Biomedical subjects

J-M Cognet

Publications and source records attributed to J-M Cognet.

8 recordsLinked to original sources

PubMed2006

[Plate fixation with locking screw for distal fractures of the radius].

PURPOSE OF THE STUDY: Fractures of the distal radius are common. No one implant has demonstrated superior efficacy in terms of maintaining the reduction over time. We report our experience with plate fixation using a locking screw. MATERIAL AND METHODS: Between September 2003 and June 2004, 67 displaced fractures of the distal radius were treated by plate fixation using the LCP-DRP 2.4 (Synthès). Three different plates (anterior, posterior, and external) were used. The patients wore a removable anatomic brace for three weeks. Self-controlled rehabilitation exercises began directly after surgery with mobilization of the digital chains. The Fernandez, Castaing and AO classifications were noted. Ulnar variance, anteversion of the radial glenoid, radial slope and the alpha angle were measured intraoperatively and at last follow-up to assess maintenance of reduction over time. The DASH test and Green and O'Brien and PRWE scores were used to assess clinical outcome. RESULTS: Mean follow-up was eight months. Mean age was 55.8 years. Eight patients were lost to follow-up. The analysis included 59 patients who could respond to the questionnaires. Bone healing was achieved at six weeks. There were no cases of secondary displacement nor loss of reduction. The Green and O'Brien score was good or very good for 85%. The mean DASH was 20.6 and the mean PRWE 32.8. DISCUSSION: The appropriate fixation method for distal fractures of the radius remains a controversial issue, leading to a variety of materials and fixation methods. Primary stability achieved with the locking screw in a plate enables early mobilization associated with more rapid recovery of function. The absence of secondary displacement, irrespective of the quality of the underlying bone enabled us to achieve equivalent results in young patients and older patients with osteoporotic bone. This study also confirmed the preference for the anterior approach, irrespective of the direction of the displacement. To date, no other material has enabled equivalent results. This is a major achievement in terms of fixation stability.

Adult↗

PubMed2005

[Transverse radioulnar branch of the dorsal ulnar nerve: anatomic description and arthroscopic implications from 45 cadaveric dissections].

PURPOSE OF THE STUDY: We conducted an anatomic study of the transverse branch of the dorsal ulnar nerve to describe its morphology and position in relation to arthroscopic exploration portals. MATERIAL AND METHODS: Forty-five non-side-matched anatomic specimens of unknown age and gender were preserved in formol. The dorsal branch of the ulnar nerve was identified and dissected proximally to distally in order to reveal the different terminal branches. The morphometric analysis included measurement of the length and diameter of the transverse branch and measurement of wrist width. We also measured the smallest distance between the transverse branch and the ulnar styloid process, and between the branch and usual arthroscopic portals (4-5, 6R, 6U) in the axis of the forearm. RESULTS: The transverse branch was inconstant. It was found in 12 of the 45 dissection specimens (27%). In two-thirds of the specimens, the branch ran over less than 50% of the wrist width, tangentially to the radiocarpal joint. Mean nerve diameter was 1 mm. It was found 5-6 mm from the ulnar styloid process and was distal to it in 83% of the specimens. The dissections demonstrated two anatomic variants. Type A corresponded to a branch running distally to the ulnar styloid process, parallel to the joint line (10/12 specimens). Type B exhibited a trajectory proximal to the ulnar styloid process, crossing the ulnar head (2/12 specimens). The relations with the arthroscopic portals (4-5, 6R, 6U) showed that the mean distance from the branch to the portal was 3.75 mm for the 4-5 portal (distally in 11/12 specimens), 3.68 mm for the 6R portal (distally in 10/12 specimens), and 4.83 mm for the 6U portal (distally in 7 specimens and proximally in 5). DISCUSSION: To our knowledge, there has been only one report specifically devoted to this transverse branch. Two other reports simply mention its existence. According to the literature, the transverse branch of the dorsal ulnar nerve occurs in 60-80% of the cases. We found two anatomic variations different than those described in the literature. Based on our findings and data reported previously, we propose a new classification, describing two main types. In Type 1, the transverse branch arises proximally to the ulnar styloid process;type 1A and type IB are described in relation to the direction of the branch. In Type II, the branch arises distally to the ulnar styloid process;type IIA and type IIB again being described in relation to the direction of the branch. On the tangential trajectory over the radiocarpal joint, the morphometric data show a zone of risk described by a rectangle measuring 10 mm wide (6 mm distal and 4 mm proximal to the ulnar styloid process) and covering 50% of the wrist width. The relations with arthroscopic portals describe a zone of risk corresponding to a 5-7 mm radius circle centered on the portals (4-5, 6R, 6U), which includes 83% of the transverse branches.

