External Rotation Strength Research Articles

Increased Tone and Stiffness of the Teres Major Muscle in Elite Handball Athletes: A Cross-Sectional Study

Background: The aim of this study was to determine whether the elite handball (HB) athletes with glenohumeral internal rotation deficit (GIRD) present differences in the mechanical properties in the teres major muscle, and strength and extensibility of the posterior shoulder tissues of the throwing shoulder (TS) compared to the non-throwing (non-TS) and non-HB athletes. Methods: A cross-sectional study was carried out, with sixty male participants: 30 HB athletes with GIRD and 30 age-matched healthy non-HB athletes. Mechanical properties of the teres major muscle were measured with MyotonPRO; also, extensibility of the posterior shoulder tissues and maximum isometric internal rotation (IR) and external rotation (ER) strength were recorded. Results: The teres major muscle of the TS in the HB group achieved a higher tone (Δ 0.34; 95% CI: 0.15, 0.53) and stiffness (Δ 30.86; 95% CI: 23.04,38.68), and a lower relaxation time compared to the non-TS of the same group (Δ −0.69; 95% CI: −1.15, −0.24;) and to the TS of the control group for the tone (Δ 0.36; 95% CI: 0.02, 0.70) and for the stiffness (Δ 27.03; 95% CI: 15.24, 38.83). The extensibility of the TS of the HB group presented a statistically significant decrease compared to the control group (Δ−7.83; 95% CI: −12.42, 3.23). A between-groups ER/IR ratio imbalance was found for the TS (Δ−12.18; 95% CI: −25.59, −1.23) and the non-TS (Δ−13.01; 95% CI: −25.79, −0.25). Conclusions: HB athletes with GIRD present a higher tone and stiffness of the teres major muscle and lack of extensibility of the tissues of the posterior part of the shoulder compared to the non-TS and to healthy non-HB athletes.

When and how much does the muscle strength recover after arthroscopic superior capsular reconstruction?

Recently, arthroscopic superior capsular reconstruction (SCR) has been performed for irreparable large to massive rotator cuff tears and its excellent clinical results have also been reported. Although the muscle strength was reported to recover, it is not clarified yet when and how much it recovers. The purpose of this study was to determine the recovery pattern of muscle strength after SCR. Thirty-five patients (mean age: 65 years) who met the following inclusion criteria were retrospectively reviewed: 1) those with large to massive, irreparable tears of the rotator cuff including the supraspinatus and infraspinatus tendons; 2) those with severe muscle atrophy and fatty change; 3) those with their muscle quality and strength assessed by MRI and a dynamometer at 6 months, 1 year, and 2 years; 4) those with a minimum follow-up of 2 years; and 5) those without severe osteoarthritis. The isometric muscle strength of scaption, internal and external rotation in adduction was measured twice for each motion by a dynamometer. Relative to the muscle strength of the uninvolved side, the involved side showed 61 ± 21% in scaption, 63 ± 20% in external rotation, and 103 ± 29% in internal rotation at 2 years after surgery. Whereas no significant differences were observed between 1-year and 2-year follow-ups, there was a significant difference in muscle strength of scaption between 6-months and 1-year (P = 0.0174). Graft retear was seen in 5 cases (14%). There was a trend that the muscle strength of scaption and external rotation in the no retear group was greater than that in the retear group despite no significant difference (P = 0.0717, P = 0.0824, respectively). The recovery of the muscle strength after SCR was observed until 1 year after surgery and the muscle strength of scaption and external rotation returned to 60% of the uninvolved side at 2 years.

Functional and radiographic results of anatomic total shoulder arthroplasty in the setting of subscapularis dysfunction: 5-year outcomes analysis

Subscapularis management is a critical component to the success of anatomic total shoulder arthroplasty (TSA). Failure to heal the subscapularis can result in pain, weakness, loss of function, and revision. However, not all patients have poor outcomes. The purpose of this study is to compare patients with normal and dysfunctional subscapularis function following TSA in regard to (1) patient-reported outcome measures (PROMs); (2) range of motion (ROM) and strength; (3) achievement of minimal clinically important differences (MCIDs); and (4) specific functional internal rotation tasks. A retrospective review of patients treated with TSA for osteoarthritis with a minimum 2-year follow-up was performed to identify patients with subscapularis dysfunction. Subscapularis dysfunction was diagnosed when any degree of weakness in internal rotation was detected on physical examination (positive belly press sign). These patients were case controlled matched on a 1:3 ratio to patients with normal subscapularis function based on age and sex. PROMs, measured active motion, revision rates, patient satisfaction, and postoperative radiographic findings were compared. Population-specific institutional anchor-based MCID values were used to compare the improvement in PROM. Of the 668 patients included, 34 patients (5.1%) demonstrated evidence of subscapularis dysfunction. Mean follow-up for the normal subscapularis function cohort was 63.4±29.7 and 58.7±26.8 for the dysfunctional subscapularis cohort. Patients with subscapularis dysfunction demonstrated significantly worse postoperative Simple Shoulder Test, Single Assessment Numerical Evaluation, visual analog scale (VAS) function, VAS pain, and American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) scores with higher rates of unsatisfactory results when compared to patients with normal subscapularis function. Abduction, elevation, internal rotation ROM, along with supraspinatus and external rotation strength were also significantly worse in the dysfunctional group. Similarly, these patients were more likely to have decreased ability to perform functional internal rotation tasks, with only 47% of the patients being able to reach the small of their back compared to 85% with normal subscapularis function. Radiographically, the dysfunctional cohort demonstrated higher rates of anterior subluxation (56% vs. 7%; P<.001) and glenoid loosening (24% vs. 5%; P=.004). Similarly, revision rates were significantly higher for patients with subscapularis dysfunction (8 patients, 23.5%). Nonetheless, the dysfunctional subscapularis cohort demonstrated improvements in VAS pain (4.0±3.7) and ASES (46.4±35.9) scores that exceeded MCID thresholds. Patients who develop subscapularis dysfunction after TSA have significantly worse PROMs, ROM, functional tasks of internal rotation, and radiographic outcomes, as well as increased rates of revision. Although patients show worse outcomes and high revision rates compared with their normal-functioning counterparts, these patients maintained improvement above MCID thresholds for pain and function at a mean 5-year follow-up.

