This article is about the evaluation of possible differences in biomechanical or histomorphological properties of bone healing between saw osteotomy and random fracturing after 6 months. A standardized, 308 oblique monocortical saw osteotomy of sheep tibia was carried out, followed by manual fracture completion of the opposed cortical bone. Fixation was performed by bridge plating (4.5 mm, LCDCP, broad). X-rays were taken immediately after surgery and at the end of the study. Polychrome fluorescent staining was performed according to a standardized protocol in the 2nd, 4th 6th, 10th, 14th, 18th, 22th and 26th week. Ten sheep were comprehensively evaluated. Data for stiffness and histomorphology are reported. The average bending stiffness of the operated bone was higher (1.7 (SD 0.3) with plate (MP) vs. 1.5 without plate) than for the intact bone (1.4 (SD 0.2), though no significant differences in bending stiffness were observed (P > 0.05). Fluorescence staining revealed small numbers of blood vessels and less fragment resorption and remodeling in the osteotomy gap. Bone healing after saw osteotomy shows a very close resemblance to 'normal' fracture healing. However, vascular density, fragment resorption, fragment remodeling, and callus remodeling are reduced at the osteotomy. There have been extensive studies of the biology of fracture healing in the sheep tibia. 1-7 Diaphyseal saw osteotomy of long bones, although a common surgical procedure in the forearm, femur, tibia, and metatarsal, [8][9][10][11] is not always free from complications. Nonunion or refracturing following implant removal is a seldom, but well-known complication. 12,13 Experimental studies have shown that vascular perfusion of the cortical bone can be disturbed during osteotomy and plate osteosynthesis as a result of a variety of factors. 14 Iatrogenicinduced, circumscribed heat necrosis of the bone or microscopic sequestrum formation at the level of the osteotomy can trigger infections and interfere with normal bone healing. 15 Several methods of osteotomy have already been evaluated with an animal model. [16][17][18][19] However, these studies always assumed that bone healing is identical to that occuring after common fracturing over a specified period of time.To our knowledge, there have been no studies evaluating differences between partial osteotomy and a neighboring partial fracture. The present study was therefore designed to test the hypothesis of whether differences in bone healing between saw osteotomy and random fracturing, in terms of tissue necrosis, vascularization, and remodeling, are apparent under long-term observation. The aim of the study was to determine histomorphological and biomechanical properties of the partially osteotomied sheep tibia after a period of 6 months. The osteotomy of the same bone, at the same level as the manual fracture, should provide an answer to the question of whether bone healing is the same over the same time course. MATERIALS AND METHODS Integrated Fracture and Osteotomy ModelEleven mat...

Primary medullary nailing of femoral fractures is burdened by the risk of central and pulmonary complications in patients with polytrauma, especially in conjunction with craniocerebral or thoracic trauma. This also applies to unreamed medullary nailing. Primary treatment with external fixation necessitates secondary surgery with an altered procedure, the timing of which is not predictable. Plate osteosynthesis with anatomical repositioning of the fragments and rigid fixation is a technically demanding procedure, but can lead to fragment necrosis due to fragment denudation. In a prospective study conducted from 1 September 1994 to 30 June 1996 on 17 polytraumatized patients (average ISS:30 points), simple femoral stem fractures (A-1 to B-3 of the AO-classification) were stabilized by elastic plate osteosynthesis using biological technique. While cautiously preserving the periosteal and muscle connections to the bone, a plate is inserted as a bridge without any interfragmentary compression. At least two to four holes are left free in the center of the plate. This allows micro-movements in the fracture gap without the risk of material fatigue. All of the fractures were immediately stabilized on the day of the accident. In four patients with severe craniocerebral trauma or manifest shock, the procedure was changed to plate osteosynthesis after application of primary external fixation. Secondary injuries (joint and pelvic fractures or craniocerebral trauma) delayed early loading in 12 cases. Four patients were mobilized postoperatively under partial loading. A fixation callus was radiologically detectable on average 6 weeks after surgery. This often allowed additional loading, depending on the secondary injuries. Full loading was possible after 14 weeks. Complications included one case of surgery-related malpositioning, one soft-tissue infection, one case of plate detachment after a fall and one case of periosseous calcification. There were no cases of bone infections or pseudoarthroses. Elastic plate osteosynthesis is thus a conservative osteosynthesis procedure with a low complication rate in polytraumatized patients, even in those with simple femoral fractures.

Thirty-five patients were prospectively examined on average 5.9 and 11.1 months after reconstruction of the anterior cruciate ligament. Eighteen patients were treated postoperatively with a regular physiotherapy (PT) program 2-3 times per week for 30 min, 17 patients with a special, extended, and supervised rehabilitation program 3-5 times per week for 2.5 h. Criteria for exclusion from this study were previous operation or fractures of the affected knee. The bases for the evaluation of the clinical results were the clinical examination, the Lysholm and Tegner scores, KT 1000, angular reproducibility according to Barrett (proprioception), and the figure-of-eight hop test. It appeared that patients treated with extended ambulatory physiotherapy (EAP) gained a significantly higher degree of functionality in the Lysholm score after 5.9 months (p < 0.02) and the Tegner score after 11.1 months (p < 0.05) than patients treated with regular physiotherapy. Patients treated with EAP also displayed better results in the proprioceptive capability test with an angular deviation of 5.8 degrees after 5.9 months compared to 11 degrees in patients receiving regular PT. After 11.1 months, there were no differences in proprioceptive capability between the two groups. Although the EAP patients were faster in the figure-of-eight hop test (0.39 s difference compared to 0.58 s in the PT patients), the results were not statistically significant. In KT 1000 ventral tibial instability was on average 21% lower in the PT patients than in the EAP patients. After 11.1 months, both groups exhibited the same median value of 3 mm. Furthermore, EAP patients were able to return to work after 36.7 days on average, a 35% shorter period than in the case of PT patients (55 days), also of statistical significance (p < 0.02). To conclude, the primarily higher costs of this intensive rehabilitation program are justified by the better functional outcome linked with an earlier return to work.

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