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).     

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.     

SLAP lesions of the glenoid labrum diagnosed with MR imaging

Tears of the superior portion of the glenoid labrum in patients without shoulder instability have recently been described. These tears, which include the anchor of the biceps tendon to the labrum, have been labeled SLAP lesions (superior /abrum anterior to posterior). This study was performed to determine the magnetic resonance (MR) findings in patients with SLAP lesions. Retrospective review of the shoulder arthroscopy reports on patients who underwent MR imaging using a 1.5-T unit and subsequent arthroscopy by a single surgeon identified six patients with SLAP lesions (average age 36 years, range 17–65 years). MR images demonstrated atypical morphology indicative of tear in the superior portion of the labrum in four of the six patients, but only one tear had been identified preoperatively. Radiologists interpreting MR images of the shoulder should be aware of the MR findings of SLAP lesions as these tears can be a significant cause of patient disability and are difficult to diagnose clinically.     

Schultergelenkverletzungen bei Überkopfsportarten

Overhead sport places great demands on the shoulder joint. Shoulder pain in overhead athletes and throwers can in the majority of cases be attributed to lesions resulting from chronic overuse of tendons and capsuloligamentous structures or to sequels of microinstability and secondary impingement. Due to its great impact on therapeutic decisions, imaging in athletes with unclear shoulder pain is a challenge. In this connection, magnetic resonance (MR) arthrography represents the cross-sectional imaging modality of first choice, as it allows depiction and exclusion of pathologic alterations of all relevant joint structures with sufficient confidence. This article reviews the biomechanical and clinical aspects and MR arthrographic features of the most common shoulder pathologies in overhead athletes, including biceps tendinopathy, superior labral anterior-posterior (SLAP) lesions, rotator cuff lesions, as well as extrinsic and intrinsic impingement syndromes.     

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.     

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.     

The MR arthrographic anatomy of the biceps labral insertion and its morphological significance with labral tears in patients with shoulder instability

Introduction

Most of the fibres of the long head of biceps tendon attach on the superior labrum just posterior to the supraglenoid tubercle.

Aim

Our hypothesis was that posteriorly attached biceps tendons predispose to posterior superior labral tears and SLAP lesions.

Methods and materials

A prospective analysis of all MR shoulder arthrograms for shoulder instability referred from the shoulder specialist clinics, performed during a one year period were reviewed by two independent observers who were blinded to clinical history. The biceps attachment was classified into four groups according to the method described in an earlier cadaveric study into four groups; posterior-type 1, predominantly posterior-type 2, equal contributions to both anterior and posterior labrum-type 3 and predominantly anterior labral attachment-type 4. Data was analysed using Kappa statistics and Fischer's exact test.

Results

48 patients (33 males and 15 females) were included in this study with a mean age of 32 years. Majority, 22 patients (46%) had a type 1 attachment of the biceps on the superior labrum. There was moderate intra-observer and good interobserver agreement with a Kappa of 0.58 and 0.63 respectively. There was a significant association between a type 2 attachment and posterior tears (p ≤ 0.04) and also between a type 2 attachment and SLAP tears (p ≤ 0.04).

Conclusion

Our results suggest that variation in anatomy of biceps origin influences the type of labral tears that occur in patients with shoulder instability. The importance of these findings could influence selection of individuals in throwing sports like cricket and baseball.     

SLAP tears of the glenoid labrum in contact athletes.

OBJECTIVE: To describe the distribution and clinical presentation of labral injuries in rugby players and the time taken for them to return to sports. DESIGN: Retrospective cohort study. SETTING: Busy shoulder practice in the North West of England, treating a large number of professional athletes. PATIENTS: A review of 51 shoulder arthroscopies performed on professional rugby players over a 35 month period. All patients diagnosed with a SLAP lesion at arthroscopy were identified. Eighteen patients had a documented SLAP tear; this group represented our study population. INTERVENTIONS: Arthroscopic debridement and/or stabilization was carried out for all labral injuries using Panaloc anchors and No. 2 PDS via a 2 portal technique. MAIN OUTCOME MEASUREMENTS: Classification of injury, Satisfaction, Time to return to play. RESULTS: The incidence of SLAP tears in our study population was 35%. There were 11 isolated SLAP tears (61%), 3 SLAP tears associated with a Bankart lesion (17%), 2 SLAP tears associated with a posterior labral lesion (11%), and 2 SLAP tears associated with an anterior and posterior labral injuries (11%). Of the 18 SLAP tears, 14 (78%) were type 2, 3 (17%) were type 3, and 1 (5%) was type 4. None of the patients with a SLAP tear presented with symptoms of instability. MR Arthrogram had a 76% sensitivity for detecting SLAP tears. By 6 months postsurgery, 89% of patients were satisfied. Patients with isolated SLAP tears were the quickest to return to sports, at an average of 2.6 months postsurgery. CONCLUSIONS: SLAP tears are a common injury in rugby players. These can often be diagnosed with MR arthrography. Arthroscopic repair is associated with excellent results and early return to sports.     

