Humeral head retroversion in competitive baseball players and its relationship to glenohumeral rotation range of motion

Differences in humeral retroversion in dominant and nondominant sides of young baseball players

BACKGROUND

The relationship between the disabled throwing shoulder and humeral retroversion has recently attracted a great deal of attention. However, none of the previous studies clarified when the side-to-side difference of humeral retroversion in young baseball players would start. This study aimed to clarify when the difference of humeral retroversion in the dominant and nondominant sides appeared in baseball players.

METHODS

The bicipital-forearm angle in bilateral shoulders of 172 elementary school baseball players was measured by ultrasound. The bicipital-forearm angle was defined as an angle between the perpendicular line to the bicipital groove and the ulnar long axis with the elbow flexed at 90°. The correlation between the bicipital-forearm angle and the grade and the difference of the bicipital-forearm angle between the dominant and nondominant sides were analyzed.

RESULTS

In the nondominant shoulders, the bicipital-forearm angle increased with the grade in school (r = 0.32, P < .0001), but this was not observed in the dominant shoulders. In the fourth to sixth graders, the bicipital-forearm angles were significantly smaller in the dominant shoulders than in the nondominant shoulders.

CONCLUSION

Our findings indicated that humeral retroversion decreased with age in the nonthrowing side but not in the throwing side and that the side-to-side difference of humeral retroversion in the baseball players became obvious from the fourth grade. We assume that the repetitive throwing motion restricts the physiologic humeral derotation process and the difference became apparent from the fourth grade when the growth spurt begins in boys.

Acute effects of self-myofascial release and stretching in overhead athletes with GIRD

OBJECTIVE

To examine the acute effects of self-myofascial release (SMR), static stretching (SS), and the combination of self-myofascial release and static stretching (SMR + SS) on glenohumeral internal rotation range of motion (GH IR ROM) in overhead athletes with glenohumeral internal rotation deficit (GIRD).

PARTICIPANTS

Twelve asymptomatic adult male amateur softball position players exhibiting GIRD.

RESULTS

All three methods significantly improved GH IR ROM. Post hoc testing revealed that SS alone and SMR + SS improved GH IR ROM significantly more than SMR alone. However, there were no significant differences in GH IR ROM between SS alone and SMR + SS.

CONCLUSIONS

If an athlete has a limited time to perform a warm-up (e.g., 3-4 min), SS alone is recommended to improve GH IR ROM. However, if the athlete has more time available to warm up (e.g., 7-8 min), combining SMR + SS may result in a greater increase in GH IR ROM.

Effects of a Short-Duration Stretching Drill After Pitching on Elbow and Shoulder Range of Motion in Professional Baseball Pitchers

BACKGROUND

A glenohumeral internal rotation (IR) deficit or a total rotational motion (IR plus external rotation [ER]) deficit in the throwing shoulder compared with the nonthrowing shoulder has been shown to increase the risk of shoulder and elbow injuries. After a pitching session, both IR and total rotational motion deficits have been shown to occur naturally for an extended period of time in asymptomatic pitchers, but it is unclear how to best control these deficits between pitching sessions. Purpose/Hypothesis: The purpose of this study was to determine whether performing a short-duration stretching/calisthenics drill after pitching will result in an increase in IR, ER, total rotational motion, and elbow extension in professional baseball pitchers. It was hypothesized that these shoulder and elbow passive range of motion (PROM) measurements would all decrease after pitching but would subsequently return to prepitching values after the short-duration stretching/calisthenics drill.

STUDY DESIGN

Controlled laboratory study.

METHODS

A convenience sample of 20 male professional baseball pitchers served as study participants. The following sequence of activities was performed for all participants: (1) a 5- to 10-minute dynamic warm-up consisting of running and light throwing, (2) elbow extension and IR and ER PROM measurements taken before pitching, (3) 40 full-effort pitches off the pitching mound, (4) 8 minutes of rest, (5) elbow extension and IR and ER PROM measurements taken after pitching, (6) a short-duration stretching/calisthenics drill (two-out drill), and (7) elbow extension and IR and ER PROM measurements taken after the two-out drill. A 1-way repeated-measures analysis of variance ( P < .05) was employed to assess differences in elbow extension, IR, ER, and total rotational motion in the 3 measurement conditions (prepitching, postpitching, and postdrill). To assess intrarater and interrater reliability, intraclass correlation coefficients (ICCs) were calculated, and the measurement error was calculated using the standard error of measurement (SEM).

RESULTS

Significant differences were observed among the 3 conditions for ER ( P = .002), IR ( P = .027), and total rotational motion ( P < .001), but there was no significant difference in elbow extension ( P = .117). Bonferroni post hoc analyses revealed (1) significantly greater ER during prepitching and postdrill versus the postpitching condition (94° ± 7° [prepitching] and 94° ± 8° [postdrill] vs 88° ± 8°; P = .010 and .005, respectively), (2) significantly greater IR during prepitching and postdrill versus the postpitching condition (36° ± 10° [prepitching] and 35° ± 9° [postdrill] vs 30° ± 10°; P = .034 and .043, respectively), and (3) significantly greater total rotational motion during prepitching and postdrill versus the postpitching condition (129° ± 13° [prepitching] and 129° ± 13° [postdrill] vs 119° ± 13°; P = .034 and .004, respectively). There were no significant differences in ER, IR, or total rotational motion between the prepitching and postdrill conditions ( P > .999 for all). The intrarater reliability (ICC_3,1) was 0.91 for ER (SEM, 1.3°) and 0.90 for IR (SEM, 1.9°), and the interrater reliability (ICC_2,1) was 0.81 for ER (SEM, 3.3°) and 0.77 for IR (SEM, 4.3°).

CONCLUSION

After a 40-pitch bullpen session, IR and ER PROM as well as total rotational motion were significantly lower than prepitching values; however, these deficits were restored back to their prepitching levels after the players performed the two-out drill, which may increase pitching performance and decrease the risk of shoulder and elbow injuries. More research is needed to test these hypotheses and assess the clinical efficacy of the two-out drill.

CLINICAL RELEVANCE

The findings from the current study will assist clinicians better understand the positive effects of performing a short duration stretching/calisthenics drill on shoulder internal and external rotation range of motion between innings while pitching during a baseball game.

Use of the Spencer Technique on Collegiate Baseball Players: Effect on Physical Performance and Self-Report Measures

CONTEXT

Repeated overhead throwing in baseball players alters range of motion (ROM), contributing to shoulder injury. The Spencer technique has been used, anecdotally, to reduce the effects of throwing-induced limitations in ROM.

OBJECTIVE

To quantify the effects of a single administration of the Spencer technique on the ROM and performance of collegiate baseball pitchers.

METHODS

Pitchers from the Seton Hill University men's baseball team were randomly assigned to 2 treatment groups: Spencer technique or sham therapy. The first week consisted of baseline outcome measurements (1 week before treatment), including ROM (flexion, extension, abduction, adduction, internal rotation, and external rotation) of the dominant throwing arm, 10 maximum velocity throws, and self-reported performance using the Kerlan-Jobe Orthopaedic Clinic Shoulder and Elbow Score (KJOC-SES). The second week consisted of pretreatment ROM measurement, followed by a single treatment and repeated measurement of all outcomes.

RESULTS

Of 16 players, 15 met inclusion criteria. An effect of training on ROM between weeks 1 and 2 for all players consisted of significantly decreased internal rotation (P=.02) and increased external rotation (P=.04). A differential effect of treatment was found on the mean difference in internal rotation after treatment, compared with the mean difference before treatment on the same day (P=.01). Additionally, a trend toward statistical significance for abduction (P=.08) was noted. Analyses reveal that these effects were caused by significant increases in the internal rotation and abduction for the Spencer group only (P=.02). All other analyses of ROM, as well as performance measured by maximum velocity throws and the KJOC-SES, revealed no differential effect of treatment.

CONCLUSION

The results of this study support the use of the Spencer technique in counteracting the potentially negative effects of repeated throwing on internal rotation. However, a single administration did not affect functional ability in this study. Future studies of longer duration and including differing levels of play, injury status, and playing position will be needed to further evaluate the full potential of the Spencer technique in athletes who engage in repeated overhead arm movements.