Hip rotation muscle strength is implicated in the progression of early post-traumatic osteoarthritis: A longitudinal evaluation up to 5 years following ACL reconstruction

IntroductionFollowing ACL reconstruction (ACLR), deficits in hip muscle strength and relationships to future outcomes are unknown. Methods111 participants one year after ACLR, completed hip external rotation (ER) and internal rotation (IR) strength assessment. At 1 (n = 111) and 5 (n = 74) years post-ACLR, participants completed a battery of functional, symptomatic (Knee Osteoarthritis Outcome Score (KOOS)) and structural assessments (radiography, magnetic resonance imaging (MRI)). Cartilage health of the patellofemoral and tibiofemoral compartments was assessed with the semiquantitative MRI Osteoarthritis Knee Score. Hip rotation strength was compared between-limbs, and relationships between hip strength at 1 year and functional, symptomatic and cartilage outcomes at 1 and 5 years were investigated with regression models. ResultsThe index (ACLR) limb had weaker hip ER (but not IR) strength compared to the contralateral side (standardised mean difference ER = −0.33 (95%CI -0.60, −0.07; IR = −0.11 (95%CI -0.37, 0.15). Greater hip ER and IR strength was associated with superior function at 1 and 5 years, and better KOOS-Patellofemoral symptoms at 5 years. Greater hip ER strength was associated with lower odds of worsening tibiofemoral cartilage lesions at 5 years (odds ratio 0.01, 95%CI 0.00, 0.41). ConclusionHip rotation strength may play a role in worsening function, symptoms and cartilage health after ACLR.

Poster 106: Association Between Glenoacromial Spacing and the Risk for Shoulder Instability

Objectives: Biomechanical studies have shown how the muscular dynamics about the shoulder are affected by the relative glenoid and acromion positions. Some believe these dynamics may play a role in predisposing shoulders to develop either osteoarthritis or rotator cuff disease. It is unclear if these dynamics also place individuals at increased risk for shoulder instability. To address these gaps in the literature, our objectives were to establish normative values for shoulder morphology in young physically active military service members and determine the influence of shoulder morphology, specifically the critical shoulder angle (CSA) and acromial index (AI) on rotator cuff strength and risk of shoulder instability. Methods: A subset of 160 US Service Academy cadets (25 Female, 18.81 ± 0.95 years, 177.01 ± 8.14 cm, and 72.52 ± 12.12 kg) were analyzed from a larger prospective cohort study, including all participants who sustained a shoulder instability injury during the 4-year follow-up period (n=36, all anterior). The remaining participants served as healthy controls. Upon entry to the primary study, baseline bilateral shoulder magnetic resonance imaging (MRI) and rotator cuff strength data were collected. Baseline MRIs were used to assess critical shoulder angle (CSA) defined as the angle formed between the glenoid plane at the inferior most glenoid to the lateral most aspect of the acromion and acromial index (AI) defined as glenoacromial distance (GA) divided by the glenohumeral distance (GH). Additionally, isometric internal rotation (IR) and external rotation (ER) strength was assessed at both 0° and 45° of glenohumeral abduction. Normative values for healthy shoulder morphology were reported by limb dominance. Multivariate linear regression models were used to estimate the association between shoulder morphology and strength. Finally, odds ratios (OR) were calculated using multivariate logistic regression models to estimate the likelihood of shoulder instability based on shoulder morphological outcomes. All multivariable models statistically controlled for the influence of potential confounding variables, including sex, height, weight, and limb dominance. Results: Normative baseline values for CSA, AI, glenohumeral distance and glenoacromial distance were established in young physically active military service members. In multivariate modeling, a positive relationship was detected between GH and ER strength at 45° abduction (Coefficient = 0.35, 95% CI: 0.04, 0.67), and between GA and IR strength at both 0° abduction (Coefficient = 4.29, 95% CI: 0.01, 8.56) and 45° abduction (Coefficient = 4.48, 95% CI: 0.81, 8.14). A positive relationship was detected between shoulder morphology and the likelihood of sustaining a shoulder instability injury (CSA: OR = 1.29, 95% CI: 0.97, 1.72; GA: OR = 14.63, 95% CI: 1.03, 206.98). These results indicate every 1° increase in CSA was associated with being 29% more likely to suffer a shoulder instability injury, while every 1cm increase in GA was associated with being 14 times more likely to suffer a shoulder instability injury. No other significant relationships were detected. Conclusions: Shoulder morphology was observed to play a role in both rotator cuff strength and the likelihood of glenohumeral instability injury. Interestingly, glenoacromial distance, specifically, was associated with both ER and IR strength, and the likelihood of shoulder instability. One theory is the larger the glenoacromial distance, the greater the moment arm for the anterior and posterior deltoid to act on the humerus. This increased mechanical advantage and resultant shear at the glenohumeral joint may be what contributes to the increased risk for instability. Another theory is the laterally placed acromion could be providing a fulcrum for the humerus to dislocate. Shoulder instability is a complex problem with many contributing factors and the glenoacromial scapular morphology may be yet another risk factor contributing to relative rotator cuff weakness and risk of shoulder instability in young active- duty military service members.

