Keith Kenter

Intra- and Interobserver Reproducibility of the Shoulder Laxity Examination

The present study evaluates the inter- and intraobserver reproducibility of clinical examination of glenohumeral laxity in the unanesthetized shoulder. Forty-three asymptomatic Division I collegiate athletes underwent bilateral shoulder laxity examination initially and again after 3 months. Translation of the humeral head on the glenoid fossa in the anterior, posterior, and inferior directions was graded by four physicians who were blinded to their own previous grading and that of the other examiners. Overall intraobserver reproducibility of examination was 46%. When grades 0 and 1 were equalized, overall intraobserver reproducibility improved to 74%. For both the equalized and non-equalized reproducibility values reported by all examiners, the kappa values for intraobserver correlation were less than 0.5, which suggests that correlations were not better than those achieved by chance alone. Overall interobserver reproducibility was 47%. When grades 0 and 1 were equalized, interobserver reproducibility improved to 78%. Kappa values were greater than 0.5 only in equalized posterior and inferior laxity. The data demonstrate that the laxity examination of the unanesthetized shoulder is not easily reproducible in either intra- or interobserver comparison. Equalization of grade 0 and grade 1 laxity improves both intra- and interobserver reproducibility. We recommend caution when determining diagnosis and treatment based on this examination.

Glenohumeral Translation in the Asymptomatic Athlete's Shoulder and Its Relationship to Other Clinically Measurable Anthropometric Variables

To determine the degree of shoulder translation in uninjured athletes, we examined 76 Division I colle giate athletes (44 women and 32 men) for passive range of motion in both shoulders and for knee and elbow hyperextension. Translation was based on a scale of 0 to 3+. Shoulders with symptoms of pain or a history of instability or dislocation were excluded from this study. Forty-six shoulders had 0 anterior transla tion, 75 had 1+, and 31 had 2+. Thirteen shoulders had 0 posterior translation, 56 had 1 +, and 83 had 2+. Thirty-eight shoulders had 0 inferior translation, 105 had 1 +, and 9 had 2+. No shoulder had translation of 3+ in any direction. Twenty-four athletes, 12 men and 12 women, had translational asymmetry of a minimum of one grade in at least one direction. No shoulder was asymmetric in all three directions. There was a signif icant correlation between dominant hand and in creased translation; 19 of 24 athletes with asymmetric shoulders had greater translation in the nondominant extremity. There was no relationship between transla tion and range of motion, knee or elbow hyperexten sion, thumb-to-forearm distance, or years spent in sports participation. Asymmetry of shoulder translation may exist in the normal shoulder. This review shows that up to 2+ translation in any direction cannot be considered abnormal.

Acute elbow injuries in the National Football League

We performed a retrospective review to evaluate acute medial collateral ligament injuries of the elbow in professional football players from 1991 to 1996 (5 seasons). There were 5 acute medial collateral ligament injuries in 4 players (1 player with bilateral involvement). All injuries occurred with the hand planted on the playing surface while a valgus or hyperextension force was applied to the elbow. There were 2 centers, both involved with long-snapping situations, 1 running back, and 1 quarterback. All elbows had valgus instability on physical examination. Despite this instability, all players were able to function without operative reconstruction of the medial collateral ligament. No evidence of valgus instability was seen at the time of follow-up (average, 3.4 years). Next, we reviewed all acute elbow injuries in the National Football League from the same 5-season period. Ninety-one acute elbow injuries were reviewed. Overall, there were 70 (76.9%) elbow sprains, 16 (17.6%) dislocation/subluxation patterns, 4 (4.4%) fractures, and 1 (1.1%) miscellaneous injury. Review of the acute elbow sprains revealed 39 (55.7%) hyperextension injuries, 14 (20%) medial collateral ligament injuries, 2 (2.9%) lateral collateral ligament sprains, and 15 (21.4%) nonspecific sprains. The epidemiology of the 14 medial collateral ligament injuries was studied in more detail. The 2 most common mechanisms of injury were blocking at the line of scrimmage (50%) and the application of a valgus force with the hand planted on the playing surface (29%). There were 8 linemen, 4 receivers, 1 running back, and 1 quarterback. All injuries were managed with nonoperative treatment. The average time lost was 0.64 games (range, 0 to 4). We report 19 acute medial collateral ligament injuries of the elbow in elite football players, 2 of whom are considered overhead throwing athletes, who were able to function at a competitive level without surgical repair or reconstruction, in contrast to baseball players, in whom the mechanics and demands may differ.

