Recombinant Human Parathyroid Hormone Biocomposite Promotes Bone-to-Tendon Interface Healing by Enhancing Tenogenesis, Chondrogenesis, and Osteogenesis in a Rabbit Model of Chronic Rotator Cuff Tears.

PURPOSE: To investigate the effect of recombinant human parathyroid hormone (rhPTH) biocomposite on bone-to-tendon interface (BTI) healing for surgical repair of a chronic rotator cuff tear (RCT) model of rabbit, focusing on genetic, histologic, biomechanical and micro-computed tomography (CT) evaluations. METHODS: Sixty-four rabbits were equally assigned to the 4 groups: saline injection (group A), nanofiber sheet alone (group B), rhPTH-soaked nanofiber sheet (nanofiber sheet was soaked with rhPTH, group C), and rhPTH biocomposite (rhPTH permeated the nanofiber sheet by coaxial electrospinning, group D). The release kinetics of rhPTH (groups C and D) was examined for 6 weeks in vitro. Nanofiber scaffolds were implanted on the surface of the repair site 6 weeks after the induction of chronic RCT. Genetic and histologic analyses were conducted 4 weeks after surgery. Furthermore, genetic, histologic, biomechanical, micro-CT, and serologic analyses were performed 12 weeks after surgery. RESULTS: In vivo, group D showed the highest collagen type I alpha 1 (COL1A1), collagen type III alpha 1 (COL3A1), and bone morphogenetic protein 2 (BMP-2) messenger RNA (mRNA) expression levels (all P < .001) 4 weeks after surgery; however, there were no differences between groups at 12 weeks postsurgery. After 12 weeks postsurgery, group D showed better collagen fiber continuity and orientation, denser collagen fibers, more mature bone-to-tendon junction, and greater fibrocartilage layer formation compared with the other groups (all P < .05). Furthermore, group D showed the highest load-to-failure rate (28.9 ± 2.0 N/kg for group A, 30.1 ± 3.3 N/kg for group B, 39.7 ± 2.7 N/kg for group C, and 48.2 ± 4.5 N/kg for group D, P < .001) and micro-CT outcomes, including bone and tissue mineral density, and bone volume/total volume rate (all P < .001) at 12 weeks postsurgery. CONCLUSIONS: In comparison to rhPTH-soaked nanofiber sheet and the other control groups, rhPTH biocomposite effectively accelerated BTI healing by enhancing the mRNA expression levels of COL1A1, COL3A1, and BMP-2 at an early stage and achieving tenogenesis, chondrogenesis, and osteogenesis at 12 weeks after surgical repair of a chronic RCT model of rabbit. CLINICAL RELEVANCE: The present study might be a transitional study to demonstrate the efficacy of rhPTH biocomposites on BTI healing for surgical repair of chronic RCTs as an adaptable polymer biomaterial in humans.

Outcomes of arthroscopic single-row repair alone vs. repair with human dermal allograft patch augmentation in patients with large to massive, posterosuperior rotator cuff tears: a retrospective comparative study.

BACKGROUND: Large to massive rotator cuff tears (RCTs) affect shoulder functions profoundly with unmanageable disability without intervention. The retear rates with arthroscopic rotator cuff repair (ARCR) in these patients are abysmal. Patch augmentation has been credited for preventing retears, improving functions by increasing the strength, and acting as a bioconductive scaffold. This study aimed to assess the retear rates and compare the clinical and radiological outcomes between the ARCR with and without acellular human dermal allograft (HDA) augmentation. METHODS: This is a retrospective comparative study among patients diagnosed with large to massive, posterosuperior RCTs, operated between January 2020 and December 2021, including 36 patients (group I) with and 131 patients (group II) without HDA augmentation, with a mean follow-up of 20 (range, 12-35) months. The average age was 64 (range, 49-80) and 66 (range, 41-81) years in groups I and II, respectively. In group I, there were 16 male and 20 female patients, whereas in group II, there were 58 male and 73 female patients. RESULTS: The visual analog scale score improved to 1.1 ± 1.7 in group I and 2.1 ± 1.7 in group II (P = .005). There was a greater improvement in the University of California, Los Angeles shoulder score to 30.1 ± 4.2 in group I compared with 23.2 ± 3.9 in group II (P = .046). Forward flexion (degrees) improved from a mean of 103.2 ± 18.6 to 138.9 ± 23.5 in group I and from 106.4 ± 21.3 to 127.0 ± 19.5 in group II (P = .004). The acromiohumeral interval (mm) measured in anteroposterior radiographs increased to 8.4 ± 1.8 in group I and 8.2 ± 2.0 in group II (P = .006). The satisfaction after the procedure was 4.4 ± 0.6 in group I and 3.1 ± 1.1 in group II (P = .044). The retear rate in the HDA-augmented group was 5.6% as compared with 29.1% in the nonaugmented group, which was statistically significant (P = .007). There were no complications or adverse tissue reactions against HDA seen in any patients. CONCLUSION: In patients with large to massive, posterosuperior RCTs, patch augmentation with acellular HDA significantly averted the retears after ARCR without any graft-related complications. The augmentation also resulted in improved shoulder function and greater range of motion compared with the nonaugmented group.

Does timing influence rehabilitation outcomes in arthroscopic rotator cuff repair with biceps rerouting? a prospective randomized study.