The Effect of 8-week Online Scapular-focused Training on Scapular Kinematics, Proprioception, and Selected Muscles Strength in Female Volleyball Players With Glenohumeral Internal Rotation Deficit

Purpose: One of the most significant risk factors for throwing athletes is an internal rotation deficit of the shoulder joint. This study aims to investigate 8-week online scapular-focused training on the scapular kinematics, proprioception, and strength of particular shoulder muscles in female volleyball players with glenohumeral internal rotation deficit. Methods: The present study was conducted using a two-group with pre and post-test design. Based on the inclusion and exclusion criteria, 30 female athletes with abnormalities in the shoulder joint’s internal rotation were split into two groups, experimental (n=15) and control (n=15). In the pre-test, goniometers were used to measure shoulder range of motion, isokinetic devices were used to measure proprioception and rotator cuff muscle strength, and inclinometers were used to measure scapular kinematics. The experimental group’s participants underwent 8-week online scapular-focused training, lasting 30 minutes over three sessions each week. These exercises encompassed strength (with TheraBand) and stretching activities. Ultimately, intra-group and inter-group differences were examined using SPSS software, version 20 using paired t-tests and analysis of covariance (ANCOVA) at a significance level of 0.95. Results: The results of paired t-test revealed that only the experimental group and the pre-test and post-test had a significant difference in all study variables (P&lt;0.05). Additionally, the results of the analysis of covariance (ANCOVA) demonstrated a significant difference between the two groups’ shoulder proprioception at 45° and 90° in the post-test (P=0.001 and P=0.01, respectively). The two groups also differed significantly in the scapular kinematics at all angles of 45°, 90°, and 135° as well as at the limit of the shoulder’s range of motion (P=0.01, P=0.04, P=0.001, and P=0.001, respectively). Additionally, significant differences were observed between the two groups in all variables of isokinetic strength of concentric internal rotation, isokinetic strength of concentric external rotation, isokinetic strength of eccentric internal rotation, and isokinetic strength of eccentric external rotation (P=0.001, P=0.02, and P=0.001, respectively). Conclusion: Based on the results, it can be concluded that 8-week online scapular-focused training improves scapular kinematics, proprioception, and shoulder internal and external rotator muscle strength in female volleyball players experiencing internal rotation deficiencies of the shoulder joint. It is advised that coaches, experts, and occupational therapists employ these workouts to enhance the aforementioned factors in female volleyball players experiencing shoulder internal rotation deficiencies.

Effect of a Neuromuscular Training on Knee Valgus, Range of Motion and Muscle Strength of Soccer Players With Dynamic Knee Valgus

Background and Aims The present study aims to investigate the effect of a neuromuscular training program on knee valgus angle, and range of motion (ROM) and muscle strength of hip and ankle in male adolescent football players with dynamic knee valgus (DKV). Valgus knee is one of the most common neuromuscular abnormalities that is involved in causing non-contact damage to the anterior cruciate ligament (ACL). Methods This is a quasi-experimental study. Participants were 25 adolescent male football players with DKV who were purposefully selected from Shahin Football Academy in Amol, Iran and randomly divided into two groups of control and training. The existence of DKV was assessed by Squats test and the valgus angle were assessed by jump-landing test and Kinovea software. The abduction and external rotation strength and ROM of hip and the dorsiflexion and plantarflexion strength and ROM of ankle were evaluated with Manual Muscle Testing and a goniometer, respectively. After performing the pre-test assessments, the subjects in the training group performed neuromuscular training for 8 weeks, while the control group also participated in the physical fitness program of Shahin Football Academy. At the end, assessments were performed again in two groups. To examine the differences, repeated measures analysis of variance and Bonferroni post hoc test were used in SPSS software, version 24. The significance level was set at 0.05. Results The results showed a significant difference in knee valgus angle (P=0.001), abduction ROM of hip (P=0.01), external rotation ROM of hip (P=0.01), dorsiflexion ROM of ankle with knee extension (P=0.001), dorsiflexion ROM of ankle with knee flexion (P=0.001), hip abduction strength (P=0.002), hip external rotation strength (P=0.01), and plantarflexion strength of ankle (P=0.03) between the control and training groups. However, the results showed no significant difference in plantarflexion ROM of ankle and dorsiflexion strength of ankle (P&gt;0.05). After one month, the results showed the sustainability of the effect of training on abduction and external rotation ROM of hip, dorsiflexion ROM of ankle with knee extension and flexion, and dorsiflexion and plantarflexion strength of ankle. Conclusion The neuromuscular training can reduce the risk of non-contact ACL injury in male football players with DKV by improving strength and ROM of hip and ankle.

Exploration of the clinical course of frozen shoulder: A longitudinal multicenter prospective study of functional impairments