The Paratenon Contributes to Scleraxis-Expressing Cells during Patellar Tendon Healing

The origin of cells that contribute to tendon healing, specifically extrinsic epitenon/paratenon cells vs. internal tendon fibroblasts, is still debated. The purpose of this study is to determine the location and phenotype of cells that contribute to healing of a central patellar tendon defect injury in the mouse. Normal adult patellar tendon consists of scleraxis-expressing (Scx) tendon fibroblasts situated among aligned collagen fibrils. The tendon body is surrounded by paratenon, which consists of a thin layer of cells that do not express Scx and collagen fibers oriented circumferentially around the tendon. At 3 days following injury, the paratenon thickens as cells within the paratenon proliferate and begin producing tenascin-C and fibromodulin. These cells migrate toward the defect site and express scleraxis and smooth muscle actin alpha by day 7. The thickened paratenon tissue eventually bridges the tendon defect by day 14. Similarly, cells within the periphery of the adjacent tendon struts express these markers and become disorganized. Cells within the defect region show increased expression of fibrillar collagens (Col1a1 and Col3a1) but decreased expression of tenogenic transcription factors (scleraxis and mohawk homeobox) and collagen assembly genes (fibromodulin and decorin). By contrast, early growth response 1 and 2 are upregulated in these tissues along with tenascin-C. These results suggest that paratenon cells, which normally do not express Scx, respond to injury by turning on Scx and assembling matrix to bridge the defect. Future studies are needed to determine the signaling pathways that drive these cells and whether they are capable of producing a functional tendon matrix. Understanding this process may guide tissue engineering strategies in the future by stimulating these cells to improve tendon repair.

The relationships among spatiotemporal collagen gene expression, histology, and biomechanics following full-length injury in the murine patellar tendon

Tendon injuries are major orthopedic problems that worsen as the population ages. Type‐I (Col1) and type‐II (Col2) collagens play important roles in tendon midsubstance and tendon‐to‐bone insertion healing, respectively. Using double transgenic mice, this study aims to spatiotemporally monitor Col1 and Col2 gene expression, histology, and biomechanics up to 8 weeks following a full‐length patellar tendon injury. Gene expression and histology were analyzed weekly for up to 5 weeks while mechanical properties were measured at 1, 2, 5, and 8 weeks. At week 1, the healing region displayed loose granulation tissue with little Col1 expression. Col1 expression peaked at 2 weeks, but the ECM was highly disorganized and hypercellular. By 3 weeks, Col1 expression had reduced and by 5 weeks, the ECM was generally aligned along the tendon axis. Col2 expression was not seen in the healing midsubstance or insertion at any time point. The biomechanics of the healing tissue was inadequate at all time points, achieving ultimate loads and stiffnesses of 48% and 63% of normal values by 8 weeks. Future studies will further characterize the cells within the healing midsubstance and insertion using tenogenic markers and compare these results to those of tendon cells during normal development.

Pediatric traumatic atlanto-occipital dislocation: five cases and a review.

Traumatic atlanto-occipital dislocation (AOD) has been thought to be a rare and fatal injury. Recently, more survivors, especially children, have been reported. During a 10-year period, the authors have encountered five children with traumatic AOD. A retrospective review of traumatic AOD in children from 1985 to 1995 was performed. Clinical presentation, initial radiologic findings, and final outcome were emphasized. Distance from the dens to the basion and the ratio of Powers were measured from initial lateral cervical spine radiographs. The average distance from the dens to the basion was 9.8 mm. The average ratio of Powers was 1.38. There were three survivors, two having a concomitant spinal cord injury. All survivors underwent a posterior occipitovertebral fusion. Three cases initially went undiagnosed. The diagnosis of AOD by lateral cervical spine radiographs can be difficult. The authors recommend detailed measurements of the initial cervical spine radiographs in pediatric patients at risk for traumatic AOD.

Relationship between MRI and clinical findings in the acromioclavicular joint.

Abstract.Objective: To determine the relationship between the magnetic resonance (MR) appearance of the acromioclavicular (AC) joint and the physical findings. Design: A total of 116 consecutive patients underwent routine MR imaging (MRI) of the shoulder over an 18-month period. All MR studies were interpreted by a blinded, experienced musculoskeletal radiologist. Eleven variables were studied: the presence of osteophytes; fluid in the joint; fluid outside the joint; high signal in the clavicle or in the acromion; fluid in the subacromial bursa; irregularity of the joint margins; bulging of the capsule; widening of the joint; the age of the patient; and the presence of a rotator cuff tear. The clinical information was supplied by an experienced shoulder surgeon blinded to the MRI findings. A control group of 23 normal volunteers was also studied. Results: The only statistically significant correlation (P=0.0249) was between high signal in the distal clavicle and degenerative changes found clinically. A weaker relationship existed between fluid in the joint and the clinical examination and between increasing degenerative changes and advancing age. Otherwise, no material relationship was found between any of the other MR abnormalities and the clinical picture. Conclusion: There appears to be no real correlation between the MR appearances and the clinical findings in the AC joint.

Interscalene Block for Elective Shoulder Surgery

This study assessed patient experiences with interscalene block anesthesia for elective shoulder surgery. Routine use of interscalene anesthesia was introduced at our institution in 1997. All patients who underwent interscalene anesthesia during the first 3 years of our experience with this regional anesthetic technique were asked to respond to an anesthesia-related questionnaire. Overall patient satisfaction with interscalene anesthesia was 87%, and success rate in achieving a complete motor and sensory block was 79%. The duration of pain relief postoperatively was 10.5 hours for patients with a successful block. Patients consistently reported that having an interscalene block was less painful than anticipated; 90% said they would have interscalene anesthesia again for shoulder surgery. This study demonstrates that interscalene anesthesia for elective shoulder surgery is safe and well accepted in this patient population.