BACKGROUND: Arthroscopic rotator cuff repair with biceps rerouting (ABR) has emerged as a reliable option for treating large posterosuperior rotator cuff tears (RCTs). This study aims to compare functional and structural outcomes of early vs. delayed motion rehabilitation protocols following ABR. METHODS: A total of 101 patients with semirigid, large, posterosuperior RCTs undergoing ABR were randomized into 2 groups: group I (early motion) with 53 patients (34 females, 19 males) and group II (delayed motion) with 48 patients (31 females, 17 males). In group I, the mean age was 63.9 years (range, 46-79), and in group II, it was 65.4 years (range, 43-78). The mean follow-up periods for group I and group II were 16.2 and 15.5 months, respectively. Preoperative and postoperative assessments were conducted at 3, 6, and 12 months, with structural integrity assessed with magnetic resonance imaging at a minimum follow-up of 12 months. Statistical analyses were performed to compare outcomes between the 2 groups. RESULTS: Both groups demonstrated significant improvements in visual analog scale score (group I: 4.0-1.6, group II: 3.7-1.4, P = .501), University of California-Los Angeles shoulder score (group I: 21.5-31.4, group II: 22.4-30.6, P = .331), and acromiohumeral interval (group I: 8.2 mm-9.1 mm, group II: 8.6 mm-9.5 mm, P = .412), with no statistically or clinically meaningful differences. Active range of movements (ROM) were not significantly different between groups, except for active forward flexion at 3 months (group I: 140.1°, group II: 119.2°, P = .006), that was not shown to be translated clinically into differences in function or healing between the groups in this study. Notably, retear rates were similar between groups (group I: 22.6%, group II: 20.8%, P = .826). CONCLUSION: This study's findings reveal no clinically discernible differences in active range of motion at 1-year follow-up between patients who underwent ABR for semirigid, large, posterosuperior RCTs and were assigned to either early or delayed motion protocols. Notably, the early motion group demonstrated a plateau in maximum range of movement improvement as early as 3 months postsurgery. Based on these results, implementing an early motion protocol is recommended as an effective approach in the postoperative rehabilitation following ABR.

Increased HbA1c Levels in Diabetics During the Postoperative 3-6 Months After Rotator Cuff Repair Correlated With Increased Retear Rates.

PURPOSE: To evaluate whether glycemic control affects the integrity of the repaired rotator cuff during the postoperative healing period after arthroscopic double-row suture bridge rotator cuff repair (RCR) METHODS: We retrospectively reviewed patients with diabetes mellitus (DM) who underwent arthroscopic double-row suture bridge RCR at our institution between March 2016 and November 2019. We included the patients who evaluated for serum glycosylated hemoglobin (HbA1c) levels within 1 month before and 3-6 months after surgery. Magnetic resonance imaging was conducted 6 months after surgery to evaluate the integrity of the repaired cuff tendon. Patients were categorized into two groups based on comparison between preoperative and postoperative HbA1c values: Group I (increased postoperative HbA1c) and Group D (same or decreased postoperative HbA1c). The correlation between preoperative/postoperative HbA1c, HbA1c increase/same or decrease (during the healing period), and post-RCR integrity was evaluated, including various demographic and radiologic factors. RESULTS: A total of 103 patients were analyzed, group I was 47, and group D was 56, respectively. The retear rate of 51.1% (24/47) in Group I was significantly higher than 14.3% (8/56) in Group D (P < .001). HbA1c levels measured 3-6 months after surgery (mean: 6.9; 95% CI: 6.6-7.3 vs mean: 6.5; 95% CI: 6.3-6.7, P = .034), and the proportion of group I and group D were significantly different (75%/25% vs 32.4%/67.6%, P < .001) between the retear and healing groups. Multivariable logistic regression analysis identified increased HbA1c as an independent risk factor for retear (odds ratio: 5.402; 95% CI: 2.072-14.086; P < .001). CONCLUSIONS: The glycemic control within 3-6 months after surgery when the healing process of the tendon was in progress had a significant effect on retear rate. In particular, the retear rate was higher when the HbA1c level increased at postoperative 3-6 months compared to before surgery. LEVEL OF EVIDENCE: Retrospective case-control comparative study, Level III.

Rotator cuff repairs with all-suture tape anchors: no difference in outcomes between with or without all-suture tape anchors.

PURPOSE: This study aimed at comparing the outcomes of medium- to large-sized rotator cuff repairs performed using the suture bridge technique either with or without tape-like sutures, and single row techniques with conventional sutures. METHODS: A total of 135 eligible patients with medium to large rotator cuff tears were identified and analyzed retrospectively, from 2017 to 2019. Only repairs using all-suture anchors were included in the study. Patients were divided into the following three groups: single-row (SR) repair (N = 50), standard double-row suture bridge (DRSB) repair with conventional sutures (N = 35), and DRSB with tape-like sutures (N = 50). The average postoperative follow-up period was 26.3 ± 9.8 months (range, 18-37). RESULTS: DRSB with tapes had the highest re-tear rate of 16% (8/50), but there was no significant difference with the re-tear rates observed in SR (8%, 4/50) and DRSB with conventional sutures (11.4%, 4/35) (n.s.). DRSB with tapes demonstrated higher rate of type 2 re-tears (10%) compared to type 1 re-tears (6%), but the other two groups showed either similar or higher rates of type 1 re-tears compared to that of type 2. Post-operative functional scores of the three groups improved significantly (all p < 0.05), but the differences between the groups were not statistically significant. CONCLUSIONS: No clinical difference in functional outcomes and re-tear rates were observed in DRSB with tapes when compared with SR and DRSB using the conventional sutures. Tape-like DRSB suture which was expected to be superior by its biomechanical advantage was clinically non-superior to conventional DRSB suture. There were no significant differences in VAS scores and UCLA scores. LEVEL OF EVIDENCE: Level III.

