Spine & Sports Institute

Background During the throwing motion, the lower extremity is responsible for creating power that is transmitted through the core to the upper extremity. Research has shown that good hip range of motion and strength in throwing athletes results in greater performance and decreased stress placed on the upper extremity. Although research has investigated bilateral differences in hip characteristics among baseball pitchers, little is known about differences between pitchers and position players.

Hypothesis Pitchers will have decreased passive hip rotation range of motion and gluteus medius strength compared with position players.

Study Design Cross-sectional study; Level of evidence, 3.

Methods Forty professional baseball pitchers and 40 position players with no recent history of lower extremity injury participated. Bilateral hip external and internal rotation range of motion, total arc of motion, and gluteus medius strength were measured with a digital inclinometer and handheld dynamometer.

Results A Hotelling T² multivariate analysis of variance showed position players to have significantly more hip internal rotation range of motion (3.1º, P = .01, effect size = .53) and abduction strength (3.5 kg, P =.04, effect size = .53) in the trail leg compared with the pitchers. There were no significant differences for any other hip characteristics between groups (P > .07).

Conclusion The results of this study indicate that baseball pitchers have significantly smaller amounts of hip internal rotation range of motion and abduction strength of the trail leg compared with position players. However, these differences may not be clinically significant.

Clinical Relevance Position players may be able to develop more energy in the lower extremity, while pitchers may rely more on energy created in the core and upper extremity, potentially placing pitchers at an increased risk for upper extremity injury. These descriptive hip characteristics may help clinicians detect inadequacies and provide appropriate prevention, diagnostic, and treatment interventions for such athletes.

Background The objective of this study was to determine the effects of increased horizontal abduction with maximum external rotation, as occurs during the late cocking phase of throwing motion, on shoulder internal impingement.

Hypothesis An increase in glenohumeral horizontal abduction will cause overlap of the rotator cuff insertion with respect to the glenoid and increase pressure between the supraspinatus and infraspinatus tendon insertions on the greater tuberosity and the glenoid.

Study Design Controlled laboratory study.

Methods Eight cadaveric shoulders were tested with a custom shoulder testing system with the specimens in 60° of glenohumeral abduction and maximum external rotation. The amount of internal impingement was evaluated by assessing the location of the supraspinatus and infraspinatus articular insertions on the greater tuberosity relative to the glenoid using a MicroScribe 3DLX. Pressure in the posterior-superior quadrant of the glenoid was measured using Fuji prescale film. Data were obtained with the humerus in the scapular plane and 15°, 30°, and 45° of horizontal abduction from the scapular plane.

Results At 30° and 45° of horizontal abduction, the articular margin of the supraspinatus and infraspinatus tendons was anterior to the posterior edge of the glenoid and less than 2 mm from the glenoid rim in the lateral direction; the contact pressure was also greater than that found in the scapular plane and 15° of horizontal abduction.

Conclusion Horizontal abduction beyond the coronal plane increased the amount of overlap and contact pressure between the supraspinatus and infraspinatus tendons and glenoid.

Clinical Relevance Excessive glenohumeral horizontal abduction beyond the coronal plane may cause internal impingement, which may lead to rotator cuff tears and superior labral anterior to posterior (SLAP) lesions.

Background The main clinical symptom of lumbar spondylolysis is lower back pain. Radiculopathy rarely occurs without vertebral slippage.

Hypothesis Spondylolysis in young athletes can cause lumbar radiculopathy.

Study Design Case series; Level of evidence, 4.

Methods Ten patients (7 males and 3 females) were included in this study. The age of the patients ranged from 12 to 27 years. We employed plain radiography, computed tomography, magnetic resonance imaging, and selective radiculography if needed.

Results The pathomechanism was classified into nonspondylolytic radiculopathy (3 cases) and spondylolytic radiculopathy (7 cases). In the nonspondylolytic group, 1 patient had a juxta-facet cyst at L4-5 and 2 patients had a herniated nucleus pulposus. In the other group, spondylolytic-related factors caused radiculopathy, and spondylolysis was in the early or progressive stage in all 7 patients. Radiologic findings indicated that radiculopathy was caused by extraosseous hematoma or edema in the vicinity of the fracture site. The radiculopathy disappeared within a month of nonoperative management, and radiologic abnormalities disappeared 3 to 6 months later.