BackgroundContradictory evidence exists regarding the clinical course of frozen shoulder (FS). ObjectivesTo explore the clinical course of FS regarding disabilities, pain, range of motion (ROM), muscle strength, scapular upward rotation, and proprioception and to establish longitudinal correlations between these variables. MethodsPatients with FS were prospectively followed for 9 months at 3-month intervals. Assessment included the Disabilities of the Arm, Shoulder and Hand questionnaire; visual analogue scale for pain; an inclinometer for shoulder external rotation (ER), internal rotation (IR), flexion, and abduction ROM, and scapular upward rotation and proprioception, as well as handheld dynamometry for muscle strength in shoulder abduction, ER, and IR. ResultsInitially, 149 patients (98 females; mean (SD) age 53 (9) years) were included, with 88 completing all follow-up assessments. Most variables showed early improvement in the clinical course of FS, particularly ER and IR at 90° abduction, which continued to improve from 6 to 9 months of follow-up. Associations were observed between disabilities and pain (r = 0.61), disabilities/pain and ROM (r=-0.62 to -0.59 and r=-0.47 to -0.39, respectively), disabilities/pain and muscle strength (r=-0.24 to -0.35 and r=-0.36 to -0.17, respectively), and between disabilities/pain and scapular upward rotation below shoulder level (r = 0.23 to 0.38 and r = 0.24 to 0.30, respectively). ROM correlated with muscle strength (r = 0.14 to 0.44), while both ROM and ER muscle strength correlated with scapular upward rotation below shoulder level (r=-0.37 to -0.23 and r=-0.17 to -0.12, respectively). Muscle strength correlated with scapular upward rotation above shoulder level (r = 0.28 to 0.38) and lift-off muscle strength correlated with joint repositioning (r=-0.17 to -0.15). ConclusionAlmost all factors improved in the early phase (3–6 months) after baseline assessment, while ER and IR ROM at shoulder level continued to improve long term.

Poster 177: Does Prior Ipsilateral Steroid Injection Affect Outcomes After Rotator Cuff Repair?

Objectives: Rotator cuff pathology is a common problem, affecting approximately 17 million individuals in the US. Among professional and competitive athletes, only 49.9% have returned to play at the same level as before their injury. Initial treatment often includes corticosteroid injections, but some patients continue to have pain resulting in surgical treatment. Although steroids are the mainstay of conservative treatment, recent studies have shown concerns for increased rates of postoperative infections and revision surgeries after RCR. This study aimed to determine the effect of prior ipsilateral steroid injection on outcomes following arthroscopic rotator cuff repair. Methods: A retrospective chart review was performed on 295 patients who underwent rotator cuff repair by a single fellowship-trained orthopedic surgeon from 2017-2019. Of the 225 patients that met inclusion criteria and underwent analysis, 42 patients were in the injection group (IG) and 183 in the control group (CG). Demographics, range of motion (ROM), patient-reported pain and satisfaction (0- 10), subjective shoulder value (SSV), complications and reoperations were compared between groups. Delta ROM and strength were defined as postoperative ROM minus preoperative ROM. Complications were defined as reoperations, retears, or subsequent infection. Statistical analysis included chi-square and student t-tests. Results: The cohort consisted of 57.4% males with an average age of 58.3, BMI of 29.5, and mean follow-up of 7.3 months. The mean time from injection to surgery was 5.6 months. There were no significant differences in demographics between the injection and control group. Preoperatively, the injection group had a significantly greater median supraspinatus strength (p=0.002), summed strength (p=0.003), forward elevation (p=0.003), abduction (p=0.005), and active external rotation (p&lt;0.001). This was specific to injections received within the 12 months before surgery. Postoperatively, there were no significant differences between the groups on measures of pain, shoulder function, shoulder strength, range of motion, or SSV. The frequency of complications was also comparable between the no injection and injection group, having similar rates of persistent pain, limited ROM or stiffness, numbness or tingling, weakness, cervicalgia, adhesions, retear, and upper extremity DVT, and postoperative infections. Conclusions: The results of our study indicate that ipsilateral shoulder injection within one year of arthroscopic rotator cuff repair improves preoperative functional outcomes, namely improvements in forward flexion, abduction, external rotation, and relative strength. Despite enhancements preoperatively, postoperative measures of strength, range of motion, and complications are comparable between groups, which persists when analyzing the timing and number of injections. These results support the use of subacromial corticosteroid injections as an effective conservative treatment prior to rotator cuff repair. However, there is still a lack of consensus on how close in proximity to surgery it is safe to receive an injection and what preoperative patient characteristics may be more likely to benefit from injection prior to surgery. Future studies are needed to assess the short-term impact of corticosteroid injections on outcomes of rotator cuff repair, particularly in athletes.

Effect of Retear After Arthroscopic Rotator Cuff Repair on Return to Work and Sports in Nonathletes: A Retrospective Cohort Study.

The impact of retear after arthroscopic rotator cuff repair (ARCR) on clinical outcomes of patients remains controversial. The purpose of this study was to determine the effects of retear on strength recovery, return to previous levels of work, and return to sports participation. It was hypothesized that retears (1) would not have a significant effect on patient-reported outcome measures (PROMs) and (2) would significantly inhibit strength recovery and return to previous work and sports. Cohort study; Level of evidence, 3. The authors collected data from patients who underwent ARCR between January 2015 and December 2019. All included patients had undergone magnetic resonance imaging (MRI) and strength measurements 1 year postoperatively. Minimum 2-year postoperative PROMs (Constant score, pain visual analog scale, American Shoulder and Elbow Surgeons score, and Single Assessment Numeric Evaluation) and status on work and sports participation were collected, and PROM scores, strength recovery (percentage compared with the contralateral shoulder), return to work, and return to sports were compared between patients with versus without retear on 1-year postoperative MRI. Additionally, factors related to return to work and sports were identified through multivariable regression analysis. A total of 159 patients were included, of whom 19 (11.9%) had evidence of retear. Return-to-work and return-to-sports status was evaluated in 134 (84.3%) and 93 (58.5%) patients, respectively. There were no significant differences in PROM scores between patients with and without retears; however, patients with retears exhibited significantly worse supraspinatus strength recovery (73% vs 86%; P = .018) and external rotation strength recovery (78% vs 88%; P = .030) compared with patients with intact shoulders. There were no between-group differences in return to work or sports. Active workload was associated with unsuccessful return to work, whereas preoperative participation in shoulder sports was associated with successful return to work. Patients with postoperative retears had significantly worse postoperative strength recovery than patients with intact shoulders. Active workload and preoperative shoulder sports participation were factors associated with ability to return to work.

