Shoulder MR arthrography: which patient group benefits most?

OBJECTIVE: We sought to compare the diagnostic accuracy of conventional MRI versus MR arthrography of the shoulder in the assessment of high-performance athletes (professional baseball players) and to compare our findings in these patients with the conventional MRI and MR arthrographic findings in an age-matched control group of nonprofessional athletes. MATERIALS AND METHODS: Conventional MRI and MR arthrographic examinations of the shoulder in 20 consecutive professional baseball players with shoulder pain were reviewed retrospectively by two musculoskeletal radiologists in consensus. These interpretations were compared with retrospective consensus interpretations of conventional MRI and MR arthrographic examinations of the shoulder obtained in a control group of 50 consecutive nonprofessional athletes with shoulder pain. MR images were assessed for full- or partial-thickness supraspinatus tendon tears, superior labral anteroposterior (SLAP) tears, and anterior or posterior labral tears. RESULTS: In the 20 consecutive professional athlete patients, two full-thickness and six partial-thickness undersurface supraspinatus tendon tears were seen on MR arthrography but not seen on conventional MRI as well as six SLAP tears, two anterior labral tears, and one posterior labral tear. Three patients had both SLAP tears and full- or partial-thickness supraspinatus tendon tears. Of 14 patients with findings on MR arthrography that were not seen on MRI, 11 had arthroscopic correlation. In all 11, arthroscopic findings confirmed findings on MR arthrography. In the group of 50 nonprofessional athlete patients, five had additional findings on MR arthrography not seen on conventional MRI: two anterior labral tears, two partial-thickness supraspinatus tendon tears, and two SLAP tears. One patient had both a partial-thickness supraspinatus tendon tear and a SLAP tear seen on MR arthrography. The five patients with additional findings on MR arthrography had arthroscopy. In all five, arthroscopic findings confirmed the findings on MR arthrography. CONCLUSION: MR arthrography is considerably more sensitive for detection of partial-thickness supraspinatus tears and labral tears than conventional MRI. MR arthrography showed injuries in addition to those seen on conventional MRI in 14 of 20 patients in the high-performance athlete group. These results suggest high-performance athletes may be a subgroup of patients for whom MR arthrography yields considerably more diagnostic information than conventional MRI.     

How often do surgeons intervene on shoulder labral lesions detected at MR examination? A retrospective review of MR examinations correlated with arthroscopy

Objective:

We report the prevalence of surgical intervention on shoulder labral lesions detected at MR examinations and how surgeons describe labral tears seen at MR examinations in their arthroscopy reports.

Methods:

A retrospective review of 100 consecutive patients aged 50 years or younger who had shoulder labral tears on MR and went on to have surgery performed. It was determined whether surgical intervention was performed on the MR lesions.

Results:

Of these 100 patients, 72 had superior labral anterior to posterior (SLAP) tears, 38 had posterior labral tears and 28 had anterior labral tears on MR examination. All 100 patients went on to arthroscopy. All lesions described on MRI were described on arthroscopy. Of the 72 SLAP tears, 64 were described as fraying on arthroscopy with 51 debrided. The remaining eight SLAP tears were tacked surgically. Of the 38 posterior labral tears, 36 were described as fraying on arthroscopy with 29 debrided and 2 had surgical tacking performed. Of the 28 anterior labral tears described on MR examination, 26 had surgical tacking performed and 2 were debrided. There were four SLAP tears, two anterior labral tears and three posterior labral tears seen on arthroscopy but not seen on MR examination.

Conclusion:

In this series, a high percentage of SLAP tears and posterior labral tears described on MR examination did not have surgical tacking. Most anterior labral tears had surgical tacking. Based on the above, our surgeons request we describe superior and posterior labral lesions as fraying and/or tearing, unless we can see a displaced tear. Most anterior labral lesions are treated with surgical tacking.