Percutaneous balloon humeroplasty for Hill-Sachs lesions: a novel technique

INTRODUCTION Hills-Sachs lesions are commonly associated with anterior shoulder dislocations and can be a source of recurrent instability. Studies have shown that, even after soft tissue repair of a Bankart lesion, there is still a risk for redislocation in a patient with significant bony defects. The purpose of this study is to ascertain whether balloon humeroplasty is an effective technique of reducing acute Hill-Sachs defect in a cadaveric model. METHODS Eighteen cadaveric humerii dissected free of soft tissue were used for this study. Hill-Sachs lesions were created in a reproducible manner in the anatomical posterolateral aspect of the head with a mallet edge. An inflatable balloon tamp (balloon, IBT) was used to reduce the lesion via a small transcortical window. Cement was used to fill the void created by the balloon. We utilized computed tomography (CT) to collect volume data of each humeral head pre- and post-procedure. From this data, we calculated the volume of the Hill-Sachs defect and the percent corrected. A paired t test was performed to analyze the data statistically. RESULTS The average prereduction Hill-Sachs defect volume was 1515.5 mm(3). The average post-reduction lesion residual volume was 31 mm(3) with 99.3% reduction to the original humeral head volume. The Hill-Sachs lesion reduction was statistically significant with P value of .0004. CONCLUSION Balloon humeroplasty proved to be an effective technique for reducing Hill-Sachs lesions in a cadaveric model. This technique may be used as an adjunct to arthroscopic versus open Bankart procedure for engaging acute Hill-Sachs lesions.

Orthopaedic surgery milestones.

Peter J. Stern, MD, is Norman S. & Elizabeth C.A. Hill Professor and Chairman of Orthopaedic Surgery at the University of Cincinnati College of Medicine; Stephen Albanese, MD, is Professor and Chair of Orthopedic Surgery and Medical Director of Orthopedic Surgery Clinic at SUNY Upstate Medical University; Mathias Bostrom, MD, is Residency Program Director and Academic Director of Orthopaedics at Hospital for Special Surgery and Professor of Orthopaedic Surgery, Weill Cornell Medical College, Helen Hayes Hospital; Charles S. Day, MD, MBA, is Rabkin Fellow in Medical Education, Associate Professor of Orthopedic Surgery at Harvard Medical School, and Chief/Program Director of Hand and Upper Extremity Surgery at Beth Israel Deaconess Medical Center; Steven L. Frick, MD, is Chairman of Orthopedic Surgery at Nemours Children’s Hospital and Professor of Orthopedic Surgery at the University of Central Florida College of Medicine; William Hopkinson, MD, is Professor, Vice-Chair, and Program Director of Orthopaedic Surgery & Rehabilitation at Loyola University Stritch School of Medicine; Shepard Hurwitz, MD, is Executive Director of the American Board of Orthopaedic Surgery and Professor of Orthopaedics at the University of North Carolina; Keith Kenter, MD, is Director of the Orthopaedic Surgery Residency Program, Associate Professor of Orthopaedic Surgery, and Associate Professor of Physical Medicine and Rehabilitation at the University of Cincinnati College of Medicine; John S. Kirkpatrick, MD, is Professor and Chair of Orthopaedic Surgery and Rehabilitation and Program Director of Orthopaedic Surgery Residency at the University of Florida College of Medicine; J. L. Marsh, MD, is Program Director of Residency Training Program and Professor and Carroll B. Larson Chair of Orthopaedics and Rehabilitation at the University of Iowa; Anand M. Murthi, MD, is Chief of Shoulder and Elbow Surgery and Fellowship Director at MedStar Union Memorial Hospital; Lisa A. Taitsman, MD, MPH, is Associate Professor of Orthopaedics and Sports Medicine at the University of Washington; Brian C. Toolan, MD, is Associate Professor of Surgery and Director of the Residency Program of Orthopaedic Surgery at the University of Chicago Medicine; Kristy Weber, MD, is Virginia & William Percy Professor of Orthopaedic Surgery, Division Chief of Orthopaedic Oncology, and Director of the Sarcoma Center at Johns Hopkins School of Medicine; Rick W. Wright, MD, is Dr Asa C. Dorothy W. Jones Professor of Orthopaedic Surgery, Residency Program Director, and Co-Chief of Sports Medicine at Washington University School of Medicine; Pamela L. Derstine, PhD, MHPE, is Executive Director of the Review Committees for Colon and Rectal Surgery, Neurological Surgery, Orthopaedic Surgery, and Otolaryngology at the Accreditation Council for Graduate Medical Education; and Laura Edgar, EdD, CAE, is Senior Associate Director of Outcome Assessment at the Accreditation Council for Graduate Medical Education.