Humeral Retrotorsion and Glenohumeral Motion in Youth Baseball Players Compared With Age-Matched Nonthrowing Athletes

BACKGROUND

Baseball players exhibit a more posteriorly oriented humeral head in their throwing arm. This is termed humeral retrotorsion (HRT) and likely represents a response to the stress of throwing. This adaptation is thought to occur while the athlete is skeletally immature, however currently there is limited research detailing how throwing activity in younger players influences the development of HRT. In addition, it is presently unclear how this changing osseous orientation may influence shoulder motion within young athletes.

PURPOSE

To determine the influence of throwing activity and age on the development of side-to-side asymmetry in HRT and shoulder range of motion (ROM).

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Healthy athletes (age range, 8-14 years) were categorized into 2 groups based upon sports participation; throwers (n = 85) and nonthrowers (n = 68). Bilateral measurements of HRT, shoulder external rotation (ER), internal rotation (IR), and total range of motion (TROM) at 90° were performed using diagnostic ultrasound and a digital inclinometer. Side-to-side asymmetry (dominant minus nondominant side) in HRT and in shoulder ER, IR, and TROM were assessed. Statistical analysis was performed with 2-way analysis of variance and Pearson correlation coefficients.

RESULTS

Throwers demonstrated a larger degree of HRT on the dominant side, resulting in greater asymmetry compared with nonthrowers (8.7° vs 4.8°). Throwers demonstrated a gain of ER (5.1°), a loss of IR (6.0°), and no change in TROM when compared with the nondominant shoulder. Pairwise comparisons identified altered HRT and shoulder ROM in all age groups, including the youngest throwers (age range, 8-10.5 years). A positive correlation existed between HRT and ER ROM that was stronger in nonthrowers ( r = 0.63) than in throwers ( r = 0.23), while a negative correlation existed with IR that was stronger in throwers ( r = -0.40) than in nonthrowers ( r = -0.27).

CONCLUSION

Throwing activity causes adaptive changes in HRT and shoulder ROM in youth baseball players at an early age. Other factors in addition to HRT influence shoulder motion within this population.

Metatarsal Shape and Foot Type: A Geometric Morphometric Analysis

Planus and cavus foot types have been associated with an increased risk of pain and disability. Improving our understanding of the geometric differences between bones in different foot types may provide insights into injury risk profiles and have implications for the design of musculoskeletal and finite-element models. In this study, we performed a geometric morphometric analysis on the geometry of metatarsal bones from 65 feet, segmented from computed tomography (CT) scans. These were categorized into four foot types: pes cavus, neutrally aligned, asymptomatic pes planus, and symptomatic pes planus. Generalized procrustes analysis (GPA) followed by permutation tests was used to determine significant shape differences associated with foot type and sex, and principal component analysis was used to find the modes of variation for each metatarsal. Significant shape differences were found between foot types for all the metatarsals (p < 0.01), most notably in the case of the second metatarsal which showed significant pairwise differences across all the foot types. Analysis of the principal components of variation showed pes cavus bones to have reduced cross-sectional areas in the sagittal and frontal planes. The first (p = 0.02) and fourth metatarsals (p = 0.003) were found to have significant sex-based differences, with first metatarsals from females shown to have reduced width, and fourth metatarsals from females shown to have reduced frontal and sagittal plane cross-sectional areas. Overall, these findings suggest that metatarsal bones have distinct morphological characteristics that are associated with foot type and sex, with implications for our understanding of anatomy and numerical modeling of the foot.

Baseball Players With an Ulnar Collateral Ligament Tear Display Increased Nondominant Arm Humeral Torsion Compared With Healthy Baseball Players

BACKGROUND

Previous work has suggested that an increase in the amount of developmentally acquired, dominant arm humeral retrotorsion (D HRT) in the thrower's shoulder may be a potentially protective mechanism. Although the relationship between HRT and shoulder injuries has been reported, the relationship between HRT and ulnar collateral ligament (UCL) tears in baseball players is not known.

PURPOSE

To determine whether D HRT and nondominant arm HRT (ND HRT) measurements in baseball players with a UCL tear differ statistically from a matched healthy cohort.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

D HRT and ND HRT were measured in 112 male competitive high school and collegiate baseball players seen over an 18-month period from 2013 to 2015. A total of 56 participants with a clinical and magnetic resonance imaging-confirmed diagnosis of a throwing-arm UCL tear (UCLInj group) were compared with 56 healthy baseball players with no history of an elbow injury who were matched for age, experience, and position (NUCLInj group). The mean ages in the UCLInj and NUCLInj groups were 17.9 ± 2.2 and 17.6 ± 2.8 years, respectively. Using a previously validated ultrasound method, D HRT and ND HRT were measured in the supine position, and the HRT side-to-side difference (D HRT - ND HRT) was calculated. A 1-way multivariate analysis of variance was used to determine the mean statistical differences between groups ( P < .05).

RESULTS

Baseball players with a UCL tear displayed significantly more humeral torsion (ie, less retrotorsion) in their nondominant arm compared with healthy baseball players (UCLInj = 33.27° ± 10.27°, NUCLInj = 27.82° ± 10.88°; P = .007). Baseball players with a UCL tear did not display any differences in D HRT compared with healthy baseball players (UCLInj = 18.67° ± 9.41°, NUCLInj = 17.09° ± 9.92°; P = .391). Significant side-to-side differences in HRT existed between groups (UCLInj = -14.60° ± 6.72°, NUCLInj = -10.72° ± 6.88°; P = .003).

CONCLUSION

There was a significant increase in mean nondominant arm humeral torsion (ie, less retrotorsion) in the UCL tear group, but there was no significant difference in the mean D HRT between the injured and uninjured groups. A greater HRT side-to-side difference was displayed in the UCL tear group. The extent to which a thrower has developmentally acquired both D HRT and ND HRT may affect elbow UCL tear risk. Furthermore, it is possible that the extent of genetically predisposed ND HRT may influence the throwing-related increase in D HRT.

Humeral Retroversion in Children with Shoulder Internal Rotation Contractures Secondary to Upper-Trunk Neonatal Brachial Plexus Palsy

BACKGROUND

The most common sequela of neonatal brachial plexus palsy is an internal rotation contracture of the shoulder that impairs function and leads to skeletal deformation of the glenohumeral joint. Treatment options include release, transfers, and humeral osteotomy, all ultimately striving for better function through increased external rotation. Prior studies have shown that neonatal brachial plexus palsy alters humeral retroversion but with conflicting findings. We studied retroversion in children with internal rotation contractures from neonatal brachial plexus palsy to clarify its effect on version and surgical planning.

METHODS

Bilateral shoulder and elbow magnetic resonance imaging scans of 21 children with neonatal brachial plexus palsy were retrospectively analyzed. Retroversion referenced to the transepicondylar line at the elbow was measured with respect to 2 different proximal reference axes, the longest diameter of an axial cut of the proximal part of the humerus (the skew axis) and the line perpendicular to the articular surface (the humeral center line). Glenoid version and glenohumeral morphology type (concentric glenoid, posterior-concentric glenoid, biconcave, or pseudoglenoid) were also determined. All geometric variables were assessed for correlation with patient age and the severity of the internal rotation contracture.

RESULTS

Retroversion on the involved side was decreased at 6° compared with 19° (p = 0.003), as measured between the skew axis and transepicondylar line. Retroversion referenced to the humeral center line was also decreased at -2° (anteversion) compared with 20° (p < 0.001). Patient age was inversely correlated with retroversion, but was only significant for the skew axis (r = -0.497, p = 0.022), decreasing in linear regression by 2.4° per year (p = 0.038). Humeral retroversion did not correlate with the severity of the internal rotation contracture, glenoid version, or glenoid morphology type.

CONCLUSIONS

Humeral retroversion is likely to be less on the affected side in children with internal rotation contractures from upper trunk neonatal brachial plexus palsy and merits consideration in surgical planning.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Incidence of Posttraumatic Shoulder Dislocation in Poland

Background

The incidence of shoulder joint dislocation has been estimated at 11–26 per 100 000 population per year. In our opinion, basic epidemiological data need to be continually updated in studies of large populations.

To study the incidence of posttraumatic dislocation of the shoulder joint in the Polish population.

