Marc R. Safran

Distal biceps tendon ruptures: incidence, demographics, and the effect of smoking.

The purpose of the current study was to determine the incidence of distal biceps tendon ruptures within a defined population, to describe the demographics of affected individuals, and to identify potential risk factors. The healthcare system in this study provides care to a known number of members in an area defined by zip codes and proximity to the medical center. Medical records for all members who presented with injuries about the elbow during a 5-year period were reviewed. Thirteen men and one woman with an average age of 47 years comprised the study population. The dominant extremity was involved in 86% of patients. All patients described a mechanism involving excessive eccentric tension as the arm was forced from a flexed position. The incidence of injury in the membership population averaged 1.2 ruptures per 100,000 patients per year. Forty-three percent reported regular tobacco use, whereas only 9% of all members were smokers. A Poisson regression analysis revealed a 7.5 times greater risk of distal biceps tendon rupture in patients who smoke. The incidence of distal biceps tendon ruptures is 1.2 per 100,000 patients, with the majority in the dominant elbow of men who smoke and who are in their fourth decade of life.

Warm-up and muscular injury prevention: An update

SummaryMusculotendinous injuries are responsible for a significant proportion of injuries incurred by athletes. Many of these injuries are preventable. Importantly, musculotendinous injuries have a high incidence of recurrence. Thus, muscle injury prevention is advocated by coaches and trainers. Yet, most of the recommendations for muscle injury prevention are attempted by athletes and taught by coaches without supporting scientific evidence.This paper reviews the mechanics of muscular injury, associated and predisposing factors, and methods of prevention with a review of the supporting research and rationale for these methods with an emphasis on warm-up, stretching and strengthening.Muscles that are capable of producing a greater force, a faster contraction speed and subjected to a greater stretch are more likely to become injured. Many factors have been associated with muscular injury. From current research, some conclusions and recommendations for muscle injury prevention can be made. Overall and muscular conditioning and nutrition are important. Proper training and balanced strengthening are key factors in prevention of musculotendinous injuries as well. Warm-up and stretching are essential to preventing muscle injuries by increasing the elasticity of muscles and smoothing muscular contractions. Improper or excessive stretching and warming up can, however, predispose to muscle injury. Much research is still needed in this important aspect of sports medicine.

Biomechanical comparison of stimulated and nonstimulated skeletal muscle pulled to failure

We compared the biomechanical properties of passive and stimulated muscle rapidly lengthened to failure in an experimental animal model. The mechanical param eters compared were force to tear, change in length to tear, site of failure, and energy absorbed by the muscle- tendon unit before failure. Paired comparisons were made between 1) muscles stimulated at 64 Hz (tetanic stimulation) and passive (no stimulation) muscles, 2) muscles stimulated at 16 Hz (wave-summated stimu lation) and passive muscles, and 3) muscles stimulated at 64 Hz and at 16 Hz. Both tetanically stimulated and wave-summation con tracted muscles required a greater force to tear (at 64 Hz, 12.86 N more, P < 0.0004; and at 16 Hz, 17.79 N more, P < 0.003) than their nonstimulated controls, while there was no statistical difference in failure force between muscles stimulated at 16 Hz and 64 Hz. The energy absorbed was statistically greater for the stim ulated muscles than for the passive muscles in Groups 1 and 2 (at 64 Hz, 100% more, P < 0.0003; and 16 Hz, 88% more, P < 0.0002). In Group 3, the tetanically contracted muscle-tendon units absorbed 18% more energy than the wave-summated stimulated muscles (P < 0.01). All muscles tore at the distal musculotendi nous junction, and there was no difference in the length increase at tear between muscles in each group. These findings may lead to enhanced understanding of the mechanism and physiology of muscle strain injuries.

The role of warmup in muscular injury prevention

This study is an attempt to provide biomechanical sup port for the athletic practice of warming up prior to an exercise task to reduce the incidence of injury. Tears in isometrically preconditioned (stimulated before stretching) muscle were compared to tears in control (nonstimulated) muscle by examining four parameters: 1) force and 2) change of length required to tear the muscle, 3) site of failure, and 4) length-tension defor mation. The tibialis anterior (TA), the extensor digitorum longus (EDL), and flexor digitorum longus (EDL) mus cles from both hindlimbs of rabbits comprised our ex perimental model. Isometrically preconditioned TA (P < 0.001), EDL (P < 0.005), and FDL (P < 0.01) muscles required more force to fail than their contralateral controls. Precondi tioned TA (P < 0.05), EDL (P < 0.001), and FDL (P < 0.01) muscles also stretched to a greater length from rest before failing than their nonpreconditioned con trols. The site of failure in all of the muscles was the musculotendinous junction; thus, the site of failure was not altered by condition. The length-tension deforma tion curves for all three muscle types showed that in every case the preconditioned muscles attained a lesser force at each given increase in length before failure, showing a relative increase in elasticity, although only the EDL showed a statistically significant differ ence. From our data, it may be inferred that physiologic warming (isometric preconditioning) is of benefit in pre venting muscular injury by increasing the and length to failure and elasticity of the muscle-tendon unit.

