffs and patients with postoperative structural failure (retear after complete or partial repair) and (2) to identify factors associated with clinical outcomes in patients with postoperative structural failure.nnnMETHODSnWe conducted a retrospective study of consecutive patients with large or massive cuff tears who underwent arthroscopic repair at our institution between 2005 and 2012. On the basis of intraoperative findings and magnetic resonance imaging at final follow-up, the patients were divided into 3 groups: healed group, retear group (after complete repair), and partial-repair group. The outcome measures comprised the Japanese Orthopaedic Association (JOA) and University of California, Los Angeles (UCLA) scores; muscle strength; and range of motion. The tear length, tear width, muscle atrophy, and fatty degeneration were evaluated by preoperative and postoperative magnetic resonance imaging. The extent of tendon reattachment to the superior, middle, and inferior facets and the lesser tuberosity was examined on magnetic resonance images at final follow-up.nnnRESULTSnIn total, 74 patients (healed, 41; retear, 19; and partial repair, 14) were included in this study. The mean age was 63.8 ± 8.5 years, with a mean follow-up period of 3.6 ± 1.4 years. The postoperative JOA and UCLA scores significantly improved in all 3 groups, but the differences were not significant. In the retear and partial-repair groups, postoperative tendon preservation at the middle facet significantly affected the JOA and UCLA scores (Pxa0= .003 and Pxa0=xa0.014, respectively).nnnCONCLUSIONSnThe JOA and UCLA scores were significantly improved in patients with structural failure. Under these conditions, the only clinical factor that affected patient outcome was tendon healing at the middlexa0facet. Thus tendon preservation at the middle facet was a predictor of good clinical outcomes in patients who underwent arthroscopic rotator cuff repair of large or massive tears and had postoperative structural failure.nnnLEVEL OF EVIDENCEnLevel III, case-control study.

Effect of Preoperative Fatty Degeneration of the Rotator Cuff Muscles on the Clinical Outcome of Patients With Intact Tendons After Arthroscopic Rotator Cuff Repair of Large/Massive Cuff Tears

Background: Fatty degeneration of the rotator cuff muscles is associated not only with postoperative retear but also with postoperative muscle weakness; therefore, fatty changes in the muscles may affect the clinical outcome even in patients with these tears who have intact tendons after arthroscopic rotator cuff repair (ARCR). Purpose: To evaluate the effect of fatty infiltration on the clinical outcome in patients with intact tendons after arthroscopic repair of large/massive cuff tears. Study Design: Case-control study; Level of evidence, 3. Methods: One hundred fifty-five consecutive patients with large/massive rotator cuff tears underwent ARCR. Of these, 55 patients (mean ± SD age, 64.4 ± 9.1 years) in whom intact tendons after surgery were confirmed with magnetic resonance imaging at final follow-up (mean ± SD, 2.5 ± 1.4 years) were included in this study. Depending on their University of California Los Angeles (UCLA) score at the final follow-up, they were assigned to either the unsatisfactory group (score ≤27; n = 12) or the satisfactory group (score >27; n = 43). Various clinical parameters affecting the clinical outcome were examined through univariate and multivariate analyses. Results: The UCLA score of all patients significantly improved from 18.1 ± 4.4 points preoperatively to 29.8 ± 4.5 points postoperatively (P < .0001). The mean preoperative UCLA scores were not significantly different between the satisfactory and unsatisfactory groups (P = .39). Multivariate analysis showed that the preoperative Goutallier stages of the infraspinatus (odds ratio [OR], 8.87; 95% confidence interval [CI], 1.51-52.0; P = .016) and/or subscapularis (OR, 7.53; 95% CI, 1.58-35.9; P = .011) were significantly associated with outcome. Receiver operating characteristic curve analysis revealed a cutoff value of Goutallier stage 1 in both muscles, with area under the curve values of 0.79 (sensitivity 91% and specificity 51%) and 0.84 (sensitivity 100% and specificity 54%) in the infraspinatus and subscapularis, respectively. Conclusion: Preoperative fatty degeneration of the infraspinatus and/or subscapularis with Goutallier stage 2 or higher was significantly associated with worse outcome in patients with large/massive tears who had intact tendons after ARCR.

