OBJECTIVE: To investigate short-term effectiveness of arthroscopic repair via modified subacromial viewing portal (hereinafter referred to as modified viewing portal) in treatment of LafosseⅠsubscapularis tendon tears. METHODS: A clinical data of 52 patients with LafosseⅠsubscapularis tendon tears, who underwent the arthroscopic repair via modified viewing portal between October 2020 and November 2022 and met the selective criteria, was retrospectively analyzed. There were 15 males and 37 females with an average age of 63.4 years (range, 41-76 years). Twelve patients had trauma history and the other 40 patients had no obvious inducement. The main clinical symptom was shoulder pain and the hug resistance tests were positive in all patients. The interval between symptom onset and admission ranged from 3 to 26 months (mean, 7.2 months). The shoulder pain and function were evaluated by visual analogue scale (VAS) score, American Shoulder and Elbow Surgeons (ASES) score, and University of California Los Angeles (UCLA) score before operation and at 12 months after operation. The shoulder range of motion (ROM) of forward flexion, abduction, and external rotation and the internal rotation strength were measured before operation and at 3 and 12 months after operation. MRI was performed at 3-6 months after operation to assess the tendon healing and the structural integrity and tension of reattached tendon. Patient's satisfactions were calculated at last follow-up. RESULTS: All incisions healed by first intention, no complication such as incision infection or nerve injury occurred. All patients were followed up 12-37 months (mean, 18.5 months). The VAS, UCLA, and ASES scores at 12 months after operation significantly improved when compared with those before operation ( P<0.05). The ROMs of abduction and forward flexion and the internal rotation strength at 3 and 12 months significantly improved when compared with those before operation ( P<0.05); and the ROMs at 12 months significantly improved compared to that at 3 months ( P<0.05). However, there was no significant difference ( P>0.05) in the ROM of external rotation at 3 months compared to that before operation; but the ROM at 12 months significantly improved compared to that before operation and at 3 months after operation ( P<0.05). Thirty-one patients underwent MRI at 3-6 months, of which 28 patients possessed intact structural integrity, good tendon tension and tendon healing; 3 patients underwent tendon re-tear. At last follow-up, 41 patients (78.8%) were very satisfied with the effectiveness, 7 were satisfied (13.5%), and 4 were dissatisfied (7.7%). CONCLUSION Arthroscopic repair via modified viewing portal for Lafosse Ⅰsubscapularis tendon tears, which can achieve the satisfactory visualization and working space, can obtain good short-term effectiveness with low overall re-tear risk.
Male ; Female ; Humans ; Middle Aged ; Rotator Cuff/surgery* ; Rotator Cuff Injuries/surgery* ; Shoulder Pain ; Retrospective Studies ; Treatment Outcome ; Arthroscopy ; Shoulder Joint/surgery* ; Tendons/surgery* ; Range of Motion, Articular

OBJECTIVE: To explore the long-term effectiveness of arthroscopic partial repair in treatment of massive irreparable rotator cuff tears from both the radiological and clinical perspectives. METHODS: A retrospective analysis was conducted on the clinical data of 24 patients (25 sides) with massive irreparable rotator cuff tears who met the inclusion criteria between May 2006 and September 2014. Among them, there were 17 males (18 sides) and 7 females (7 sides) with an age range of 43-67 years (mean, 55.0 years). There were 23 cases of unilateral injury and 1 case of bilateral injuries. All patients were treated with the arthroscopic partial repair. The active range of motion of forward elevation and abduction, external rotation, and internal rotation, as well as the muscle strength for forward flexion and external rotation, were recorded before operation, at the first postoperative follow-up, and at last follow-up. The American Association of Shoulder and Elbow Surgeons (ASES) score, the University of California at Los Angeles (UCLA) shoulder scoring, and Constant score were used to evaluate shoulder joint function. And the visual analogue scale (VAS) score was used to evaluate shoulder joint pain. MRI examination was performed. The signal-to-noise quotient (SNQ) was measured above the anchor point near the footprint area (m area) and above the glenoid (g area) in the oblique coronal T2 fat suppression sequence. The atrophy of the supraspinatus muscle was evaluated using the tangent sign. The global fatty degeneration index (GFDI) was measured to assess fat infiltration in the supraspinatus muscle, infraspinatus muscle, teres minor muscle, upper and lower parts of the subscapularis muscle. The mean GFDI (GFDI-5) of 5 muscles was calculated. RESULTS: The incisions healed by first intention. All patients were followed up with the first follow-up time