Superior labrum anterior posterior lesions of the shoulder: Operative techniques of management

Since the advent of shoulder arthroscopy, pathology of the superior glenoid labrum and biceps anchor has been increasingly recognized as a source of shoulder pain and disability. Additional biomechanical testing has substantiated the role of the superior labrum and biceps anchor in glenohumeral stability. The diagnosis of superior labral injury such as the superior labrum anterior posterior (SLAP) lesion remains difficult, as the history, clinical examination, and radiographic evaluation can only raise suspicion. The ultimate diagnosis of the SLAP lesion can only be made with a well-directed diagnostic glenohumeral arthroscopy. The treatment of SLAP lesions depends on the type of SLAP lesion encountered at arthroscopy. This includes debridement of most type I and III lesions, and repair of type II and many type IV SLAP lesions. In this report, we will present our basic approach towards evaluation and treatment of SLAP lesions at the Southern California Orthopedic Institute.     

Incidence of SLAP lesions in a military population

OBJECTIVES: SLAP (superior labrum anterior and posterior) lesions are a recognised cause of shoulder pain and instability. They can occur following a direct blow, biceps traction and compression injuries, and are commonly seen in overhead athletes. Military personnel are physically active and often subjected to trauma. We assessed the incidence of SLAP lesions within a military population presenting with shoulder symptoms. METHODS: A retrospective review, of all shoulder arthroscopies performed by a single surgeon between June 2003 and December 2004 at a district general hospital serving both a military and civilian population, was undertaken. The presentation and incidence of SLAP lesions were recorded for both military and civilian patients. RESULTS: One hundred and seventy eight arthroscopies were performed on 70 (39.3%) military and 108 (60.7%) civilian patients. The average age was 42.3 (range 17-75), 50 females and 128 males were included. Indications for arthroscopy included pain (75.3%), instability (15.7%), pain and instability (7.9%), or "other symptoms" (1.1%). 39 SLAP lesions (22%) were found and grouped according to the Snyder classification--20.5% type 1, 69.3% type 2, 5.1% type 3, 5.1% type 4. Patients with a history of trauma or symptoms of instability were more likely to have a SLAP lesion (p<0.0001). The incidence of SLAP lesions in the military patients was 38.6% compared to 11.1% in civilian patients (p<0.0001). After allowing for the increased incidence of trauma and instability in the military, SLAP lesions were still more common in the military patients (p<0.001). CONCLUSIONS: There is a higher than average incidence of SLAP lesions in military patients compared to civilian patients. They tend to present with a history of trauma, as well as symptoms of pain and instability. Given the high incidence in military personnel, this diagnosis should be considered in military patients presenting with shoulder symptoms, and there should be a low threshold for shoulder arthroscopy.     

MR-arthrography in superior instability of the shoulder: correlation with arthroscopy

Purpose

This study was undertaken to evaluate magnetic resonance (MR) arthrography in the detection and classification of lesions that may cause superior instability.

Materials and methods

Forty-two consecutive patients with clinical signs of chronic superior instability of the shoulder underwent MR arthrography followed by arthroscopic surgery. For each patient we retrospectively reviewed the MR arthrography and surgical findings.

Results

We detected 31 superior labral anterior posterior (SLAP) lesions, all confirmed on arthroscopy with three cases of underestimation: in the detection of SLAP lesions, the sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of MR arthrography were 100%; in the evaluation of the type of SLAP lesion, sensitivity was 100%, specificity was 78.5%, accuracy was 92.8%, PPV was 71.7% and NPV was 100%. All cases of capsular laxity (13/42) and biceps tendon lesions (3/42) were confirmed on arthroscopy with sensitivity, specificity, accuracy, PPV and NPV of 100%. Eleven cuff lesions were detected on MR arthrography, 10 of which confirmed at arthroscopy: sensitivity was 100%, specificity was 96.8%, accuracy was 97.6%, PPV was 90.9% and NPV was 100%. Associated lesions were found in 38/42 patients.

Conclusions

Superior instability is frequently associated with different anatomical variants or pathological conditions, such as SLAP lesions. The role of MR arthrography is to describe the key features of lesions affecting the superior portion of the shoulder, including location, morphology, extent, and associated injuries and leanatomical variants and to correlate these features with clinical symptoms.     

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.     

Inter- and intraobserver variability of MR arthrography in the detection and classification of superior labral anterior posterior (SLAP) lesions: evaluation in 78 cases with arthroscopic correlation

Purpose

The purpose of this study was to determine inter- and intraobserver variability of MR arthrography of the shoulder in the detection and classification of superior labral anterior posterior (SLAP) lesions.