Anterior capsular reconstruction in irreparable subscapularis tear: human dermal allograft.

BACKGROUND: The irreparable subscapularis (SSc) tears pose an extremely difficult situation to manage, especially in the younger population. The anterior capsular reconstruction (ACR) with human dermal allograft (HDA) is an alternative to tendon transfer with sound biomechanical advantages and clinical outcomes. The purpose of this study was to evaluate the early clinical and radiologic outcomes of open ACR with HDA in patients with irreparable SSc tears. METHODS: Eighteen patients who had an open ACR with HDA for irreparable SSc tears between August 2020 and January 2022 were enrolled. There were 11 male and 7 female patients with a mean age of 63.7 years and a mean follow-up of 17 months (range, 12-28 months). The dominant side was affected in 10 patients. One of the 18 patients had reconstruction with single-layer HDA, 14 had double-layer HDA, and 3 had SSc augmentation over double-layer HDA. Clinical and radiologic outcomes were assessed and compared pre- and postoperatively. RESULTS: There was significant improvement in visual analog scale score from 6.6 ± 1.6 to 1.6 ± 1.5 (P < .001) and in the total University of California-Los Angeles shoulder score from 12.4 ± 4.3 to 29.0 ± 4.5 (P < .001). Forward flexion, abduction, and internal rotation (IR) increased by 28.6°, 32.5°, and 11.8°, respectively (P < .001). External rotation decreased by 6.4° (P = .020). There was notable improvement in IR strength (percentage of that of the opposite, normal side) from 66.0% ± 19.4% to 84.4% ± 22.3% (P = .008). The mean postoperative coracohumeral distance improved from 3.0 to 6.0 mm (P < .001), the anterior translation of the humeral head reduced from 1.5 to 0.5 mm (P = .210), and the acromiohumeral interval from 8.1 to 8.8 mm (P = .070). The patients' satisfaction at final follow-up was rated 4.1 of 5.0 (P < .001). Sixteen of 18 patients (88.9%) had the HDA healed at the glenoid and humeral side, and 2 (11.1%) had retear at the final follow-up. Among the 17 who had double-layer HDA, none showed any healing between the layers. CONCLUSION: This study showed that early significant and comprehensive improvement inclusive of pain relief, improvement in range of motion, IR strength, and reduction of anterosuperior translation was achievable by open ACR with HDA for irreparable SSc tear.

Subacromial notching after reverse total shoulder arthroplasty.

BACKGROUND: Scapular notching is a well-known postoperative complication of reverse total shoulder arthroplasty (RTSA). However, subacromial notching (SaN), a subacromial erosion caused by repeated abduction impingement after RTSA, has not been previously reported in a clinical setting. Therefore, this study aimed to assess the risk factors and functional outcomes of SaN after RTSA. METHODS: We retrospectively reviewed the medical records of 125 patients who underwent RTSA with the same design between March 2014 and May 2017 and had at least 2 years of follow-up. SaN was defined as subacromial erosion observed at the final follow-up but not on the X-ray 3 months after surgery. Radiologic parameters representing the patient's native anatomy and degrees of lateralization and/or distalization during surgery were evaluated using preoperative and 3 months postoperative X-rays. The visual analogue scale of pain, active range of motion, and American Shoulder and Elbow Surgeons score were assessed preoperatively and at the final follow-up to evaluate the functional outcomes of SaN. RESULTS: SaN occurred in 12.8% (16/125) of enrolled patients during the study period. Preoperative center of rotation-acromion distance (P = .009) and postoperative humerus lateralization offset, which evaluated the degree of lateralization after RTSA (P = .003), were risk factors for SaN. The preoperative center of rotation-acromion distance and postoperative humerus lateralization cutoff values were 14.0 mm and 19.0 mm, respectively. The visual analogue scale of pain (P = .01) and American Shoulder and Elbow Surgeons score (P = .04) at the final follow-up were significantly worse in patients with SaN. CONCLUSIONS: SaN might adversely affect postoperative clinical outcomes. As SaN correlated with patients' anatomical characteristics and degree of lateralization during RTSA, the implant's degree of lateralization should be adjusted according to the patient's own anatomical characteristics.

The correlation of the spinoglenoid ganglion cyst size with the electrophysiological alterations of suprascapular nerve and the rotator cuff muscle power.

