Subscapularis Repair in Reverse Total Shoulder Arthroplasty: Differences in Outcomes Based on Preoperative Quality of Subscapularis Tendon.

Purpose: This study examines the influence of preoperative fatty infiltration (FI) of the subscapularis tendon (SBS) on outcomes following reverse total shoulder arthroplasty (rTSA) with SBS repair. Methods: A cohort of 161 rTSA patients with SBS repair, followed for a mean of 45.3 months, was divided into three groups based on FI: Group A (intact upper and lower portions, n = 85), Group B (intact lower portions, n = 44), and Group C (fatty infiltrated in both portions, n = 32). The mean age was 74.5 years (range: 65-95). Results: Preoperative FI displayed significant disparity among the groups: Group A (1.18 ± 0.60), Group B (2.95 ± 0.56), and Group C (4.0 ± 0.00) (p < .001). Group A exhibited a more positive trend in activities of daily living, particularly in toileting ability (81% in Group A, 68% in Group B, and 72% in Group C), although without statistical significance (p = 0.220). Complication rates varied: Group A had seven acromial fractures (8%), three cases of instability (3%), and six instances of scapular notching (7%). Group B experienced four acromial fractures (9%) and four cases of scapular notching (9%), while Group C had only one case of scapular notching (3%) (p = 0.733). Conclusion: In cases characterized by favorable preoperative SBS quality, there was an elevation in functional internal rotation (IR) post-surgery, accompanied by an increased incidence of postoperative complications. Hence, careful consideration is advised when determining the necessity for SBS repair. Level of Evidence: Level III, retrospective comparative study.

The Effect of Combining Hyaluronic Acid and Human Dermal Fibroblasts on Tendon Healing.

BACKGROUND: The incidence of rotator cuff tears is rapidly increasing, and operative techniques for rotator cuff repair have been developed. However, the rates of postoperative retear remain high. PURPOSE/HYPOTHESIS: The purpose was to determine the effects of human dermal fibroblasts (HDFs) with hyaluronic acid (HA) on tendon-to-bone healing in a rabbit model of chronic rotator cuff tear injury. It was hypothesized that HA would enhance HDF proliferation and that a combination of HA and HDFs would produce a synergistic effect on the healing of repaired rotator cuff tendons of rabbits. STUDY DESIGN: Controlled laboratory study. METHODS: For in vitro study, HDFs were plated on a 24-well plate. After 1 day, 2 wells were designated as the test group and treated with 0.75% HA in phenol red-free Dulbecco's modified Eagle medium (DMEM). An other 2 wells served as control groups and were treated with the same volume of phenol red-free DMEM without HA. Each group was duplicated, resulting in a total of 4 wells, with 2 wells in each group for replication purposes. The cells were incubated for 24 hours, followed by 72-hour cultivation. Absorbance ratios at 96 and 24 hours were compared to evaluate cell proliferation. For the in vivo study, a total of 24 rabbits were randomly allocated to groups A, B, and C (n = 8 each). Supraspinatus tendons were detached bilaterally and left for 6 weeks to establish a chronic rotator tear model. Torn tendons were subsequently repaired using the following injections: group A, 0.5 × 106 HDFs with HA; group B, HA only; and group C, saline only. At 12 weeks after repair, biomechanical tests and histological evaluation were performed. RESULTS: In vitro study showed that HDF proliferation significantly increased with HA (HDFs with HA vs HDFs without HA; 3.96 ± 0.09 vs 2.53 ± 0.15; P < .01). In vivo, group A showed significantly higher load-to-failure values than the other groups (53.8 ± 6.9 N/kg for group A, 30.6 ± 6.4 N/kg for group B, and 24.3 ± 7.6 N/kg for group C; P < .001). Histological evaluation confirmed that group A showed higher collagen fiber density and better collagen fiber continuity, tendon-to-bone interface maturation, and nuclear shape than the other groups (all P < .05). CONCLUSION: This controlled laboratory study verified the potential of the combination of HDFs and HA in enhancing healing in a chronic rotator cuff tear rabbit model. CLINICAL RELEVANCE: A potential synergistic effect on rotator cuff tendon healing may be expected from a combination of HDFs and HA.