Material/Methods

We retrospectively investigated the entire Polish population between 1 January 2010 and 1 January 2015. To identify the study group, data collected in the electronic database of the National Health Fund were used. The study group was divided into subgroups to detect possible differences in the incidence of shoulder dislocation with regard to age, sex, and season of the year (month) when the dislocation occurred.

Results

The cumulative size of the study sample was 192.72 million over the 5 years of the study. We identified 51 409 patients with first posttraumatic shoulder dislocation, at a mean age of 50.83 years (SD 21.12), from 0 to 104 years. The incidence of traumatic shoulder dislocations for the entire study group ranged from 24.75/100 000/year (number of posttraumatic shoulder dislocations per 100 000 persons per year) to 29.09/100 000/year, for a mean of 26.69/100 000/year.

Conclusions

In this study, the overall incidence of first-time posttraumatic shoulder dislocations in the Polish general population was 26.69 per 100 000 persons per year. These results are higher than estimates presented by other authors. It is necessary to study, regularly update, and monitor this problem in the general population.

The Relationship Between Humeral Retrotorsion and Shoulder Range of Motion in Baseball Players With an Ulnar Collateral Ligament Tear

BACKGROUND

Humeral retrotorsion has been investigated in relation to shoulder range of motion (ROM) in healthy baseball players. Currently, there is limited information on the osseous anatomy and development of ulnar collateral ligament (UCL) tears.

PURPOSE

To determine the relationship between humeral retrotorsion and shoulder ROM in baseball players with a UCL tear.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Fifty-four baseball players (mean age, 18.5 ± 2.0 years) with a UCL tear volunteered for this study. Participants were measured bilaterally for shoulder internal (IR) and external rotation (ER) ROM and humeral retrotorsion. Differences between sides (involved to uninvolved) were used to calculate the glenohumeral internal rotation deficit (GIRD), external rotation ROM difference (ERDiff), total rotational motion difference (TRM), and humeral retrotorsion difference (HTDiff). A multivariate regression analysis was performed with GIRD, ERDiff, and TRM regressing on HTDiff. Univariate analysis was performed to further evaluate the effect of the predictors on each outcome separately. To control for the effect of age, weight, duration of symptoms, and years of experience, the variables were included as covariates. An a priori level was set at P < .05.

RESULTS

There was a statistically significant relationship between the GIRD, ERDiff, and TRM results compared with HTDiff (P = .003). Independent analysis revealed a statistically significant relationship between GIRD and HTDiff (P = .004) and between ERDiff and HTDiff (P = .003) but no significant relationship between TRM and HTDiff (P = .999). After adjusting for age, weight, duration of symptoms, years of experience, dominant arm, and position, a significant relationship was found between GIRD and HTDiff (P = .05) and between ERDiff and HTDiff (P = .01). No significant relationship was found between TRM and HTDiff (P = .54). Adjusted univariate regression analysis determined that HTDiff explains approximately 16% of the variance in GIRD (r² = 0.158) and approximately 24% of the variance in ERDiff (r² = 0.237).

CONCLUSION

In baseball players with a UCL tear, approximately 16% of the variance in GIRD and 24% of the variance in ERDiff can be attributed to differences found in humeral retrotorsion between sides. This indicates that humeral retroversion contributes significantly to GIRD and increased ER ROM in baseball players. Recognition of differences in humeral retrotorsion between the dominant and nondominant upper extremities may help explain some but not all of the changes in shoulder ROM commonly seen in baseball players.

Glenohumeral and Hip Range-of-Motion and Strength Measures in Youth Baseball Athletes

CONTEXT

The repetitive demands of throwing affect glenohumeral (GH) range of motion (ROM) and strength. Less is known about hip alterations in skeletally immature athletes.

OBJECTIVE

To compare GH and hip ROM and strength between age, position, and side of youth baseball athletes.

DESIGN

Cross-sectional study.

SETTING

Multicenter testing.

PATIENTS OR OTHER PARTICIPANTS

Seventy-two healthy baseball athletes. Participants' self-reported characteristics were age group (7-11 years [n = 28] or 12-18 years [n = 44]), position (pitcher [n = 22], position player [n = 47], unreported [n = 3]), and side (throwing or nonthrowing arm, lead or stance leg).

MAIN OUTCOME MEASURE(S)

Bilateral GH and hip internal- and external-rotation ROM were measured passively and summed for total arc of motion (TAM). Glenohumeral and hip rotation and gluteus medius strength were measured. Analyses included linear mixed models.

RESULTS

Glenohumeral internal rotation was less in throwing than in nonthrowing arms (P < .05) except in younger pitchers (P = .86). Compared with older athletes, younger athletes had more GH external rotation (103.3° ± 7.7° versus 97.5° ± 9.4°; P = .002), TAM (156.4° ± 8.7° versus 147.9° ± 10.9°; P = .04), and external rotation in throwing compared with nonthrowing arms (101.9° ± 1.2° versus 97.9° ± 1.1°; P < .001). Glenohumeral TAM was less in throwing than in nonthrowing arms (150.5° ± 2.1° versus 154.9° ± 1.3°; P = .01). Younger athletes had more hip internal rotation (38.9° ± 6.8° versus 31.2° ± 7.5°; P < .001) and TAM (68.4° ± 10.0° versus 60.7° ± 9.8°; P = .001) than older athletes. Lead-leg hip internal-rotation ROM was greater than in the stance leg (34.8° ± 8.9° versus 32.8° ± 7.7°; P = .01). Overall, older players were stronger than younger players (P < .05), and the throwing arm was stronger in internal rotation than the nonthrowing arm (10.12 ± 3.72 lb [4.59 ± 1.69 kg] versus 9.43 ± 3.18 lb [4.28 ± 1.44 kg]; P = .047).

CONCLUSIONS

Youth baseball athletes had typical GH ROM adaptations of less internal rotation and more external rotation in the throwing versus the nonthrowing arm. Greater ROM in younger athletes may be explained by prepubertal characteristics. We obtained hip-strength values in youth baseball athletes, and as expected, older athletes were stronger.

Humeral retroversion and shoulder rotational mobility in young handball practitioners

OBJECTIVE

: To evaluate the prevalence of humeral retroversion and rotational mobility (RHH) in young handball practitioners and non-practitioners.

METHODS

: This is a cross-sectional study performed with two groups: the handball group, with 14 female students practicing handball and the control group, with 13 young participants non-practicing pitch sports.

RESULTS

: The handball group presented full rotational movement (FRM) hi-gher than the control group in both the dominant shoulder (p=0.001) and the non-dominant shoulder (p=0.0001). The mobility of active and passive internal rotation was significantly higher in handball players in both shoulders. The handball group presented lower internal rotation range of motion for the dominant shoulder as compared to the non-dominant shoul-der (p=0.001).

CONCLUSION

: Young handball practitioners, des-pite skeletally immature, showed a higher MRT than the control group. The handball group showed loss of internal rotation (medial) on the dominant shoulder as compared to the non--dominant shoulder. Level of Evidence II, Prospective Study.

Deficits in Glenohumeral Passive Range of Motion Increase Risk of Shoulder Injury in Professional Baseball Pitchers: A Prospective Study

BACKGROUND

Shoulder injuries from repetitive baseball pitching continue to be a serious, common problem.

PURPOSE

To determine whether passive range of motion of the glenohumeral joint was predictive of shoulder injury or shoulder surgery in professional baseball pitchers.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Passive range of motion of the glenohumeral joint was assessed with a bubble goniometer during spring training for all major and minor league pitchers of a single professional baseball organization over a period of 8 successive seasons (2005-2012). Investigators performed a total of 505 examinations on 296 professional pitchers. Glenohumeral external and internal rotation was assessed with the pitcher supine and the arm abducted to 90° in the scapular plane with the scapula stabilized anteriorly at the coracoid process. Total rotation was defined as the sum of internal and external glenohumeral rotation. Passive shoulder flexion was measured with the pitcher supine and the lateral border of the scapula manually stabilized. After examination, shoulder injuries and injury durations were recorded by each pitcher's respective baseball organization and reported to the league as an injury transaction as each player was placed on the disabled list.