BACKGROUND: Although various treatment options are available for spinoglenoid cyst, including conservative and surgical methods, there is no standard guideline for its surgical decompression. Thus, the purpose of the study was to correlate the size of the spinoglenoid notch ganglion cyst (GC) as revealed by magnetic resonance imaging (MRI) with electrophysiological alterations, muscle power, and pain severity, and to estimate a cut-off value of cyst size to perform a decompression. METHODS: Between January 2010 and January 2018, the patients with a GC at the spinoglenoid notch diagnosed on MRI, and who had a minimum follow-up of 2 years after the decompression were included. Maximum cyst diameter as measured on MRI was used for comparison. Electromyography (EMG) and nerve conduction velocity (NCV) studies were performed before the surgery. Peak torque deficit (PTD) percentage compared to opposite shoulder was calculated preoperatively and at 1 year after surgery. Pain severity was estimated using visual analogue scale (VAS) preoperatively. RESULTS: Ten (50%) of 20 patients with GC > 2.2 cm and 1 (5.9%) of 17 patients with GC < 2.2 cm showed EMG/NCV abnormalities (p = 0.019). There was a correlation between the cyst size and the positive EMG/NCV findings (Correlation coefficient (CC) = 0.535, p < 0.001). The preoperative peak torque deficit on the external rotation was correlated with the positive EMG/NCV findings (CC = 0.373, p = 0.021). The PTD was improved significantly at 1 year postoperatively in patients with a GC size >2.2 cm (p = 0.029). The cyst size was not related to the preoperative pain VAS and muscle power. CONCLUSIONS: The spinoglenoid cyst size >2.2 cm, but not pain severity or muscle power, correlates with the positive finding of EMG for compressive suprascapular neuropathy. The GC size >2.2 cm can be a reference to decide the need of decompression surgery. LEVEL OF EVIDENCE: IV, case series.

Long-term outcomes after humeral head replacement and total shoulder replacement for osteonecrosis of the humeral head: a mean follow-up of 8 years.

INTRODUCTION: The purpose of this study was to compare the outcomes and complications after humeral head replacement (HHR) and total shoulder replacement (TSR) in patients with osteonecrosis of the humeral head (ONHH). MATERIALS AND METHODS: Twenty-six patients who underwent shoulder replacement (13 HHRs and 13 TSRs) for nontraumatic ONHH were included. The mean follow-up period was 96.4 months. The visual analog scale (VAS) pain score, the University of California at Los Angeles (UCLA) score, the American Shoulder and Elbow Surgeon (ASES) score, and range of motion (ROM) at the final follow-up evaluation were used for the assessment of clinical outcomes. RESULTS: The mean VAS pain score, UCLA score, and ASES score showed significant improvement from 6.3, 11.6, and 35.0 before surgery to 2.2, 28.9, and 82.6 at the final follow-up evaluation (all p < 0.001). No significant differences regarding all clinical scores and ROMs were observed between the HHR group and the TSR group, except that a greater abduction angle was observed in the HHR group compared with the TSR group (123.1° versus 96.9°, p = 0.014). Two patients in the TSR group underwent multiple reoperations due to periprosthetic joint infection. No revision surgeries were performed for glenoid erosion following HHR or aseptic glenoid loosening following TSR. CONCLUSIONS: The findings of this study showed satisfactory clinical and radiological outcomes with implant longevity for both HHR and TSR in patients with nontraumatic ONHH. The HHR group had a greater abduction angle compared with the TSR group.

The scissors sign: a provocative test for detecting the leading-edge tear of subscapularis tendon: a diagnostic study.

BACKGROUND: Several physical examination tests and signs have been described to aid in the diagnosis of subscapularis (SSC) tear, but have limitations and variable sensitivity. This study aimed to introduce a novel test for detecting a leading-edge tear of the subscapularis (LETS), the most important tendinous portion of SSC. METHODS: A total of 233 patients who underwent arthroscopic repair for anterior and superior cuff tears between January 2018 to September 2019 were retrospectively reviewed. The provocative test we have coined as the "scissors sign" and the other related clinical tests (i.e., belly press, belly off, Napoleon, lift off, internal rotation lag, bear hug tests) were performed preoperatively. Whether the patient has a LETS or the complete tear of the SSC (CTS) was confirmed by arthroscopic findings. Sensitivity, specificity, and areas under the receiver operating characteristic curve were calculated for each test. RESULTS: In patients who had LETS with or without supraspinatus tear, the scissors sign showed the highest sensitivity (91.4%) with a specificity of 81.6%, positive predictive value (PPV) of 80.2%, and negative predictive value (NPV) of 92.1%. In patients with isolated LETS, the scissors sign also showed the highest sensitivity (90.3%) with a specificity of 81.6%, PPV of 57.1%, and NPV of 96.8%. The scissors sign for the complete tear of the subscapularis (CTS) with or without supraspinatus tear and the isolated CTS had a sensitivity of 73.1 and 75%, respectively. CONCLUSIONS: The scissors sign is a novel provocative test that can be helpful in the diagnosis of subscapularis tears, especially LETS, with its high sensitivity and diagnostic accuracy. In combination with other tests, the scissors sign will be a good screening tool.

Retear After Arthroscopic Rotator Cuff Repair Results in Functional Outcome Deterioration Over Time.