Arthroscopic transosseous anchorless rotator cuff repair reduces bone defects related to peri-implant cyst formation: a comparison with conventional suture anchors using propensity score matching.

BACKGROUND: The transosseous anchorless repair (ToR) technique was recently introduced to avoid suture anchor-related problems. While favorable outcomes of the ToR technique have been reported, no previous studies on peri-implant cyst formation with the ToR technique exist. Therefore, this study compared the clinical outcomes and prevalence of peri-implant cyst formation between the ToR technique and the conventional transosseous equivalent technique using suture anchors (SA). METHODS: Cases with arthroscopic rotator cuff repair (ARCR) between 2016 and 2018 treated with the double-row suture bridge technique were retrospectively reviewed. Patients were divided into ToR and SA groups. To compare clinical outcomes, 19 ToR and 57 SA cases without intraoperative implant failure were selected using propensity score matching (PSM). While intraoperative implant failure rate was analyzed before PSM, retear rate, peri-implant cyst formation rate, and functional outcomes were compared after PSM. RESULTS: The intraoperative implant failure rate (ToR, 8% vs. SA, 15.3%) and retear rate (ToR, 5.3% vs. SA, 19.3%) did not differ between the two groups (all P>0.05). However, peri-implant cysts were not observed in the ToR group, while they were observed in 16.7% of the SA group (P=0.008). Postoperative functional outcomes were not significantly different between the two groups (all P>0.05). CONCLUSIONS: The ToR technique produced comparable clinical outcomes to conventional techniques. Considering the prospect of potential additional surgeries, the absence of peri-implant cyst formation might be an advantage of ToR. Furthermore, ToR might reduce the medical costs related to suture anchors and, thereby, could be a useful option for ARCR. Level of evidence: III.

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.

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.

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.

Serum Vitamin D Level Correlations With Tissue Vitamin D Level and Muscle Performance Before and After Rotator Cuff Repair.

BACKGROUND: There is a lack of studies about serum and tissue vitamin D levels of the rotator cuff muscle on muscle power, fatty degeneration, and healing failure after rotator cuff repair (RCR). Furthermore, no studies have evaluated vitamin D receptor proteins in the rotator cuff that show a close association with serum vitamin D levels. PURPOSE: To evaluate the correlations between serum vitamin D and tissue vitamin D as well as perioperative variables of arthroscopic RCR. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: From March 2017 to October 2017, a total of 36 patients who underwent RCR were prospectively enrolled, and supraspinatus muscle tissue was obtained during surgery to analyze tissue vitamin D levels. Serum vitamin D levels were checked preoperatively and at 6 months and 1 year postoperatively. Tissue vitamin D levels were assessed using liquid chromatography, and the vitamin D receptor was measured by western blotting. Isokinetic muscle performance test (IMPT; peak torque and torque deficiency compared with the opposite shoulder) results and fatty degeneration of the rotator cuff using the Goutallier classification were assessed preoperatively and at 1 year after surgery. The American Shoulder and Elbow Surgeons score and Constant score were collected at 2 years after surgery. Healing failure of the repaired rotator cuff was analyzed by magnetic resonance imaging at 1 year after surgery. RESULTS: Overall, only three patients (8.3%) had serum vitamin D sufficiency (>20 ng/mL). Among 36 patients, 26 patients returned for their 1-year follow-up. Lower preoperative serum vitamin D levels resulted in lower serum vitamin D levels at 6 months and 1 year postoperatively (all P < .05). Lower preoperative and 1-year postoperative serum vitamin D levels resulted in more torque deficiency on the IMPT in abduction than higher preoperative and 1-year postoperative serum vitamin D levels (all P < .05). Tissue vitamin D levels had a strong correlation with preoperative serum vitamin D levels (P = .001). Lower tissue vitamin D levels were associated with lower peak torque on the IMPT in abduction (P = .043) and a tendency of lower peak torque on the IMPT in external rotation (P = .077) at 1 year postoperatively. There was no correlation between tissue and serum vitamin D levels and functional outcomes, fatty degeneration, and healing failure after surgery (all P > .05). The vitamin D receptor showed no correlation with any variables (all P > .05). CONCLUSION: Lower preoperative serum vitamin D levels had a strong correlation with lower tissue vitamin D levels and lower serum vitamin D levels at 1 year after surgery. Furthermore, the patients with lower serum vitamin D levels showed more weakness of muscle power perioperatively. The results of this study emphasized the association between vitamin D levels and rotator cuff muscle power.