Poster 161: Musculoskeletal Adaptations to Baseball Pitching Differ Markedly Between Righthand Dominant Versus Lefthand Dominant Pitchers

Objectives: Musculoskeletal adaptations on the dominant arm of baseball pitchers are typically (1) a gain in glenohumeral external rotation (ER) range of motion (ROM), (2) a loss of glenohumeral internal rotation (IR) ROM, (3) posterior shoulder tightness, (4) weakness in the empty can test, and (5) increased IR strength. The purpose of this study was to determine if these adaptations differed between righthand dominant (RHD) versus lefthand dominant (LHD) pitchers. Based on recent work it was hypothesized that ROM adaptations would be less apparent in LHD pitchers, but strength adaptations would not differ between RHD and LHD pitchers. Methods: Shoulder ROM and strength were measured in 327 baseball pitchers in preseason screening (91 were tested on more than one season, 418 player-seasons, 322 RHD vs. 96 LHD). There were 157 youth pitchers (age 11-15 yr) 146 adolescent pitchers (age 16-17 yr) and 115 adult pitchers (age 18-24 yr). ER ROM, IR ROM and posterior shoulder ROM (Tyler test) were measured with a digital level. Empty can, ER, IR and scapular retraction strength were measured with a hand-held dynamometer. Differences between the dominant and nondominant arms, between RHD and LHD pitchers, and between age groups, were assessed using mixed model analysis of variance (mean and SD reported). Results: ROM Adaptations RHD pitchers had 11±10° more ER ROM on the dominant versus nondominant arm (P&lt;0.001) but LHD pitchers had no ER ROM difference (0±10°, P=0.685). The difference in ER ROM between RHD and LHD pitchers (P&lt;0.001) was unaffected by age (P=0.829). IR ROM loss on the dominant versus nondominant arm for RHD pitchers (10±11°) was greater (P&lt;0.001) than for LHD pitchers (5±10°). This difference was apparent for youth pitchers (RHD 9±9° vs. LHD 1±9°, P&lt;0.001) and adolescent pitchers (RHD 12±10 vs. LHD 5±11°, P&lt;0.001) but not for adult pitchers (RHD 9±14° vs. LHD 8±10°, P=0.863; RHD vs. LHD by Age Group P=0.040). Total ROM (ER+IR ROM) adaptations also differed between RHD and LHD pitchers (P&lt;0.001) and this effect was more apparent in the adult pitchers (Age Group by RHD vs. LHD P=0.027): RHD adult pitchers had a 4±15° gain in total ROM on the dominant side (P=0.007) while LHD adult pitchers had a 7±10° loss in total ROM on the dominant side (P=0.002). Posterior shoulder tightness on the dominant side was affected by arm dominance and age (P=0.038); for youth and adolescent pitchers there was no difference between RHD and LHD pitchers (youth RHD 6±13° vs. LHD 10±11°, P=0.156; adolescent RHD 5±10° vs. LHD 8±15°) but for adult pitchers, posterior shoulder tightness was greater for RHD versus LHD pitchers (6±8° vs. 1±11°, P=0.032). Strength Adaptations For the empty can test, RHD pitchers were weaker on the dominant versus nondominant arm (5±15%, P&lt;0.001) while there was no difference between the dominant and nondominant arms for LHD pitchers (3±16% stronger on dominant side P=0.100; RHD vs. LHD P&lt;0.001). For IR strength, RHD pitchers were stronger on the dominant arm (7±17%, P&lt;0.001) while there was no difference between the dominant and nondominant arms for LHD pitchers (2±21% P=0.360; RHD vs. LHD P=0.032). By contrast, for scapular retraction strength, LHD pitchers were stronger on the dominant arm (6±19%, P=0.007) while there was no difference between the dominant and nondominant arms for RHD pitchers (0±15% P=0.723; RHD vs. LHD P=0.003). Dominant versus nondominant ER strength was not different between RHD and LHD pitchers (P=0.323). Conclusions: The typical strength and ROM adaptations seen in baseball pitchers were mostly absent, or diminished, in LHD pitchers, but with some age dependent effects for ROM. Adult RHD pitchers had IR ROM loss and posterior shoulder tightness, but paradoxically adult LHD pitchers had IR ROM loss without associated posterior shoulder. The opposite was the case for youth and adolescent pitchers, with LHD pitchers having posterior shoulder tightness in the absence of IR ROM loss. Differences in strength adaptations between RHD and LHD pitchers have not been reported previously. Epidemiological studies examining the role of strength and ROM in injury risk for baseball pitchers have not previously accounted for differences between lefthanded and righthanded pitchers.

Effects of gender and fatigue on strength and activity of gluteus medius muscle during a controlled cutting maneuver in preadolescent athletes

The present study aimed to investigate the effects of gender on hip muscle strength and activity during a controlled cutting maneuver in preadolescent athletes. Fifty-six football and handball preadolescent players participated (35 females and 21 males). Normalized mean activity of the gluteus medius (GM) muscle was measured using surface electromyography during cutting maneuvers in pre-activation and eccentric phases. The stance duration and the strength of hip abductors and external rotators were recorded with a force plate and a handheld dynamometer, respectively. Descriptive statistics and mixed model analysis were used to assess statistical difference (α=0.05). The results showed that boys activate the GM muscle significantly more than girls during the pre-activation phase (P=0.022). Boys also demonstrated greater normalized strength of hip external rotation than girls (P=0.038), but not for hip abduction or duration of stance (P>0.05). When adjusted for abduction strength, however, boys had significantly shorter stance duration than girls (P=0.006). It seems that sex-dependent differences are present in preadolescent athletes as observed in the strength of hip external rotator muscles and neuromuscular activity of the GM muscle during a cutting maneuver. Future studies are needed to investigate whether these changes influence risk of lower limb/ACL injury during sport activities.

