Nickel-titanium arched shape-memory alloy connector combined with bone grafting in the treatment of scaphoid nonunion.

Purpose: To summarize the techniques and clinical effectiveness in treating scaphoid nonunion with nickel-titanium (Ni-Ti) arched shape-memory alloy connector in combination with autologous iliac bone grafts.

Methods: This study retrospectively analyzed 18 scaphoid nonunion cases treated with arched connectors with autologous iliac bone grafts. Based on scaphoid nonunion, 2 cases were classified as type II (fibrous union), 4 cases as type III (mild sclerotic union), 6 cases as type IV (moderate resorption and sclerosis), 5 cases as type V (severe bone resorption and sclerosis), and 1 case as type VI (pseudarthrosis formation). At the first 4, 8 and 12 weeks after the surgery, wrist anteroposterior, lateral X-ray were obtained, respectively, to evaluate bone healing. Patients who had not yet reached the standard of healing at 12 weeks after surgery would continue to receive additional appointments for follow-up visits, such as 14 weeks, 16 weeks, 18 weeks after surgery, until their imaging studies had achieved satisfactory bone healing. Clinical effectiveness was evaluated comprehensively, based on bone union time, Mayo wrist score, and visual analog pain score.

Results: All 18 patients achieved satisfactory reduction and fixation with a mean union time of 4.2 months. Preoperative Mayo wrist score averaged 57.4 and average final postoperative follow-up was 91.4. On the other hand, mean preoperative VAS score was 6.8, and final postoperative follow-up average was 1.6. Mayo wrist score of the overall treatment effectiveness was excellent (90-100) in 12 cases, good (80-90) in 5 cases, and acceptable (60-80) in 1 case with zero poor (below 60) cases observed. Statistical analysis suggested that a statistically significant improvement in fracture healing, wrist function recovery and visual analog pain after surgery when compared to the scores of the patients before surgery.

Conclusion: Using Ni-Ti arched shape-memory alloy connector in combination with autologous bone grafting provided a new modality to treat scaphoid nonunions in a less traumatic, convenient to operate and satisfactory manner in treatment outcomes, and thus is worthy of further application.