Synovial Osteochondromatosis: Clinical Characteristics Unique to the Shoulder.

Background: Synovial osteochondromatosis (SOC) of the shoulder is a rare condition with unclear characteristics. This study evaluated the clinical features and postoperative functional outcomes of SOC of the shoulder that are distinct from SOC of other joints. Methods: The characteristics of 28 shoulders with SOC that underwent arthroscopy were retrospectively assessed. Ten shoulders (35.7%) had rotator cuff tears (RCTs) and underwent concomitant arthroscopic rotator cuff repair. The mean follow-up period was 83.6 months (range, 24-154 months). Demographic characteristics and loose bodies localized under arthroscopy were compared between cases with and without concomitant RCTs. Radiography, ultrasonography, or magnetic resonance imaging were performed preoperatively and postoperatively. Visual analog scale (VAS) scores for pain and satisfaction were evaluated for all cases, and functional scores were assessed in shoulders with concomitant RCTs. Results: The average age was 36.2 ± 15.6 years among patients without RCTs and 58.3 ± 7.2 years among patients with RCTs. Seven shoulders (7%) had osteoarthritis. Arthroscopy revealed loose bodies in multiple spaces, including the glenohumeral joint, subacromial (SA) space, and biceps tendon sheath. Overall, loose bodies were found in multiple spaces in 12 shoulders (42.9%). Loose bodies were found in the SA space only in 4 shoulders (22.2%) without RCTs and in 7 shoulders (70.0%) with RCTs. VAS for pain decreased significantly from 3.9 ± 2.3 to 1.1 ± 1.3 (p < 0.001). The functional scores increased significantly after arthroscopic management for patients with concurrent RCTs (all p < 0.05). Recurrence of SOC occurred in 3 of the 22 shoulders (13.6%) who underwent postoperative imaging, but no patient had a recurrent RCT. Conclusions: Pain relief and patient satisfaction were achieved via arthroscopic management. Unlike in other joints, loose bodies can occur simultaneously in several spaces in the shoulder, including the glenohumeral joint, SA space, and biceps tendon sheath. Early diagnosis of SOC of the SA space can help prevent osteoarthritis and RCT progression.

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.

Anteroposterior and Lateral Coverage of the Acromion: Prediction of the Rotator Cuff Tear and Tear Size.

Background: The aim of this study was to assess whether the anteroposterior coverage of the acromion reflecting acromial morphology affects the rotator cuff tear (RCT) and tear size, in addition to the lateral coverage. Methods: Medical records of 356 patients with RCTs, concentric osteoarthritis, and calcific tendinitis identified using three-dimensional computed tomography between January 2016 and December 2017 were retrospectively analyzed. The patients were divided into group A (those with RCTs) and group B (those with concentric osteoarthritis or calcific tendinitis). Subsequently, group A was subdivided into three categories according to the size of RCTs: small-to-medium, large, and massive. The lateral coverage was measured through the lateral acromial angle (LAA) and critical shoulder angle (CSA), whereas the anteroposterior coverage was measured via the acromial tilt (AT), acromiohumeral interval (AHI) in the sagittal view, and anteroposterior coverage index (APCI) as a new radiologic parameter. Results: Between groups A and B, CSA (34.5° ± 3.4° and 30.8° ± 3.4°, respectively), APCI (0.83 ± 0.10 and 0.75 ± 0.08, respectively), and AHI (6.3 ± 2.0 mm and 7.8 ± 1.8 mm, respectively) were significantly different (all p < 0.001), whereas LAA and AT did not show a significant difference between the groups (p = 0.089 and p = 0.665, respectively). The independent predictive radiologic parameters of the RCT were the CSA, APCI, and AHI (p < 0.001, p < 0.001, and p = 0.043, respectively); among these, the APCI showed the highest regression coefficient (odds ratio = 2.82). The parameters associated with the size of RCTs were CSA (p = 0.022) and AHI, of which AHI, in particular, had the most significant effect on both small-to-medium and large tears (all p < 0.001). Conclusions: Large CSA, high APCI, and low AHI were predictors of RCTs, with the APCI showing the strongest correlation. In addition to the large CSA, low AHI also correlated with the size of RCTs and affected the entire size groups. We suggest that both the lateral coverage and anteroposterior coverage of the acromion should be considered essential factors for predicting the presence of RCTs and tear size.