Osteochondritis Dissecans of the Knee

&NA; Osteochondritis dissecans is a condition of the joints that appears to affect subchondral bone primarily, with secondary effects on articular cartilage. With progression, this pathology may present clinically with symptoms related to the integrity of the articular cartilage. Early signs, associated with intact cartilage, may be related to a softening phenomenon and alteration in the mechanical properties of cartilage. Later stages, because of the lack of underlying support of the cartilage, can present with signs of articular cartilage separation, cartilage flaps, loose bodies, inflammatory synovitis, persistent or intermittent joint effusion, and, in severe cases, secondary joint degeneration. Selecting and recommending a surgical intervention require balancing application of nonsurgical interventions with assessment of the degree of articular cartilage stability and the potential for spontaneous recovery.

The Effects of Joint Position and Direction of Joint Motion on Proprioceptive Sensibility in Anterior Cruciate Ligament-Deficient Athletes

We studied a group of anterior cruciate ligament-defi cient athletes to identify whether joint position and direction of joint motion have a significant effect on proprioception. Twenty-nine anterior cruciate ligament- deficient athletes were tested for their threshold to detect passive motion at both 15° and 45° moving into the directions of both flexion and extension. The single- legged hop test was used to identify function in the deficient limb. Results demonstrated statistically signif icant deficits in threshold to detect passive motion for the deficient limb at 15° moving into extension. For the deficient limb, threshold to detect passive motion was significantly more sensitive moving into extension than flexion at a starting angle of 15°; at a starting angle of 15° moving into extension threshold was significantly more sensitive than at a starting angle of 45° moving into extension. We conclude that in deficient limbs proprioception is significantly more sensitive in the end ranges of knee extension (15°) and is significantly more sensitive moving into the direction of extension. To effectively restore reflex stabilization of the lower limb we recommend a rehabilitation program empha sizing performance-based, weightbearing, closed ki netic chain exercise for the muscle groups that act on the knee joint.

Lateral ankle sprains: a comprehensive review: part 1: etiology, pathoanatomy, histopathogenesis, and diagnosis.

Ankle sprains are among the most common injuries sustained by athletes and seen by sports medicine physicians. Despite their prevalence in society, ankle sprains still remain a difficult diagnostic and therapeutic challenge in the athlete, as well as in society in general. The purpose of this section of our two-part study is to review scope of the problem, the anatomy and biomechanics of the lateral ankle ligaments, review the pathoanatomical correlates of lateral ankle sprains, the histopathogenesis of ligament healing, and define the mechanisms of injury to understand the basis of our diagnostic approach to the patient with this common acute and chronic injury. We extensively review the diagnostic evaluation including historical information and physical examination, as well as options for supplementary radiographic examination. We further discuss the differential diagnosis of the patient with recurrent instability symptoms. This will also serve as the foundation for part two of our study, which is to understand the rationale for our treatment approach for this common problem.

The Development and Validation of a Self-Administered Quality-of-Life Outcome Measure for Young, Active Patients With Symptomatic Hip Disease: The International Hip Outcome Tool (iHOT-33)

PURPOSE The purpose of this study was to develop a self-administered evaluative tool to measure health-related quality of life in young, active patients with hip disorders. METHODS This outcome measure was developed for active patients (aged 18 to 60 years, Tegner activity level ≥ 4) presenting with a variety of symptomatic hip conditions. This multicenter study recruited patients from international hip arthroscopy and arthroplasty surgeon practices. The outcome was created using a process of item generation (51 patients), item reduction (150 patients), and pretesting (31 patients). The questionnaire was tested for test-retest reliability (123 patients); face, content, and construct validity (51 patients); and responsiveness over a 6-month period in post-arthroscopy patients (27 patients). RESULTS Initially, 146 items were identified. This number was reduced to 60 through item reduction, and the items were categorized into 4 domains: (1) symptoms and functional limitations; (2) sports and recreational physical activities; (3) job-related concerns; and (4) social, emotional, and lifestyle concerns. The items were then formatted using a visual analog scale. Test-retest reliability showed Pearson correlations greater than 0.80 for 33 of the 60 questions. The intraclass correlation statistic was 0.78, and the Cronbach α was .99. Face validity and content validity were ensured during development, and construct validity was shown with a correlation of 0.81 to the Non-Arthritic Hip Score. Responsiveness was shown with a paired t test (P ≤ .01), effect size of 2.0, standardized response mean of 1.7, responsiveness ratio of 6.7, and minimal clinically important difference of 6 points. CONCLUSIONS We have developed a new quality-of-life patient-reported outcome measure, the 33-item International Hip Outcome Tool (iHOT-33). This questionnaire uses a visual analog scale response format designed for computer self-administration by young, active patients with hip pathology. Its development has followed the most rigorous methodology involving a very large number of patients. The iHOT-33 has been shown to be reliable; shows face, content, and construct validity; and is highly responsive to clinical change. In our opinion the iHOT-33 can be used as a primary outcome measure for prospective patient evaluation and randomized clinical trials.

