Lateral parapatellar approach versus transpatellar splitting approach in intramedullary nailing of diaphyseal tibia fractures, a prospective randomized controlled study

Background: Anterior knee pain (AKP) is a frequent complaint after tibial intramedullary nailing (IMN), and the choice of entry approach may contribute to its occurrence. This trial compared the lateral parapatellar semi-extended (LPP) approach versus the midline transpatellar splitting (MLTP) approach for IMN of closed diaphyseal tibial fractures, focusing on AKP and knee function. Methods: In this single-blinded randomized controlled trial, 50 adults with acute closed AO/OTA 42 tibial shaft fractures were allocated 1:1 to IMN performed through either the LPP or MLTP approach. Follow-up assessments were performed at 3 and 6 months after surgery. Primary outcomes were AKP during weight-bearing, quantified using a visual analog scale (VAS), and knee function measured by the Lysholm Knee Score. Results: LPP achieved higher Lysholm scores at 3 months (82.36 ± 5.2 vs. 75.76 ± 6.1; P < 0.001) and 6 months (87.32 ± 4.8 vs. 84.20 ± 5.4; P = 0.024), indicating superior early functional recovery. VAS AKP was lower with LPP at 3 months (2.40 ± 0.9 vs. 3.60 ± 1.2; P = 0.001), but similar by 6 months (1.80 ± 0.7 vs. 1.96 ± 0.8; P = 0.122), suggesting the benefit is mainly early. Operative time favored LPP (62.1 ± 8.7 vs. 68.4 ± 10.2 min; P = 0.02) with fewer fluoroscopy shots (29.2 ± 5.4 vs. 38.5 ± 6.1; P < 0.001). All fractures united; time to union was comparable (16.8 ± 2.4 vs. 16.2 ± 2.1 weeks; P = 0.41). Complications were minor in both groups. Conclusions: LPP semi-extended tibial IMN was associated with lower early AKP, better early knee function, and improved operative efficiency without compromising union during 6-month follow-up. A Longer follow-up is required to determine whether anterior knee pain and functional outcomes converge over time.