Arm↗

PubMed2005

[Not Available].

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Journal Article↗

PubMed2004

[Exercise-induced acute bilateral isolated anterolateral compartment syndrome of the leg: a case report of a rare condition].

Acute compartment syndrome of the leg is generally a consequence of trauma. Exercise-induced acute compartment syndrome of the leg is an exceptional clinical entity observed in the context of a chronic compartment syndrome or as an isolated acute syndrome subsequent to an intense effort. Our patient was a young athlete with no history of exercise-induced leg pain. Following a soccer game, he developed an acute leg syndrome involving the anterolateral compartment of both legs. The diagnosis was not suggested by the patient's history (no notion of chronic compartment syndrome) nor the natural history of the condition but was retained on the basis of the clinical presentation and course then confirmed by intramuscular pressure measurements. Emergency treatment by fasciotomy under general anesthesia in the operating room led to cure with no sequela. The fasciotomy was closed on day 9 with simple skin sutures. Surgeons should be aware that acute exercise-induced compartment syndrome (with the risk of severe functional consequences) may be the cause of unexplained intense leg pain. The diagnosis is established on the basis of clinical findings and measurement of intramuscular pressures. Pain is the cardinal sign, sometimes associated with sensorial deficit. The compartment is hard and painful at palpation. Passive stretching exacerbates the pain. Compartment pressure is required for certain diagnosis, most Authors accepting > 30mmHg as a positive test. Emergency fasciotomy is required.

Acute Disease↗

PubMed2003

[Coverage of heel tissue loss by two pediculated flaps in a single procedure].

We report the case of a traffic accident victim who suffered major tissue loss of the heal. We used two pediculated flaps to close the gap in a single procedure. The remaining tissue presented zones of necrosis from the plantar aspect to the posterior half of the calcaneum, up to the insertion of the calcaneus tendon, extending 5 cm on the posterior aspect of the heal. We decided to combine a medial plantar flap with a lateral supramalleolar flap. The thick medial plantar flap allowed cover of the calcaneum and sensitivity. The calcaneus tendon was covered with the lateral supramalleolar flap. The thickness of the flap was adapted to match the tissue defect. At six months, the patient had recovered walking function with satisfactory weight bearing on the heal. Flap sensitivity was satisfactory with no slipping phenomenon.

Accidents, Traffic↗

PubMed2003

[Pinctada margaritifera nacre (mother-of-pearl): physico-chemical and biomechanical properties, and in vitro cytocompatibility].