of 1.0-1.7 years (mean, 1.3 years) and the last follow-up time of 7-11 years (mean, 8.4 years). At last follow-up, the range of motion and muscle strength of forward elevation and abduction, ASES score, Constant score, UCLA score, and VAS score of the patients significantly improved when compared with those before operation ( P<0.05). Compared with the first follow-up, except for a significant increase in ASES score ( P<0.05), there was no significant difference in the other indicators ( P>0.05). Compared with those before operation, the degree of supraspinatus muscle infiltration worsened at last follow-up ( P<0.05), GFDI-5 increased significantly ( P<0.05), and there was significant difference in the tangent sign ( P<0.05); while there was no significant difference in the infiltration degree of infraspinatus muscle, teres minor muscle, and subscapularis muscle, upper and lower parts of the subscapularis muscle ( P>0.05). Compared with the first follow-up, the SNQm and SNQg decreased significantly at last follow-up ( P<0.05). At the first and last follow-up, there was no correlation between the SNQm and SNQg and the ASES score, Constant score, UCLA score, and VAS score of the shoulder ( P>0.05). CONCLUSION Arthroscopic partial repair is effective in treating massive irreparable rotator cuff tear and significantly improves long-term shoulder joint function. For patients with severe preoperative fat infiltration involving a large number of tendons and poor quality of repairable tendons, it is suggested to consider other treatment methods.
Male ; Female ; Humans ; Adult ; Middle Aged ; Aged ; Rotator Cuff Injuries/surgery* ; Retrospective Studies ; Shoulder Joint/surgery* ; Treatment Outcome ; Arthroscopy/methods* ; Range of Motion, Articular

OBJECTIVE: To evaluate the effectiveness of tendon insertion medialized repair in treatment of large-to-massive rotator cuff tears (L/MRCT). METHODS: The clinical and imaging data of 46 L/MRCT patients who underwent arthroscopic insertion medialized repair between October 2015 and June 2019 were retrospectively analyzed. There were 26 males and 20 females with an average age of 57.7 years (range, 40-75 years). There were 20 cases of large rotator cuff tears and 26 cases of massive rotator cuff tears. Preoperative imaging evaluation included fatty infiltration (Goutallier grade), tendon retraction (modified Patte grade), supraspinatus tangent sign, acromiohumeral distance (AHD), and postoperative medializaiton length and tendon integrity. The clinical outcome was evaluated by visual analogue scale (VAS) score, American Society for Shoulder and Elbow Surgery (ASES) score, shoulder range of motion (including anteflexion and elevation, lateral external, and internal rotation) and anteflexion and elevation muscle strength before and after operation. The patients were divided into two groups (the intact tendon group and the re-teared group) according to the integrity of the tendon after operation. According to the medializaiton length, the patients were divided into group A (medialization length ≤10 mm) and group B (medialization length >10 mm). The clinical function and imaging indexes of the patients were compared. RESULTS: All patients were followed up 24-56 months, with an average of 31.8 months. At 1 year after operation, MRI showed that the medializaiton length of supraspinatus tendon was 5-15 mm, with an average of 10.26 mm, 33 cases in group A and 13 cases in group B. Eleven cases (23.91%) had re-teared, including 5 cases (45.45%) of Sugaya type Ⅳ and 6 cases (54.55%) of Sugaya type Ⅴ. At last follow-up, the VAS score, ASES score, shoulder anteflexion and elevation range of motion, lateral external rotation range of motion, and anteflexion and elevation muscle strength significantly improved when compared with those before operation ( P<0.05); there was no significant difference in internal rotation range of motion between pre- and post-operation ( P>0.05). The Goutallier grade and modified Patte grade of supraspinatus muscle in the re-teared group were significantly higher than those in the intact tendon group, and the AHD was significantly lower than that in the intact tendon group ( P<0.05). There was no significant difference in other baseline data between the two groups ( P>0.05). Except that the ASES score of the intact tendon group was significantly higher than that of the re-teared group ( P<0.05), there was no significant difference in the other postoperative clinical functional indicators between the two groups ( P>0.05). There was no significant difference in the incidence of re-tear, VAS score, ASES score, range of motion of shoulder joint, and anteflexion and elevation muscle strength between group A and group B ( P>0.05). CONCLUSION Tendon insertion medialized repair may be useful in cases with L/MRCT, and shows good postoperative shoulder function. Neither tendon integrity nor medialization length shows apparent correlations with postoperative shoulder function.
