Faculty Bibliography

Synovial chondromatosis is a rare, benign, proliferative cartilaginous lesion arising from the synovial tissue or bursal lining of or near joints. This disease process can be classified into intra-articular and extra-articular, or tenosynovial, subtypes. Diagnosis can often be delayed due to the rarity of the disease and its nonspecific symptoms of pain, reduced range of motion, or swelling. This article reviews the literature and describes the classification, clinical course, demographics, diagnosis, histology, and treatment of synovial chondromatosis and tenosynovial chondromatosis in the upper extremity.

BACKGROUND: Each Orthopaedic In-Training Examination (OITE) question references one or more journal articles or textbook sections as the evidence-based origin of its "preferred response." Previous studies identified the number of references to the top sources but not the number of questions covered by these top sources. The current study analyzes the question yield, time lag from publication, and sequential benefit-in terms of OITE questions covered-of the most referenced sources in order to provide residents and educators strategies for developing an efficient reading program. METHODS: We analyzed all OITE references from 2002 to 2009 and identified 1. The most referenced journals, text- books, authors, and journal articles; 2. The question yield of the top journals; 3. The time lag from article publication to OITE reference; and 4. The additional question benefit of the top sources when added sequentially. We repeated the analysis considering only journal articles published within 5 years of each respective OITE. RESULTS: The most referenced journals were the The Journal of Bone and Joint Surgery, American Edition (JBJS-Am), Clinical Orthopaedics and Related Research (CORR), and the The Journal of the American Academy of Orthopaedic Surgeons (JAAOS). JBJS-Am accounted for 14% of all references and was referenced on 24% of questions; CORR and JAAOS each contributed 6% of references and were referenced on 11% of questions. The average time from article publication to OITE reference was 8.1 years (median: 6 years, mode: 2 years). The top 29 authors were referenced on 15% of OITE questions. The two most-referenced articles were each referenced 7 times in 8 years. Regarding question yield, 18% of published JAAOS articles were referenced on an OITE, as opposed to 7% of JBJS-Am articles and 2% of CORR articles. Considering articles published within 5 years of an OITE, the number of questions referencing JBJS-Am decreased from 24% to 10%. The sequential benefit of adding JAAOS and CORR during the 5 years was an additional 8% of total questions. CONCLUSIONS: When developing a reading curriculum, educators and residents should be aware of the question yield, reading efficiency, and time lag to publication of the most common OITE reference sources.

Although many studies report the role of matrix metalloproteinases (MMPs) in rotator cuff tears, a paucity of data exists correlating the clinical severity of the disease with the implicated MMP levels. The purpose of this study was to investigate and compare the levels of expression of MMP-1, -3, -9 and -13 in patients with rotator cuff tears. We hypothesized that patients with clinically worse symptoms as measured by a standardized pain and function scale would have a higher expression of MMPs.Rotator cuff specimens were obtained from 16 consecutive patients undergoing rotator cuff repair. Total protein was extracted from these specimens and quantified. Equalized total protein extracts were used for performing enzyme-linked immunosorbent assay for quantitative determination of MMP-1, -3, -9 and -13. Preoperatively, the University of California, Los Angeles (UCLA) Shoulder Rating Scale was administered to each patient. Statistical comparisons were performed using analysis of variance. The expression of MMP-13 was notably increased in the rotator cuff extracts of all patients (P=.02). In addition, MMP-13 levels showed a significant proportional correlation with the patient pain score as per their UCLA ratings (r=-0.5). Although higher MMP-9 levels were assayed, this was not statistically significant. Expression of MMP-1 and-3 was insignificant.Our data suggest a critical role for MMP-13 in rotator cuff tears; elevated levels are a possible indicator for an impending tear. Further studies with increased sample size are warranted to prove the possible use of MMP-13 as therapeutic targets that may be inhibited by anti-inflammatory agents to limit disease progression.

A wide range of conditions can lead to intrinsic contractures of the thumb. A thorough understanding of the normal and pathologic anatomy as well as the disease processes and their effect on thumb function is essential in understanding and treating these contractures. Because intrinsic contractures of the thumb rarely present in isolation, a patient-specific approach based on functional needs is required. Prevention of iatrogenic contractures and progression of predictable contractures regardless of etiology is the health care provider's primary responsibility

Excessive scissoring or overlap of fingers can cause discomfort, weaken grip strength, and affect cosmesis. The treatment of little finger fractures is guided by the degree of scissoring or rotational deformity perceived in the digit. The purpose of this study is to assess the variation of little finger scissoring or overlap in the normal population using standard clinical examination. We evaluated 80 uninjured little fingers in 40 normal patients. The digital images of photographed hands, taken in both extension and flexion, were used to evaluate the overlap percentage of the adjacent fingernail as a proxy for rotation of the digits. Paired t tests were used for statistical analysis. The average fingernail overlap was 25% +/- 20%, ranging from 0% to 71%. The average overlap on the left hand was significantly less at 21% +/- 18% as compared to 30% +/- 21% on the right (P < .01). The average variation between hands in individuals was 16% +/- 13%.This study confirms that overlap or scissoring of the little finger varies between the hands of a given individual. Our results question the usefulness of assessing rotational deformity of the little finger by checking for overlap and comparing with the contralateral side. This has implications not only in assessing patients for possible surgery, but also in planning and performing surgical reductions of acute fractures and for correction of malunions.