RESULTS

Highly significant side-to-side differences were noted within subjects for each range of motion measurement. There were 75 shoulder injuries and 20 surgeries recorded among 51 pitchers, resulting in 5570 total days on the disabled list. Glenohumeral internal rotation deficit, total rotation deficit, and flexion deficit were not significantly related to shoulder injury or surgery. Pitchers with insufficient external rotation (<5° greater external rotation in the throwing shoulder) were 2.2 times more likely to be placed on the disabled list for a shoulder injury (P = .014; 95% CI, 1.2-4.1) and were 4.0 times more likely to require shoulder surgery (P = .009; 95% CI, 1.5-12.6).

CONCLUSION

Insufficient shoulder external rotation on the throwing side increased the likelihood of shoulder injury and shoulder surgery. Sports medicine clinicians should be aware of these findings and develop a preventive plan that addresses this study's findings to reduce pitchers' risk of shoulder injury and surgery.

The Development of Humeral Retrotorsion and Its Relationship to Throwing Sports

Context:

Several investigations have noted that throwing athletes exhibit a more posteriorly oriented humeral head (humeral retrotorsion) in the dominant arm. This asymmetry is believed to represent an adaptive response to the stress of throwing that occurs during childhood. The significance of this alteration and factors that affect its development are currently not clear.

Evidence Acquisition:

Basic science, research studies, and review articles were searched through PubMed with search terms including humeral torsion, humeral retrotorsion, and with 1 of the following: pediatric, adult, baseball, pitching, shoulder, and range of motion. The references from each article were reviewed for further inclusion. This review included articles through March 2015.

Study Design:

Clinical review.

Level of Evidence:

Level 4.

Results:

The throwing motion creates stressors that result in bony adaptations that occur while skeletally immature. These osseous changes likely contribute to the observed shift in the arc of rotational range of motion noted in throwing athletes and may play a protective role against injury. However, too much or too little retrotorsion may predispose the shoulder to injury. The degree of “optimal” humeral retrotorsion and factors that influence its development are not fully understood.

Conclusion:

Evidence supports the assertion that the throwing motion creates stressors that alter bony anatomy while young. It is important to determine what specific factors affect this adaptation and its relationship to injury.

Results of Arthroscopic Bankart Lesion Repair in Patients with Post-Traumatic Anterior Instability of the Shoulder and a Non-Engaging Hill-Sachs Lesion with a Suture Anchor after a Minimum of 6-Year Follow-Up

Background

Shoulder instability is an important clinical problem. Arthroscopic surgery is an established treatment modality in shoulder instability, but it continues to be associated with a high rate of recurrences and complications. The purpose of the study was to analyze late outcomes of arthroscopic repair of Bankart lesions in patients with post-traumatic anterior shoulder instability and non-engaging Hill-Sachs lesion, with special focus on the incidence and causes of recurrences and complications.

Material/Methods

We investigated 92 patients (92 shoulders) who underwent surgery on account of post-traumatic anterior shoulder instability. The duration of follow-up ranged from 6 to 12.5 years (mean: 8.2 years). All patients were operated on in the lateral decubitus position using FASTak 2.8-mm suture anchors (FASTak, Arthrex, Naples, Florida). Treatment outcomes were evaluated using the Rowe and University of California at Los Angeles rating system (UCLA).

Results

According to Rowe scores, there were 71 (81.5%) excellent, 12 (12.6%) good, 5 (5.3%) satisfactory, and 2 (2.1%) poor results. Rowe scores improved in a statistically significant manner (p=0.00) post-surgery, to a mean of 90 (range: 25–100). Treatment outcomes measured as UCLA scores improved in a statistically significant manner (p=0.00), reaching post-operative levels of 12–35 (mean: 33.5). There were 9 recurrences, 1 case of axillary nerve praxia, and 1 case of anchor loosening.

Conclusions

With rigorous criteria for qualifying patients for surgery, arthroscopic treatment of post-traumatic anterior shoulder instability produces good outcomes and low recurrence and complication rates irrespective of the number of previous dislocations, age, or sex.

Professional Pitchers With Glenohumeral Internal Rotation Deficit (GIRD) Display Greater Humeral Retrotorsion Than Pitchers Without GIRD

BACKGROUND

Dominant shoulder glenohumeral internal rotation deficit (GIRD) has been associated with pitching arm injuries. The relationship of humeral torsion on development of GIRD is not clear.

HYPOTHESIS

Pitchers displaying GIRD will display greater humeral retrotorsion when compared with those without GIRD.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Humeral torsion and shoulder range of motion (ROM) were measured in 222 professional pitchers before spring training from 2009 to 2012. Shoulder external rotation (ER) and internal rotation (IR) ROM were assessed in 90° of abduction with the scapula stabilized. Humeral torsion was measured via ultrasound using previously described and validated methods. Side-to-side differences in total arc of motion (ER + IR), ER, and IR ROM and humeral torsion were calculated as nondominant minus dominant arm measures for analysis. Pitchers were classified as having GIRD if their dominant arm displayed an IR deficit ≥15° concomitant with a total arc of motion deficit ≥10° compared with their nondominant arm. A mixed-model analysis of variance (side × GIRD) was used to compare dominant and nondominant humeral torsion between pitchers with GIRD (n = 60) and those without GIRD (n = 162). Independent t tests were used to compare the side-to-side difference in humeral torsion between pitchers with GIRD and those without GIRD (α = 0.05).

RESULTS

Pitchers with GIRD displayed significantly less humeral torsion (ie, greater retrotorsion) in their dominant arm as compared with those without GIRD (GIRD = 4.5° ± 11.8°, no GIRD = 10.4° ± 11.7°; P = .002). Pitchers with GIRD also displayed a greater side-to-side difference in humeral torsion (GIRD = 19.5° ± 11.9°, no GIRD = 12.3° ± 12.4°; P = .001). However, pitchers with GIRD did not display an increase in dominant ER ROM (dominant ER = 131.8° ± 14.3°, nondominant ER 126.6° ± 13.1°) when compared with those without GIRD (dominant ER = 132.0° ± 14.2°, nondominant ER 122.6° ± 13.1°; P = .03). Pitchers with GIRD displayed expected alterations in ROM (IR = 28.8° ± 9.6°, total arc = 160.6° ± 15.4°; P < .01 for both) when compared with those without GIRD (IR = 39.9° ± 9.9°, total arc = 171.2° ± 15.5°).

CONCLUSION

Pitchers with GIRD displayed greater side-to-side differences and dominant humeral retrotorsion as compared with those without GIRD. The greater humeral retrotorsion may place greater stress on the posterior shoulder resulting in ROM deficits. Pitchers with greater humeral retrotorsion appear to be more susceptible to developing ROM deficits associated with injury and may need increased monitoring and customized treatment programs to mitigate their increased injury risk.

Current rehabilitation applications for shoulder ultrasound imaging

The available body of knowledge on shoulder ultrasound imaging has grown considerably within the past decade, and physical therapists are among the many health care professions currently exploring the potential clinical integration of this imaging technology and the knowledge derived from it. Therefore, the primary purpose of this commentary was to review the recent evidence and emerging uses of ultrasound imaging for the clinical evaluation of shoulder disorders. This includes a detailed description of common measurement techniques along with their known clinimetric properties. Specifically provided are critical appraisals of the existing measures used to estimate soft tissue and bony morphometry, muscle contractile states, and lean muscle density. These appraisals are intended to help clinicians clarify the scope of physical therapy practice for which these measurement techniques are effectively utilized and to highlight areas in need of further development.

Conventional Humeral Retroversion Measurements Using Computed Tomography Slices or Ultrasound Images Are Not Correlated With the 3-Dimensional Humeral Retroversion Angle

Background:

Humeral retroversion angles determined by previous techniques are varied and/or biased by morphologic variations of the proximal and distal humerus, and their validity should be revisited. To overcome the limitations of previous studies associated with 2-dimensional (2D) images and the reference axes, a 3-dimensional (3D) measurement of humeral retroversion is required. However, comparisons of 2D imaging methods with the 3D computed tomography (CT) measurement as a reference standard have not been heretofore performed.

Purpose:

To determine whether the 3D CT humeral retroversion angle in baseball players is correlated with conventional humeral retroversion measurements.

Study Design:

Cohort study (diagnosis); Level of evidence, 2.