PURPOSE: This study aimed to evaluate the effect of retear on long-term functional outcomes and glenohumeral joint osteoarthritis (OA) progression after arthroscopic rotator cuff repair (ASRCR). METHODS: We retrospectively reviewed 201 patients who underwent ASRCR and were followed up for at least 5 years. Rotator cuff tendon structural integrity was evaluated using magnetic resonance imaging and/or ultrasonography. Pain, active range of motion, and the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) were evaluated for functional outcomes. To evaluate deterioration over time, the minimal clinically important difference value of pain and ASES were used. RESULTS: The mean follow-up period was 8.6 ± 2.2 years and overall retear rate was 21.4%. OA progression was strongly associated with retear (odds ratio 5.1, P < .001). Functional outcomes at the 2-year postoperative follow-up significantly improved compared to the preoperative status (all P < .017), regardless of retear. However, the retear group presented worse functional outcomes at the final follow-up (pain: 3.1 ± 2.6; ASES: 72.0 ± 17.4) than at the 2-year postoperative follow-up (pain: 1.2 ± 2.3, P = .014; ASES: 91.1 ± 9.9, P= .015) than the healed tendon group at final follow-up (pain: .6 ± 1.7; P < .001; ASES 95.5 ± 11.8; P < .001). The time for deterioration of pain (healed group vs. retear group: 5.5 ± 0.5 vs. 10.6 ± 0.4 years; P < .001) and ASES (healed group vs. retear group: 7.5 ± 0.5 vs. 12.8 ± 0.2 years; P < .001) decreased in the retear group. CONCLUSIONS: The functional status improved after ASRCR in short- and long-term follow-up, regardless of retear. However, retear was strongly associated with OA progression, and long-term functional outcomes deteriorated over time in retear cases, which was not observed during short-term follow-up. STUDY DESIGN: III, retrospective cohort study.

Allogeneic Dermal Fibroblasts Improve Tendon-to-Bone Healing in a Rabbit Model of Chronic Rotator Cuff Tear Compared With Platelet-Rich Plasma.

PURPOSE: To compare the effects of allogeneic dermal fibroblasts (ADFs) and platelet-rich plasma (PRP) on tendon-to-bone healing in a rabbit model of chronic rotator cuff tear. METHODS: Thirty-two rabbits were divided into 4 groups (8 per group). In 2 groups, the supraspinatus tendon was detached and was left as such for 6 weeks. At 6 weeks after creating the tear model, we performed transosseous repair with 5 × 106 ADFs plus fibrin injection in the left shoulder and PRP plus fibrin in the right shoulder. The relative expression of the COL1, COL3, BMP2, SCX, SOX9, and ACAN genes was assessed at 4 weeks (group A) and 12 weeks (group B) after repair. Histologic and biomechanical evaluations of tendon-to-bone healing at 12 weeks were performed with ADF injection in both shoulders in group C and PRP injection in group D. RESULTS: At 4 weeks, COL1 and BMP2 messenger RNA expression was higher in ADF-injected shoulders (1.6 ± 0.8 and 1.0 ± 0.3, respectively) than in PRP-injected shoulders (1.0 ± 0.3 and 0.6 ± 0.3, respectively) (P = .019 and P = .013, respectively); there were no differences in all genes in ADF- and PRP-injected shoulders at 12 weeks (P > .05). Collagen continuity, orientation, and maturation of the tendon-to-bone interface were better in group C than in group D (P = .024, P = .012, and P = .013, respectively) at 12 weeks, and mean load to failure was 37.4 ± 6.2 N/kg and 24.4 ± 5.2 N/kg in group C and group D, respectively (P = .015). CONCLUSIONS: ADFs caused higher COL1 and BMP2 expression than PRP at 4 weeks and showed better histologic and biomechanical findings at 12 weeks after rotator cuff repair of the rabbit model. ADFs enhanced healing better than PRP in the rabbit model. CLINICAL RELEVANCE: This study could serve as a transitional study to show the effectiveness of ADFs in achieving tendon-to-bone healing after repair of chronic rotator cuff tears in humans.

Perianchor cyst formation in all-suture anchor after rotator cuff repair: an evaluation of anchor insertion angle.

BACKGROUND: Previous studies reported that micromotion after all-suture anchor implantation can lead to perianchor cyst formation (PCF), leading to risk of retear. Modifying anchor insertion angle (AIA) is known to be one of the various ways to increase anchor stability. However, there currently are few studies that assess the correlation between PCF, AIA, and retear. PURPOSE: To find the correlation of PCF and the repaired rotator cuff integrity with AIA after arthroscopic double-row suture-bridge rotator cuff repair (RCR) using an all-suture anchor in the medial row. METHODS: A total of 218 patients who underwent arthroscopic double-row suture-bridge RCR were retrospectively reviewed. All patients underwent RCR using all-suture anchors and polyether ketone anchors in the medial and lateral rows, respectively. Magnetic resonance imaging was conducted 6 months after the surgery to evaluate PCF, AIA, and integrity of the repaired cuff. The all-suture anchor insertion angle in the medial row was measured with reference to the greater tuberosity to assess the relationship between the AIA and PCF. The correlations between PCF, AIA, and post-RCR integrity were evaluated including various demographic and radiologic factors. RESULTS: Perianchor cysts were formed in 93 patients (42.7%). Mediolateral tear size (2.1 ± 1.2 cm vs. 1.7 ± 0.9 cm, P = .034) and AIA (61.9° ± 15.2° vs. 68.4° ± 13.0°, P = .001) were significantly different between patient groups with and without perianchor cysts. Multivariate logistic regression analysis showed that mediolateral tear size (odds ratio [OR] 1.318, 95% confidence interval [CI] 1.008-1.724; P = .043) and AIA (OR 0.967, 95% CI 0.947-0.988; P = .002) were independent risk factors for PCF. In addition, PCF was observed more frequently (69.6% vs. 32.1%, P < .001) and the AIA was lower (59.4° ± 13.7° vs. 67.8° ± 13.8°, P < .001) in the retear group than in the healed group. CONCLUSIONS: Perianchor cysts were formed in approximately 40% of patients who underwent arthroscopic double-row suture-bridge RCR using all-suture anchors. Low AIA and large mediolateral tear size were risk factors for PCF. Moreover, perianchor cyst and AIA were correlated with post-RCR integrity. Therefore, a high AIA must be carefully considered when all-suture anchors are inserted into the medial row when performing RCR.