Methods

MR arthrograms of 78 patients who underwent MR arthrography before arthroscopy were retrospectively analysed by three blinded readers for the presence and type of SLAP lesions. MR arthrograms were reviewed twice by each reader with a time interval of 4 months between the two readings. Inter- and intraobserver agreement for detection and classification of SLAP lesions were calculated using κ coefficients.

Results

Arthroscopy confirmed 48 SLAP lesions: type I (n?=?4), type II (n?=?37), type III (n?=?3), type IV (n?=?4). Sensitivity and specificity for detecting SLAP lesions with MR arthrography for each reader were 88.6%/93.3%, 90.9%/80.0% and 86.4%/76.7%. MR arthrographic and arthroscopic grading were concurrent for 72.7%, 68.2% and 70.5% of SLAP lesions for readers 1–3, respectively. Interobserver agreement was excellent (κ?=?0.82) for detection and substantial (κ?=?0.63) for classification of SLAP lesions. For each reader intraobserver agreement was excellent for detection (κ?=?0.93, κ?=?0.97, κ?=?0.97) and classification (κ?=?0.94, κ?=?0.84, κ?=?0.93) of SLAP lesions.

Conclusion

MR arthrography allows reliable and accurate detection of SLAP lesions. In addition, SLAP lesions can be diagnosed and classified with substantial to excellent inter- and intraobserver agreement.     

Compression or distraction of the anterior cruciate injured knee

100 consecutive patients with a recent anterior cruciate ligament injury were examined with respect to type of sports activity that caused the injury, mechanism of injury and the occurrence of collateral ligament and meniscal lesions. There were 53 medial collateral ligament injuries, 12 medial, 35 lateral and 11 bicompartmental meniscal lesions. 59 patients were injured during contact sports, 30 in downhill skiing and 11 in other recreational activities, traffic accidents or at work. An associated medial collateral, ligament tear was more common in skiing (22/30) than during contact sports (23/59), whereas a bicompartmental meniscal lesion was found more frequently in contact sports (9/59) than in skiing (0/30). Weightbearing was reported by 56/59 of the patients with contact sports injuries and by 8/30 of those with skiing injuries. Non-weightbearing in the injury situation led to the same rate of MCL tears (18/28) as those reporting weightbearing (35/72) but significantly more intact menisci (19/28 vs 23/72). Thus, contact sports injuries were more often sustained during weightbearing, with a resultant joint compression of both femuro-tibial compartments as shown by the higher incidence of bicompartmental meniscal lesions. This might be an important prognostic factor for future joint disease and arthrosis. The classic unhappy triad was a rare finding (8/100) and we suggest that this entity should be replaced by the unhappy compression injury.     

Moderate value of non-contrast magnetic resonance imaging after non-dislocating shoulder trauma

Purpose

The purpose of the present study was to determine the value of shoulder magnetic resonance imaging (MRI) obtained in the community setting interpreted by musculoskeletal radiologists in patients with shoulder pain initiated by a single non-dislocating shoulder trauma.

Methods

In 56 of 61 consecutive patients who underwent shoulder arthroscopy due to pain after a single non-dislocating shoulder trauma, the data sets of non-contrast MRI were complete. These were retrospectively interpreted by three radiologists specialized on musculoskeletal MRI who were blinded for patients’ history and who did not have access to the reports of arthroscopy. Standard evaluation forms were used to assess the MRIs for superior labrum anterior and posterior (SLAP) lesions, anterior or posterior labrum lesions, lesions of the long head of biceps tendon (LHB) and for partial tears of the supraspinatus tendon and the upper quarter of the subscapularis tendon. Quality of the MRI was assessed by each radiologist on a four-point scale.

Results

The pooled sensitivity for the three radiologists for the detection of SLAP lesions was 45.0 %, for anterior or posterior labrum tears 77.8 and 66.7 %, for lesions of the LHB 63.2 % and for partial tears of the supraspinatus or subscapularis tendon tears 84.8 and 33.3 %. Corresponding inter-rater reliabilities were poor (SLAP lesions) to substantial (anterior labrum tears). Quality of MRI only influenced the accuracy for the detection of posterior labrum tears.

Conclusion

A non-contrast shoulder MRI obtained in the community setting after non-dislocating shoulder trauma has a moderate sensitivity for most intraarticular pathologies when interpreted by musculoskeletal radiologists. Accuracy is dependent on the observer and not on the assessed quality.

Level of evidence

Case series, Level IV.

