Rotational Alignment in tibia diaphyseal fractures with the Suprapatellar Semi-extended Versus Standard Upper Entry Tibial Intramedullary Nailing: A Randomized Controlled Trial (RASPUTIN).

Objectives: To determine whether suprapatellar or infrapatellar approach makes a difference in the rate of rotational malalignment in tibial diaphyseal fractures treated with intramedullary nailing.

Methods: Design: Non inferiority, randomized controlled trial, with 2 arms (Suprapatellar and Infrapatellar approach).

Setting: Single centre trial at a Level I trauma centre in South India.

Patient selection criteria: Adults presenting with tibial diaphyseal fractures (OTA/AO 42A, B and C, 43A) planned for intramedullary nailing between September 2021 to July 2022.

Outcome measures and comparisons: The primary outcome compared was the degree of rotational malignment in patients undergoing tibia nailing with Suprapatellar and Infrapatellar approaches. This was done using CT scan in the immediate post-operative period. Secondary outcomes included across the 2 groups were post-operative entry site pain, anterior knee pain (Kujala score), functional scores and union rates.

Results: 50 patients, 25 in each arm were included and followed up to a period of 1 year. The mean age was 34 (16-67) years (68% male) in the suprapatellar group and 45 (16-72) years (72% male) in the infrapatellar group. The rate of rotational malalignment was 34% with 8 (32%) in the suprapatellar group and 9 (36%) in the infrapatellar group and was independent of approach (P=0.76). The rotational malalignment had no association with knee functional scores (P=0.24). Factors such as location of fracture (P=0.81), mechanism of injury (P=0.76), type of injury (P=0.24) and surgeon seniority (P=0.2) had no association with malrotation. Suprapatellar and infrapatellar groups were similar in terms of knee function (P=0.52), knee (P=0.31) and ankle P=0.23) range of movement and union rates (P=0.84). Entry site pain was found to be significantly less (P=0.021) in the suprapatellar group (6/25) as compared to the infrapatellar group (14/25).This difference persisted at 1 year.

Conclusions: Rotational malalignment in tibial diaphyseal fractures treated by intramedullary nailing was independent of the approach used. Entry site pain was less common with suprapatellar approach.

Level of evidence: Level I.