Advances in knowledge:

MRI allows for sensitive detection of labral tears. The tears often are not clinically significant.Labral tears are common injuries that often require surgical intervention. In our practice, we commonly see labral tears on MR examination and report them to surgeons. With modern high-resolution MRI, as well as increased awareness of labral tears by radiologists, labral tears are commonly reported findings on MR examinations. Sensitivities and specificities for detection of labral tears as compared with those from arthroscopy at 3.0 T have been reported as follows: superior labral anterior to posterior (SLAP) tears (90% sensitive and 100% specific), anterior labral tears (89% sensitive and 100% specific) and posterior labral tears (86% sensitivity and 100% specific).¹ Sensitivities of 100% for anterior labral tears, 86% for superior labral tears and 74% for posterior labral tears as compared with those from arthroscopy have been reported using high-resolution 1.5 T conventional MR examinations.²In our practice, we have been told by our surgeons that we describe some SLAP tears and posterior labral tears on MR that they find on arthroscopy to be degenerative fraying. For this reason, we sought to find (1) how often does a surgeon intervene on labral tears and (2) how do surgeons describe labral tears seen at MR examinations in their arthroscopy reports.     

Return to play after treatment of shoulder labral tears in professional hockey players

Objectives: Shoulder labral injuries in professional hockey players are often treated surgically to minimize missed ice time. Previous studies have shown that post-operative outcomes in these players are favorable, although they have not specifically focused on athletic performance and time to return to sport. Our objective was to report time to return to play and post-operative on-ice performance metrics after shoulder labral repair in professional ice hockey players.

Methods: We performed a retrospective review of the clinical records of all professional hockey players (NHL) who underwent arthroscopic shoulder labral repair by one surgeon between January 2004 and December 2008. Operative data included labral injury type, number of anchors used, concomitant pathology, and complications. Player information included position, shooting hand, games played before and after surgery, date of return to play (RTP), time on ice (TOI) and shots on goal before and after surgery. Paired sample t-test and independent sample t-tests or their non-parametric equivalents were used to compare pre-and post-operative player performance variables using the SPSS statistical package.

Results: Eleven NHL Players (13 shoulders) were included in the study. The average follow-up was 19.4 months (12.7–37 months, SD 7.4) and average age was 29 years (20–36, SD 5.1). Of the 13 shoulders, there were various types of labral tears including three Bankart tears, three superior (SLAP) tears, two posterior tears, three combined anterior/posterior tears, and two panlabral tears. All 11 players returned to play (RTP) after surgery at an average time of 4.3 months. There were no significant differences between time to RTP for players with dominant-sided injuries (4.2 months) and non-dominant injuries (4.6 months), p = 0.632. Five players had increased time-on-ice (TOI) and five players had decreased TOI after surgery, though this difference was not significant (p = 0.3804). On average, the shots on goal per game played (SOG/GP) decreased by 0.13 after surgery which was not significantly different (p = 0.149). There were no post-operative complications observed.

Conclusion: Professional ice hockey players can safely return to full competition at an average of 4.3 months after arthroscopic shoulder labral repair without significant decline in player performance.     

Arthroscopic labral debridement. A three-year follow-up study.

This is a retrospective review of 40 patients who underwent arthroscopic labral debridement of the shoulder. All patients were active participants in sports involving use of the shoulder. All patients presented with shoulder pain. Only 40% were found to have distinct glenohumeral instability on examination. At surgery, all patients had labral injury. Ten patients had anterosuperior labral tears, 20 had anteroinferior labral tears or detachments, and 10 had posteroinferior labral tears or detachments. Outcome was assessed at a minimum of 2 years (average, 43 months) postoperatively. Overall, only 7% of the patients had significant symptomatic relief at followup. However, 72% noted relief of symptoms during the 1st year after surgery, but there was deterioration over time. Conclusion: Arthroscopic labral debridement is not an effective long-term solution for symptomatic relief in the overhead athlete.     

