gms | German Medical Science

Background: Malunions of phalangeal fractures of the hand form a real challenge to the treating surgeon. Corrective osteotomies of the proximal phalanx need stable fixation to allow immediate active finger motion to prevent postoperative tendon adhesions. Typically this is achieved with plate/screw osteosynthesis. Despite rigourous postoperative mobilization, results are often disapointing due to stiffness. Intramedullary fixation of phalangeal fractures has been popularized recently. These offer a strong and reliable fixation allowing early mobilization. This technique can be performed with minimal disturbance of the soft tissue envelope of the finger. The stability of this type of fixation after open wedge osteotomy has not been tested.

Methods: 24 paired fresh frozen proximal phalanges were divided into two groups. In twelve phalanges, an apex volar osteotomy was created. In the other half, an apex medial osteotomy was created. In each group, 6 phalanges were stabilized with a dorsal 1.3 mm angular stable plate. The contralateral, paired phalanx was stabilized with a 2.4 mm intramedullary screw. The phalanges were tested in a custom mount in a 3 point bending, load-to-failure protocol. The load was transmitted onto the volar side of the phalanx as this mimics the physiological load of the tendons on the phalanx. A paired t test was used for statistical comparison of the 2 groups.

Results and Conclusions: The load to failure in the apex medial osteotomy group was 178,5N and 143,8N for the plate and screw and intramedullary screw group, respectively (p=0.3). Stiffness was 63,33N/mm and 55,83N/mm (p=0,22). For the apex volar osteotomy group, these numbers were 263,7N and 160N (p=0,0072) and 220N/mm versus 60N/mm (p=0,0012).

For fixation of an apex medial osteotomy, there is no statistically significant difference in load to failure between an intramedullary screw and an angular stable plate/screw construct. However, after apex volar osteotomy, plate/screw fixation is stronger.

Based on the available evidence, the rigidity provided by an intramedullary screw is probably sufficient to allow immediate active motion after both types of osteotomies. Combined with the advantage of minimal soft tissue disturbance, it seems to be a valid alternative for fixation of these osteotomies. Further clinical investigation in regards to feasibility is needed however.