A new, low cost, locking plate for the long-term fixation of a critical size bone defect in the ratfemur: in vivo performance, biomechanical and finite element analysis.

BACKGROUND: The optimum fixation device for the critical size bone defect is not established yet. OBJECTIVE: A reliable, feasible and low-cost fixation device for the long-term maintenance of a critical bone defect. METHODS: A custom-made plate made of poly-methyl-methacrylate was used for the fixation of a critical defect of rats' femurs. The screws were securely fixing both on the plate and the bone. A three point bending test, aimed to resemble the in vivo loading pattern, a Finite Element Analysis and a 24-week in vivo monitoring of the integrity of the plate fixation were utilized. RESULTS: The plate has linear and reproducible behavior. It presents no discontinuities in the stress field of the fixation. Its properties are attributed to the material and the locking principle. It fails beyond the level of magnitude of the normal ambulatory loads. In vivo, 100% of the plates maintained the bone defect intact up to 12 weeks and 85% of them at 24 weeks. CONCLUSION: This novel locking plate shows optimal biomechanical performance and reliability with high long-term in vivo survival rate. It is fully implantable, inexpensive and easily manufactured. It can be qualified for long term critical defect fixation in bone regeneration studies.

Flow cytometry as a diagnostic tool for identifying total hip arthroplasty loosening and differentiating between septic and aseptic cases.

PURPOSE: Implant loosening represents one of the major factors of total hip arthroplasty (THA) failure. The purpose of this study was to identify specific markers indicative of septic and aseptic loosening in patients that underwent THA. METHODS: Flow cytometry was performed in blood samples of 20 patients with loosening (10 septic/10 aseptic). Additional ten healthy individuals served as a control group. The expression of surface receptors and cytoplasmic molecules in patients that underwent THA was quantified. CD62L, CD18, CD11a, CD11b and CD11c expressions were evaluated and correlated with the presence of loosening. Also, a comparison between septic and aseptic THA loosening characteristics was performed. RESULTS: The mean fluorescence intensity (MFI) for CD18 was significantly decreased on all leukocytes subsets in both septic and aseptic loosening compared to control group (p < 0.005 in all occasions). Patients with aseptic loosening showed increased MFI for CD11b in granulocytes and for CD11c in monocytes and granulocytes compared to the control and aseptic group (p = 0.02 and p = 0.005, respectively). In patients with septic loosening, an increase in MFI for CD11c was observed in monocytes only compared to control group (p = 0.03). The comparison between aseptic and septic loosening showed significantly lower CD18 MFI value in granulocytes for aseptic loosening (p = 0.008). CONCLUSIONS: CD11 and CD18 MFI values appear to be indicative of loosening in THAs. Flow cytometry markers can be used to identify THA loosening, as well as to differentiate between septic and aseptic cases.

Management of proximal interphalangeal joint hyperextension injuries: a randomized controlled trial.

PURPOSE: To compare the effectiveness of buddy strapping and aluminum orthosis for treatment of proximal interphalangeal (PIP) joint hyperextension injuries. We also evaluated the effect of age on the outcome by comparing our results in adults and children. METHODS: One hundred twenty-one consecutive patients with a PIP joint hyperextension injury of the index, middle, ring, or little finger and without fracture were evaluated. Patients were randomly assigned into 2 groups. In the first group, treatment included buddy strapping of the injured finger to its neighbor noninjured finger for a week. In the second group, immobilization was secured with an aluminum extension blocking orthosis for a week in 15° flexion. Assessment of motion, edema, pain, and strength were performed weekly for the first month and then at 3, 6, and 12 months after injury. RESULTS: The patients treated with buddy strapping exhibited similar outcomes compared with those treated with aluminum orthoses. In patients with full recovery, buddy strapping allowed earlier recovery of motion and resolution of edema and pain compared with aluminum orthosis immobilization. Furthermore, PIP injuries appear to have better outcomes in children than in adults. CONCLUSIONS: Buddy strapping is easy and effective treatment for PIP joint hyperextension injuries. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic I.

Comparison of early mobilization protocols in radial head fractures.