High-field and low-field MR imaging of superior glenoid labral tears and associated tendon injuries

OBJECTIVE: The purpose of this study was to determine the performance characteristics of high-field and low-field MR imaging for the diagnosis of a glenoid superior labral anteroposterior (SLAP) tear. MATERIALS AND METHODS: High-field (n = 46) or low-field (n = 21) MR imaging was performed on 41 patients with SLAP tears and 26 patients with normal superior labra. The superior labrum was classified into one of four types on the basis of patterns of intralabral signal intensity. The relative frequency of rotator cuff tears and long head of the biceps tendinopathy was also assessed. RESULTS: For the diagnosis of SLAP tear, the sensitivity of high-field MR imaging was 90% (95% confidence interval = 74%, 98%), specificity was 63% (35%, 85%), and accuracy was 80% (66%, 91%). The sensitivity of low-field MR imaging was 64% (31%, 89%), specificity was 70% (35%, 93%), and accuracy was 67% (43%, 85%). A branched linear or stellate focus of abnormal intralabral signal intensity was associated with a SLAP tear in 86% of patients. Conversely, two other labral patterns correlated with a normal superior labrum in 71% of patients. Abnormal signal intensity in the biceps tendon was seen in 15% of patients with a SLAP tear. Full-thickness (37%) and partial-thickness (31%) rotator cuff tears were often seen. CONCLUSION: The performance characteristics of high-field MR imaging are superior to those of low-field MR imaging for the diagnosis of a superior labral tear. Rotator cuff tears can be seen in many patients with superior labral tears, but abnormal signal intensity in the biceps tendon is uncommon.     

Prevalence of HAGL lesions and associated abnormalities on shoulder MR examination

Objective

Humeral avulsion of the glenohumeral ligament (HAGL) is an uncommon shoulder injury. We report the prevalence of HAGL lesions and other associated shoulder injuries in a large series of shoulder MR examinations. All results were correlated with surgery.

Materials and methods

MR reports of 1,000 consecutive conventional shoulder MR exams performed on patients with shoulder pain were reviewed in our information system for the word HAGL. A total of 743 patients went on to surgery. There were 23 HAGL lesions reported at surgery. Those 23 examinations were reviewed retrospectively in consensus by two musculoskeletal radiologists. Scans were assessed for HAGL lesions, full or partial thickness supraspinatus, infraspinatus or subscapularis tendon tears, superior labral anterior posterior (SLAP) tears, anterior or posterior labral tears, and Hill–Sachs lesions.

Results

All 23 patients had HAGL lesions at surgery. Sixteen HAGL lesions were seen on prospective MR reading and 17 HAGL lesions were seen on retrospective MR consensus reading. Six HAGL lesions were not seen on retrospective consensus reading. Sixteen patients had Hill–Sachs deformities, ten had subscapularis tendon tears, five had supraspinatus tendon tears, six had superior labral tearing, and six had anterior labral tears. The above findings were confirmed on arthroscopy.

Conclusions

In this series, there was a 1.6 % prevalence on all MR examinations, and prevalence of 2.1 % seen on MR examination for those who went to surgery. Common injuries associated with HAGL lesions are Hill–Sachs deformities and subscapularis tendon tears. Anterior labral tears were seen in only six cases despite Hill–Sachs deformities in 16 patients. In patients with Hill–Sachs deformities without anterior labral tears, one must carefully assess for the presence of a HAGL lesion.     

Repair of full-thickness rotator cuff tears in professional baseball players

BACKGROUND: Despite the relative frequency of partial-thickness rotator cuff tears seen in baseball players, full-thickness rotator cuff tears in baseball players are uncommon. HYPOTHESIS: Return to competitive baseball is difficult after surgical treatment of a full-thickness rotator cuff tear. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: We evaluated the results of 16 professional baseball players after a mini-open repair of a full-thickness rotator cuff tear. Twelve patients were pitchers with injury to their dominant shoulders. Four patients were position players; 2 had injuries involving their dominant shoulders, and 2 had injuries to their nondominant shoulders. RESULTS: At a mean follow-up of 66.6 months for the pitchers, only 1 player (8%) was able to return to a high competitive level of baseball with no significant shoulder dysfunction after mini-open repair of a full-thickness rotator cuff tear. Of the 2 position players with mini-open repairs of the full-thickness rotator cuff tear of their dominant shoulders, 1 was able to return to professional baseball. Of the 2 position players with mini-open repairs of the full-thickness rotator cuff tear of their nondominant shoulders, both were able to return to professional baseball at the same or higher level. CONCLUSION: It is very difficult for a professional baseball pitcher to return to a competitive level of pitching after a full-thickness rotator cuff repair with a mini-open approach.     

