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Biomedical subjects

J I Acevedo

Publications and source records attributed to J I Acevedo.

7 recordsLinked to original sources

Coaxial portals for posterior ankle arthroscopy: An anatomic study with clinical correlation on 29 patients.

PURPOSE: The authors performed a cadaveric study on 10 ankles and retrospectively reviewed 29 arthroscopic synovectomies to determine the trajectory, minimal safe distances, and complications using a new approach for posterior ankle arthroscopy. TYPE OF STUDY: Anatomic study and case series. MATERIALS AND METHODS: A posterolateral portal was established immediately posterior to the peroneal tendon sheath. While staying within the posterior ankle capsule, an inside-out technique was then used to establish the posteromedial portal directly behind the medial malleolus adjacent to the posterior tibial tendon. The cadaveric ankles were frozen, sectioned, and photographed to measure the proximity of neurovascular structures to these coaxial portals. From 1988 to 1994, arthroscopic synovectomy was performed on 23 patients (29 ankles) with hemophilia using these modified portals. RESULTS: Results of the anatomic study showed that the posterior tibial nerve and posterior tibial artery were located a mean distance of 5.7 mm (SEM, 0.6 mm) and 6.4 mm (SEM, 0.7 mm) from the edge of the cannula, respectively. Neither penetration nor contact of nerve or vessel was observed at either posterior portal. In the 29 clinical cases, posterior capsular synovectomy was achieved arthroscopically with no detectable complications at an average 45-month follow-up. CONCLUSIONS: Our anatomic data show that the coaxial portals described here are essentially equidistant to the neurovascular structures compared with conventional portals. Our clinical results suggest that his technique for posteromedial and posterolateral portals is safe, effective, and reproducible.

Adolescent↗

Fixation of metatarsal osteotomies in the treatment of hallux valgus.

Osteotomies as a treatment for hallux valgus require careful preoperative planning and meticulous attention to surgical technique. The procedure selected should be tailored to fit the deformity. For a patient with mild hallux valgus, the chevron osteotomy is the most intrinsically stable of the distal osteotomies and has the least potential for complications. Interest in the Ludloff osteotomy has had a resurgence because of its improved stability compared with more traditional osteotomies for correction of metatarsus primus varus. This osteotomy, however, is less forgiving and more dependent on technique than other procedures. The proximal chevron osteotomy, with plantar-to-dorsal screw placement, is easier to perform than the Ludloff and provides excellent stability. Regardless of the osteotomy used, screw fixation has been shown to be mechanically superior to all other modes of fixation (K-wire, staples, or no fixation). Postoperatively, a hard-soled postoperative shoe that permits weight-bearing on the heel and lateral foot is recommended; however, for the more unstable osteotomies and for those performed in patients with poor bone quality, a period of non-weight-bearing should be considered. Future studies with cyclic loading may help modify these current postoperative restrictions.

Absorbable Implants↗

Mechanical comparison of plates used in the treatment of unstable subtrochanteric femur fractures.

OBJECTIVES: To determine the stiffness and strength characteristics of certain plate-composite femur models designed to simulate unstable subtrochanteric femur fractures (OTA 31-A2.3). DESIGN: Fifteen identical composite femora were osteotomized to produce like models of an unstable subtrochanteric femur fracture. The femora were fixed with either the Synthes 95 degree angled condylar blade plate, a 95 degree dynamic condylar screw plate (DCS), or a 135 degree dynamic compression hip screw (DHS). MAIN OUTCOME MEASUREMENTS: A materials testing machine was used to apply compression to the femoral head through an adapter plate. Stiffness values were calculated from the load-deformation curves obtained. RESULTS: The DHS-femur model was the stiffest (586 newtons/ millimeter), followed by the 95 degree DCS (404 newtons/millimeter) and the 95 degree condylar blade plate (260 newtons/ millimeter). The DHS also had the highest ultimate load-to-failure (4,877 newtons), followed by the 95 degree DCS (3,107 newtons) and the 95 degree condylar blade plate (2,272 newtons). All of these differences were statistically significant (p < 0.00001 ). CONCLUSIONS: Our findings suggest that the Synthes 95 degree DCS has greater stiffness and strength than the Synthes 95 degree condylar blade plate when tested in this model of an unstable subtrochanteric femur fracture. This model may not be completely appropriate for testing the 135 degree DHS because the hard plastic "cortex" of the model prevented cut-out of the screw.

Bone Plates↗

Complications of plantar fascia rupture associated with corticosteroid injection.

From 1992 to 1995, 765 patients with a clinical diagnosis of plantar fasciitis were evaluated by one of the authors. Fifty-one patients were diagnosed with plantar fascia rupture, and 44 of these ruptures were associated with corticosteroid injection. The authors injected 122 of the 765 patients, resulting in 12 of the 44 plantar fascia ruptures. Subjective and objective evaluations were conducted through chart and radiographic review. Thirty-nine of these patients were evaluated at an average 27-month follow-up. Thirty patients (68%) reported a sudden onset of tearing at the heel, and 14 (32%) had a gradual onset of symptoms. In most cases the original heel pain was relieved by rupture. However, these patients subsequently developed new problems including longitudinal arch strain, lateral and dorsal midfoot strain, lateral plantar nerve dysfunction, stress fracture, hammertoe deformity, swelling, and/or antalgia. All patients exhibited diminished tension of the plantar fascia upon examination by the stretch test. Comparison of calcaneal pitch angles in the affected and uninvolved foot showed a statistically significant difference of 3.7 degrees (P = 0.0001). Treatment included NSAIDs, rest or cross-training, stretching, orthotics, and boot-brace immobilization. At an average 27-month follow-up, 50% had good/excellent scores and 50% had fair/poor scores. Recovery time was varied. Ten feet were asymptomatic by 6 months post rupture, four feet by 12 months post rupture, and 26 feet remained symptomatic 1 year post rupture. Our findings demonstrate that plantar fascia rupture after corticosteroid injection may result in long-term sequelae that are difficult to resolve.

Adrenal Cortex Hormones↗