This article examines basic tendon biomechanics, the anatomy and mechanics of digital flexor tendons, and the digital flexor pulley system. It also explores the various models that have tried to simulate the motion of the flexor tendons and several testing modalities that have been used. Finally, clinical applications are considered, including the biomechanics of flexor tendon repairs and tendon transfers. As we reach limits in the care of flexor tendon injuries, research into molecular, biochemical, and micromechanical methods of tendon repair will become the forefront of future investigation

This is a retrospective review of nine coronal shear fractures of the distal humerus. Two were isolated fractures and seven were associated with other peri-articular elbow injuries, termed 'complex' coronal shear fractures. All cases underwent immediate open reduction and internal fixation (ORIF) and were then followed for an average of 14 months (range: 6.5 to 23 months) with outcomes evaluated using the Mayo Elbow Performance Scoring system. There was a significant difference found between injuries limited to the radiocapitellar (RC) joint (isolated coronal shear fractures, or those associated only with radial head fractures) and the complex injuries extending beyond the RC joint. Scores for the RC injuries were 100 and other complex injuries had an average score of 69 (range: 35 to 95; p = .025). All complications were limited to the group with the complex injuries, including stiffness, nonunion, pain, and gross instability. Much of the current thinking in treatment of this fracture was upheld in this study; computed tomography aids in diagnosis, ORIF is a necessity, and there is a need for anatomic reduction. When a coronal shear fracture is complicated by a concomitant injury outside the RC joint, both the surgeon's and patient's expectation need to be adjusted accordingly

The purpose of this study was to investigate the effect of age, dominance, joint position, and lidocaine injection on proprioception of the normal shoulder. Position sense and the detection of passive shoulder motion were investigated in 40 young (20 to 30 years) and old (50 to 70 years) subjects. An additional 20 young subjects were tested before and after a glenohumeral (n = 10) or a subacromial (n = 10) lidocaine injection was performed. A significant decline occurred in proprioception between the young and old age groups. No difference was observed between dominant and nondominant sides. Position sense was consistently less accurate in the maximum range of motion tested when compared with the lesser ranges tested for flexion and abduction. No differences were identified in the ability to detect motion in flexion, abduction, and external rotation in the younger group, whereas in the older group a difference was observed in flexion. No learning effect was detected for any test trial. No significant changes occurred in proprioceptive ability after either glenohumeral or subacromial lidocaine injection was performed

Tyrosine-derived polycarbonates are a new class of degradable polymers developed for orthopedic applications. In this study the long-term (48 week) in vivo degradation kinetics and host bone response to poly(DTE carbonate) and poly(DTH carbonate) were investigated using a canine bone chamber model. Poly(L-lactic acid) (PLA) served as a control material. Two chambers of each test material were retrieved at 6-, 12-, 24-, and 48-week time points. Tyrosine-derived polycarbonates were found to exhibit degradation kinetics comparable to PLA. Each test material lost approximately 50% of its initial molecular weight (Mw) over the 48-week test period. Poly(DTE carbonate) and poly(DTH carbonate) test chambers were characterized by sustained bone ingrowth throughout the 48 weeks. In contrast, bone ingrowth into the PLA chambers peaked at 24 weeks and dropped by half at the 48-week time point. A fibrous tissue layer was found surrounding the PLA implants at all time points. This fibrous tissue layer was notably absent at the interface between bone and the tyrosine-derived polycarbonates. Histologic sections revealed intimate contact between bone and tyrosine-derived polycarbonates. From a degradation-biocompatibility perspective, the tyrosine-derived polycarbonates appear to be comparable, if not superior, to PLA in this canine bone chamber model

We evaluated 2 techniques of cement augmentation to enhance fixation of intertrochanteric hip fractures. 4 fixation groups with 6 cadaver femurs in each group were compared: stainless steel lag screw and side plate with and without cement augmentation and a titanium alloy expandable dome plunger and side plate with and without cement augmentation. Gauges were used to establish the mechanical behavior of intact and then fractured femurs to simple uniaxial loads. Subsequent loading to failure allowed determination of maximum fixation strengths and modes of failure. Cement augmentation of each device increased its load to failure. There was no significant difference between the cemented lag screw and the uncemented dome plunger groups with average loads to failure of 4.0 x 10(3) N. The greatest average load to failure was in the cemented dome plunger group (5.6 x 10(3) N) with the lowest in the uncemented sliding hip screw group (3.6 x 10(3) N). Device cut-out as a cause of failure occurred mostly in the uncemented lag screw group. Sliding was enhanced by those methods that increased the fixation surface area within the femoral head, unless cement encroached in the region of the barrel-screw junction. Strain analysis showed that the dome plunger unloaded the bone at the calcar, regardless of cement augmentation, while the sliding hip screw allowed for compressive stresses in this area. Proper cement augmentation increases load to failure and minimizes nail cut-out for both devices studied. However, the dome plunger, a device with a large fixation area in the femoral head, was equally effective and eliminated potential cement encroachment. Failure of intertrochanteric fracture fixation in osteoporotic bone may be minimized by an appropriate choice of device or cement augmentation