Conclusion Radiculopathy can occur together with lumbar spondylolysis without slippage in young athletes. We propose extra-osseous hematoma or edema at the site of spondylolysis as the unique pathomechanism causing radiculopathy in young athletes. Radiculopathy is rare in athletes with spondylolysis. Magnetic resonance imaging is a useful tool to clarify the pathologic changes that induce the radiculopathy for both spondylolytic and nonspondylolytic factors.

Abstract

Background The amount of medial compartment opening for medial knee injuries determined by valgus stress radiography has not been well documented. The purpose of this study was to develop clinical guidelines for diagnosing medial knee injuries using valgus stress radiography.

Hypothesis Measurements of medial compartment gapping can accurately differentiate between normal and injured medial structure knees on valgus stress radiographs.

Study Design Controlled laboratory study.

Methods Valgus stress radiographs were obtained on 18 adult lower extremities using 10-N·m and clinician-applied valgus loads at 0° and 20° of flexion to intact knees and after sequential sectioning of the superficial medial collateral ligament proximally and distally, the meniscofemoral and meniscotibial portions of the deep medial collateral ligament, the posterior oblique ligament, and the cruciate ligaments. Three independent observers of different experience levels measured all of the radiographs during 2 separate occasions to determine intraobserver repeatability and interobserver reproducibility.

Results Compared with the intact knee, significant medial joint gapping increases of 1.7 mm and 3.2 mm were produced at 0° and 20° of flexion, respectively, by a clinician-applied load on an isolated grade III superficial medial collateral ligament simulated injury. A complete medial knee injury yielded gapping increases of 6.5 mm and 9.8 mm at 0° and 20°, respectively, for a clinician-applied load. Intraobserver repeatability and interobserver reproducibility intraclass correlation coefficients were .99 and .98, respectively.

Conclusion Valgus stress radiographs accurately and reliably measure medial compartment gapping but cannot definitively differentiate between meniscofemoral- and meniscotibial-based injuries. A grade III medial collateral ligament injury should be suspected with greater than 3.2 mm of medial compartment gapping compared to the contralateral knee at 20° of flexion, and this injury will also result in gapping in full extension.

Clinical Significance Valgus stress radiographs provide objective and reproducible measurements of medial compartment gapping, which should prove useful for definitive diagnosis, management, and postoperative follow-up of patients with medial knee injuries.

1. Robert F. LaPrade, MD, PhD*,
2. Andrew S. Bernhardson, BS, ENS, USNR,
3. Chad J. Griffith, MD,
4. Jeffrey A. Macalena, MD and
5. Coen A. Wijdicks, MSc

Abstract

Background The objective of this study was to determine the effects of increased horizontal abduction with maximum external rotation, as occurs during the late cocking phase of throwing motion, on shoulder internal impingement.

Hypothesis An increase in glenohumeral horizontal abduction will cause overlap of the rotator cuff insertion with respect to the glenoid and increase pressure between the supraspinatus and infraspinatus tendon insertions on the greater tuberosity and the glenoid.

Study Design Controlled laboratory study.

Methods Eight cadaveric shoulders were tested with a custom shoulder testing system with the specimens in 60° of glenohumeral abduction and maximum external rotation. The amount of internal impingement was evaluated by assessing the location of the supraspinatus and infraspinatus articular insertions on the greater tuberosity relative to the glenoid using a MicroScribe 3DLX. Pressure in the posterior-superior quadrant of the glenoid was measured using Fuji prescale film. Data were obtained with the humerus in the scapular plane and 15°, 30°, and 45° of horizontal abduction from the scapular plane.

Results At 30° and 45° of horizontal abduction, the articular margin of the supraspinatus and infraspinatus tendons was anterior to the posterior edge of the glenoid and less than 2 mm from the glenoid rim in the lateral direction; the contact pressure was also greater than that found in the scapular plane and 15° of horizontal abduction.

Conclusion Horizontal abduction beyond the coronal plane increased the amount of overlap and contact pressure between the supraspinatus and infraspinatus tendons and glenoid.

Clinical Relevance Excessive glenohumeral horizontal abduction beyond the coronal plane may cause internal impingement, which may lead to rotator cuff tears and superior labral anterior to posterior (SLAP) lesions.

1. Teruhisa Mihata, MD, PhD*†,
2. Michelle H. McGarry, MS*,
3. Mitsuo Kinoshita, MD, PhD† and
4. Thay Q. Lee, PhD*‡