Abstract
Purpose
Malrotation of the femur has been documented in as few as 0% and as many as 28% of fractures treated with an intramedullary(IM) nail. Patients with more than 15 degrees of malrotation sometimes require derotation osteotomy. Recognizing malrotation intraoperatively is the most efficient way to avoid corrective surgery. The purpose of this paper is to inform orthopaedic surgeons of the best estimate of incidence of femoral malrotation after IM nailing. This may lead to increased attention toward intraoperative control of malrotation.
Method
A literature search was performed by a library sciences professional. Two authors excluded papers not relevant to the study in two stages with clearly outlined criteria and adjudication. Inter-observer agreement was measured with the kappa statistic. Data extraction was performed by the same two authors with measure of agreement and adjudication from a third author. Data extraction included: incidence of malrotation, method used for measurement of malrotation and use of intraoperative techniques to minimize malrotation.
Results
Six-hundred-and-seventy-one papers were identified in 3 databases. First stage exclusion based on title and abstract yielded 149 papers. Second stage exclusion based on full text review yielded 51 papers. Inter-observer agreement for exclusion of papers was “very good” (93%, kappa=0.843).
The overall incidence of post-traumatic malrotation of the femur after IM nailing was 6%, 95% CI (5%, 8%). The incidence of malrotation identified by clinical examination alone was 3%, 95% CI (2%, 4%), while malrotation diagnosed by radiographic examination (CT, ultrasound and biplanar radiography) was 15%, 95% CI (10%, 20%). If intraoperative techniques to minimize malrotation were applied, incidence decreased to 9%, 95% CI (2%,16%) while without intraoperative attention to rotation, incidence was 19%, 95% CI (13%, 26%).
Conclusion
We have found femoral malrotation after IM nailing to be reported in 19% of cases when measured objectively. The present study offers the best available report of incidence for post-traumatic malrotation of the femur by combining all available studies, from Kunchner's initial publication on intramedullary nailing of the femur to date.
Jaarsma and Tornetta have reported that clinical examination is poor for detection of malrotation when compared with CT. Our study supports this finding. The quoted incidence for malrotation is consistently lower when measured by clinical examination compared to radiographic measures. This suggests that surgeons under-recognize malrotation intra-operatively, and therefore often fail to correct it. This study has found that any intraoperative effort to minimize rotation decreases its incidence to 9%. It is therefore crucial to have radiographic methods, such as those described by Krettek (lesser trochanter, cortical width and cortical diameter) available for use intra-operatively to diagnose malrotation.