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.

Subacromial Erosion After Hook Plate Fixation in Acute Acromioclavicular Joint Dislocation.

OBJECTIVES: To determine the incidence of subacromial erosion, perform quantitative analysis, and identify risk factors after locking hook plate fixation for acute acromioclavicular joint injury. DESIGN: A retrospective case series study. SETTING: A single tertiary university hospital. PATIENTS/PARTICIPANTS: The study was conducted on 35 patients who had acute acromioclavicular joint injury. INTERVENTION: Patients underwent the locking hook plate fixation. MAIN OUTCOME MEASUREMENTS: The computed tomography (CT) was conducted to measure the subacromial erosion. The acromioclavicular slope (AC slope) of the unaffected side, the acromion-hook angle, the acromioclavicular anteroposterior distance (AC-AP distance), and the preoperative acromioclavicular interval of the affected side were analyzed to identify the risk factors of subacromial erosion. RESULTS: According to the CT findings, subacromial erosion was found in all cases, and the mean value was 5.0 mm, which is 53% of the entire acromion thickness. The AC slope (B = -0.159, P < 0.001) and AC-AP distance (B = 0.233, P = 0.004) were found to have a significant influence on postoperative subacromial erosion. The AC slope showed a negative correlation with the amount of erosion, whereas the AC-AP distance showed a positive correlation with erosion. CONCLUSION: The CT findings revealed that subacromial erosion occurred in all cases, and the mean erosion depth was about 50% of the acromial thickness. If the preoperative AC slope of the unaffected side was more acute and the AC-AP distance was larger, the incidence of subacromial erosion was higher. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Antegrade Intramedullary Fixation for Clavicular Shaft Fracture: A Technical Trick.

SUMMARY: The standard open reduction and internal fixation technique with a plate and screws for a simple mid shaft clavicular fracture necessitates a relatively large incision and can also lead to variable amount of keloid scar formation. Historically, other techniques of more minimally invasive retrograde intramedullary fixation with the entry point posterolaterally on the shoulder have shown their own disadvantages and complications. We present a surgical technique of antegrade intramedullary fixation for mid shaft clavicular fractures and an illustrative case series.

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.

Clinical Outcomes of Revision Arthroscopic Capsulolabral Repair for Recurrent Anterior Shoulder Instability With Moderate Glenoid Bone Defects: A Comparison With Primary Surgery.

BACKGROUND: The optimal revision surgery for failed primary arthroscopic capsulolabral repair (ACR) has yet to be determined. Revision ACR has shown promising results. PURPOSE: To compare the functional, strength, and radiological outcomes of revision ACR and primary ACR for anterior shoulder instability. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Between March 2007 and April 2017, a total of 85 patients underwent ACR (revision: n = 23; primary: n = 62). Functional outcome scores and positive apprehension signs were evaluated preoperatively, at 1 year, and then annually. Isokinetic internal and external rotation strengths were evaluated preoperatively and at 1 year after surgery. RESULTS: The mean follow-up was 36.5 ± 10.2 months (range, 24-105 months). There was no significant difference between the revision and primary groups in the glenoid bone defect size at the time of surgery (17.3% ± 4.8% vs 15.4% ± 5.1%, respectively; P = .197). At the final follow-up, no significant differences were found in the American Shoulder and Elbow Surgeons score (97.6 ± 3.1 vs 98.0 ± 6.2, respectively; P = .573), Western Ontario Shoulder Instability Index score (636.7 ± 278.1 vs 551.1 ± 305.4, respectively; P = .584), or patients with a positive apprehension sign (17.4% [4/23] vs 11.3% [7/62], respectively; P = .479) between the revision and primary groups. There was no significant difference between the revision and primary groups for returning to sports at the same preoperative level (65.2% vs 80.6%, respectively; P = .136) and anatomic healing failure at 1 year after surgery (13.0% vs 3.2%, respectively; P = .120). Both groups recovered external rotation strength at 1 year after surgery (vs before surgery), although the strength was weaker than in the uninvolved shoulder. In the revision group, a larger glenoid bone defect was significantly related to a positive apprehension sign (22.0% ± 3.8%) vs a negative apprehension sign (16.0% ± 3.2%; cutoff = 20.5%; P = .003). CONCLUSION: In patients with moderate glenoid bone defect sizes (10%-25%), clinical outcomes after revision ACR were comparable to those after primary ACR. However, significant glenoid bone loss was related to a positive remaining apprehension sign in the revision group. Surgeons should consider these findings when selecting their revision strategy for patients with failed anterior shoulder stabilization.