Methods:

A total of 28 humeri from 14 male baseball players were used for measuring humeral retroversion. Participants underwent CT scans, and geometric bone models were created for measuring the 3D CT humeral retroversion angle. Using CT slices, the 2D CT humeral retroversion angle was also determined. Bicipital forearm angle was assessed using the indirect ultrasound technique. Linear regressions and Bland-Altman plots were used to determine whether there were agreements among 3 variables: the 3D CT retroversion, 2D CT retroversion, and bicipital forearm angles.

Results:

In linear regression analyses, the 3D humeral retroversion angle was not predicted by the 2D CT retroversion (R = 0.167, R² = 0.028, P = .395) or the bicipital forearm angle (R = 0.049, R² = 0.002, P = .805). The bias of these 2 methods was 20.9° and –15.3°, respectively. Regression analysis demonstrated that the bicipital forearm angle was a significant predictor of the 2D CT retroversion angle (R = 0.632, R² = 0.400, P < .001).

Conclusion:

The 3D CT humeral retroversion angle was found to be underestimated by the 2D CT retroversion angle and overestimated by the bicipital forearm angle obtained by the indirect ultrasound, although a previously observed relationship between the 2D CT retroversion and bicipital forearm angles was confirmed.

Clinical Relevance:

Precise measurement of humeral retroversion angle is important because retroversion has been linked to upper extremity disorders, including throwing-related shoulder and elbow disorders in baseball players.

Morphologic features of humeral head and glenoid version in the normal glenohumeral joint

BACKGROUND

The morphologic features and clinical significance of version of the humeral head and glenoid remain unclear. The purpose of this study was to evaluate the normal values of humeral head version and glenoid version on computed tomography scans and to clarify their features in the normal glenohumeral joint.

METHODS

Images for analysis were computed tomography scans of 410 normal shoulders from healthy volunteers. Values of humeral head and glenoid version were measured. In glenoid version measurement, 3-dimensionally corrected slices were reconstructed to eliminate scapular inclination. Differences in humeral head version and glenoid version were assessed between dominant and nondominant shoulders and between men and women. Correlation analyses were also performed in the values of version between dominant and nondominant shoulders and between humeral head version and glenoid version.

RESULTS

The values of humeral head retroversion were widely distributed from -2° to 60°, with an average of 26° ± 11°. Average glenoid retroversion was 1° ± 3°, ranging from -9° to 13°. Both humeral head retroversion and glenoid retroversion were significantly higher on the dominant side than on the nondominant side and significantly higher in men than in women. Humeral head version and glenoid version values were well correlated with those of the contralateral shoulder. No correlation was found between humeral head version and glenoid version.

CONCLUSIONS

This study found differences in humeral head version and glenoid version by sex and shoulder dominance in a large sample. Both the humeral head and glenoid are thought to be more retroverted in high-demand shoulders.

Reliability of measurement of glenohumeral internal rotation, external rotation, and total arc of motion in 3 test positions

CONTEXT

Athletes who participate in throwing and racket sports consistently demonstrate adaptive changes in glenohumeral-joint internal and external rotation in the dominant arm. Measurements of these motions have demonstrated excellent intrarater and poor interrater reliability.

OBJECTIVE

To determine intrarater reliability, interrater reliability, and standard error of measurement for shoulder internal rotation, external rotation, and total arc of motion using an inclinometer in 3 testing procedures in National Collegiate Athletic Association Division I baseball and softball athletes.

DESIGN

Cross-sectional study.

SETTING

Athletic department.

PATIENTS OR OTHER PARTICIPANTS

Thirty-eight players participated in the study. Shoulder internal rotation, external rotation, and total arc of motion were measured by 2 investigators in 3 test positions. The standard supine position was compared with a side-lying test position, as well as a supine test position without examiner overpressure.

RESULTS

Excellent intrarater reliability was noted for all 3 test positions and ranges of motion, with intraclass correlation coefficient values ranging from 0.93 to 0.99. RESULTS for interrater reliability were less favorable. Reliability for internal rotation was highest in the side-lying position (0.68) and reliability for external rotation and total arc was highest in the supine-without-overpressure position (0.774 and 0.713, respectively). The supine-with-overpressure position yielded the lowest interrater reliability results in all positions. The side-lying position had the most consistent results, with very little variation among intraclass correlation coefficient values for the various test positions.

CONCLUSIONS

The results of our study clearly indicate that the side-lying test procedure is of equal or greater value than the traditional supine-with-overpressure method.

Deficits in glenohumeral passive range of motion increase risk of elbow injury in professional baseball pitchers: a prospective study

BACKGROUND

Injuries to the elbow joint in baseball pitchers appear common. There appears to be a correlation between shoulder range of motion and elbow injuries.

PURPOSE

To prospectively determine whether decreased ROM of the throwing shoulder is correlated with the onset of elbow injuries in professional baseball pitchers.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

For 8 consecutive years (2005-2012), passive range of motion of both the throwing and nonthrowing shoulders of all major and minor league pitchers within a single professional baseball organization were measured by using a bubble goniometer during spring training. In total, 505 examinations were conducted on 296 pitchers. Glenohumeral external rotation and internal rotation were assessed in the supine position with the arm at 90° of abduction and in the plane of the scapula. The scapula was stabilized per methods previously established. Total rotation was defined as the sum of external rotation and internal rotation. Passive shoulder flexion was assessed with the subject supine and the scapula stabilized per methods previously established. Elbow injuries and days missed because of elbow injuries were assessed and recorded by the medical staff of the team. Throwing and nonthrowing shoulder measurements were compared by using Student t tests; 1-tailed Fisher exact tests were performed to identify significant associations between shoulder motion and elbow injury. Nominal logistic regression was performed to determine the odds of elbow injury.

RESULTS

Significant differences were noted during side-to-side comparisons within subjects. There were 49 elbow injuries and 8 surgeries in 38 players, accounting for a total of 2551 days missed. Neither glenohumeral internal rotation deficit nor external rotation insufficiency was correlated with elbow injuries. Pitchers with deficits of >5° in total rotation in their throwing shoulders had a 2.6 times greater risk for injury. Pitchers with deficit of ≥5° in flexion of the throwing shoulder had a 2.8 times greater risk for injury.

CONCLUSION

Bilateral differences in shoulder total rotation and flexion had a significant effect on the risk for elbow injuries in pitchers. Clinicians need to be aware of these findings and plan preventive programs that address these issues in hopes of reducing elbow injuries.

Dominant-limb range-of-motion and humeral-retrotorsion adaptation in collegiate baseball and softball position players

CONTEXT

Biomechanically, the motions used by baseball and softball pitchers differ greatly; however, the throwing motions of position players in both sports are strikingly similar. Although the adaptations to the dominant limb from overhead throwing have been well documented in baseball athletes, these adaptations have not been clearly identified in softball players. This information is important in order to develop and implement injury-prevention programs specific to decreasing the risk of upper extremity injury in softball athletes.

OBJECTIVE

To compare range-of-motion and humeral-retrotorsion characteristics of collegiate baseball and softball position players and of baseball and softball players to sex-matched controls.

DESIGN

Cross-sectional study.

SETTING

Research laboratories and athletic training rooms at the University of North Carolina at Chapel Hill.

PATIENTS OR OTHER PARTICIPANTS

Fifty-three collegiate baseball players, 35 collegiate softball players, 25 male controls (nonoverhead athletes), and 19 female controls (nonoverhead athletes).

INTERVENTION(S)

Range of motion and humeral retrotorsion were measured using a digital inclinometer and diagnostic ultrasound.

MAIN OUTCOME MEASURE(S)

Glenohumeral internal-rotation deficit, external-rotation gain, total glenohumeral range of motion, and humeral retrotorsion.

RESULTS

Baseball players had greater glenohumeral internal-rotation deficit, total-range-of-motion, and humeral-retrotorsion difference than softball players and male controls. There were no differences between glenohumeral internal-rotation deficit, total-range-of-motion, and humeral-retrotorsion difference in softball players and female controls.

CONCLUSIONS

Few differences were evident between softball players and female control participants, although range-of-motion and humeral-retrotorsion adaptations were significantly different than baseball players. The throwing motions are similar between softball and baseball, but the athletes adapt to the demands of the sport differently; thus, stretching/strengthening programs designed for baseball may not be the most effective programs for softball athletes.

