Review Question - QID 218845

Suprapatellar nailing has been shown to have less post-operative anterior knee pain and decreased risk for malunion when compared to infrapatellar nailing techniques.

Tibial shaft fractures are most commonly treated with intramedullary nailing. Proximal 1/3 tibial shaft fractures are notorious for being difficult to treat without developing the classic valgus and procurvatum deformity. The ligamentotaxis of the patellar tendon induces a procurvatum deformity while the ligamentotaxis of the pes anserine musculature induces a valgus deformity. Infrapatellar techniques require terminal flexion at the knee in order to place the final nail implant without abutting against the femoral condyles. This often places excessive tension on the patellar tendon, promoting the procurvatum deformity. When a knee is placed in the semi-extended position to facilitate the suprapatellar approach, there is considerably less tension placed through the patellar tendon, minimizing the risk for procurvatum deformity.

Metcalf and colleagues performed a retrospective case-control evaluation to compare the clinical, radiographic, and functional outcomes between suprapatellar and infrapatellar intramedullary nail fixation of tibia fractures. After multivariable analysis, they found that suprapatellar nailing was associated with decreased risk of malunion and a decreased risk of postoperative knee pain compared to infrapatellar nailing. They conclude that suprapatellar nailing provides superior fracture alignment and decreased risk of post-operative knee pain.

Ponugoti and colleagues performed a systematic review comparing suprapatellar and infrapatellar nailing techniques for tibial fractures. Utilizing a total of 12 included studies, they found that postoperative pain scores and improved functional outcomes were shown in the suprapatellar nailing group while there was no difference in operative time, deep infection, non-union, or secondary operation rates. The authors concluded that further studies are required to confirm their findings and assess long-term results, however, suprapatellar nailing has notable aforementioned advantages compared to infrapatellar nailing.

Figure A shows AP and lateral radiographic imaging of a proximal 1/3 tibial shaft fracture.

Incorrect Answers:
Answer 1: Open fractures, in general, have an increased risk of developing postoperative infections in comparison to closed injuries. However, the different nailing approaches for this patient's tibia does not impart an increased risk of developing a postoperative infection.
Answer 3: As discussed above, the relaxation of the extensor mechanism in a semi-extended suprapatellar nailing approach DECREASES the procurvatum and valgus deformity.
Answer 4: Multiple studies have shown equivalent operative and fluoroscopy times between suprapatellar and infrapatellar nailing techniques.
Answer 5: Some authors have hypothesized that the increased knee pain from infrapatellar nailing is due to patellar tendon splitting, proximal nail protrusion, chondral injury, or involvement of the infrapatellar nerve. In any case, suprapatellar nailing has consistently been shown to impart less post-operative knee pain when compared to infrapatellar nailing.