Isokinetic rotator muscles fatigue in glenohumeral joint instability before and after Latarjet surgery A pilot prospective study

Isokinetic Strength and Balance Analyses for Predicting Return to Sports After the Latarjet Procedure: A Prospective Cross-sectional Study

BACKGROUND

Isokinetic torque in shoulder internal rotation (IR) and external rotation (ER) can be considered as potential indicators for dynamic stability of the glenohumeral joint.

PURPOSE

To assess the efficacy of 4-month isokinetic testing in predicting the 6-month return-to-sports (RTS) status after Latarjet surgery, explore its correlations with testing parameters, and identify optimal thresholds to ensure a safe RTS.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

The study assessed athletes who underwent the Latarjet stabilization procedure between January 2022 and June 2023. The primary outcome was RTS at 6 months after surgery. The primary examined predictors were isokinetic testing metrics at 4 months postoperatively. Secondary outcomes comprised the modified Closed Kinetic Chain Upper Extremity Stability Test (mCKCUEST) and several patient-reported outcome measures, including the Walch-Duplay score, the Western Ontario Shoulder Instability Index (WOSI), and the Shoulder Instability-Return to Sports after Injury scale. To assess the predictors, patients were divided into those who returned to any level of sports compared with those who did not return to sports. The correlation between isokinetic testing results and other outcome scores was also analyzed.

RESULTS

A total of 71 patients (mean age, 27.43 ± 9.09 years) were included in the study. Of these, 23.61% did not return to sports, 38.89% returned at a lower level, and 37.50% returned to the same level. Significant rotational strength disparities were noted. Patients who did not return to sports at 6 months demonstrated inferior strength in concentric ER at 60 deg/s, concentric ER at 240 deg/s, concentric IR at 240 deg/s, and eccentric IR at 30 deg/s (P < .05). Similar trends appeared for all studied patient-reported outcome measures and the mCKCUEST (P < .05). Receiver operating characteristic analysis emphasized the significance of isokinetic testing in concentric ER at 240 deg/s (area under the curve = 0.759; P = .001; cutoff = 0.32 N·m/kg; sensitivity = 100.0%; specificity = 49.1%) and eccentric ER at 30 deg/s (area under the curve = 0.760; P = .001; cutoff = 0.51 N·m/kg; sensitivity = 94.1%; specificity = 49.1%) for RTS prediction. Additionally, ER strength moderately correlated with the Walch-Duplay score across all examined velocities (r = 0.26-0.34; P < .05). The modified WOSI score was weakly linked to ER strength at 240 deg/s and 30 deg/s (r = 0.24-0.25; P < .05) as well as moderately linked to the limb symmetry index in ER at 60 deg/s and 30 deg/s (r = 0.30-0.38; P < .05).

CONCLUSION

Isokinetic testing can act as an independent predictor of successful RTS after Latarjet surgery, with concentric ER at 240 deg/s, concentric IR at 240 deg/s, eccentric ER at 30 deg/s, and eccentric IR at 30 deg/s showing the most accuracy. Strength recovery in ER was associated with better Walch-Duplay and modified WOSI scores.

Subscapularis atrophy and function after arthroscopic Trillat procedure

INTRODUCTION

Several studies have reported a strength deficit in internal rotation (IR) following a Latarjet procedure, which can persist for months or even years. The arthroscopic Trillat procedure does not require splitting the subscapularis muscle, potentially making it less damaging.

HYPOTHESIS

The arthroscopic Trillat procedure does not cause any atrophy or strength deficit in the subscapularis muscle.

METHODS

This was a single center, retrospective study of patients treated between 2013 and 2021. Included were patients who had chronic anterior shoulder instability with an indication for surgical stabilization using an arthroscopic Trillat procedure and who underwent a CT scan before surgery and a second one at 6 months postoperative. The following morphological parameters were measured on all the rotator cuff muscles: cross-sectional area (CSA), thickness and fatty infiltration using the mean muscle attenuation (MMA) measurement. Isokinetic tests were done 1 year post-surgery.