Clinical outcomes and tendon lengthening after arthroscopic rotator cuff repair.

There is a phenomenon in which the tendon appears to increase the length after rotator cuff repair. However, it is unclear in which cases tendon lengthening occurs and how the degree of lengthening affects the surgical outcome. This study aimed to evaluate preoperative and postoperative musculotendinous junction (MTJ) and tendon length on magnetic resonance imaging and assess the postoperative tendon lengthening and its impact on postoperative outcomes. We reviewed 109 patients with good repair integrity after arthroscopic rotator cuff repair. Patients whose supraspinatus tendons were simply pulled out laterally without any additional procedures were included. They underwent serial magnetic resonance imaging before surgery and at 3, 6, and 24months after surgery. The location of the MTJ in relation to the line of the glenoid fossa and the supraspinatus tendon length were measured. Clinical evaluation was conducted 2years after surgery, including the range of shoulder motion, shoulder strength index (affected/unaffected strength), Constant score, University of California, Los Angeles score, and pain numeric rating scale. The characteristics of the preoperative tendon, change in tendon length over time, amount of the lateral shift of MTJ location and tendon length, and impact of tendon lengthening on postoperative clinical outcomes were analyzed. The preoperative tendon retraction significantly correlated with the MTJ location (r=-0.75; P<.0001) and preoperative tendon length (r=-0.46; P<.0001). The tendon length at 3, 6, and 24months after surgery was significantly longer than those before surgery (26.7±5.8mm, 27.9±6.6mm, 28.5±5.6mm, and 21.5±5.1mm, respectively). From before surgery to 24months after surgery, the MTJ location moved 8.4±8.6mm laterally and the tendon length increased 7.0±6.1mm. A significant and weak negative correlation was found between tendon lengthening and the abduction strength index (r=-0.22; P=.03); however, no significant correlation with pain, range of shoulder motion, external rotation strength index, Constant score, and University of California, Los Angeles score was found. Multiple linear regression analysis also showed that tendon lengthening was only associated with the abduction strength index (standardized coefficient=-0.20, P=.03). Tendon lengthening and lateral shift of MTJ location were observed after arthroscopic rotator cuff repair, and they correlated with preoperative tendon retraction. Although the amount of tendon lengthening had negative weak correlation with abduction strength index, it did not affect other postoperative outcomes.

The effect of humeral component retroversion on external rotation and shoulder function outcomes in patients undergoing reverse total shoulder arthroplasty with a lateralized glenoid component

BackgroundDeficits in shoulder external rotation create significant limitations in activities of daily living, including eating and reaching the top of the head. Reverse total shoulder arthroplasty (rTSA) changes the mechanics of the shoulder and improves forward elevation reliably, but external rotation deficits frequently persist. There is currently a wealth of information regarding the impact of glenoid component lateralization, neck shaft angle, and angulation of the glenoid component on external rotation. However, the impact of humeral component retroversion is less understood. The purpose of this study was to compare strength and range of motion in external rotation of patients undergoing rTSA at different degrees of humeral retroversion. We hypothesized that humeral retroversion at 30 degrees would result in superior external rotation and strength postoperatively than 0 degrees of retroversion. MethodsThis is a retrospective study of prospectively collected data on patients who underwent rTSA with either 0 or 30 degrees of humeral component retroversion between November 2016 and 2018. A 36-mm-sized glenosphere with a system that lateralizes off the glenoid was utilized in all patients. Patient demographic information and postoperative outcomes at 3 months, 6 months, and latest follow-up including degree of external rotation, strength in external rotation, visual analog scale for pain, Simple Shoulder Test score, and American Shoulder and Elbow Surgeons score were recorded. ResultsOutcomes for 38 patients were included (N = 18 at 0-degree; N = 20 at 30-degree). No preoperative difference was observed between the two cohorts. There was no significant interaction between time and retroversion for any variable (P ≥ .16). Time had a significant effect on all outcomes (P ≤ .002) except for internal rotation (P = .17). Retroversion did not have a significant effect on outcomes at any time point (P ≥ .07), though external rotation strength nearly reached significance (P = .07). External rotation at the side increased from 25.0 to 35.3 degrees and external rotation in abduction increased from 39.2 degrees to 63.4 degrees from 3 months to final follow-up. External rotation at the side strength increased from 1.6 kg to 1.8 kg and external rotation in abduction strength increased from 1.2 kg to 1.7 kg from 3 months to final follow-up. ConclusionsNo differences in outcomes were observed between 0° and 30° of humeral component retroversion. Strength in external rotation may be impacted by humeral component retroversion. Further clinical studies with larger sample sizes are needed to study the impact of humeral component retroversion on external rotation strength.

The Influence of Gender on Hip Range of Motion, Hip Muscle Strength, Gluteus Medius Thickness and M-Mode Ultrasound Examination in Asymptomatic University Athletes: A Cross-Sectional Study

IntroductionPhysical activity is a proposed factor int the development of hip pathologies in male and female. The main objectives of this study were to investigate the influence of gender on isometric hip muscle strength, hip range of motion and gluteus medius thickness at rest, during contraction and onset activation.Material and methodsA cross-sectional study was carried out. Hip range of motion, hip muscle strength and gluteus medius thickness at rest, (B-Mode) and onset activation (M-Mode) were measured in thirty asymptomatic university athletes without history hip pain.ResultsA total of fifteen males (30 hips) and fifteen females (30 hips) with a mean age of 22 ± 6.5 and 20 ± 2.75 years old were recruited. Females demonstrated greater hip range of motion in flexion, abduction and internal rotation in dominant and non-dominant legs (p &lt; .05) but no differences were found extension, adduction and external rotation (p &gt; .05). Furthermore, females showed less isometric hip muscle strength in hip flexion, extension, abduction, adduction, internal and external rotation (p &lt; .05) but not in strength ratios (p &gt; .05). In addition, female exhibited less gluteus medius thickness at muscle contraction, less differences in rest-contaction thickness, but no differences were observed for rest thickness or contraction velocity.ConclusionsThis study found that asymptomatic female athletes demonstrated greater hip flexion, abduction and internal rotation ROM, less isometric hip muscle strength and different gluteus medius thickness and onset activation compared with asymptomatic male athletes.