Three-dimensional humeral morphologic alterations and atrophy associated with obstetrical brachial plexus palsy

BACKGROUND

Obstetrical brachial plexus palsy (OBPP) is a common birth injury, resulting in severe functional losses. Yet, little is known about how OBPP affects the 3-dimensional (3D) humeral morphology. Thus, the purpose of this study was to measure the 3D humeral architecture in children with unilateral OBPP.

METHODS

Thirteen individuals (4 female and 9 male patients; mean age, 11.8 ± 3.3 years; mean Mallet score, 15.1 ± 3.0) participated in this institutional review board approved study. A 3D T1-weighted gradient-recalled echo magnetic resonance image set was acquired for both upper limbs (involved and noninvolved). Humeral size, version, and inclination were quantified from 3D humeral models derived from these images.

RESULTS

The involved humeral head was significantly less retroverted and in declination (medial humeral head pointed anteriorly and inferiorly) relative to the noninvolved side. Osseous atrophy was present in all 3 dimensions and affected the entire humerus. The inter-rater reliability was excellent (intraclass correlation coefficient, 0.96-1.00).

DISCUSSION

This study showed that both humeral atrophy and bone shape deformities associated with OBPP are not limited to the axial plane but are 3D phenomena. Incorporating information related to these multi-planar, 3D humeral deformities into surgical planning could potentially improve functional outcomes after surgery. The documented reduction in retroversion is an osseous adaptation, which may help maintain glenohumeral congruency by partially compensating for the internal rotation of the arm. The humeral head declination is a novel finding and may be an important factor to consider when one is developing OBPP management strategies because it has been shown to lead to significant supraspinatus inefficiencies and increased required elevation forces.

Increase in humeral retrotorsion accounts for age-related increase in glenohumeral internal rotation deficit in youth and adolescent baseball players

BACKGROUND

Glenohumeral internal rotation deficit (GIRD) is the difference in internal rotation range of motion (IRROM) between the dominant and nondominant limbs. Pathological GIRD of greater than 15° to 25° has previously been linked to shoulder and elbow injuries in baseball players. Because of its relationship to shoulder and elbow disorders, research has focused on understanding the underlying factors that contribute to changes in IRROM and ultimately GIRD. The rotation deficit reportedly increases during adolescence, but it remains unclear whether this change is caused by changes in osseous properties or soft tissue tightness.

PURPOSE

To evaluate the influence of age group on GIRD, humeral retrotorsion, retrotorsion-adjusted GIRD, and total range of motion (TROM) in healthy baseball players.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Four groups of healthy baseball players participated in the study: 52 youth (aged 6-10 years), 52 junior high school (JH) (aged 11-13 years), 70 junior varsity (JV) (aged 14-15 years), and 113 varsity (aged 16-18 years) players. Internal rotation range of motion, external rotation range of motion (ERROM), and humeral retrotorsion were measured bilaterally using a digital inclinometer and diagnostic ultrasound. Retrotorsion-adjusted IRROM was calculated as the available IRROM from the humeral retrotorsion position; TROM was calculated as the sum of IRROM and ERROM; and GIRD, the difference in humeral retrotorsion between limbs, adjusted GIRD, and the difference in TROM between limbs were calculated as the difference between the dominant and nondominant sides. Four separate analyses of variance were used to compare these variables between age groups.

RESULTS

There was a significant group difference in GIRD (F3,284 = 8.957; P < .001) and a difference in humeral retrotorsion between limbs (F3,284 = 9.688; P < .001). Also, GIRD was greater in varsity participants compared with youth (mean difference [MD], 5.05°) and JH (MD, 4.95°) participants and in JV participants compared with JH (MD, 5.36°) and youth (MD, 5.47°) participants. The difference in humeral retrotorsion between limbs was greater in varsity participants compared with youth (MD, 8.79°) and JH (MD, 5.52°) participants and in JV participants compared with youth participants (MD, 7.88°). There were no significant differences in adjusted GIRD (F3,284 = 1.136; P = .335) or TROM (F3,284 = 1.214; P = .305).

CONCLUSION

Glenohumeral internal rotation deficit and humeral retrotorsion increased with age in youth/adolescent baseball players, while retrotorsion-adjusted GIRD and TROM remained unchanged. An age-related increase in GIRD is primarily attributed to humeral retrotorsion rather than soft tissue tightness.

CLINICAL RELEVANCE

While there was an increase in GIRD from youth league to high school participants, TROM and retrotorsion-adjusted GIRD remained constant across the age groups, indicating that this increase between the age groups is not pathological GIRD and may not contribute to an increased injury risk.

The disabled throwing shoulder: spectrum of pathology-10-year update

In the 10 years since the current concept series entitled "The Disabled Throwing Shoulder: Spectrum of Pathology" was conceived and written, many studies have been reported that add much more information to the understanding of the disabled throwing shoulder (DTS). The editors of Arthroscopy and the authors of the original series believed that an update to the original series would be beneficial to provide an organized overview of current knowledge that could update the thought process regarding this problem, provide better assessment and treatment guidelines, and guide further research. A dedicated meeting, including current published researchers and experienced clinicians in this subject, was organized by the Shoulder Center of Kentucky. The meeting was organized around 5 areas of the DTS that were highlighted in the original series and appear to be key in creating the DTS spectrum and to understanding and treating the DTS: (1) the role of the kinetic chain; (2) the role and clinical evaluation of the scapula; (3) the role of deficits in glenohumeral rotation, glenohumeral internal rotation deficit, and total range-of-motion deficit in the causation of labral injury and DTS; (4) the role of superior labral (SLAP) injuries and rotator cuff injuries; and (5) the composition and progression of rehabilitation protocols for functional restoration of the DTS. The meeting consisted of presentations within each area, followed by discussions, and resulted in summaries regarding what is known in each area, what is not known but thought to be important, and strategies to implement and enlarge the knowledge base.

Humeral retroversion and its association with posterior capsule thickness in collegiate baseball players

HYPOTHESIS AND BACKGROUND

Baseball players commonly present with decreases in internal rotation (IR) and concurrent increases in external rotation (ER) motion. Several glenohumeral (GH) adaptations have been theorized to cause these changes in motion, including humeral retroversion (HR) and posterior capsule thickness (PCT). However, limited data exist examining the inter-relationship between HR and PCT. Therefore, the purpose of this study was to measure HR, GH IR and ER rotation, and PCT.

MATERIALS AND METHODS

HR and PCT were measured with an ultrasound system (Sonosite Titan; Sonosite, Bothell, WA, USA), and GH IR and ER were measured with a digital inclinometer.

RESULTS

The dominant arm had significantly more HR (15.6°, P = .0001) than the nondominant arm. Pearson correlation coefficients showed a significant negative relationship between HR and GH IR (-0.472, P = .001) and a significant positive relationship between HR and GH ER (0.295, P = .042). A significant positive correlation was also found between HR and PCT (0.427, P = .003).

DISCUSSION

This was the first study to identify a relationship between HR and PCT in addition to GH IR and ER. The identification of these multiple correlations appears to suggest that the loss of IR caused by HR may be placing additional stress on the posterior capsule during the deceleration phase of the throw, thereby causing a fibroblastic healing response.

CONCLUSIONS

HR has previously been identified as a positive adaptation because of the increase in ER without anterior capsule attenuation. However, this study suggests that HR may be contributing to the negative adaptation of PCT.

Passive range of motion characteristics in the overhead baseball pitcher and their implications for rehabilitation

BACKGROUND

Repetitive overhead throwing motion causes motion adaptations at the glenohumeral joint that cause injury, decrease performance, and affect throwing mechanics. It is essential to define the typical range of motion (ROM) exhibited at the glenohumeral joint in the overhead thrower.

QUESTIONS/PURPOSES

We (1) assessed the glenohumeral joint passive range of motion (PROM) characteristics in professional baseball pitchers; and (2) applied these findings clinically in a treatment program to restore normal PROM and assist in injury prevention.

METHODS

From 2005 to 2010, we evaluated 369 professional baseball pitchers to assess ROM parameters, including bilateral passive shoulder external rotation (ER) at 45° of abduction, external and internal rotation (IR) at 90° abduction while in the scapular plane, and supine horizontal adduction.

RESULTS

The mean ER was greater for the throwing and nonthrowing shoulders at 45° of abduction, 102° and 98°, respectively. The throwing shoulder ER at 90° of abduction was 132° compared with 127° on the nonthrowing shoulder. Also, the pitcher's dominant IR PROM was 52° compared with 63° on the nondominant side. We found no statistically significant differences in total rotational motion between the sides.