Magnetic resonance imaging of the long head of the biceps tendon: benefit of coplanar image

PURPOSE: To evaluate coplanar imaging of the long head of the biceps tendon. METHODS: We retrospectively compared coronal oblique magnetic resonance images aligned with the principal supraspinatus tendon and with the intra-articular biceps tendon in 21 patients. Magnetic resonance images were analyzed for lesions depicted, including superior labral anteroposterior (SLAP) tears. Arthroscopic findings were reviewed. RESULTS: Coronal oblique images aligned with intra-articular biceps tendon depicted 18 (86%) of 21 coplanar intra-articular biceps tendons. Coplanar images identified 6 cases of tendinosis, 1 tear, 3 intra-articular ruptures, and 20 (95.2%) of 21 exact origins of the tendon. Arthroscopy revealed 18 SLAP tears. The detection of SLAP lesions between both coronal oblique magnetic resonance images was significantly different (P = 0.007). CONCLUSION: Advantages included imaging of the intra-articular biceps tendon with least partial-volume effects, definition of SLAP lesions and the tendinous origin at the supraglenoid tubercle, depiction of intra-articular bicipital ruptures, and increased sensitivity and specificity for intra-articular lesions.     

SLAP lesions: anatomy, clinical presentation, MR imaging diagnosis and characterization

Superior labral anterior posterior (SLAP) tears are an abnormality of the superior labrum usually centered on the attachment of the long head of the biceps tendon. Tears are commonly caused by repetitive overhead motion or fall on an outstretched arm. SLAP lesions can lead to shoulder pain and instability. Clinical diagnosis is difficult thus imaging plays a key diagnostic role. The normal anatomic variability of the capsulolabral complex can make SLAP lesions a diagnostic challenge. Concurrent shoulder injuries are often present including rotator cuff tears, cystic changes or marrow edema in the humeral head, capsular laxity, Hill-Sachs or Bankart lesion. The relevant anatomy, capsulolabral anatomic variants, primary and secondary findings of SLAP tears including MR arthrography findings, types of SLAP lesions and a practical approach to labral lesions are reviewed.     

Greater tuberosity notch: an important indicator of articular-side partial rotator cuff tears in the shoulders of throwing athletes.

We examined the location of rotator cuff tears, associated labral injuries, and notches on the greater tuberosity of the humeral head in shoulders of throwing athletes. Arthroscopic findings (rotator cuff tear, labral condition, and greater tuberosity notch) as well as other factors (duration of playing baseball, range of motion, and joint laxity) of 61 baseball players were retrospectively studied. The presence of a greater tuberosity notch was also evaluated for by plain radiographs. Forty patients had articular-side partial rotator cuff tears, most of which occurred in the interval between the supraspinatus and infraspinatus tendons. The existence of a rotator cuff tear was not related to the range of motion, joint laxity, the detachment of the superior glenoid labrum, or posterosuperior labral injury. Greater tuberosity notches were recognized in 38 shoulders by arthroscopy and most were detected on plain radiographs. The presence of a notch was significantly related to the existence of a rotator cuff tear, while the size of the notch was significantly related to the depth and width of the tear. The greater tuberosity notch seems to be one of the most important diagnostic indicators for a rotator cuff tear in throwing athletes.     

