Recurrent Extra- and Intra-articular Synovial Chondromatosis of the Ankle with Tarsal Tunnel Syndrome: A Rare Case Report.

INTRODUCTION: Synovial chondromatosis is a rare, benign monoarticular condition characterized by the metaplastic formation of cartilaginous nodules from the synovium of joints (intra-articular), tendons and bursae (extra-articular). These nodules have the potential to detach and form loose bodies within the joint space. The most common locations are the large joints such as the knees, hips, elbows, and shoulders, with less common locations being the foot and ankle joints. Synovial chondromatosis primarily occurs in men between the third and fifth decades of life, and it typically presents as chronic joint pain with swelling, decreased joint range of motion, and osteoarthritis. Treatment is usually centered on excision and retrieval of nodules and loose bodies. Prognosis is usually good with a low-moderate likelihood of recurrence. CASE REPORT: We report the very rare case of a 27-year-old male with recurrent intra- and extra-articular ankle synovial chondromatosis, who also reported symptoms consistent with tarsal tunnel syndrome. His initial presentation was left ankle pain which was managed by open surgical debridement. Two years after, he re-presented with continued pain and tingling along the plantar aspect of his foot. On his second presentation, a dual approach was taken with arthroscopic as well as open debridement. He reported resolution of his symptoms postoperatively as well as at 3 years of follow-up. CONCLUSION: Simultaneous extra- and intra-articular chondromatosis of the ankle is very rare and can be difficult to treat. It is important to recognize this disease as a rare but plausible cause of tarsal tunnel syndrome. Treatment may be complicated with early or late recurrence despite complete excision, highlighting the need for intentional follow-up of all cases.

Arthroscopic Treatment of Traumatic Hip Dislocations in Children and Adolescents: A Preliminary Study.

INTRODUCTION: Traumatic hip dislocations in children and adolescents require prompt concentric reduction. Incomplete reduction with or without retained osteochondral fragments has traditionally been addressed with open reduction. We report on the use of arthroscopy to remove loose bodies and reduce enfolded soft tissues to obtain concentric reduction in the pediatric and adolescent population. Specific note is made of underlying pathology and arthroscopic intervention. METHODS: After obtaining Institutional Review Board approval, we performed a retrospective review of patients under the age of 19 who were treated with hip arthroscopy following hip dislocation reduction at a single children's hospital from 2006 to 2013. Clinic notes, operative reports, radiographic images, and arthroscopic photographs were reviewed. RESULTS: Seven patients were identified (aged 8 to 17) who underwent hip arthroscopy after a posterior hip dislocation. Intra-articular bone fragments were found in 6 of 7 patients and 5 of 7 patients had an incongruent hip joint identified by imaging before surgery. The predominant pathology was avulsion of a small bony fragment attached to the posterior capsular labral soft-tissue complex, which became enfolded and blocked reduction (5 of 7 patients). In all cases, the enfolded soft tissue was reduced without soft tissue or bone repair. Additional loose osteochondral fragments were removed, and in 2 cases an avulsed ligamentum teres was debrided. Average follow-up was 10 months. No avascular necrosis or recurrent instability was identified in any case. CONCLUSIONS: When incongruent hip joints were arthroscopically evaluated after traumatic dislocation, a consistent pattern of interposition of avulsed posterior bone fragment with attached capsule and labrum was found. Reduction of the capsulolabral complex without repair provided satisfactory short-term outcomes. Arthroscopic treatment of such cases was effective and well tolerated and could lead to considerably less postoperative pain and surgical morbidity than open surgical treatment. LEVEL OF EVIDENCE: Level IV-case series.

The Role of the O-GlcNAc Modification in Regulating Eukaryotic Gene Expression.

O-linked ß-N-acetylglucosamine (O-GlcNAc) modification of proteins has been shown to be involved in many different cellular processes, such as cell cycle control, nutrient sensing, signal transduction, stress response and transcriptional regulation. Cells have developed complex regulatory systems in order to regulate gene expression appropriately in response to environmental and intracellular cues. Control of eukaryotic gene transcription often involves post-translational modification of a multitude of proteins including transcription factors, basal transcription machinery, and chromatin remodeling complexes to modulate their functions in a variety of manners. In this review we describe the emerging functional roles for and techniques to detect and modulate the O-GlcNAc modification and illustrate that the O-GlcNAc modification is intricately involved in at least seven different general mechanisms for the control of gene transcription.

Development of an isothermal heat-conduction photocalorimeter.

Assessing photostability (particularly of pharmaceuticals) is of growing importance, but hampered by a lack of reliable, rapid experimental testing protocols and instrumentation. In particular, most approaches require irradiation of the sample separately from the analytical measurement, which increases both experimental complexity and the number of assumptions that must be made when calculating stability. One technique that may obviate this is photocalorimetry, principally because the reporter of change (heat) is measured directly as a sample is irradiated. Although not a new idea, the design challenges of photocalorimeters are complex, primarily because light power is being introduced to the calorimeter which can thus both saturate the amplifiers and swamp the response of the sample. Careful instrument design is thus paramount. The aim of this work was to develop a robust, compact, and easy to use photocalorimeter with the immediate focus of developing photostability assays for pharmaceuticals. The final instrument design, arrived at through a series of iterative design modifications, is based on a twin differential heat-conduction principle and achieves an average base line deflection of -0.04+/-0.11 microW with light irradiating the sample cell. The performance capabilities of the instrument were demonstrated using a model system; the photodegradation of 2-nitrobenzaldehyde in solution.