Hyaluronic Acid Accelerates Tendon-to-Bone Healing After Rotator Cuff Repair:

Background: There is growing evidence that the subacromial injection of hyaluronic acid (HA) is effective for pain relief in rotator cuff tears; however, its effect on tendon-to-bone healing remains unknown. Purpose: To examine the effect of HA on the chondrogenesis of mesenchymal stem cells (MSCs) in vitro and on tendon-to-bone healing in a rotator cuff repair model. Study Design: Controlled laboratory study. Methods: Bilateral complete tears of the infraspinatus tendon were made in rabbits and subsequently repaired. Before closure, 1 mL HA was applied to the repaired site, and phosphate-buffered saline was used in the opposite side as a control. Biomechanical, histological, and immunohistochemical analyses were performed at 4, 8, and 12 weeks after surgery. After euthanizing each animal, the bone marrow was isolated from the femoral bone in the same rabbits. Then, MSCs were cultured in media for chondrogenic differentiation, and the chondral pellet production and cartilage-related gene expression levels in the cells were examined at various concentrations of HA. Results: At 4 and 8 weeks after surgery, ultimate load-to-failure was significantly greater in the HA group than in the control group (45.61 ± 9.0 N vs 32.42 ± 9.4 N at 4 weeks, 90.7 ± 16.0 N vs 66.97 ± 10.0 N at 8 weeks; both P < .05) but not at 12 weeks after surgery (109.6 ± 40.2 N vs 108.1 ± 42.6 N, P > .05). Linear stiffness was not significant throughout the time point evaluation. The chondroid formation area at the tendon-bone interface stained by safranin O (control vs HA group) was 0.33% ± 0.7% versus 13.5% ± 12.3% at 4 weeks after surgery (P < .05) and 3.0% ± 5.9% versus 12.9% ± 12.9% at 8 weeks after surgery (P < .05), but there was no significant difference at 12 weeks after surgery. Maturity of collagen at the repaired site stained by PicroSirius Red (control vs HA group) was 16.2 ± 10.6 versus 43.5 ± 21.3 at 4 weeks after surgery (P < .05), but there were no significant differences at 8 and 12 weeks after surgery. MSCs were cultured in media for chondrogenic differentiation, and the chondral pellet production and cartilage-related gene expression levels in the cells were examined at various concentrations of HA. The number of CD44-positive cells (control vs HA group) was 8.3% ± 1.4% versus 26.2% ± 5.2% at 3 days after surgery (P < .05), 1.8% ± 1.1% versus 26.6% ± 11.6% at 4 weeks after surgery (P < .05), 0.6% ± 0.9% versus 0.5% ± 0.6% at 8 weeks after surgery (P > .05), and 1.8% ± 4.0% versus 5.4% ± 4.2% at 12 weeks after surgery (P > .05). Compared with the control group, HA significantly increased the volume of cartilaginous pellet produced by MSCs (0.0016 ± 0.0015 mm3 at 0 mg/mL of HA, 0.0041 ± 0.0023 mm3 at 1.0 mg/mL, and 0.0041 ± 0.0018 mm3 at 4.0 mg/mL), with increased mRNA expression (relative ratio to control) of type 2 collagen (1.34 ± 0.38), SOX9 (1.58 ± 0.31), and aggrecan (1.30 ± 0.22) genes in the pellet (P < .01). Conclusion: HA accelerated tendon-to-bone healing in the rotator cuff repair model, enhancing the biomechanical strength and increasing chondroid formation and tendon maturity at the tendon-bone interface. Based on the data of in vitro experiments, HA-activated MSCs may play a crucial role in the acceleration of tendon-to-bone healing. Clinical Relevance: The data suggest the relevance of clinical application of HA to accelerate tendon-to-bone healing. It may decrease the number of retears after surgery.