Outcome of the isolated SLAP lesions and analysis of the results according to the injury mechanisms

Superior labral anterior posterior (SLAP) lesions of the shoulder arise from various causes and have some controversies in their treatment. The purpose of this study is to evaluate the outcomes of arthroscopic SLAP repair and the relationship between injury mechanisms and outcomes. We evaluated the clinical results of 24 patients (mean 33 months follow-up) who had an arthroscopic isolated SLAP (type II: 21, type III: 1, type IV: 2 patients) repair with suture anchors. These labral tears were arthroscopically repaired with 1–4 anchors (mean 1.8). All patients were evaluated with University of California, Los Angeles (UCLA) and Visual Analogue Scale (VAS) scores. There were the following injury mechanisms: compression-type, 10; traction-type, 9; combined or other-type, 5 patients. We also compared the clinical results according to the injury mechanisms. Preoperatively, the mean of UCLA and VAS scores were 22.7 and 6.4 points, respectively. At an average of 33 months postoperatively, the mean of UCLA and VAS scores were 29.9 and 2.1 points, respectively. There was statistical improvement in the subjective scores from the pre- to post-operation. UCLA and VAS scores of the pre- and post-operation were not statistically different according to the injury mechanisms. Arthroscopic repair is effective in the treatment of isolated SLAP lesion and injury mechanisms do not affect the clinical outcomes.     

First-time shoulder dislocation: High prevalence of labral injury and age-related differences revealed by MR arthrography

PURPOSE: To evaluate abnormalities and age-related differences after first-time shoulder dislocation. MATERIALS AND METHODS: MRA images of first-time dislocators were assessed for labral-ligamentous-capsular / rotator cuff abnormalities and analyzed the age-related differences (< and >/=30 years old). RESULTS: Sixty-six patients (34 <30 years old vs. 32 >/=30 years; 51 males; all anterior dislocations) were imaged. Forty-eight patients (73%) showed anteroinferior labral avulsion, consisting of: 6% (4/34 vs. 0/32) Perthes; 23% (8/34 vs. 7/32) free ALPSA (anterior labrum periosteal sleeve avulsion) lesion); 6% (1/34 vs. 3/32) adherent ALPSA; 23% (9/34 vs. 6/32) Bankart; 14% (5/34 vs. 4/32) inferiorly displaced avulsed labrum; 2% (1/34 vs. 0/32) GLAD. Extensive labral detachment (extended above 3 o'clock position) was present in 31% (11/28 vs. 4/20). There were 14% (6/34 vs. 3/32) superior labrum anterior-posterior (SLAP) lesion; 27% (1/34 vs. 17/34) rotator cuff tendon tear; 71% (25/34 vs. 22/32) Hill-Sachs defect. Young patients were more likely to have extensive labral avulsions (P = 0.054), but less likely to have rotator cuff tears (P < 0.001). CONCLUSION: A high prevalence and wide variety of labral avulsions after first-time shoulder dislocation, especially adherent ALPSA, inferiorly displaced avulsed labrum, or GLAD lesion, may influence treatment choice and outcome, suggesting a role for early MRA to assist in treatment triage.     

Superior labral anterior posterior (SLAP) lesions of the glenoid labrum: reliability and accuracy of MR arthrography for diagnosis

PURPOSE: To determine the reliability and accuracy of magnetic resonance (MR) arthrography for the diagnosis of superior labral anterior posterior (SLAP) tears. MATERIALS AND METHODS: The MR arthrograms in 80 patients who underwent arthroscopy and MR arthrography during a 54-month period were retrospectively reviewed. MR arthrograms were independently scored by three observers for the presence and type of SLAP lesion. Type I SLAP lesions were regarded as negative as they most often are not clinically relevant. Interobserver agreement for detection of SLAP lesions was calculated by using kappa coefficients. The differences in areas under the receiver operating characteristic (ROC) curves were assessed with a univariate z score test. RESULTS: At arthroscopy, there were 25 SLAP tears: type II (n = 22), type III (n = 2), and type IV (n = 1). Sensitivity, specificity, and accuracy of each reader were 92%, 84%, and 86%; 92%, 82%, and 85%; and 84%, 69%, and 74%, respectively. Interobserver agreement for SLAP tears was substantial (kappa = 0.77) to moderate (kappa = 0.52, kappa = 0.44). The areas under the ROC curves for each reader were 0.94, 0.93, and 0.83, which were not significantly different. CONCLUSION: MR arthrography of the shoulder is reliable and accurate for detection of SLAP tears.     