The Pattern and Technique in the Clinical Evaluation of the Adult Hip: The Common Physical Examination Tests of Hip Specialists

PURPOSE The purpose of this study was to systematically evaluate the technique and tests used in the physical examination of the adult hip performed by multiple clinicians who regularly treat patients with hip problems and identify common physical examination patterns. METHODS The subjects included 5 men and 6 women with a mean age (+/-SD) of 29.8 +/- 9.4 years. They underwent physical examination of the hip by 6 hip specialists with a strong interest in hip-related problems. All examiners were blind to patient radiographs and diagnoses. Patient examinations were video recorded and reviewed. RESULTS It was determined that 18 tests were most frequently performed (>or=40%) by the examiners, 3 standing, 11 supine, 3 lateral, and 1 prone. Of the most frequently performed tests, 10 were performed more than 50% of the time. The tests performed in the supine position were as follows: flexion range of motion (ROM) (percentage of use, 98%), flexion internal rotation ROM (98%), flexion external rotation ROM (86%), passive supine rotation test (76%), flexion/adduction/internal rotation test (70%), straight leg raise against resistance test (61%), and flexion/abduction/external rotation test (52%). The tests performed in the standing position were the gait test (86%) and the single-leg stance phase test (77%). The 1 test in the prone position was the femoral anteversion test (58%). CONCLUSIONS There are variations in the testing that hip specialists perform to examine and evaluate their patients, but there is enough commonality to form the basis to recommend a battery of physical examination maneuvers that should be considered for use in evaluating the hip. CLINICAL RELEVANCE Patients presenting with groin, abdominal, back, and/or hip pain need to have a basic examination to ensure that the hip is not overlooked. A comprehensive physical examination of the hip will benefit the patient and the physician and serve as the foundation for future multicenter clinical studies.

Interobserver Agreement in the Classification of Rotator Cuff Tears Using Magnetic Resonance Imaging

Background Although magnetic resonance imaging (MRI) is a standard method of assessing the extent and features of rotator cuff disease, the authors are not aware of any studies that have assessed the interobserver agreement among orthopaedic surgeons reviewing MRI scans for rotator cuff disease. Hypothesis Fellowship-trained orthopaedic shoulder surgeons will have good interobserver agreement in predicting the more salient features of rotator cuff disease such as tear type (full thickness versus partial thickness), tear size, and number of tendons involved but only fair agreement with more complex features such as muscle volume, fat content, and the grade of partial-thickness cuff tears. Study Design Cohort study (diagnosis); Level of evidence, 3. Methods Ten fellowship-trained orthopaedic surgery shoulder specialists reviewed 27 MRI scans of 27 shoulders from patients with surgically confirmed rotator cuff disease. The ability to interpret full-thickness versus partial-thickness tears, acromion type, acromioclavicular joint spurs or signal changes, biceps lesions, size and grade of partial-thickness tears, acromiohumeral distance, number of tendons involved and amount of retraction for full-thickness tears, size of full-thickness tears, and individual muscle fatty infiltration and atrophy were assessed. Surgeons completed a standard evaluation form for each MRI scan. Interobserver agreement was determined and a kappa level was derived. Results Interobserver agreement was highest (>80%) for predicting full- versus partial-thickness tears of the rotator cuff, and for quantity of the teres minor tendon. Agreement was slightly less (>70%) for detecting signal in the acromioclavicular joint, the side of the partial-thickness tear, the number of tendons involved in a full-thickness tear, and the quantity of the subscapularis and infraspinatus muscle bellies. Agreement was less yet (60%) for detecting the presence of spurs at the acromioclavicular joint, a tear of the long head of the biceps tendon, amount of retraction of a full-thickness tear, and the quantity of the supraspinatus. The best kappa statistics were found for detecting the difference between a full- and partial-thickness rotator cuff tear (0.77), and for the number of tendons involved for full-thickness tears (0.55). Kappa for predicting the involved side of a partial-thickness tear was 0.44; for predicting the grade of a partial-thickness tear, it was −0.11. Conclusions Fellowship-trained, experienced orthopaedic surgeons had good agreement for predicting full-thickness rotator cuff tears and the number of tendons involved and moderate agreement in predicting the involved side of a partial-thickness rotator cuff tear, but poor agreement in predicting the grade of a partial-thickness tear.