Surgical Treatment Of Delayed Calcaneal Fractures Accompanied By Subtalar Joint Injury By Subtalar Osteotomy With External Fixation And Gradual Limb Lengthening

BackgroundCalcaneal fractures are common clinical diseases, accounts for about 1% to 2% of the whole body fractures, of which about 75% for intra-articular fractures. Because of the intra-articular fractures associated with severe soft tissue damage, the early internal fixation for fractures are often delayed. Sequela of the calcaneal intra-articular fractures with serious dislocation affects the tibial astragaloid joint, the subtalar joint, the calcaneocuboid joint, leads to a foot pain and lesion, seriously influence the life of the patients and employment, also brings to the serious burden for society.Calcaneal malunion after intra-articular fractures were often with bone collapses, height loss. Because of the joint instability the subtalar joint had been under wear, and arthritis were formed the next time, patients suffered foot pain. In the process of malunion, the width of calcaneus increased, which affect tissue functions surrounding calcaneus, such as peroneal tendons hitting. The purpose of operation is for the fusion joints, eliminating the arthritis, relieving the pain, the soft tissue function recovery, rebuilding the foot arch physiological function, throuth removing osteophyte, restoring calcaneus width and calcaneus height.Mainly two ways for dealing with calcaneus intra-articular fractures: one, is the most common the subtalar joint in-situ fusion, its advantage is easier to operate without bone graft surgery, less skin tension, and small incision easy to heal, but can't restore bone height and the talus will tilt and axial line of calcaneus is abnormal, Curative effect for old calcaneus intra-articular fractures combined with serious bone collapses deformity is limited; Second, subtalar distraction bone block arthrodesis take place of joint in-situ arthrodesis. The operation can open the subtalar joint, implant autogenous iliac piece, restore the height of calcaneus in a time, but the operation increased trauma, wound healing maybe delay, with increasing the risk of skin necrosis. peripheral nerves also are easy to neuralgia because of suddenly draft, in addition the technology of the operation exists difficulty, transplanted iliac should bring new trauma to patients.This essay analyzes the advantages and disadvantages of previous design of treatment. Old calcaneus intra-articular fractures after in situ fusion surgery, the external fixation stents slowly distract the subtalar joint, utilizing their own osteogenesis, gradually to restore the height of calcaneus. The goal is to reach the joint fusion, recovery of the height of calcaneus, as far as possible to relieve symptoms and get recovery of biomechanics function of feet, so as to improve treatment effect of fracture and dislocation of calcaneus. We performed rabbit experimental and clinical effect observation to observe the effect of operation.ObjectiveThrough the rabbit experiment and clinical effect of observation, we evaluate the value of clinical application of the operation, maybe provide effective alternative therapy for clinical treatment with old calcaneus intra-articular fractures.Methods1. Making rabbit model of old calcaneus intra-articular fractures: New Zealand white rabbit 20, weight 2.0 ~ 2.5 kg, anesthesia through ear rim intravenous with 20 g/L pentobarbital sodium solution according to 30 mg/kg, we performed a L-type calcaneal lateral incision from the apophyses of lateral malleolus to the base of the forth metatarsal bones to expose the lateral wall of the calcaneus and subtalar joint. Using electric drills to damage the surface of subtalar joint, removing sustentaculum tali, closed incision, offer general food for 1 month, X-ray confirmed bony fusion.2. Gradual subtalar distraction throuth an external fixator to treating old calcaneus intra-articular fractures: randomly take in rabbit model of old calcaneus intra-articular fractures, 20 g/L of pentobarbital sodium solution according to 30 mg/Kg ear rim intravenous anesthesia, performed a L-type calcaneal lateral incision from the apophyses of lateral malleolus to the base of the forth metatarsal bones to expose the lateral wall of the calcaneus and subtalar joint, to remove residual from the articular cartilage and under the subchondral bone, resect steophyte, restore bone with normal width, filled the subtalar joint with bone chips, two Orthofix external fixator screws were placed in the posteromedial side of the calcaneus, perpendicular to its long axis. Another two external fixator screws were placed in the interior of the middle-lower part of the tibial segment dress it fixed. Everyday draft 0.2 mm, completed it for three to four times, continuous draft for 1 month, X line with bone height recovery and evaluation from the joint fusion, and then remove the external fixator.3. 15 feet of 12 cases (single foot 9 cases, double feet 3 cases) with joint fracture dislocation from age 16 ~ 53 years old, an average of 33.6 years. Closed in 7 cases (10 feet), open in 5 patients (5 feet). Open injury in 3 cases of severe multiple injury recepted wound healing surgery over 2 months ago, 2 cases of them are still not heal. All recepted subtalar joint injury by subtalar osteotomy with external fixation and gradual limb lengthening. Remove residual from the articular cartilage and under the subchondral bone, resect steophyte, restore bone with normal width, filled the subtalar joint with bone chips. Orthofix external fixation, seven to 10 days after extended, to distract the subtalar joint and open space under 0.2cm, with bone height and Bohler Angle basic back to normal, 2-3 months later till the joint osteoarthritis fusion after the operation began to walk under weight. According to the X-ray evaluation with bone height recovery to decide whether to stop drafting or not. According to the X-ray evaluation fusion situation decided to remove the external fixator. Evaluating function of feet through AOFAS score.Results1. Success in making old calcaneus intra-articular fractures rabbit model: 100% rate of model is effective.2.The result of gradual subtalar distraction throuth an external fixator to treating old calcaneus intra-articular fractures: after a gradual subtalar distraction, bone height with good recovery, and the preoperative boehler's angle is an average 16.5°+ /-2.8°, the postoperative is 22.4°+ /-2.2°, achieve finally bone fusion.3. After 6 months to 50 months following-up, the wound of 12 patients (15 feet) healed without skin necrosis. The subtalar joints got joint osteoarthritis fusion in 3 ~ 6 months (mean 3.7 months). AOFAS score of hind feet is an average of 24.2 score before preoperation and 76.8 score.Conclusion1. After removing sustentaculum tali and the surface of subtalar joint, we can make the old calcaneus intra-articular fractures rabbit model.2. After the gradual distraction to a certain degree can restore bone height and achieve bone fusion.3. Clinical application of gradual distraction treatment for old calcaneus intra-articular fracture by external fixator can restore bone heigh in a certain degree and bone fusion, without obvious calcaneus varus and valgus complications. can be one of the effective ways to clinical application.