Male ; Female ; Humans ; Middle Aged ; Rotator Cuff Injuries/surgery* ; Retrospective Studies ; Treatment Outcome ; Rotator Cuff/surgery* ; Tendons ; Rupture/surgery* ; Shoulder Joint/surgery* ; Arthroscopy/methods* ; Range of Motion, Articular

OBJECTIVE: To investigate the effectiveness of "hybrid" suture with en masse combined with double-layer repair under arthroscopy in repair of delaminated rotator cuff tear by comparison with en masse suture. METHODS: Fifty-six patients with delaminated rotator cuff tears met selection criteria between June 2020 and January 2022 were included in the study. Patients were divided into two groups ( n=28) using a random number method. The patients in trial group underwent arthroscopic "hybrid" suture with the combination en masse and double-layer suture. The patients in control group underwent en masse suture under arthroscopy. There was no significant difference between the two groups ( P>0.05) in terms of gender, age, rotator cuff tear side, tear size, cause of injury, disease duration, and preoperative American Association of Shoulder and Elbow Surgeons (ASES) score, the University of California at Los Angeles (UCLA) shoulder scoring, visual analogue scale (VAS) score, and shoulder range of motion (forward flexion and lateral external rotation). The operation time, the difference of ASES score, UCLA score, VAS score, and shoulder range of motion (forward flexion and lateral external rotation) between pre- and post-operation were recorded and compared between the two groups ( P>0.05). The rotator cuff healing was examined by MRI and evaluated based on the classification criteria of rotator cuff healing proposed by Sugaya et al. RESULTS: Three cases (1 case in the trial group and 2 cases in the control group) were excluded from the study due to loss of follow-up. Twenty-seven cases in the trial group and 26 cases in the control group were included in the final study analysis. All operations of the two groups were completed successfully. There was no significant difference in the operation time between groups ( P>0.05). The follow-up time was 10-12 months (mean, 10.9 months) in the trial group and 10-13 months (mean, 11.4 months) in the control group. All incisions healed by first intention. No surgery-related complications occurred. The UCLA score, ASES score, VAS score, and shoulder range of motion (forward flexion and lateral external rotation) of both groups at 9 months after operation were significantly superior to those before operation ( P<0.05). The difference of UCLA score, ASES score, and VAS score between before and after operation in the trial group were significantly better than those in the control group ( P<0.05). There was no significant differences between the two groups in the difference of shoulder range of motion (forward flexion and lateral lateral rotation) ( P>0.05). At 9 months after operation, according to the classification criteria of rotator cuff healing proposed by Sugaya et al, MRI showed that the rotator cuff healing of the trial group was significantly better than that of the control group ( P<0.05). CONCLUSION Compared with en masse suture, arthroscopic "hybrid" suture for the repair of delaminated rotator cuff tear has advantages in relieving pain and improving shoulder joint function, and the rotator cuff healing is better.
Humans ; Rotator Cuff Injuries/surgery* ; Prospective Studies ; Shoulder Joint/surgery* ; Treatment Outcome ; Arthroscopy/methods* ; Sutures ; Range of Motion, Articular ; Magnetic Resonance Imaging

Superior labrum anterior posterior (SLAP) injury is a major challenge for orthopedic surgeons, due to the poor healing ability of the injured labrum. Although arthroscopic surgery is the gold standard for the treatment of SLAP injury, there are still disputes about the adaptation of different surgical techniques, the choice of anchors during operation, knotted or knotless anchors, and fixation methods. The authors believe that arthroscopic repair of SLAP lesions is effective for young patients with intact glenoid labrum(<35 years old) or with extensive activity, where single and knotless anchor is preferred. For the older patients(≥35 years old) with degeneration and wear of glenoid labrum, biceps tenodesis is more preferable, and interference screw fixation technique is recommended. As for patients with failed SLAP repair, biceps tenodesis can achieve a high success rate as a revision surgery. By review of the relevant literature in recent years, this paper summarizes the adaptation of different surgical methods of arthroscopic treatment of SLAP injury, intraoperative anchoring techniques, fixation methods and other improved surgical techniques.
