Hind foot Charcot deformity is a disastrous complication of diabetic neuropathy and can lead to instability, ulceration and major amputation. The treatment of these patients is controversial. Internal stabilization and/or external fixation have demonstrated variable results of limb salvage and some authorities thus advise patients to undergo elective major amputation. However, we report a series of 9 diabetic patients with severe hind foot deformity complicated by ulceration in 5/9, who underwent acute corrective internal fixation with successful correction of deformity, healing of ulceration in 4/5 patients and limb salvage in all cases. We treated 9 diabetic patients attending a multidisciplinary diabetic/orthopaedic foot clinic with progressive severe Charcot hind foot deformity despite treatment with total contact casting, 5 with predominant varus deformity and 2 with valgus deformity and 2 with unstable ankle joints. Five patients had developed secondary ulceration. All patients underwent corrective hind foot fusion with tibiotalo-calcaneal arthrodesis using a retrograde intra-medullary nail fixation and screws and bone grafting. One patient also with fixed plano-valgus deformity of the foot underwent a corrective mid-foot reconstruction.Introduction
Methods
Hind foot Charcot deformity is a disastrous complication of diabetic neuropathy and can lead to instability, ulceration and amputation. The treatment of these patients is controversial. Internal stabilisation and external fixation have demonstrated variable results of limb salvage and some authorities thus advise patients to undergo elective amputation. We report a series of 9 diabetic patients with severe hind foot deformity complicated by ulceration in 5/9, who underwent acute corrective internal fixation with successful correction of deformity, healing of ulceration in 4/5 patients and limb salvage in all cases. Conservative measures such as total contact casting were tried in 5 patients had predominant varus deformity, 2 with valgus deformity and 2 with unstable ankle joints. 5 patients had developed secondary ulceration. All patients underwent corrective hind foot fusion with tibio-talo-calcaneal arthrodesis using a retrograde intramedullary nail fixation and screws and bone grafting. One patient also with fixed planovalgus deformity of the foot underwent a corrective midfoot reconstruction. Patients were followed up in a diabetic/orthopaedic multidisciplinary foot clinic and were treated with total contact casting. (Mean follow up time was 15.6 ±6.9months) In all patients the deformity was corrected with successful realignment to achieve a plantigrade foot. Healing of the secondary ulcers was achieved in 4/5 cases and limb salvage was achieved in all cases. Three patients underwent further surgical procedure to promote bone fusion. One patient required removal of a significantly displaced fixation screw. Two patients had postoperative wound infections which that were treated with initially intravenous antibiotic therapy and then negative pressure wound therapy. In conclusion, internal fixation for severe hind foot deformity together with close follow up in a multidisciplinary diabetic/orthopaedic foot clinic can be successful in diabetic patients with advanced Charcot osteoarthropathy and secondary ulceration.
Computer aided joint replacement surgery has become very popular during recent years and is being done in increasing numbers all over the world. The accuracy of the system depends to a major extent, on accurate registration and immobility of the tracker attachment devices to the bone. This study was designed to assess the forces needed to displace the tracker attachment devices in the bone simulators. Bone simulators were used to maintain the uniformity of the bone structure during the study. The fixation devices tested were 3mm diameter self drilling, self tapping threaded pin, 4mm diameter self tapping cortical threaded pin, 5mm diameter self tapping cancellous threaded pin and a triplanar fixation device ‘ortholock’ used with three 3mm pins. All the devices were tested for pull out, translational and rotational forces in unicortical and bicortical fixation modes. Also tested was the normal bang strength and forces generated by leaning on the devices. The forces required to produce translation increased with the increasing diameter of the pins. These were 105 N, 185 N, and 225 N for the unicortical fixations and 130N, 200N, 225 N for the bicortical fixations for 3mm, 4mm and 5 mm diameter pins respectively. The forces required to pull out the pins were 1475N, 1650N, 2050N for the unicortical, 1020N, 3044N and 3042N for the bicortical fixated 3mm, 4mm and 5mm diameter pins. The ortholock translational and pull out strength was tested to 900N and 920N respectively and still it did not fail. Rotatory forces required to displace the tracker on pins was to the magnitude of 30N before failure. The ortholock device had rotational forces applied up to 135N and still did not fail. The manual leaning forces and the sudden bang forces generated were of the magnitude of 210 N and 150 N respectively. The strength of the fixation pins increases with increasing diameter from three to five mm for the translational forces. There is no significant difference in pull out forces of four mm and five mm diameter pins though it is more than the three mm diameter pins. This is because of the failure of material at that stage rather than the fixation device. The rotatory forces required to displace the tracker are very small and much less than that can be produced by the accidental leaning or bang produced by the surgeon or assistants in single pins. Although the ortholock device was tested to 135 N in rotation without failing, one has to be very careful not to put any forces during the operation on the tracker devices to ensure the accuracy of the procedure.
The group treated with ESIN procedure 1 patient fell down and bend the C-Nail, which was straightened in situ, and the fracture healed with slight curvature of the femur, which corrected slowly with growth. The forearm fractures did not have any rotational deformity. The recovery period post removal of the ESIN was very short.