     

Diagnostic performance of MR arthrography in the assessment of superior labral anteroposterior lesions of the shoulder

OBJECTIVE: The purpose of this study was to evaluate the diagnostic performance of MR arthrography in the assessment of superior labral anteroposterior (SLAP) lesions of the shoulder with emphasis on the classification of SLAP lesions. MATERIALS AND METHODS: Two hundred sixty-five MR arthrograms including 68 MR arthrograms of patients with arthroscopically proven SLAP lesions of the shoulder and 197 MR arthrograms of patients with an intact superior labrum and biceps anchor were retrospectively reviewed in random order. MR arthrography was performed using triplanar T1-weighted spin-echo sequences and a coronal oblique T2-weighted fast spin-echo sequence. MR arthrograms were evaluated by two radiologists with agreement by consensus, and the results were compared with arthroscopic findings. RESULTS: Of 68 SLAP lesions, seven (10%) were arthroscopically classified as type I, 41 (60%) as type II (including 20 type II lesions with coexisting Bankart lesions [29%]), 14 (21%) as type III, and six (9%) as type IV. Compared with arthroscopy as the gold standard, MR arthrography showed a sensitivity of 82% and a specificity of 98% for the overall detection of SLAP lesions. MR arthrographic grading and arthroscopic grading were concurrent in 45 (66%) of 68 arthroscopic diagnoses. Of the surgically confirmed SLAP lesions, involvement of the biceps insertion and SLAP type II lesions with coexisting Bankart lesions were assessed correctly in 75% and 95% of cases, respectively. CONCLUSION: MR arthrography is a highly effective method for the detection of SLAP lesions, but this technique is limited in the classification of different types of SLAP lesions. However, for preoperative planning MR arthrography provides accurate information about the stability of the biceps insertion and the presence of associated anteroinferior labral injuries.     

Posterior detachment of the glenoid labrum in athletes with posttraumatic chronic shoulder pain

We examined 20 consecutively admitted athletes suffering from chronic shoulder pain for more than 6 months following a single shoulder trauma without dislocation. Two of them suffered from a posterior detachment of the glenoid labrum. Both had pain during loading, especially during over-the-head activities, with a clicking sensation. No previous dislocation of the involved dominant arm was recorded. Both were resistant to conservative treatment. On examination both patients had slightly decreased range of motion, a positive posterior apprehension sign and a negative impingement sign/test. One shoulder was clinically unstable. Special X-ray identified one minor avulsion of the posterior margin of the glenoid cavity. Magnetic resonance imaging revealed a total posterior glenolabral detachment in both patients and also a bony avulsion of the glenoid posterior margin in one. Arthroscopy identified the posterior labral lesions and reinsertion of the detached labrum using the Mitek-anchor system was performed. After 1 year, both were able to participate in shoulder-demanding sports. In conclusion, posterior labral detachment might cause chronic shoulder pain after a single nondislocating shoulder trauma in athletes.     

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.     

Trends in the diagnosis of SLAP lesions in the US military

Purpose

Shoulder pathology, particularly SLAP (superior labrum anterior-posterior) lesions, is prevalent in overhead athletes and physically active individuals. The aim of this study is to quantify the burden of SLAP lesions in the military and establish risk factors for diagnosis.

Methods

A retrospective analysis of all service members diagnosed with a SLAP lesion (International Classification of Disease, Ninth Revision code 840.70) in the Defense Medical Epidemiological Database between 2002 and 2009 was performed. Available epidemiological risk factors including age, sex, race, military rank, and branch of service were evaluated using multivariate Poisson regression analysis, and cumulative and subgroup incidence rates were calculated.

Results

During the study period, approximately 23,632 SLAP lesions were diagnosed among a population at risk of 11,082,738, resulting in an adjusted incidence rate of 2.13 per 1,000 person-years. The adjusted annual incidence rate for SLAP lesions increased from 0.31 cases per 1,000 person-years in 2002 to 1.88 cases per 1,000 person-years in 2009, with an average annual increase of 21.2 % (95 % CI 20.7 %, 22.0 %, p < 0.0001) during the study period. Age, sex, race, branch of military service, and military rank were independent risk factors associated with the incidence rate of SLAP lesion (p < 0.01). Male service members were over twofold more likely (IRR, 2.12; 95 % CI 2.01, 2.23) to sustain a SLAP lesion when compared with females. Increasing age category was associated with a statistically significant increase in the incidence rate for SLAP lesions in the present study (p < 0.001). After controlling for the other variables, those individuals of white race, enlisted ranks, or Marine Corps service experienced the highest incidence rates for SLAP.

Conclusion

This is the first study to establish the epidemiology of SLAP lesions within an active military cohort in the American population. Sex, age, race, military rank, and branch of military service were all independently associated with the incidence rate of SLAP lesions in this physically active population at high risk for shoulder injury.

Level of evidence

II.