OBJECTIVES: We compared 2 different protocols of early mobilization with a protocol of delayed mobilization in patients with simple radial head fractures (B2.1 type of Orthopaedic Trauma Association Classification). An attempt to correlate certain characteristics of the radial head fractures with outcome was made. DESIGN: Prospective randomized comparative study. SETTING: Level 1 trauma center. PATIENTS/PARTICIPANTS: One hundred eighty consecutive patients were randomly allocated into 3 different protocols. INTERVENTION: In the first group, immediate mobilization of the elbow joint was applied. In the second, a sling was used for 2 days and then active mobilization was introduced. The third protocol represented the control group where immobilization in a cast for 7 days before the mobilization was applied. MAIN OUTCOME MEASUREMENTS: Broberg and Morrey score, The American Shoulder and Elbow Surgeons-Elbow score, visual analogue scale, and grip and pinch strength were evaluated. RESULTS: The 2 protocols introducing early mobilization resulted in better outcome compared with immobilization. The first protocol resulted in worse pain in the first 3 days. Range of motion, strength, and functional outcome was better in patients allocated to the second protocol. These differences were more evident in displaced fractures. A fragment displacement of more than 4 mm and an angulation of more than 30 degrees proved to impair outcome. CONCLUSIONS: Early mobilization of simple radial head fractures seemed to be a safe and an effective treatment option. It seems that a delay of 48 hours before early mobilization could be advantageous. Individualization of treatment in accordance to the characteristics of fracture could be a decisive factor for outcome. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Bifocal pyomyositis in a 3-year-old child with eczema: a case report.

Pyomyositis is an infection of the skeletal muscles, resulting in a pus-filled abscess. Immunodeficiency of the patient is considered to play an important role in pathogenesis. We report a case of a 3-year-old child, who presented with multifocal pyomyositis in the gastrocnemius muscle, extending to the posterior muscles of the thigh. Even though there was no evidence of immunodeficiency, the presence of atopic eczema in the big toe of the affected limb could interfere with the immune system response, and therefore, could be associated with pyomyositis. The increasing incidence of pyomyositis in non-tropical areas and its severe complications requires an acute clinical awareness.

Comparative study of surgical treatment of ulnar nerve compression at the elbow.

HYPOTHESIS: The optimal surgical treatment for cubital tunnel syndrome remains unclear. We aim to evaluate the long-term outcome of surgical treatment by comparing the results of the different methods proposed. MATERIALS AND METHODS: We retrospectively reviewed 113 patients in whom 3 different surgical methods were used for cubital tunnel syndrome treatment. In situ decompression, partial epicondylectomy, and anterior subcutaneous transposition were performed from 1997 to 2007. RESULTS: Results were graded as excellent in 51 patients (45%), good in 34 (30%), fair in 8 (7%), and poor in 20 (18%). When we compared the results among the different surgical procedures, good and excellent results were achieved in 26 of 31 patients (84%) treated with in situ decompression, 36 of 45 (80%) treated with release and partial medial epicondylectomy, and 23 of 37 (62%) treated with release and anterior subcutaneous transposition of the nerve. CONCLUSIONS: Our results indicate that in situ decompression and partial epicondylectomy both represent efficient and safe methods for cubital tunnel syndrome management. In patients in whom anterior subcutaneous transposition was performed, although they had a significant improvement of their clinical signs and symptoms, they had an inferior outcome when compared with patients treated with the other 2 methods.

The role of erythropoietin in central and peripheral nerve injury.

Erythropoietin (Epo) is a cytokine which controls red cell production. Apart from the red cell surface, erythropoietin's receptor (Epo-R) is also expressed in a large variety of normal tissues. Erythropoietin, as well as its receptor, is present in the central and peripheral nervous system. As erythropoietin having direct and indirect effect on nerve cells, enhances antioxidotic enzyme production, antagonizes glutamate's cytotoxic action, metabolizes free radicals, normalizes cerebral blood flow, affects neurotransmitters release and stimulates neoangiogenesis. After injury of the central as well as the peripheral nervous system, Epo presents an anti-apoptotic action. In combination with its anti-apoptotic effect, Epo, by reducing the inflammatory response plays a crucial role in neuroprotection in many types of injury in the central and the peripheral nervous system. Epo's administration contributes to the recovery of mechanical allodynia and may be effective in peripheral nerve regeneration after neurorrhaphy.