RESULTS

One hundred seventeen patients underwent arthroscopic Trillat surgery between 2013 and 2021; 58 were included, 30 were analyzed and 17 patients underwent isokinetic testing. The CSA of the subscapularis was significantly smaller by 5.3% (17.0 vs. 16.1; p = 0.03). None of the other rotator cuff muscles had a smaller CSA. The MMA of the subscapularis increased significantly while the MMA of the external rotators decreased postoperatively. No strength deficit was found at 1 year postoperative in the internal and external rotators.

DISCUSSION

The arthroscopic Trillat procedure produces minor atrophy of the subscapularis muscle at 6 months, with no strength deficit at 1 year postoperative. Several studies have reported a deficit in internal rotation strength after a Latarjet procedure, ranging from 6% to 19% depending on the study.

LEVEL OF EVIDENCE

IV.

Isokinetic Evaluation of the Shoulder After Bristow/Latarjet Surgical Procedure in Athletes

Objectives  To evaluate the muscular strength of the internal (IR) and external (ER) rotators of the shoulder after Bristow/Latarjet surgery. Methods  Cross-sectional study with 18 patients (36 shoulders). The isokinetic evaluation was performed using the Biodex 3 System Pro dynamometer (Biodex Medical System, Inc., Shirley, NY, USA). The athletic shoulder outcome rating scale (ASORS) and the visual analogue scale (VAS) were applied. Results  The values of peak torque and maximum work in concentric and eccentric mode on the non-operated shoulder were higher than on the operated side for both the IR and ER ( p  < 0.01). The conventional and functional balance between the ER and IR showed no differences between the operated and the non-operated side. When comparing patients with postoperative time < 1 year or 1 year, no differences were observed in peak torque values at 60°/s and 240°/s and maximum work at 60°/s and 240°/s of the IR to the operated shoulder. However, the peak torque values of 60°/s and 240°/s and maximum work at 60°/s and 240°/s of the ER were higher in subjects with postoperative time ≥ 1 year in all variables ( p  < 0.05). Conclusions  There was a decrease in the strength of the IR and ER in the operated shoulder compared with the healthy shoulder. However, the conventional and functional balance was maintained.

Comparison of Structural Subscapularis Integrity After Latarjet Procedure Versus Iliac Crest Bone Graft Transfer

Background:

Although clinical outcome scores are comparable after coracoid transfer procedure (Latarjet) and iliac crest bone graft transfer (ICBGT) for anterior shoulder instability with glenoid bone loss, a significant decrease in internal rotation capacity has been reported for the Latarjet procedure.

Hypothesis:

The subscapularis (SSC) musculotendinous integrity will be less compromised by ICBGT than by the Latarjet procedure.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

We retrospectively analyzed pre- and postoperative computed tomography (CT) scans at short-term follow-up of 52 patients (26 Latarjet, 26 ICBGT) previously assessed in a prospective randomized controlled trial. Measurements included the preoperative glenoid defect area and graft area protruding the glenoid rim at follow-up and tendon thickness assessed through SSC and infraspinatus (ISP) ratios. Fatty muscle infiltration was graded according to Goutallier, quantified with muscle attenuation in Hounsfield units, and additionally calculated as percentages. We measured 3 angles to describe rerouting of the SSC musculotendinous unit around the bone grafts.