Humans ; Adult ; Shoulder Joint/surgery* ; Arthroscopy/methods* ; Tendon Injuries/surgery* ; Shoulder Injuries/surgery* ; Tenodesis/methods*

OBJECTIVE: To investigate early effectiveness of arthroscopic superior fulcrum reconstruction in the treatment of irreparable massive rotator cuff tear (IMRCT). METHODS: A retrospective analysis was conducted on the clinical data of 24 patients with IMRCT who met the inclusion criteria between January 2020 and April 2022. Among them, there were 11 males and 13 females with an average age of 56.2 years (range, 42-68 years). There were 12 cases of falling injuries, 3 cases of traction injuries, and the other 9 cases had no obvious causes. The disease duration ranged from 1 to 25 months (median, 6 months). The rotator cuff tears were classified as Hamada grade 2 in 18 cases and grade 3 in 6 cases, and Goutallier grade 1 in 3 cases, grade 2 in 20 cases, and grade 3 in 1 case. All patients were treated with arthroscopic superior fulcrum reconstruction. Visual analogue scale (VAS) score, Constant-Murley score, the University of California at Los Angeles (UCLA) score, and the American Shoulder and Elbow Surgeons (ASES) score were recorded before operation and at 1, 3, 6, and 12 months after operation. RESULTS: The operations were all successfully completed. The incisions healed by first intention and no related complications occurred. All patients were followed up 12-33 months (mean, 24.6 months). The VAS, Constant-Murley, UCLA, and ASES scores at different time points after operation were superior to those before operation ( P<0.05). All of the above indicators further improved with time. Except for no significant difference in VAS and Constant-Murley scores between 6 and 12 months ( P>0.05), the differences between the other time points were significant ( P<0.05). At 12 months after operation, according to UCLA scoring standard, shoulder joint function was rated as excellent in 4 cases, good in 19 cases, and poor in 1 case, with an excellent and good rate of 96.0%. MRI showed that there was no graft re-tear and the transplanted tendon and bone tunnel healed. CONCLUSION The arthroscopic superior fulcrum reconstruction for IMRCT can effectively relieve the pain, improve the shoulder range of motion, and restore good shoulder function.
Male ; Female ; Humans ; Middle Aged ; Rotator Cuff Injuries/surgery* ; Rotator Cuff/surgery* ; Retrospective Studies ; Treatment Outcome ; Arthroscopy ; Shoulder Joint/surgery* ; Range of Motion, Articular

OBJECTIVE: To explore clinical effect of arthroscopy-assisted rotator cuff tendon transfer in treating irreparable rotator cuff tears (IRCT). METHODS: From May 2015 to May 2018, 23 patients with unrepairable rotator cuff tears were treated with arthroscopy-assisted rotator cuff tendon transfer, and 21 patients were followed up finally, including 8 males and 13 females, aged from 48 to 82 years old with an average of(64.3±9.1) years old;the courses of disease ranged from 6 to 36 months with an average of (14.0±6.4) months. American Rotator and Elbow Surgeons Score(ASES) and Constant-Murley score were used to evaluate clinical efficacy before surgery and at the latest follow-up. RESULTS: All 21 patients were followed up for 36 to 54 months with an average of (39.4±4.4) months. Axillary incision of 1 patient was redness, swelling and exudation after surgery, which healed after 3 weeks of dressing change, and exudate culture was negative. At the latest follow-up, MRI showed partial tearing of the metastatic tendon in 2 patients, but pain and movement of the affected shoulder were still better than before surgery. ASES increased from preoperative (41.0±9.6) scores to the latest follow-up (75.6±14.0) scores, and had statistical difference (t=10.50, P<0.01). Constant-Murley score increased from (49.8±7.1) scores before operation to (67.5±11.6) scores at the latest follow-up (t=11.27, P<0.01). CONCLUSION Arthroscopic assisted latissimus dorsalis tendon transposition restores physiological and anatomical structure of glenohumeral joint by reconstructing balance of horizontal and vertical couples of shoulder joint, thus achieving the stability of the shoulder joint, relieving shoulder pain and improving shoulder joint function.