CONCLUSIONS

Although we found side-to-side differences for rotational ROM and horizontal adduction, the total rotational ROM was similar.

CLINICAL RELEVANCE

The clinician can use these PROM values, assessment techniques, and treatment guidelines to accurately examine and develop a treatment program for the overhead-throwing athlete.

Ultrasonographic assessment of humeral retrotorsion in baseball players: a validation study

BACKGROUND

Recently, clinicians and researchers started using diagnostic ultrasound to measure humeral torsion as an alternative to radiological assessments in overhead-throwing athletes and other clinical populations. Ultrasound appears to be a reliable, nonradiological alternative, but ultrasound assessment has not been validated against computed tomography (CT), the current gold standard.

PURPOSE

This study aimed to establish the validity of an ultrasound assessment of humeral torsion by comparing data obtained using both ultrasound and CT, the current standard.

STUDY DESIGN

Cohort study (Diagnosis); Level of evidence, 2.

METHODS

Humeral torsion was measured using both ultrasound and CT in 24 collegiate-aged baseball players. Comparisons between the assessments were made using both regression and Bland-Altman plots. Reliability and precision were also established.

RESULTS

A strong relationship existed between humeral torsion variables obtained with ultrasound and CT (R = .797, R (2) = .635, P < .001). The ultrasound assessment yielded reliability coefficients ranging from .991 to .997, with approximately 1° of measurement error. The CT method's reliability coefficients ranged from .805 to .933, with approximately 3.5° of measurement error.

CONCLUSION

There was a strong relationship between humeral torsion obtained with ultrasound and CT, the current standard of assessment. Ultrasound provides a reliable, valid alternative to CT for obtaining an indication of the amount of humeral torsion in the upper extremity.

Validity of measuring humeral torsion using palpation of bicipital tuberosities

The magnitude of humeral torsion (HT) affects the internal and external rotation range of motion at the shoulder. Currently imaging is required to quantify the HT angle, however, factors such as cost and non-availability of imaging to musculoskeletal clinicians limits its use. The aim of this study was to examine the validity of palpation of the bicipital tuberosities as an alternative to imaging for quantifying HT angles. The bicipital-forearm angle, an indirect measure of HT, was measured using palpation and real-time ultrasound imaging in 25 subjects. The agreement among the two methods was excellent with the Intraclass Correlation Coefficient (3,k)  =  0.92, and the mean difference between the two methods was -0.2° (SD 4.1°) with 95% limits of agreement of -8.3° to 7.9°. Pearson's correlation coefficient (r) among the two methods was 0.85. In a clinical setting, palpation appears to be a practical alternative to US imaging for measuring HT.

The influence of proximal ulnar morphology on elbow range of motion

BACKGROUND

Physiologic dorsal apex angulation of the proximal ulna is present in 96% of the population. We hypothesize that a correlation exists between the physiologic dorsal ulnar angulation and elbow range of motion (ROM).

METHODS

Fifty healthy adults underwent bilateral lateral elbow radiographs in neutral forearm rotation in the following positions: terminal flexion (TF), 90° of flexion, and terminal extension (TE). The proximal ulna dorsal angulation (PUDA), TF, and TE were measured on the digital lateral radiographs by 2 independent observers. ROM was calculated as the difference between TF and TE measurements. Subjects were divided into 2 groups: those with PUDA measurements less than the median and those with PUDA measurements equal to or greater than the median. The relationship between the PUDA and TE, TF, and ROM was evaluated by use of Pearson correlation coefficients.

RESULTS

The mean age of the cohort was 31 ± 9 years, and there were 30 women among the 50 volunteers. The sample of 100 elbow radiographs had a mean TF of 150.8° ± 4.5°, a mean TE (ie, flexion contracture) of 11.5° ± 7.3°, and a mean ROM of 139.3° ± 8.4°. The mean PUDA was 5.2° ± 2.8°. Elbows with a greater PUDA had significantly less TE (r = 0.381, P ≤ .001) and ROM (r = -0.351, P ≤ .001). The group of elbows with a lesser PUDA had better TE (9.4° vs 13.6°, P = .004) and ROM (142.0° vs 136.7°, P = .001) than elbows with a greater PUDA.

CONCLUSION

The increasing magnitude of the PUDA is associated with decreased maximal elbow extension and global elbow ROM.

The effect of humeral torsion on rotational range of motion in the shoulder and throwing performance

Several recent studies have found that throwing athletes typically have lower humeral torsion (retroversion) and a greater range of external rotation at the shoulder than non-athletes. How these two parameters are related is debated. This study uses data from a sample of both throwers and non-throwers to test a new model that predicts torsion values from a range of motion data. The model proposes a series of predicted regressions which can help provide new insight into the factors affecting rotational range of motion at the shoulder. Humeral torsion angles were measured from computed tomography scans collected from 25 male subjects. These values are compared to predicted torsion values for the same subjects calculated from both kinematic and goniometric range-of-motion data. Results show that humeral torsion is negatively correlated (goniometric: r = -0.409, P = 0.047; kinematic: r = -0.442, P = 0.035) with external rotational range of motion and positively correlated (goniometric: r = 0.741, P < 0.001; kinematic: r = 0.559, P = 0.006) with internal rotational range of motion. The predicted torsion values are highly correlated (goniometric: r = 0.815, P < 0.001; kinematic: r = 0.617, P = 0.006) with actual torsion values. Deviations in the data away from predicted equations highlight significant differences between high torsion and low torsion individuals that may have significant functional consequences. The method described here may be useful for non-invasively assessing the degree of torsion in studies of the evolution and biomechanics of the shoulder and arm, and for testing hypotheses about the etiology of repetitive stress injuries among athletes and others who throw frequently.

A profile of glenohumeral internal and external rotation motion in the uninjured high school baseball pitcher, part I: motion

CONTEXT

The magnitude of motion that is normal for the throwing shoulder in uninjured baseball pitchers has not been established. Chronologic factors contributing to adaptations in motion present in the thrower's shoulder also have not been established.

OBJECTIVES

To develop a normative profile of glenohumeral rotation motion in uninjured high school baseball pitchers and to evaluate the effect of chronologic characteristics on the development of adaptations in shoulder rotation motion.

DESIGN

Cohort study.

SETTING

Baseball playing field.

PATIENTS OR OTHER PARTICIPANTS

A total of 210 uninjured male high school baseball pitchers (age = 16 ± 1.1 years, height=1.8±0.1 m, mass=77.5±11.2 kg, pitching experience=6±2.3 years).

INTERVENTION(S)

Using standard goniometric techniques, we measured passive rotational glenohumeral range of motion bilaterally with participants in the supine position.

MAIN OUTCOME MEASURE(S)

Paired t tests were performed to identify differences in motion between limbs for the group. Analysis of variance and post hoc Tukey tests were conducted to identify differences in motion by age. Linear regressions were performed to determine the influence of chronologic factors on limb motion.

RESULTS

Rotation motion characteristics for the population were established. We found no difference between sides for external rotation (ER) at 0° of abduction (t(209) = 0.658, P = .51), but we found side-to-side differences in ER (t(209) =-13.012,P < .001) and internal rotation (t(209) =15.304, P < .001) at 90° of abduction. Age at the time of testing was a significant negative predictor of ER motion for the dominant shoulder (R(2) = 0.019, P = .049) because less ER motion occurred at the dominant shoulder with advancing age. We found no differences in rotation motion in the dominant shoulder across ages (F(4,205) range, 0.451-1.730,P > .05).

CONCLUSIONS

This range-of-motion profile might be used to assist with the interpretation of normal and atypical shoulder rotation motion in this population. Chronologic characteristics of athletes had no influence on range-of-motion adaptations in the thrower's shoulder.

Postoperative malrotation of humeral shaft fracture after plating compared with intramedullary nailing

OBJECTIVE

We supposed difference of rotation alignment of postoperative humeral shaft fracutres between open reduction and internal fixation (ORIF) and intramedullay nailing (IMN) could be identified and the difference might influence the involved shoulder. This study evaluated and compared the extent of malrotation and shoulder function after humeral shaft fractures treated operatively with IMN or ORIF.