Safety and Efficacy of Autologous Dermal Fibroblast Injection to Enhance Healing After Full-Thickness Rotator Cuff Repair: First-in-Human Pilot Study.

BACKGROUND: There is growing interest in various biological supplements to improve tendon healing in patients after arthroscopic rotator cuff repair. The ideal biological supplement to strengthen rotator cuff remains unknown. PURPOSE: To assess the safety and efficacy of autologous cultured dermal fibroblast (ADF) injection on tendon-to-bone healing in patients after arthroscopic rotator cuff repair. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Included were 6 patients who underwent arthroscopic rotator cuff repair between June 2018 and March 2020; all patients had a full-thickness rotator cuff tear (>2 cm) involving the supraspinatus and infraspinatus tendons. The patients were injected with ADF between the repaired tendon and footprint during arthroscopic rotator cuff repair using the suture bridge technique. The safety of ADFs and the procedure was evaluated at 5 weeks postoperatively, and the anatomical healing of the repaired tendon was accessed at 6 months postoperatively using magnetic resonance imaging and at 12 months using ultrasonography. Outcomes including shoulder range of motion (ROM), visual analog scale (VAS) for pain, and functional scores were measured at 6 and 12 months postoperatively. RESULTS: Adverse reactions to ADF injection were not observed at 6 months after surgery. VAS and functional scores at 6 and 12 months postoperatively were significantly improved compared with preoperative scores (all P < .05). However, there was no significant difference on any ROM variable between preoperative and postoperative measurements at 6 and 12 months (all P > .05). No healing failure was found at 6 and 12 months postoperatively. CONCLUSION: There was no adverse reaction to ADF injection, and all patients had successful healing after rotator cuff repair. A simple and easily accessible ADF injection may be a novel treatment option for increasing the healing capacity of torn rotator cuff tendons. Further clinical research is needed to verify the study results.

Corrigendum: MONTI: A Multi-Omics Non-Negative Tensor Decomposition Framework for Gene-Level Integrative Analysis.

[This corrects the article DOI: 10.3389/fgene.2021.682841.].

Optimal insertion site of glenoid baseplate in reverse total shoulder arthroplasty: anatomical simulation using three dimensional image processing software.

PURPOSE: Conventionally, the central structure of the baseplate is inserted through the point where the vertical and horizontal axes of the glenoid intersect (conventional insertion site (CIS)). However, there is scanty theoretical evidence that CIS has the optimal bone stock. We evaluated the optimal insertion site for the glenoid baseplate through the three-dimensional volumetric measurement of the glenoid bone stock. METHODS: Pre-operative computed tomography (CT) images of 30 consecutive reverse total shoulder arthroplasty procedures were analyzed. Three-dimensional image processing software was used to reconstruct CT and volumetrically measure the glenoid bone stock according to the simulated central peg. A simulated central peg was inserted to the medial pole of the scapula from 49 points determined along with the intersect point of the vertical and horizontal axes of the glenoid CIS at 2-mm intervals. The overlapped volume between the simulated central peg and glenoid vault, representing the amount of glenoid bone stock along the passage of the central peg, was then automatically calculated. RESULTS: The depth of the glenoid vault was 25.5 ± 3.0 mm (range, 19.3-31.5), and the mean overlapped volume between the simulated central peg and the glenoid vault was 623.0 ± 185.8 ml. The optimal insertion site for the bony purchase of the central peg was 2 mm inferior and posterior from the CIS (765.3 ± 157.5). CONCLUSION: The optimal insertion site of the baseplate is located slightly inferiorly and posteriorly to the CIS. This anatomical information may be used as a reference to determine the optimal insertion site of the baseplate according to an implant of a surgeon's choice.