Male ; Female ; Humans ; Middle Aged ; Aged ; Aged, 80 and over ; Rotator Cuff Injuries/surgery* ; Superficial Back Muscles ; Rotator Cuff ; Treatment Outcome ; Shoulder Joint/surgery* ; Tendon Transfer ; Arthroscopy ; Range of Motion, Articular/physiology*

OBJECTIVE: To investigate the feasibility and effectiveness of "tail compression fixation+suture bridge" technology under shoulder arthroscopy for treating primary tear in medial enthesis of rotator cuff. METHODS: The clinical data of 11 patients with primary tear in medial enthesis of rotator cuff who met the selection criteria between October 2020 and October 2022 were retrospectively analyzed, including 3 males and 8 females, aged 39-79 years, with an average of 61.0 years. Rotator cuff injury was caused by traumatic fall in 8 cases, and the time from injury to admission was 1-4 months, with an average of 2.0 months; the remaining 3 cases had no obvious inducement. The active range of motion of the affected shoulder was limited, with an active forward flexion range of motion of (64.1±10.9)°, abduction of (78.1±6.4)°, internal rotation of (48.2±6.6)°, and external rotation of (41.8±10.5)°; 5 cases had shoulder stiffness. The preoperative visual analogue scale (VAS) score was 7.8±0.8 and the American Society of Shoulder and Elbow Surgeons (ASES) score was 23.9±6.4. The patients were treated with "tail compression fixation+suture bridge" technology under shoulder arthroscopy, and the pain and functional recovery were evaluated by VAS score, ASES score, and active range of motion of shoulder joint at last follow-up; MRI was performed after operation, and the integrity of rotator cuff was evaluated by Sugaya classification system. RESULTS: All the 11 patients were followed up 2-22 months, with an average of 13.5 months. All incisions healed by first intention, and there was no complication such as infection, rotator cuff re-tear, and anchor falling off. At last follow-up, the VAS score was 0.8±0.7 and the ASES score was 93.5±4.2, which significantly improved when compared with those before operation ( P<0.05). All 11 patients had no significant swelling in the shoulders, and the active range of motion was (165.1±8.8)° in flexion, (75.3±8.4)° in abduction, (56.6±5.5)° in internal rotation, and (51.8±4.0)° in external rotation, which significantly improved when compared with those before operation ( P<0.05). Shoulder MRI showed adequate tendon thickness and good continuity in 9 cases, including 4 cases with partial high signal area; and 2 cases with inadequate tendon thickness but high continuity and partial high signal area. According to Sugaya classification system, there were 4 cases of type 1 (36.4%), 5 cases of type 2 (45.5%), and 2 cases of type 3 (18.1%). CONCLUSION For the patients with primary tear in medial enthesis of rotator cuff, the "tail compression fixation+suture bridge" technology under shoulder arthroscopy is simple and effective.
Male ; Female ; Humans ; Rotator Cuff/surgery* ; Shoulder ; Arthroscopy ; Retrospective Studies ; Treatment Outcome ; Rotator Cuff Injuries/surgery* ; Rupture ; Shoulder Joint/surgery* ; Sutures ; Range of Motion, Articular

OBJECTIVE: To explore the mid-term effectiveness of arthroscopic "mini incision" transtendon repair for partial articular-sided supraspinatus tendon avulsion (PASTA) lesion. METHODS: A clinical data of 39 patients with PASTA lesions, who underwent the arthroscopic "mini incision" transtendon repair and met the selected criteria between May 2017 and April 2021, was retrospectively analyzed. There were 13 males and 26 females, with an average age of 63.7 years (range, 43-76 years). Nine patients underwent trauma history, and no obvious inducement was found in the other 30 patients. The main clinical symptom was shoulder pain with positive hug resistance test. The interval from symptom onset to operation was 3-21 months (mean, 8.3 months). The visual analogue scale (VAS) score, University of California Los Angeles (UCLA) shoulder score, American Association of Shoulder and Elbow Surgeons (ASES) score and shoulder range of motion (ROM) of forward flexion, abduction, and external rotation were used to evaluate shoulder function. MRI was performed to assess the structural integrity and tension of reattached tendon. Patient satisfactions were calculated at last follow-up. RESULTS: All incisions healed by first intention with no complications such as incision infection or nerve injury. All patients were followed up 24-71 months (mean, 46.9 months). The VAS, UCLA, and ASES scores significantly improved at 24 months after operation when compared with preoperative ones ( P<0.05). The ROMs of forward flexion and external rotation of the shoulder joint significantly increased at 3 and 24 months, and further increased at 24 months compared to 3 months, with significant differences ( P<0.05). However, the ROM of abduction of the shoulder joint at 3 months did not significantly improve compared with that before operation ( P>0.05), and it was significantly greater at 24 months than before operation and at 3 months after operation ( P<0.05). At last follow-up, the patients were very satisfied with the effectiveness in 30 cases (76.9%), satisfied in 5 cases (12.8%), and dissatisfied in 4 cases (10.3%). At 6 months after operation, 31 patients underwent reviews of MRI scans, of which 28 patients possessed intact structural integrity, good tendon tension and tendon healing, and 3 patients underwent tendon re-tear. CONCLUSION Arthroscopic "mini incision" transtendon repair in treatment of PASTA lesion could obtain satisfying mid-term effectiveness with low risk of tendon re-tear.