EFFECTS ON EXTERNAL ROTATOR MUSCLE STRENGTH IN NECK OF FEMUR FRACTURE PATIENTS OPERATED WITH SOUTHERN MOORE APPROACH FOR BIPOLAR HEMIARTHROPLASTY OF HIP

Introduction: Neck of femur fracture is one of the most common fractures of elderly age group. Bipolar Hemiarthroplasty of Hip is most widely accepted treatment protocol. Posterior (Southern moore) approach is one of the widely used approach all over the world. In this approach Short external rotators are detached from their insertion and reattached. Hence there is a need to assess the function of External rotation of Hip post operatively. A Methods: Prospective study was carried out in patients with Neck of femur fracture who underwent Bipolar Hemiarthroplasty of Hip with Southern moore approach from May 2021 to May 2022 in a single institution. All patients were followed up and assessed at 6 weeks, 3 months and 6 months and function of short external rotators was assessed with Augustssons Strength test. Control for the muscle strength was considered opposite (Normal) side of hip. Patients with Any other ipsilateral fractures were excluded. Analysis of the data was done for the external rotator muscle strength at 6 weeks, 3 months and 6 months with comparison to normal hip of patient. The overall mean age was 69 years. Results: All the patient were followed up till 6 months post operatively. There was reduced strength of short external rotators in all the patients compared to normal hip at 6 weeks, with no significant difference in strength at 3 months. 12 out of 13 had equal muscle strength at 6 months. This study concludes that Detaching of Short external rotator in southe Conclusion: rn moore approach does not affect the muscle strength at 6 months. However it is found to be weaker in initial month.

Do Highly Trained Mountain Runners Differ from Recreational Active Non-Runners on Range of Motion and Strength in the Hip and Ankle as Well as Postural Control?

The rules governing mountain running force athletes to implement into their training programmes uphill and downhill running on unstable surfaces, which are demanding for hip and ankle as well as for the postural control system. The aim of the present cross-sectional study was to compare highly trained mountain runners (MR) and recreational active non-runners (NR) on range of motion (ROM) and strength in the hip and ankle, as well as dynamic postural control. Thirty MR and thirty-two NR were included in the study. ROM was assessed using a digital inclinometer. Strength was measured using a hand-held dynamometer. Postural control was evaluated using the lower quarter Y-balance test (YBT-LQ). The results showed that MR, in relation to NR, had statistically significant smaller hip external rotation ROM (p = 0.007), lower hip external rotator (p = 0.006) and extensor (p = 0.023) strength and greater normalised anterior reach in the YBT-LQ (p = 0.028). Mountain running training may reduce hip external rotation ROM as well as hip external rotator and extensor strength. Moreover, such training may improve postural control. MR should implement exercises targeted at developing hip ROM and strength. Furthermore, it seems that mountain running training may be a good way to improve postural control.

Traumatic rotator cuff tears with concomitant shoulder dislocation: tear characteristics and postsurgical outcomes.

Arthroscopic rotator cuff repair has been shown to have favorable outcomes following traumatic rotator cuff tear with concomitant shoulder dislocation. The aim of this study was to compare outcomes and tear characteristics between patients who underwent arthroscopic rotator cuff repair following traumatic tear with shoulder dislocation to those without dislocation. A retrospective review of 226 consecutive patients with traumatic rotator cuff tears who underwent arthroscopic repair between 2013 and 2017 with a minimum of 1-year follow-up was performed. Patients with traumatic dislocations and concomitant rotator cuff tears were placed in the Dislocation & Tear cohort (DT cohort) and were matched 1:2 with a second cohort sustaining traumatic cuff tears without dislocation (T cohort). Primary outcomes were injury characteristics including tendon involvement and atrophy and tear size and thickness. Secondary outcomes were postoperative strength and range of motion (ROM) in forward flexion (FF), external rotation (ER), and internal rotation (IR); patient-reported outcomes including Subjective Shoulder Value, visual analog scale, and American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form; complications including repair failure (defined as symptomatic retear confirmed on postoperative magnetic resonance imaging), infection, adhesive capsulitis, and impingement; and rates of revision surgery. There were 18 patients in the DT Cohort and 36 patients in the T Cohort with no significant differences in time to final follow-up (50.4±24.5 months vs. 49.0±30.4 months, P=.73). The DT cohort displayed a larger mean tear size (34±12 mm vs. 19±12 mm, P=.01) and had greater infraspinatus involvement (78% vs. 36%, P=.004) and subscapularis involvement (72% vs. 39%, P=.02) than the T cohort. With regard to strength, postoperative ER strength was less likely to be 5/5 in the DT Cohort (53% vs. 94% of patients with 5/5 strength, P=.002) compared with the T cohort. With regard to ROM, the DT cohort had significantly lower preoperative FF (90°±55° vs. 149°±33°, P<.001), ER (36±21° vs. 52° ±14°, P=.02), and IR (5.4 ±2.1 vs. 7.5 ±1.2, P=.002) compared with the T cohort but had similar FF, ER, and IR outcomes postoperatively. There were no differences between the groups for complications and postoperative patient-reported outcomes. Traumatic rotator cuff tears with concomitant dislocations are associated with larger tear size and greater infraspinatus and subscapularis involvement than traumatic tears without dislocation. Arthroscopic repair of this injury is associated with lower preoperative ROM in FF, ER, and IR, as well as lower postoperative ER strength compared with traumatic tears without dislocation. Nonetheless, excellent patient-reported outcomes can be achieved following arthroscopic repair similar to patients without dislocation.