Medialized vs. lateralized humeral implant in reverse total shoulder arthroplasty: the comparison of outcomes in pseudoparalysis with massive rotator cuff tear.

BACKGROUND: With the increasing use of lateralized humeral implants in reverse total shoulder arthroplasty (RTSA), it is still unclear whether this design will be as advantageous as the medialized humeral implants in the setting of pseudoparalysis (PP). METHODS: A total of 51 eligible RTSA cases for PP signs due to massive rotator cuff deficiency were selected for the retrospective review. Twenty-five patients were allocated to group L in which the isolated humeral side lateralization was performed (neck-shaft angle of 145°), and 26 patients were allocated to group M (neck-shaft angle of 155°). Pre- and postoperative radiologic measurements including critical shoulder angle, acromiohumeral distance (AHD), lateral humeral offset (LHO), and deltoid wrapping offset (DWO), as well as range of motion (ROM) and clinical outcome scores, were compared. The mean age was 71.0 ± 6.5 years for group L and 70.3 ± 7.0 years for group M, and the overall mean follow-up period was 49.0 ± 13.5 months (range, 25.7-68.9). RESULTS: The preoperative radiologic measurements were similar, but the postoperative LHO and DWO were significantly larger for group L, whereas the postoperative AHD was larger for group M compared with group L, with the values being 39.8 ± 9.7 mm and 33.6 ± 10.4 mm, respectively (P = .034). For the ROM, active forward elevation did improve significantly for both, starting preoperatively with the active ranges of 39° ± 19° (passively 153° ± 24°) for group L and 42° ± 18° (passively 156° ± 11°) for group M-the final postoperative active ranges being 142° ± 16° and 133° ± 33°, respectively, without significant difference between the groups (P = .426). The postoperative recovery of PP for group L was 100% (25 of 25), whereas for group M, it was 96.2% (25 of 26). The final visual analog scale (VAS) scores and University of California Los Angeles (UCLA) shoulder scores improved significantly for both groups, but the differences between the groups at the final assessments were insignificant. The 4 complications were periprosthetic fracture, acromial stress fracture, periprosthetic joint infection, and neuropraxia, all of which were in group M, and scapular notching with higher grades were more prevalent for group M (26.9%, 7 of 26). CONCLUSIONS: With RTSA, good outcomes and recovery were achieved in most cases of PP. The postoperative active elevation range and functional outcomes were not affected by medialization or lateralization of the humeral implant. Earlier recovery of motion was observed with the lateralized group, but no significant differences were seen in the final ROM between the groups.

Three-dimensionally printed recombinant human parathyroid hormone-soaked nanofiber sheet accelerates tendon-to-bone healing in a rabbit model of chronic rotator cuff tear.

BACKGROUND: Recombinant human parathyroid hormone (rhPTH) promotes tendon-to-bone healing in humans and animals with rotator cuff tear (RCT). However, problems regarding repeated systemic rhPTH injections in humans exist. This study was conducted to evaluate the effect of topical rhPTH administration using 3-dimensionally (3D) printed nanofiber sheets on tendon-to-bone healing in a rabbit RCT model compared to that of direct topical rhPTH administration. METHODS: Eighty rabbits were randomly assigned to 5 groups (n = 16 each). To create the chronic RCT model, we induced complete supraspinatus tendon tears in both shoulders and left them untreated for 6 weeks. All transected tendons were repaired in a transosseous manner with saline injection in group A, hyaluronic acid (HA) injection in group B, 3D-printed nanofiber sheet fixation in group C, rhPTH and HA injection in group D, and 3D-printed rhPTH- and HA-soaked nanofiber sheet fixation in group E. Genetic (messenger RNA expression evaluation) and histologic evaluations (hematoxylin and eosin and Masson trichrome staining) were performed in half of the rabbits at 4 weeks postrepair. Genetic, histologic, and biomechanical evaluations (mode of tear and load to failure) were performed in the remaining rabbits at 12 weeks. RESULTS: For genetic evaluation, group E showed a higher collagen type I alpha 1 expression level than did the other groups (P = .008) at 4 weeks. However, its expression level was downregulated, and there was no difference at 12 weeks. For histologic evaluation, group E showed greater collagen fiber continuity, denser collagen fibers, and more mature tendon-to-bone junction than did the other groups (P = .001, P = .001, and P = .003, respectively) at 12 weeks. For biomechanical evaluation, group E showed a higher load-to-failure rate than did the other groups (P < .001) at 12 weeks. CONCLUSION: Three-dimensionally printed rhPTH-soaked nanofiber sheet fixation can promote tendon-to-bone healing of chronic RCT.