PURPOSE OF THE STUDY: Pinctada maxima nacre (mother-of-pearl) has been recently proposed as a bone substitute. The purpose of this work was to assess the in vitro cytocompatibility of Pinctada margaritifera nacre and its physico-chemical and biomechanical properties. MATERIAL AND METHODS: The cytocompatiblity was assessed in contact with human osteoprogenetic cells. Attachment was measured at one hour and three hours by determining N-acetyl-beta-D-hexosaminidase activity. Proliferation was monitored by measuring metabolic activity with the MTT test. Cell morphology was studied under scanning electron microscopy and cell differentiation was assessed by immunocytochemistry monitoring of the synthesis of type I collagen and osteocalcin. Diffraction x-ray and scanning electron microscopy was used to study the physico-chemical structure. Two samples taken from the inner part of the shell and two other samples from the outer part of the shell were tested for resistance under compression and to calculate the Young module. RESULTS: The results showed that osteoprogenetic cells attached to the nacre (2/3 of the plastic control), proliferated according to a standard pattern (increased metabolic activity followed by a plateau then decreased activity), synthetized type I collagen and osteocalcin, and presented a morphology analogous to control cells cultured on the plastic culture wells. The diffraction spectrum of the crystalline structure corresponded to crystallized calcium carbonate in the form of calcite (CaCO(3)) for the outer part and in the form of aragonite for the inner part. The Young module was 46.1 Gpa and resistance to rupture was 185 Mpa. CONCLUSION: Pinctada margaritifera nacre is cytocompatible in vitro with mechanical properties very similar to cortical bone.

Animals↗

PubMed2003

[Epiphyseal tibial osteoblastoma: report of a rare localization and review of the literature].

Osteoblastoma is an uncommon benign bone tumor diagnosed in about 1% of primary bone tumors. Predominantly observed in the axial skeleton, it can be observed in long bones (20%), generally in the diaphysis (80% of the long bone localizations). In typical cases, standard imaging is highly suggestive of the diagnosis. The typical image is a "lytic" zone surrounded by bony condensation, and a minimal osteosclerotic reaction peripherally, rarely invading the soft tissues. Diagnosis is confirmed at pathology: osteoblast-like cells disseminated in an abundant conjunctive background surrounded by immature richly vascularized bone. The tumor we report presented an unusual localization and an atypical aspect on the imaging studies. Located in the tibial epiphysis, this osteoblastoma invaded the soft tissues, as seen on the CT and MRI studies which visualized an encapsulated tumor with a calcified shell and a liquid-like tumefaction suggestive of a tumor arising from the synovial.

Adult↗

PubMed2003

[Arthroscopy-guided treatment of fractures of the distal radius: 16 wrists].

PURPOSE OF THE STUDY: We report our experience with arthroscopy-guided treatment of fractures of the distal radius. MATERIAL AND METHODS: Between November 2001 and June 2002, 16 patients (10 men, 6 women, mean age 51 years, age range 24-75 years) underwent arthroscopy-guided treatment of articular fractures of the distal radius. Patients were installed with the arm held in a horizontal position with a brace, the wrist under traction. The same procedure was used in all cases: introduction of the arthroscope, joint cleaning and shaving, search for lesions, arthroscopy-guided treatment. Kirschner 2-mm pins were used for fixation in all cases, combined with 1.2-mm pins in the event of ligament injury. RESULTS: Arthroscopic exploration revealed cartilage impaction in 25% of the wrists and ligament injuries in 30%. One fixation disassembled and was not remounted. There were two cases of reflex dystrophy. There were no arthroscopy-related complications. Bone healing was achieved in eight weeks in all cases. The mean DASH score was 22.5 at six months follow-up (range 3-10). DISCUSSION CONCLUSION: Arthroscopy-guided treatment of fractures of the distal radius was attempted for the first time in the early 90s. Per-operative arthroscopy enables a good view of the fracture and associated lesions (cartilage impaction, scapholunate, lunotriquetral ligament injury) and facilitates control of the reduction. Arthroscopy is technically simple and is the technique of choice due to the lack of morbidity. Several authors have reported their experience in more or less extensive series. Two notions should be emphasized. First, defective intra-articular reduction greater than 1 mm may lead to osteoarthritis of the wrist in 90% of the cases. Secondly, intra-operative imaging (fluoroscopy) does not provide sufficient precision to visualize a 1-mm stairstep in the articular surface, raising the risk of radiocarpal degeneration at mid term despite often satisfactory postoperative x-rays. We thus propose intra-operative arthroscopy to control the treatment of all articular wrist fractures, with or without displacement, in order to ensure satisfactory reduction with less than 1-mm defect in the articular surface and to search for and treat any associated bone or ligament injuries not diagnosed before surgery.

Adult↗