Results:

SSC fatty muscle infiltration was 2.0% ± 2.2% in the Latarjet group versus 2.4% ± 2.2% in ICBGT (P = .546) preoperatively and showed significantly higher values in the Latarjet group at follow-up (5.3% ± 4.5% vs 2.3% ± 1.7%; P = .001). In total, 4 patients (15.4%) in the Latarjet group showed a progression from grade 0 to grade 1 at follow-up, whereas no changes in the ICBGT group were noted. The measured rerouting angle of the SSC muscle was significantly increased in the Latarjet group (11.8° ± 2.1°) compared with ICBGT (7.5° ± 1.3°; P < .001) at follow-up, with a significant positive correlation between this angle and fatty muscle infiltration (R = 0.447; P = .008). Ratios of SSC/ISP tendon thickness were 1.03 ± 0.3 in the Latarjet group versus 0.97 ± 0.3 (P = .383) in ICBGT preoperatively and showed significantly lower ratios in the Latarjet group (0.7 ± 0.3 vs 1.0 ± 0.2; P < .001) at follow-up.

Conclusion:

Although clinical outcome scores after anterior shoulder stabilization with a Latarjet procedure and ICBGT are comparable, this study shows that the described decline in internal rotation capacity after Latarjet procedure has a radiographic structural correlate in terms of marked thinning and rerouting of the SSC tendon as well as slight fatty degeneration of the muscle.

Effects of a Sport-Specific Upper-Body Resistance-Band Training Program on Overhead Throwing Velocity and Glenohumeral Joint Range of Motion

Oranchuk, DJ, Ecsedy, EN, and Robinson, TL. Effects of a sport-specific upper-body resistance-band training program on overhead throwing velocity and glenohumeral joint range of motion. J Strength Cond Res XX(X): 000-000, 2020-Practitioners seek optimal, yet practical means to enhance performance while aiming to minimize injury risk. Resistance bands offer portability and safety and enable similar movements to competition. However, the effect of movement-specific resistance-band training on throwing performance and markers of injury risk has yet to be elucidated. Therefore, the purpose of this study was to compare the effects of a resistance training program using resistance bands with sport-specific (SS), or general-training (GT) exercises. Twenty-eight collegiate female softball players were randomly allocated to an SS (n = 15) or GT (n = 13) 8-week resistance-band program. Dependent variables included peak and mean throwing velocity, 1 repetition maximum (1RM) cable Chop-test, and glenohumeral internal and external rotation range of motion (ROM). No significant (p ≤ 0.338) differences were found between groups at baseline. Improvements in peak (p = 0.006, 4.9%, effect size [ES] = 0.61) and mean (p = 0.004, 3.1%, ES = 0.49) throwing velocity were seen after SS training, while the 1RM Chop-test increased in both SS (p < 0.001, 23.5%, ES = 1.06) and GT (p = 0.049, 26.1%, ES = 0.57) groups. However, no between-group differences (p ≥ 0.109, ES ≤ 0.17) were present in any variable. Neither the Chop-test nor shoulder internal or external ROM had more than moderate correlations with throwing velocity (r ≤ 0.30, p ≥ 0.119). Therefore, practitioners should not depend solely on SS resistance-band training when aiming to improve throwing velocity or measures of shoulder rotational health. However, resistance bands appear to be a practical alternative when traditional means of resistance training are not available. In addition, strength and conditioning coaches should not use the Chop-test or shoulder ROM to predict throwing performance.

Return to Play Criteria Following Surgical Stabilization for Traumatic Anterior Shoulder Instability: A Systematic Review

PURPOSE

To identify and describe in the existing literature any criteria used for return to play following surgical stabilization for traumatic, anterior shoulder instability.

METHODS

We performed a systematic review evaluating surgical stabilization for primary traumatic anterior shoulder instability in skeletally mature patients with a minimum of 1-year follow-up using Level I to IV studies in PubMed and EMBASE from January 1994 to January 2017.

RESULTS

Fifty-eight studies with at least 1 explicitly stated criterion for return to play were identified from a review of more than 5,100 published articles. Seven different categories of return to play criteria were identified, the most common of which were time from surgery (89.6%), strength (18.9%), and range of motion (13.8%). Pain, stability, proprioception, and postoperative radiographic evaluation were also used. As hypothesized, in 75.8% of the included studies (44/58), time was the only criterion explicitly used. The most commonly used time for return to play was 6 months.