Quantitative magnetic resonance imaging assessment of the infraspinatus and teres minor in massive rotator cuff tear and its significance in clinical outcome after rotator cuff repair.

BACKGROUND: Teres minor (TM) muscle hypertrophy in large to massive rotator cuff tears (RCTs) has been considered a compensatory change to atrophy of the infraspinatus (ISP). However, few reports have assessed its relation to the prognosis after rotator cuff repair. METHODS: A total of 139 patients who underwent arthroscopic repair of large to massive RCTs involving the ISP between January 2013 and December 2015 were retrospectively investigated. Occupational ratios of the ISP (OR_ISP) and TM (OR_TM) were measured by sagittal magnetic resonance imaging (MRI). Rotator cuff healing was evaluated by MRI 1 year postoperatively, and functional outcomes using the Simple Shoulder Test (SST) and Constant score and external rotator (ER) strength by isokinetic muscle performance test (IMPT) were measured. RESULTS: A total of 116 patients completed the MRI and IMPT at 1 year postoperatively, and functional scores were measured at least 2 years postoperatively. Of these, the repaired tendon had not healed in 34 patients (29%). There was a highly negative correlation between OR_ISP and OR_TM both pre- and postoperatively (Pearson correlation = -0.52 and -0.54, respectively). Preoperative OR_ISP was significantly higher in the healed than in the healing failure group (0.47 ± 0.10 vs. 0.41 ± 0.12, P = .02); however, postoperative OR_ISP and pre- and postoperative OR_TM were not. The preoperative OR_ISP cutoff value for healing was 0.46. For functional outcomes, only postoperative OR_ISP showed a statistical correlation with SST, Constant score (P = .04 and .03, respectively), and ER strength (P = .02). CONCLUSION: TM muscle hypertrophy in large to massive RCT appears to be a compensatory change in the progression of atrophy of the ISP muscle and was not a significant indicator of either better healing of the repaired rotator cuff tendon or better function. Only preoperative OR_ISP was an independent prognostic factor affecting rotator cuff healing after repair of large to massive RCTs.

Biceps Rerouting for Semirigid Large-to-Massive Rotator Cuff Tears.

PURPOSE: To compare clinical and radiographic results of arthroscopic rotator cuff repair (ARCR) with biceps rerouting (BR) and those of conventional repair for semirigid, large-to-massive rotator cuff tear. METHODS: We prospectively collected data of 111 patients who underwent either ARCR + BR (n = 59, group 1) or only ARCR (n = 52, group 2) for semirigid, large-to-massive rotator cuff tear between January 2016 and December 2018. We comparatively analyzed both groups with respect to preoperative factors including concomitant lesions of the long head of the biceps tendon (LHBT). Univariate logistic regression analysis was performed to identify predictive variables for occurrence of retear after ARCR + BR. RESULTS: Mean age of groups 1 and 2 were 62.8 and 63.7 years, respectively (P = .484). Mean follow-up period in groups 1 and 2 were 15.1 and 25.1 months, respectively (P = .102). Mean range of motion and functional scores improved significantly (P < .05) and comparably (P > .05) in both groups. In total, 11 (18.6%) and 25 (48.1%) patients from groups 1 and 2, respectively, showed retear of the repaired rotator cuff at final follow-up (P < .01). Of 45 group 1 patients who showed less than 50% partial tearing of the LHBT preoperatively, 6 (13.3%) experienced retear. Comparatively, of 14 patients with partial tearing involving more than 50% of the LHBT, 5 (35.7%) suffered postoperative retear. If the patients had partial tear involving more than 50% of LHBT preoperatively, the odds ratio (OR) to have retear was 4.222 (P = .037). Wider (OR, 1.445, P = .047) and thinner (OR, 0.166, P = .019) LHBT were the prognostic factors to have retear. Three (5.1%) group 1 patients showed the Popeye deformity at final follow-up. CONCLUSIONS: ARCR + BR for semirigid, large-to-massive rotator cuff tears effectively improved clinical and structural outcomes as also shown in the conventional repairs. However, the retear rate was significantly lower in patients who underwent ARCR + BR than those treated conventionally. Partial tearing involving more than 50% of the LHBT and wide and/or thin tendon morphology were significant risk factors for postoperative occurrence of retear. LEVEL OF EVIDENCE: Level III, retrospective therapeutic comparative trial.

Retracted Rotator Cuff Repairs Heal With Disorganized Fibrogenesis Without Affecting Biomechanical Properties: A Comparative Animal Model Study.