Male ; Female ; Humans ; Middle Aged ; Rotator Cuff/surgery* ; Rotator Cuff Injuries/surgery* ; Retrospective Studies ; Treatment Outcome ; Arthroscopy ; Shoulder Joint/surgery* ; Tendons/surgery* ; Range of Motion, Articular

OBJECTIVE: To investigate the synergistic interaction between the deltoid muscle and the rotator cuff muscle group in patients with rotator cuff tears (RCT), as well as the impact of the critical shoulder angle (CSA) on deltoid muscle strength. METHODS: A retrospective analysis was conducted on clinical data from 42 RCT patients who met the selection criteria and were treated between March 2022 and March 2023. There were 13 males and 29 females, with an age range of 42-77 years (mean, 60.5 years). Preoperative visual analogue scale (VAS) score was 6.0±1.6. CSA measurements were obtained from standard anteroposterior X-ray films before operation, and patients were divided into two groups based on CSA measurements: CSA>35° group (group A) and CSA≤35° group (group B). Handheld dynamometry was used to measure the muscle strength of various muscle group in the shoulder (including the supraspinatus, infraspinatus, subscapularis, and anterior, middle, and posterior bundles of the deltoid). The muscle strength of the unaffected side was compared to the affected side, and muscle imbalance indices were calculated. Muscle imbalance indices between male and female patients, dominant and non-dominant sides, and groups A and B were compared. Pearson correlation analysis was used to examine the relationship between muscle imbalance indices and CSA as well as VAS scores. RESULTS: Muscle strength in all muscle groups on the affected side was significantly lower than on the unaffected side ( P<0.05). The muscle imbalance indices for the supraspinatus, subscapularis, infraspinatus, and anterior, middle, and posterior bundles of the deltoid were 14.8%±24.4%, 5.9%±9.7%, 7.2% (0, 9.1%), 17.2% (5.9%, 26.9%), 8.3%±21.3%, and 10.2% (2.8%, 15.4%), respectively. The muscle imbalance indices of the anterior bundle of the deltoid, supraspinatus, and infraspinatus were significantly lower in male patients compared to female patients ( P<0.05); however, there was no significant difference in muscle imbalance indices among other muscle groups between male and female patients or between the dominant and non-dominant sides ( P>0.05). There was a positive correlation between the muscle imbalance indices of infraspinatus and VAS score ( P<0.05), and a positive correlation between CSA and the muscle imbalance indices of middle bundle of deltoid ( P<0.05). There was no correlation between the muscle imbalance indices of other muscle groups and VAS score or CSA ( P>0.05). Preoperative CSA ranged from 17.6° to 39.4°, with a mean of 31.1°. There were 9 cases in group A and 33 cases in group B. The muscle imbalance indices of the anterior bundle of the deltoid was significantly lower in group A compared to group B ( P<0.05), while there was no significant difference in muscle imbalance indices among other muscle groups between group A and group B ( P>0.05). CONCLUSION Patients with RCT have a phenomenon of deltoid muscle strength reduction, which is more pronounced in the population with a larger CSA.
Male ; Female ; Humans ; Adult ; Middle Aged ; Aged ; Shoulder ; Rotator Cuff Injuries/surgery* ; Shoulder Joint/diagnostic imaging* ; Rotator Cuff/surgery* ; Muscle Strength ; Deltoid Muscle