Shoulder injuries in rugby players: Mechanisms,examination, and rehabilitation

BackgroundThe sport of rugby is growing in popularity for players at the high school and collegiate levels.ObjectiveThis article will provided the sports therapist with an introduction to the management of shoulder injuries in rugby players.SummaryRugby matches results in frequent impacts and leveraging forces to the shoulder region during the tackling, scrums, rucks and maul components of the game. Rugby players frequently sustain contusion and impact injuries to the shoulder region, including injuries to the sternoclavicular, acromioclavicular (AC), and glenohumeral (GH) joints. Players assessed during practices and matches should be screened for signs of fracture, cervical spine and brachial plexus injuries. A three phase program will be proposed to rehabilitate players with shoulder instabilities using rugby specific stabilization, proprioception, and strengthening exercises. A plan for return to play will be addressed including position-specific activities.     

The relationship of superior labralanteroposterior (SLAP) lesions and pseudolaxity to shoulder injuries in the overhead athlete

Understanding the effect of superior labral lesions on the function of the shoulder is essential to successfullytreating the overhead athlete. Recognizing the pseudolaxity owing to superior labral anteroposterior (SLAP) lesions and the pathological "peel-back" sign is critical in evaluating the injured shoulder in general and repairing the SLAP lesion in particular. The mechanical characteristics of suture anchors are more favorable than tacks in resisting the pathological forces responsible for the peel-back mechanism. The higher success rate of arthroscopic suture anchor repair of SLAP lesions in comparison with open capsulolabral reconstruction suggests that SLAP lesions are the usual cause of the "dead arm" syndrome. In our experience, arthroscopic repair of SLAP lesions can return the overhead athlete to their preoperative level of function in the vast majority of cases (87% return to preoperative level for two or more seasons).     

Rotator cuff tears in middle-aged tennis players: results of surgical treatment

BACKGROUND: Tennis players, like participants in other overhead sports, are vulnerable to rotator cuff tears. In players who continue to play into their middle-age years, the incidence of such injury increases. HYPOTHESIS: Surgical treatment of rotator cuff tears in middle-aged tennis players is largely successful in allowing return to tennis. STUDY DESIGN: Retrospective review. METHODS: We evaluated the results of surgical treatment of 51 middle-aged tennis players (average age, 51 years) with a rotator cuff tear in their dominant shoulder. Tennis participation among the group had averaged 3.5 hours per week for an average of 25 years. Forty-two patients underwent open repair of the tear with or without biceps tenodesis, whereas 9 patients underwent arthroscopic debridement of the tear with or without a biceps tenotomy. Patients were reviewed at an average of 57 months after surgery with an activities score, a subjective questionnaire, and a questionnaire regarding their postoperative participation in tennis. RESULTS: The activities score averaged 26.6 of 30 possible points. Forty-seven patients were satisfied with their result, and 40 patients were able to return to tennis at an average of 9.8 months after surgery. No difference was found in the ability to return to tennis between the open repair group and the arthroscopic debridement group. CONCLUSIONS: The results of this study indicate that it is possible for nearly 80% of middle-aged tennis players to return to participation after operative treatment of rotator cuff tears.     

Superior labrum anterior-posterior lesions: diagnosis with MR arthrography of the shoulder

