Seok Whan Song

Ankle Deformity Secondary to Acquired Fibular Segmental Defect in Children

Background The authors report the long-term effect of acquired pseudoarthrosis of the fibula on ankle development in children during skeletal growth, and the results of a long-term follow-up of Langenskiolds supramalleolar synostosis to correct an ankle deformity induced by an acquired fibular segmental defect in children. Methods Since 1980, 19 children with acquired pseudoarthrosis of the fibula were treated and followed up for an average of 11 years. Pseudoarthrosis was the result of a fibulectomy for tumor surgery, osteomyelitis of the fibula and traumatic segmental loss of the fibula in 10, 6, and 3 cases, respectively. Initially, a Langenskiolds operation (in 4 cases) and fusion of the lateral malleolus to the distal tibial epiphysis (in 1 case) were performed, whereas only skeletal growth was monitored in the other 14 cases. After a mean follow-up of 11 years, the valgus deformity and external tibial torsion of the ankle joint associated with proximal migration of the lateral malleolus needed to be treated with a supramallolar osteotomy in 12 cases (63%). These ankle deformities were evaluated using the serial radiographs and limb length scintigraphs. Results In all cases, early closure of the lateral part of the distal tibial physis, upward migration of the lateral malleolus, unstable valgus deformity and external tibial torsion of the ankle joint developed during a mean follow-up of 11 years (range, 5 to 21 years). The mean valgus deformity and external tibial torsion of the ankle at the final follow-up were 15.2° (range, 5° to 35°) and 10° (range, 5° to 12°), respectively. In 12 cases (12/19, 63%), a supramalleolar corrective osteotomy was performed but three children had a recurrence requiring an additional supramalleolar corrective osteotomy 2-4 times. Conclusions A valgus deformity and external tibial torsion are inevitable after acquired pseudoarthrosis of the fibula in children. Both Langenskiöld supramalleolar synostosis to prevent these ankle deformities and supramalleolar corrective osteotomy to correct them in children are effective initially. However, both procedures cannot maintain the permanent ankle stability during skeletal maturity. Therefore any type of prophylactic surgery should be carried out before epiphyseal closure of the distal tibia occurs, but the possibility of a recurrence of the ankle deformities and the need for final corrective surgery after skeletal maturity should be considered.

Comparison of the effects of subcutaneous anterior transposition and in situ decompression on the histologic and electrophysiologic properties of the ulnar nerve: an experimental study in a rabbit model.

PURPOSE Although anterior transposition of the ulnar nerve is a commonly performed procedure for treatment of cubital tunnel syndrome, there are concerns that surgical mobilization puts blood supply to the nerve at risk. The purpose of this study was to compare the effects of subcutaneous anterior transposition (SAT) and in situ decompression (ISD) on the ulnar nerves histologic and electrophysiologic properties in a rabbit model. METHODS We assigned 30 male, young adult New Zealand white rabbits to 1 of 3 groups (each group, n = 10). The extensive dissection-SAT group underwent complete neurolysis of the right ulnar nerve from brachial plexus to wrist and a subsequent SAT, the ISD group underwent ISD with 4-cm-long exposure of the ulnar nerve, and the SAT group underwent SAT with 4-cm-long circumferential neurolysis of the ulnar nerve. We killed the animals 7 days after the operation. We assessed electrophysiologic changes by finding the percentage of compound motor action potential of the surgical limb compared with the contralateral limb, and histologic changes by ischemic fiber degeneration. RESULTS The extensive dissection-SAT group showed a significantly lower percentage of compound motor action potential and higher grade of ischemic fiber degeneration than the ISD and SAT groups. On the other hand, the percentage of compound motor action potential and the grade of ischemic fiber degeneration were similar between the latter 2 groups without a statistically significant difference. CONCLUSIONS This study demonstrated that surgical mobilization of the ulnar nerve during SAT has an effect similar to ISD on the nerves histologic and electrophysiologic properties at the 7th postoperative day in a rabbit model. CLINICAL RELEVANCE In a rabbit model, ISD and SAT appear to affect histologic and electrophysiologic findings of the ulnar nerve equally at postoperative day 7, which suggests that they would have the same relative safety in a clinical setting.

Pediatric posterior monteggia lesion: a greenstick fracture of the proximal ulnar metaphysis with radial neck fracture. A case report.

We report a case of posterior Monteggia lesion in a 12-year-old girl consisting of a greenstick fracture of the proximal ulnar metaphysis and a radial neck fracture with a proximal and posterior 90-degree rotational displacement of the radial head. Closed reduction of the radial head resulted in complete reversal of the radial head, which was corrected by open reduction and internal fixation. Cast immobilization without correction of the plastic deformation of the proximal ulna caused posterior bowing of the ulna and posterior displacement of the fractured radial neck. Corrective osteotomy of the ulna and third operation of radius resulted in bony union and acceptable alignment.

Two-dimensional Morphological Characteristics of the Distal Radius on Axial Magnetic Resonance Image and the Effects on Distal Screw Length

BACKGROUND Detection of dorsal cortical penetration of distal locking screws is difficult owing to the irregular shape of the dorsal surface of the distal radius. This study was designed to analyze two-dimensional morphological characteristics of the distal radius on axial magnetic resonance image, and to suggest a guideline for evaluation of screw length in distal radius fractures on the fluoroscopic or plain X-ray true lateral image. METHODS Anteroposterior length and lateral width of the distal radius, distance between the highest and the lowest point of the dorsal cortex (deceptive length), and widths of the first to second (hazard zone) and the third to fifth extensor compartments (safe zone) at the Lister tubercle level were measured on 104 axial magnetic resonance images by two hand surgeons. RESULTS The mean length and width of the distal radius at the Lister tubercle level were 22.96 mm and 30.42 mm, respectively. The mean hazard zone and safe zone widths were 8.72 mm and 19.43 mm, respectively. The mean deceptive length was 4.07 mm and the deceptive length did not have a relationship with height, sex, and age of subjects. CONCLUSIONS We suggest that 4 mm be used as a reference value for the evaluation screw length at the safe zone. If the vertical distance between a distal screw tip and the peak of the Lister tubercle is lesser than 4 mm on a fluoroscopic or plain X-ray true lateral image, dorsal cortical penetration should be suspected. When dorsal cortical penetration at the hazard zone is suspected, both oblique or pro-supination views should be checked.