CONCLUSIONS

This systematic review identifies 7 criteria that have been used in the available literature to determine when patients are ready to return to play; however, consistent with our hypothesis, 75% of studies used time from surgery as the sole listed criterion, with the most commonly used time point of 6 months postoperative. All of these criteria can be used in future research to develop a comprehensive checklist of functional criteria in hopes of reducing recurrent injury.

LEVEL OF EVIDENCE

Level IV, systematic review.

Latarjet procedure using subscapularis split approach offers better rotational endurance than partial tenotomy for anterior shoulder instability

PURPOSE

Latarjet, which is a coracoid bone block procedure, is an effective treatment for anterior shoulder instability with glenoid bone loss. During this reconstructive procedure the subscapularis may be tenotomized or be split to expose the glenoid neck. The aim of this study was to assess the effect of subscapularis management on functional outcomes and internal and external rotation durability and strength. Hypothesis is that the subscapularis split approach will result in better functional results and superior internal rotation strength and endurance.

METHODS

The study included 48 patients [median age 30 (range 16-69); 42 males, 6 females], who underwent a modified Latarjet procedure for anterior shoulder instability. There were 20 patients in the subscapularis tenotomy group and 28 patients in the subscapularis split group. The groups were compared isokinetically using a computerized dynamometer for internal and external rotation durability and strength. At the latest follow-up, the patients were evaluated with the American Shoulder and Elbow Surgeons (ASES) and ROWE scores for functional outcomes.

RESULTS

At a median follow-up period of 25 (range 12-73) months after the Latarjet procedure, the internal rotation durability was significantly higher in the split group (p = 0.045). However, a statistically significant difference could not be found for internal and external rotational strengths (n.s.). There was also no significant difference between the final ASES and ROWE scores (n.s.).

CONCLUSION

Although both approaches offer promising results, the subscapularis split approach appears to provide better internal rotation durability compared to subscapularis tenotomy. Therefore, the subscapularis split approach may be more preferable for the management of the subscapularis muscle during Latarjet procedure.

LEVEL OF EVIDENCE

Retrospective cohort study, Level III.

Is the subscapularis normal after the open Latarjet procedure? An isokinetic and magnetic resonance imaging evaluation

BACKGROUND

The Latarjet procedure is considered to be a violation of the subscapularis muscle. This study evaluated the postoperative status of the subscapularis through isokinetic and magnetic resonance imaging analysis after splitting. We hypothesized that compared with a healthy contralateral shoulder, there would be satisfactory recovery of subscapularis strength at the cost of some fatigability and some mild fatty infiltration.

MATERIALS AND METHODS

This was a case-control retrospective study of patients who underwent a Latarjet procedure between January 2013 and January 2015. A total of 20 patients were reviewed at 1 year postoperatively. With the patient seated, strength testing of both shoulders was done (concentric, eccentric, and fatigability) with a dynamometer. Trophicity and fatty infiltration were analyzed by magnetic resonance imaging.

RESULTS

Strength of the internal rotators (IRs) and external rotators (ERs) of the injured shoulder was significantly lower compared with the healthy shoulder in concentric testing at 180°/s and 60°/s (13% for IR and 20% for E, P < .05) and in eccentric testing at 60°/s (19% for IR and 16% for ER, P < .05). A peak torque ratio (ER/IR) of the operated-on shoulder was maintained. The difference in muscular endurance was significant (P < .001). There was no muscle atrophy and minimal or no fatty infiltration of the subscapularis in any patient.

CONCLUSION

At 1 year after the open Latarjet procedure, isokinetic testing showed a combined strength deficit in both internal and external rotation with a conserved muscle balance. Although no significant subscapularis fatty infiltration or atrophy was noted, there was a significant deficit in endurance compared with the healthy shoulder.