Scapular fractures osteosynthesis via Judet's posterior approach: clinical and radiographic results.

Scapular fractures are uncommon and mainly treated nonoperatively. Judet's posterior approach allows access to the fracture site through the infraspinatus fossa and may be a technical option when ORIF is decided. The aims of this study were to determine clinical and radiographic outcomes of patients who underwent scapular body and/or glenoid fractures fixation via Judet's posterior approach. We conducted a retrospective single-centre study, and all patients admitted for scapular fracture who underwent osteosynthesis via Judet's approach between January 2014 and September 2021 were included. At a minimum follow-up of oneyear, clinical outcomes were analyzed through subjective shoulder value (SSV) and Constant-Murley score (CMS). Strength in external rotation was measured in adduction and in 90° abduction and compared to healthy side. Radiographic analysis evaluated postoperative fracture reduction on CT scan and glenohumeral osteoarthritis according to Samilson's classification at last follow-up. Twenty-one patients were included with a mean follow-up of 44.9months. Mean SSV, CMS, and adjusted CMS were 73.8% ± 21.0, 65.8 points ± 19.5, and 72.8% ± 20.8, respectively. Strength in external rotation in adduction of the affected shoulder showed significant impairment when compared with the contralateral side (respectively 7.79kg ± 4.29 and 12.0kg ± 3.84, p = 0.02). All fractures healed uneventfully, but five patients (23.8%) required early revision surgery for intra-articular screws in three. Intra-articular gap measure decreased from 3.75mm ± 1.93 in preoperative to 0.59mm ± 0.97 after ORIF. The rate of arthritis was 15% at last follow-up. Patients who underwent scapular fracture osteosynthesis via Judet's posterior approach exhibited satisfactory but incomplete recovery of the affected shoulder as evidenced by functional scores and external rotation strength measurements at a mean follow-up of 44.9months. Because of the risk of intra-articular screws, postoperative CT scan is mandatory.

Effectiveness analysis of arthroscopic single/double-row suture techniques in repairing of moderate rotator cuff tears

To compare the early effectiveness of arthroscopic repair of moderate rotator cuff tears with single-row modified Mason-Allen technique and double-row suture bridge technique. The clinical data of 40 patients with moderate rotator cuff tears who met the selection criteria between January 2021 and May 2022 were retrospectively analyzed. Among them, 20 cases were repaired with single-row modified Mason-Allen suture technique (single-row group) and 20 cases with double-row suture bridge technique (double-row group). There was no significant difference in gender, age, disease duration, rotator cuff tear size, and preoperative visual analogue scale (VAS) score, Constant-Murley score, and T2* value between the two groups ( P>0.05). The VAS score, Constant-Murley score (including subjective influence, pain, flexion, internal rotation, external rotation, abduction, and muscle strength score) were compared between the two groups before operation and at 6 weeks, 3, 6, and 12 months after operation. Functional MRI and ultrashort-echo-time (UTE)-T2* technique were performed to calculate T2* value and quantitatively evaluate the healing of rotator cuff tissue; and the healing of rotator cuff was evaluated by Sugaya classification at 12 months after operation. Patients in both groups were followed up 1 year. There was no complication such as muscle atrophy, joint stiffness, or postoperative rotator cuff tear. The intra-group comparison showed that the scores of pain, subjective influence, flexion, abduction, and muscle strength in Constant-Murley scores at each time point after operation in the two groups were significantly higher than those before operation, while VAS scores were significantly lower than those before operation ( P<0.05). Internal rotation, external rotation, and total score of Constant-Murley score in the two groups were lower at 6 weeks due to abduction immobilization within 6 weeks after operation, and gradually increased at 6 months after operation, with significant differences at 3, 6, and 12 months after operation when compared with those before operation and at 6 weeks after operation ( P<0.05). The T2* values of the two groups showed a downward trend over time, and there were significant differences between the two groups at other time points ( P<0.05), except that there was no significant difference between at 6 and 12 months after operation in the single-row group and between at 3, 6, and 12 months after operation in the double-row group ( P>0.05). The comparison between groups showed that the VAS score and T2* values of the double-row group were significantly lower than those of the single-row group at 6 weeks, 3 months, 6 months, and 12 months after operation ( P<0.05). The scores of subjective influence, flexion, abduction, and internal rotation in the double-row group were significantly better than those in the single-row group at 6 weeks and 3 months after operation ( P<0.05), and the external rotation score and total score in the double-row group were significantly better than those in the single-row group at 3 months after operation ( P<0.05), but there was no significant difference at 6 and 12 months after operation ( P>0.05). There was no significant difference in muscle strength and pain scores between the two groups at 6 weeks, 3 months, 6 months, and 12 months after operation ( P>0.05). There was no significant difference in the results of Sugaya classification between the two groups at 12 months after operation ( Z=1.060, P=0.289). The effectiveness of arthroscopic repair of moderate rotator cuff tears with modified Mason-Allen technique and double-row suture bridge technique is satisfactory, but suture bridge technique is helpful to the early rehabilitation training of shoulder joint and the recovery of motor function of patients.