PURPOSE: To determine the differences in the scar tissue formation during the healing of the repaired retracted cuff tear from that of the nonretracted tear. METHODS: Eighteen right rabbit shoulders received a 1-cm transverse cuff incision over the footprint to simulate "nonretracted cuff tears" before the transosseous repairs (group A). A 1-cm tendinous portion was excised from 18 left shoulders to create defects to simulate "retracted cuff tears" before repairing the defects (group B). At week 12 postrepair, 20 and 16 shoulders underwent histologic and biomechanical analyses, respectively. Eight shoulders were used as a control group for biomechanical analyses. RESULTS: All specimens showed good healing and continuity of the repaired tendons. At low magnification, fibrous tissue firmly held the tendon-to-bone junctions in group A; however, all specimens in group B showed medially retracted tendons with fibrous tissue continuity between the tendon stumps and footprints. At medium magnification, more irregular collagen fiber orientation was observed in group B. Polarized light microscopy showed fibrous tissue continuity with medially retracted tendons in group B. When we quantified collagen fiber orientation using ImageJ software, group B had inferior grayscale measurements when compared with group A (P = .001). At week 12, no statistical differences existed in mean loads-to-failure at the repair sites between the groups (P = .783). CONCLUSIONS: In the nonretracted cuff tears, fibrous tissue bound the tendon-to-bone junction with healing. After the healing of the retracted cuff tears, continuity of nontendinous tissue was observed adjacent to the medially retracted tendon, which comprised more disorganized immature fibrous tissue than that in the nonretracted cuff tears. CLINICAL RELEVANCE: Unlike the healing of nonretracted rotator cuff tear, repairing of the "retracted" tendon end of cuff tear still resulted in retraction of the tendon back to its original position but being held down with fibrous tissue to the footprint.

Hematologic Expression After Shoulder Surgery: Normalization Curve of Serum Inflammatory Markers.

PURPOSE: To determine the normalization curves of the serologic markers including white blood cell (WBC) count, WBC differential for segmented neutrophil (WBC seg.), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) after elective shoulder surgery and to investigate the hematologic differences among different shoulder surgeries. METHODS: Seventy-seven patients underwent arthroscopic rotator cuff repair (RCR, group A), 44 patients had open rotator cuff repair (group B), and 84 patients had shoulder arthroplasty (group C). Peak and normalization times of markers were determined at preoperatively, postoperative day (POD) 1 and 2 days, 1 and 2 weeks, 1, 2, 3, 6 months, and 1 year after surgery. The normal ranges of serologic markers were set to WBC 4000 to10,000/µL, WBC seg. 40% to 60%, ESR 0 to 20 mm/h, and CRP 0 to 0.8 mg/dL. RESULTS: Groups reached peak mean WBC count and WBC seg. on POD 1; mean WBC count started decreasing on POD 2 but was within normal value afterwards. Mean WBC seg. decreased to normal value at 1 month postoperatively in group A and B and at 2 months postoperatively in group C. Mean ESR peaked at 2 weeks postoperatively and normalized after 1 month in groups A and B and 3 months in group C. Mean CRP levels peaked on POD 2 in all groups and normalized within 2 weeks postoperatively in groups A and B and 1 month postoperatively in Group C. Normalized values of WBC count, WBC seg., and ESR varied widely. In contrast, CRP showed a consistent undetectable median, upper and lower quartile values less than 0.5 after normalization. Mean serum ESR and CRP values at peak time were significantly greater in group C than in the other groups (P = .001). CONCLUSIONS: The mean CRP levels were normalized at 2 weeks after rotator cuff repair and at 1 month after arthroplasties. Unlike the other serologic markers, CRP had consistent normalized values of median, upper and lower quartile afterwards. The peak levels of the inflammatory markers were greater and therefore normalized slower following more invasive surgery. LEVEL OF EVIDENCE: Level III, case control study.

Nontendinous healing after repairing of retracted rotator cuff tear: an imaging study.

BACKGROUND: Follow-up magnetic resonance imaging (MRI) after rotator cuff repair can sometimes demonstrate healing with nontendinous tissue that extends from the footprint to the retracted tendon end, which is inferred as fibrous tissue formation. The aim was to investigate this particular finding and its significance. METHODS: There were 494 eligible cases of healed supero-posterior medium-sized to massive rotator cuff repairs, after the exclusion of retears. A retrospective review was performed for the 3 groups that were divided according to their MRI appearances of healing: type I described the direct healing of the tendon to the footprint, whereas type II demonstrated the distinctive continuity of nontendinous tissue from the footprint to the retracted tendinous portion, and type III also showed a similar appearance but with obvious thinning of the tissue, without any evidence of defect confirmed on the routine outpatient ultrasonograph. RESULTS: Only 108 of 494 patients (21.9%) demonstrated type I healing, whereas the signs of nontendinous healing were evident for the rest, with the 116 patients (23.5%) being classified as type III with attenuation. Comparing the preoperative tendon retraction, 34.8% and 37.2% of the Patte stages 2 and 3, respectively, resulted in type III healing, which were significantly higher compared with that of stage 1 (15.3%, P < .001). Type III healing had the highest average preoperative Goutallier grades. The average postoperative visual analog scale and the American Shoulder and Elbow Surgeons (ASES) scores have improved significantly for all 3 groups (P < .05), with the ASES score being 86.1±15.9 for type I, 93.7±36.1 for type II, and 87.8±15.1 for type III without significant differences between the groups (P = .3). CONCLUSIONS: Only a fifth of the rotator cuff repairs led to a direct healing to the footprint, and the rest healed with MRI appearance of nontendinous tissue formation bridging the retracted tendinous portion and the footprint. These MRI appearances did not represent the true tendinous tissue formation between the torn end of the tendon and the bone after healing. Such appearances did not seem to affect the clinical outcomes.