MATERIALS AND METHODS

Fifty humeral shaft fractures were randomly allocated into 2 groups. Group I underwent antegrade IMN and group II underwent ORIF. Malrotation was measured postoperatively by computed tomography scan (CT). Fracture union and functional outcomes were recorded at 12 months.

RESULTS

The final analysis comprised 45 patients. Group I had lower functional scores than group II (P < .05). Internal malrotation of 20° or more (humeral head internally rotated) was found in 27.2% of group I patients, but there was no malrotation in group II. The internal and external range of motion of the involved shoulder was significantly correlated with the degree of malrotation (P < .01).

DISCUSSION

This study comprehensively evaluated the degree of malrotation using CT scanning for every patient. These data bring to light some unexpected results about poor shoulder function and degeneration after humeral shaft fracture. The study can provide baseline data for larger series and longer follow-up periods.

CONCLUSIONS

Patients who underwent IMN had lower functional scores and a decreased range of motion postoperatively and also had a greater degree of malrotation than the ORIF group, which had none. The degree of malrotation correlated with a decreased range of motion and may possibly be a reason for degenerative arthritis at long-term follow-up.

The immediate effects of muscle energy technique on posterior shoulder tightness: a randomized controlled trial

STUDY DESIGN

Randomized controlled trial.

OBJECTIVES

To compare a muscle energy technique (MET) for the glenohumeral joint (GHJ) horizontal abductors and an MET for the GHJ external rotators to improve GHJ range of motion (ROM) in baseball players.

BACKGROUND

Overhead athletes often exhibit loss of GHJ ROM in internal rotation, which has been associated with shoulder pathology. Current stretching protocols aimed at improving flexibility of the posterior shoulder have resulted in inconsistent outcomes. Although utilization of MET has been hypothesized to lengthen tissue, there are limited empirical data describing the effectiveness of such stretches for treating posterior shoulder tightness.

METHODS

Sixty-one Division I baseball players were randomly assigned to 1 of 3 groups: MET for the GHJ horizontal abductors (n = 19), MET for the GHJ external rotators (n = 22), and control (n = 20). We measured preintervention and postintervention GHJ horizontal adduction and internal rotation ROM, and conducted analyses of covariance, followed by Tukey honestly significant difference post hoc analysis for significant group-by-time interactions (P<.05).

RESULTS

The group treated with the MET for the horizontal abductors had a significantly greater increase in GHJ horizontal adduction ROM postintervention (mean ± SD, 6.8° ± 10.5°) compared to the control group (-1.1° ± 6.8°) (P = .011) and a greater increase in internal rotation ROM postintervention (4.2° ± 5.3°) compared to the group treated with the MET for the external rotators (0.2° ± 6.3°) (P = .020) and the control group (-0.2° ± 4.0°) (P = .029). No significant differences among groups were found for any other variables (P>.05).

CONCLUSION

A single application of an MET for the GHJ horizontal abductors provides immediate improvements in both GHJ horizontal adduction and internal rotation ROM in asymptomatic collegiate baseball players. Application of MET for the horizontal abductors may be useful to gain ROM in overhead athletes.

LEVEL OF EVIDENCE

Therapy, level 2b-.

Surgical versus nonsurgical treatment in first traumatic anterior dislocation of the shoulder in athletes

Anterior traumatic dislocation is a common problem faced by orthopedic surgeons. After the first episode of shoulder dislocation, a combination of lesions can lead to chronic instability. The management in treatment of young athletes after the first acute anterior shoulder dislocation is controversial. The available literature supports early surgical treatment for young male athletes engaged in highly demanding physical activities after the first episode of traumatic dislocation of the shoulder. This is because of the best functional results and lower recurrence rates obtained with this treatment in this population. However, further clinical trials of good quality comparing surgical versus nonsurgical treatment for well-defined lesions are needed, especially for categories of patients who have a lower risk of recurrence.

Playing level achieved, throwing history, and humeral torsion in Masters baseball players

Humeral torsion is thought to be beneficial for throwing. To examine this hypothesis, the throwing and non-throwing arms of 84 Masters baseball players over 35 years of age were measured for humeral torsion, and the highest playing level they achieved and their playing history were recorded. Regression analyses were used to obtain predictors of the highest playing level achieved, throwing arm humeral torsion, and side-to-side difference in humeral torsion. Equations accounting for 36%, 46%, and 12% of the variance respectively were produced. Achieving representative level playing status was associated with the number of seasons played under 16 years of age and having greater throwing arm humeral retrotorsion. Throwing arm humeral retrotorsion was associated with non-throwing arm humeral retrotorsion and an increased number of seasons played before the age of 16 years. A model in which repeated throwing develops an adaptive unilateral bone torsion along with growth in baseball expertise is proposed. Thus dominant arm humeral retrotorsion is a predictor of highest baseball playing level achieved, which in turn is influenced by genetic endowment (as seen in the torsion of the non-throwing arm) and amount of throwing activity, particularly prior to the age of 16.

Metaversion can reliably predict humeral head version: a computed tomography-based validation study

HYPOTHESIS

Circumstances occur when the determination of anatomic humeral head version is difficult. In the setting of irreparable proximal humeral fracture, there are few reliable intraoperative landmarks to determine anatomic humeral head version. This study tested our hypothesis that the metaphyseal version (metaversion) is a landmark that can assist with correct head version and used computed tomography (CT) to evaluate its reliability as a predictor of anatomic version.

MATERIALS AND METHODS

CT scans from 50 consecutive patients (20 women, 30 men) were examined using commercial software. Patients were a mean age of 46 years (range, 17-85 years). Exclusion criteria included previous fracture, arthritis, or humeral deformity. The metaversion and humeral head version were measured. Measurements were conducted independently by 2 surgeons blinded to the results of the other. Interobserver and intraobserver reliability was calculated using intraclass correlation.

RESULTS

The mean difference between the metaversion and the humeral head version was 2.5° (95% confidence interval [CI], 0.9°-3.9°). The mean difference between metaversion and humeral head version was 1.8° (95% CI, 0.0°-3.6°) in women, 2.9° (95% CI, 0.6°-5.1°) in men, 2.4° (95% CI: 0.6°-4.1°) in right shoulders, and 2.5° (95% CI, -0.1° to 5.1°) in left shoulders. Interrater and intrarater reliability was excellent, 0.97 and 0.98, respectively.

CONCLUSIONS

Proximal humeral metaphyseal version (metaversion) is an accurate predictor of ipsilateral humeral head version.

Passive ranges of motion of the hips and their relationship with pitching biomechanics and ball velocity in professional baseball pitchers

BACKGROUND

Pelvis and trunk motions during baseball pitching are associated with ball velocity. Thus, limits in hip flexibility may adversely affect pitching biomechanics and the ability to generate ball velocity.

HYPOTHESES

Professional baseball pitchers will have less passive range of motion in the nondominant hip and the measured ranges of motion of both the nondominant and dominant hips will correlate with biomechanical parameters of the lower extremity among professional pitchers.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Nineteen healthy professional baseball pitchers volunteered for testing. Fluid goniometry was used to measure passive range of motion of adduction (ADD), abduction (ABD), internal rotation, external rotation, total arc of rotation, and total arc of ADD + ABD. Pitching biomechanical data were collected using an automated 3-dimensional motion analysis system while participants threw fastballs.

RESULTS

Pitchers possessed significantly less passive range of motion in the nondominant hip when compared with the dominant hip for all ranges. Total arc of rotation of the nondominant hip correlated with ball velocity (r = .50). Total arc of ADD + ABD in the nondominant hip and ABD in the nondominant hip were correlated with stride length (r = -.72 and .70, respectively). Dominant hip ABD (r = .63), total arc of rotation in the nondominant hip (r = -.45), and total arc of ADD + ABD of the dominant hip (r = .44) were correlated with trunk separation. Total arc of ADD + ABD of the nondominant hip (r = -.52) and total arc of rotation of the dominant hip (r = -.44) were correlated with pelvic orientation.

CONCLUSION

Passive range of motion is smaller in the nondominant hip than the dominant hip among professional pitchers. The measured disparity between the hips is significantly correlated with various pitching biomechanical parameters of the trunk and pelvis. Future research is required to investigate a causal relationship between less hip passive range of motion and both ball velocity and pitching biomechanics.