Primary dynamization versus standard static interlocking nailing in treatment of tibial shaft fractures in adults: a randomized controlled trial

Abstract Background Interlocking nail (ILN) is gold standard for fixation of tibial shaft fractures in adults. Delayed union and non-union of tibial shaft fractures requiring secondary dynamization are high even with modern ILN techniques. There is no consensus to which dynamization technique has better outcomes and fewer complications. The purpose of this randomised controlled trial (RCT) was comparison of functional and radiological outcomes of primary dynamization without proximal locking screws versus standard static ILN in treatment of middle or distal thirds tibial shaft fractures in adults. Methods This RCT study was conducted on 40 adult patients with middle or distal third tibial shaft fractures, treated by primary dynamization ILN without proximal locking (group A) or standard static ILN (group B), at orthopedics department of Sohag university hospital, between September 2022 and September 2024. Primary outcomes were rate of union, time to union, and incidence of complications. Secondary outcomes were Bostman knee score, American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, and visual analog score (VAS). Results Mean ages of patients at time of operation were 33.25 years for group A and 31.45years for group B. Duration of surgery in group A was 66.25 ± 4.83 min compared to group B 75 ± 5.38 min, (P = .044). The mechanism of injury in most of patients was road traffic accident. The mean time to complete radiographic union in group A was 14 ± 1.86 weeks compared to group B at 16 ± 1.86 weeks, (P < .001). Bostman knee score was higher in group A at 28.05 ± 2.33 points compared to group B at 26.1 ± 2.65 points, (P = .016). No statistically significant difference was found between the two groups with respect to AOFAS ankle-hindfoot score, VAS for pain, rate of union or incidence of complications, (P > .05). Conclusion Both techniques achieved complete bony union and pain relief with minor complications. Primary dynamization of ILN tibia without proximal locking screws had advantages of shorter duration of surgery, faster radiographic complete union, and better functional outcomes. Level of evidence Level II: Randomised controlled trial. Trial registration The trial was retrospectively registered at 19 November, 2023 at www.clinicaltrials.gov (Trial Registry no: NCT06147219).