Bone transport combined with internal fixation in post-traumatic distal humerus defects and nonunions: retrospective analysis of 16 patients

Abstract

Background: This analysis aimed to assess the functional outcomes of patients with post-traumatic distal humerus defects and nonunions treated by bone transportation combined with internal fixation, containing two surgical techniques designed to enhance docking site union and functional recovery in critical distal humerus defects.

Methods: This retrospective study included 16 patients with post-traumatic distal humerus defects who underwent bone transportation combined with internal fixation between June 2017 and December 2023. Clinical records and consecutive X-ray images were reviewed to assess bone regeneration and alignment. The ASAMI criteria were applied to assess the bone and functional recovery, whereas the functional outcomes of the elbow joint were evaluated applying the Disabilities of the Arm, Shoulder, and Hand (DASH) score. Postoperative complications were classified using the Paley classification. Radial nerve function was systematically monitored preoperatively and at follow-up visits through comprehensive motor and sensory examination, with particular emphasis on delayed radial nerve palsy. Overall patient recovery, including range of motion (ROM) and functional improvement, was correlated with the DASH scores and postoperative complications. Statistical significance was defined as P < 0.05.

Results: The study included 16 patients ( mean age of 36.1 ± 8 years) with a mean humeral defect size of 5.6 ± 1.1 cm. The mean follow-up time was 22.1 ± 1.9 months, the average external fixation time (EFT) was 9.1 ± 1.4 months and the external fixation index (EFI) was 1.65 ± 0.11 months/cm. All humeral defects were successfully reconstructed. According to the ASAMI criteria, the treatment outcome was excellent in 6 cases, good in 8, and fair in 2. Elbow function significantly improved (p<0.01) post-operatively according to the DASH score. Mild extensional dysfunction was reported in 2 cases, and no radial nerve injuries or recurrent infections were observed. Pin tract infections were observed in 9 (56.26%) patients but were effectively managed with standardized dressing changes, without compromising the overall prognosis. The remaining patients achieved satisfactory clinical and functional recovery.

Conclusion: Bone transport combined with internal plate fixation effectively addresses post-traumatic distal humerus defects and nonunions by shortening external fixation time and lowering the incidence of docking site nonunion. This approach also eliminates the need for iliac bone grafting, thereby minimizing secondary trauma and enabling satisfactory joint function recovery.

Keywords: Bone transport; Humeral defect; Internal fixation; Nonunion.

Fig. 1

Flowchart of Patient Selection and Exclusion

Fig. 2

Schematic diagram of the protocol of acute-shortening and bone transportation combined with internal fixation(Surgical technique1). A Patient’s humorous with the distal humeral defect; B A unilateral frame(Orthofix) combined with an internal fixation plate is installed after acute-shortening of the defect site and proximal humeral osteotomy is carried out; C New callus generated after gradual bone transport, the longitude of the humerus is restored; D The external frame is removed after the bone lengthening period finished

Fig. 3

Schematic diagram of the protocol of humeral bone transportation followed by internal fixation at the docking site (Surgical technique 2). A Patient’s humorous with critical distal humeral defect; B A unilateral frame(Orthofix) is installed, and the proximal humeral osteotomy is carried out; C New callus generated after gradual bone transport, then the internal fixation plate is installed after the docking site connected; D, E After the bone lengthening period finished, the external frame is removed

Fig. 4

Case 1: A 32-year-old female suffered from post-traumatic nonunion and re-fracture developed humeral defect was managed by the technique of bone transportation combined with internal fixation. a The patient suffered from a severe distal humeral fracture caused by high-energy trauma; b open reduction and internal fixation surgery was performed 4 days after the accident; c, d it developed to a nonunion and implant failure 4 months after the initial surgery; e removing of the original internal fixation devices and the thorough debridement resulted in a 4.5 cm humeral defect, the patient underwent Surgical Technique 1; f. X-ray images at 2 months after the surgery show restoration of limb longitude without axial deviation or poor mineralization; g X-ray image at 7 months after the surgery, before the removal of the external fixator; h X-ray image at one year after removing the external fixator; i last follow-up examinations shows excellent functional recovery of the elbow

Fig. 5

Case 2: A 34-year-old male who underwent the protocol with the Surgical technique 2; a The patient suffered a severe open fracture in the distal humeral shaft due to high-energy trauma; b Underwent open reduction and external fixation, which developed into osteomyelitis; c after thorough debridement, the humeral defect was 6.6 cm and the Surgical technique two was applied; d X-ray image at 1month since the distraction; e X-ray image at 8month after the surgery shows contact at the docking site and good mineralization; f X-ray at one year after the external fixator was removed and the anatomical plates were implanted

Fig. 6

Humeral cross-sectional geometry at mid-shaft and distal segments