Figure 1 Pre-operative radiography
Dome osteotomy with T-plate fixation for cubitus varus deformity in an adult patient
S. MYINT AND P. J. A. MOLITOR
Department of Orthopaedics, Scunthorpe General Hospital, Scunthorpe, UK
Keywords: cubitus varus, dome osteotomy.
A 23-year-old presented with a right elbow cubitus varus deformity. He sustained a displaced supracondylar fracture of the humerus at the age of 9 years. This was managed by manipulation. On examination there was 250 varus deformity with a range of movement from -10 to 1200. Radiographs of the right elbow (Figure 1) showed 250 varus angulation.
Figure 1 Pre-operative radiography
The surgery was performed through a standard posterior approach, splitting triceps longitudinally. A T-plate was positioned just above the olecranon fossa and the site of osteotomy marked.
A dome was marked out with multiple 3.2 dull holes and the osteotomy was completed with a narrow osteotome. Correction was made by rotating the distal fragment. The adequacy of the correction was checked under direct vision with the elbow in an extended position and then fixed with a T-.plate. No attempt was made to correct rotational deformity. The elbow was immobilized in Plaster (of Paris), POP, for 6 weeks with the elbow flexed at 900. Post-operative check radiographs (Figure 2) showed satisfactory correction. At 3-month follow up, the fracture had healed. At the final follow low up, 2 years after surgery, there was 70 valgus with no lateral condylar prominence and the patient had regained his preoperative range of elbow motion.
Figure 2 Post operative radiography
Corrective supracondylar osteotomy is performed mainly to improve the cosmetic appearance and not for functional reasons. Many methods of correction with different fixation devices have been published. One of the most popular methods was lateral closing wedge osteotomy of French, modified by many authors,3,5 who report satisfactory results. This method needs detailed preoperative planning, careful surgical technique but can still cause recurrent varus4 and lateral condylar prominence in older children.6 A medial opening wedge osteotomy requires bone grafting and anterior transposition of the ulnar nerve. A step-cut osteotomy2 or multiplanar osteotomy7 is difficult to perform and its success requires strict attention to detail.
Corrective supracondylar osteotomies of the humerus for post-traumatic varus are usually performed at the metaphyseal region to promote rapid healing. Rigid fixation and maintenance of correction in this region is difficult because the supracondylar area is thin and wide, and the area of bony contact after osteotomy is inadequate.4 In this case, we decided to use a T-plate to provide a secure and stable fixation. Dome osteotomy was performed at the humeral diaphysis to accommodate the implant and to achieve wider bony contact. We were fully aware of vulnerability of the radial nerve in this approach and increased chances of non-union by performing the osteotomy at the diaphysical region. Uhl et al.8 reported that the distance from the articular surface (at the mid-portion or dip of the trochlca) to the radial nerve as it crossed the middle of the humerus was 15.8cm in men and 15.2cm in women in cadeveric specimens.5 During the operation, proximal exposure was kept to a minimum to avoid radial nerve injury and profunda brachii artery which lies just above the artery by following the guidelines of Uhl etal.8
We believe the dome osteotomy with T-plate fixation gives very good correction of varus deformity, with stable fixation and good functional result but care must be taken to avoid injury to the radial nerve.
Paper accepted 20 November1997
Correspondence: Mr P. J. A. Molitor, Scunthorpe General Hospital, Cliff Gardens, Scunthorpe DN15 7BH, UK
© 1998 The Royal College of Surgeons of Edinburgh, J.R. Coll. Surg. Edinb., 43, October 1998, 308-309