PURPOSE: To determine the accuracy of magnetic resonance (MR) arthrography in the diagnosis of superior labrum anterior-posterior (SLAP) lesions of the shoulder. MATERIALS AND METHODS: From January 1995 to June 1998, MR arthrography of the shoulder was performed in 159 patients with a history of chronic shoulder pain or instability. Fifty-two patients underwent arthroscopy or open surgery 12 days to 5 months after MR arthrography. Diagnostic criteria for SLAP lesion included marked fraying of the articular aspect of the labrum, biceps anchor avulsion, inferiorly displaced bucket handle fragment, and extension of the tear into the biceps tendon fibers. Surgical findings were correlated with those from MR arthrography. RESULTS: SLAP injuries were diagnosed at surgery in 19 of the 52 patients (37%). Six of the 19 lesions (32%) were classified as type I, nine (47%) as type II, one (5%) as type III, and three (16%) as type IV. MR arthrography had a sensitivity of 89% (17 of 19 patients), a specificity of 91% (30 of 33 patients), and an accuracy of 90% (47 of 52 patients). The MR arthrographic classification showed correlation with the arthroscopic or surgical classification in 13 of 17 patients (76%) in whom SLAP lesions were diagnosed at MR arthrography. CONCLUSION: MR arthrography is a useful and accurate technique in the diagnosis of SLAP lesions of the shoulder. MR arthrography provides pertinent preoperative information with regard to the exact location of tears and grade of involvement of the biceps tendon.     

MR imaging of the shoulder in youth baseball players: Anatomy,pathophysiology, and treatment

With an increasing participation in youth sports and a growing popularity of overhead sports, shoulder pain and injuries are common in pediatric baseball players. In contrast to traumatic and collision injuries, which are more frequent with high-impact sports, many of the shoulder injuries are the result of repetitive overuse. Undiagnosed and untreated injury to the growth plates of skeletally immature athletes can lead to remodeling, which can negatively impact the biomechanics of the shoulder and produce long-term morbidity. Recently, there is an increasing emphasis on the association between skeletal maturation and injury patterns. The increasing use of magnetic resonance (MR) imaging has led to a better characterization of the traditionally radiographically-diagnosed growth plate injuries and awareness of other soft tissue and cartilaginous injuries that were previously thought to predominately occur in adult baseball players. The goal of this review is to: 1) highlight the normal anatomic changes that occur in the shoulder girdle during development and maturation; 2) discuss the biomechanical forces that are applied to the shoulder during a pitch; and 3) highlight the various injury patterns and adaptive remodeling that can occur in the shoulders of youth baseball athletes along with the current treatment options. These topics include growth plate injury, osteochondral injury, labral tear, capsular remodeling and rotator cuff tendinopathy.     

MR arthrography of the posterior labrocapsular complex: relationship with glenohumeral joint alignment and clinical posterior instability

OBJECTIVE: The purpose of our study was to investigate the relationship between tears of the posterior labrocapsular complex and glenohumeral alignment on MR arthrography and the presence and extent of posterior labrocapsular tears in patients with posterior instability. MATERIALS AND METHODS: Posterior labrocapsular tears identified on 24 MR arthrograms and surgically confirmed were evaluated for length of tear and labrocapsular avulsion. These examinations and a comparison cohort of 70 normal MR arthrograms with normal findings were also evaluated for humeral head position relative to the glenoid fossa. Medical records were reviewed for clinical diagnosis of posterior instability and history of shoulder trauma. RESULTS: The position of the humeral head relative to the glenoid was significantly more posterior in patients with posterior labral tear than in patients with a normal posterior labrum (4.9 mm versus 0.7 mm; p < 0.0001). The mean length (+/- SD) of posterior labral tear was 15.9 +/- 1.7 mm, and a direct correlation was found between tear length and posterior humeral translation (r = -0.65; p = 0.002). Posterior labral tears were significantly longer (18.6 vs 13.1 mm; p = 0.04), and posterior humeral translation was greater (6.4 vs 3.4 mm; p = 0.006) in patients with labrocapsular avulsion than in those without avulsion. Twelve (50%) of the patients with posterior labrocapsular tear had posterior instability, and 10 (83%) had a history of macrotrauma. On MR arthrography, the mean posterior humeral translation was greater (6.2 mm +/- 0.08; p = 0.019), posterior labral tears were longer (19.4 mm +/- 1.7; p = 0.0008), and labrocapsular avulsion was more common (83%; p = 0.0001) in patients with posterior instability than in patients who had a posterior labral tear but a clinically stable shoulder. CONCLUSION: Clinical posterior instability is associated with excessive posterior humeral translation, long posterior labral tears, and posterior labrocapsular avulsion.