Hand lesion after arthroscopic rotator cuff repair: Association with complex regional pain syndrome

BACKGROUNDnIt is known that complex regional pain syndrome (CRPS) occurs after arthroscopic rotator cuff repair (ARCR); however, few studies have investigated this complication. Therefore, the purpose of the present study was to evaluate CRPS after ARCR.nnnMETHODSnA total of 182 patients who underwent ARCR were enrolled in this study. The average age of patients was 62.8xa0±xa010.0 years, with an average follow-up period of 21.5xa0±xa038.1 months. CRPS criteria outlined by the Ministry of Health, Labor, and Welfare study team for CRPS in Japan (MHLWJ) and International Association for the Study of Pain (IASP 2005) were utilized for diagnosis. There are two rating systems for the clinical purpose and research purpose in both criteria, respectively. Clinical outcomes, including Japanese Orthopedic Association (JOA) and University of California, Los Angeles scores, were evaluated using univariate and multivariate analysis.nnnRESULTSnCRPS exclusively occurred in the hand of the operated limb, developing within 3 months of surgery. Two or more of the following symptoms were noted in patients with the hand lesion associated with CRPS: edema (93.4%), restricted range of motion (83.4%), hyperalgesia (30.1%), paridrosis (20.4%), and atrophic change (12.2%). Under these conditions, the incidences of CRPS were 24.2% (44/182) when evaluated by the MHLWJ rating system for the clinical purpose; 11% (22/182) by the MHLWJ rating system for the research purpose; 6% (11/182) by the IASP 2005 for the clinical purpose; and 0.5% (1/182) by the IASP 2005 for the research purpose. Results of multivariate analysis demonstrated that Function in the JOA score was a risk factor for the development of CRPS after ARCR, when evaluated by a system for the clinical purpose of the MHLWJ.nnnCONCLUSIONnFollowing ARCR, CRPS-induced hand lesions occur more frequently than is generally believed, thereby suggesting that its impact on surgical outcomes should be clarified in the future.

Risk factors for retear of large/massive rotator cuff tears after arthroscopic surgery: an analysis of tearing patterns

BackgroundPrevious studies have evaluated the risk factors for retear of large/massive rotator cuff tears (RCTs) that were treated arthroscopically; however, most studies did not evaluate tear patterns. The present study hypothesized that postoperative risk factors are affected by the tearing patterns in large/massive cuff tears in patients undergoing arthroscopic rotator cuff repair (ARCR).MethodsOne hundred fifty patients with large/massive cuff tears underwent ARCR at our institution. Of these, 102 patients were enrolled in this study, with an average symptom duration of 36.3xa0±xa043.9xa0months and average age of 63.9xa0±xa09.4xa0years. According to the arthroscopic findings and magnetic resonance imaging (MRI), the 102 patients were divided into three groups based on the tendon location: anterosuperior tears (Nxa0=xa059, group AS), posteosuperior tears (Nxa0=xa021, group PS), and anteroposterior-extending tears (Nxa0=xa022, group APE). Functional outcome was evaluated preoperatively and postoperatively using the Japanese Orthopedic Association (JOA) score and the University of California, Los Angeles (UCLA) score. Retear was evaluated with MRI at a minimum of 1xa0year after surgery, using Sugaya’s classification; Types IV and V were considered postoperative retears. Factors affecting postoperative retear were examined with univariate and multivariate analyses.ResultsJOA/UCLA scores significantly improved postoperatively in the three groups (Pxa0<xa00.01 for all). Postoperative retear was noted in 26 of 102 patients (25.5%) in this series: 10 patients in group AS (16.9%), 9 in group PS (42.9%), and 7 in group APE (31.8%). The retear rate was significantly higher in group PS than in the other two groups (Pxa0=xa00.02). Multivariate analysis showed that decreased preoperative active external rotation range was a unique risk factor for postoperative retear in the PS and APE groups (95% confidence interval: 0.02–0.18, cut-off value: 25°, with an area under the curve of 0.90, Pxa0=xa00.0025).ConclusionsAlthough multivariate analysis failed to detect significant risk factor for retear in patients with anterosuperior large/massive cuff tears who undergo ARCR, it demonstrated that active external rotation less than 25° before surgery is a significant risk factor in those with posterosuperior large/massive tears. This study may help surgeons understand the results of arthroscopic surgery in patients with large/massive tears.