Femoral shortening osteotomy in total hip arthroplasty for severe dysplasia: a comparison of two fixation techniques.

PURPOSE: The purpose of this study was to compare two distinct fixation methods for a total hip replacement performed via transverse femoral shortening osteotomy for patients with severe hip dysplasia.
METHODS: In this retrospective study we compared two fixation methods for total hip replacement of 78 hips in 76 patients exhibiting Crowe type IV developmental hip dysplasia (DDH). The hip replacements were performed via a transverse femoral shortening osteotomy and carried out between September 2009 and December 2013. Group I patients underwent fixation of the shortened femoral segment via a cable attached to the osteotomied segment, and group II patients underwent fixation with a plate and screw. We compared the two techniques based on operating time, osteotomy site union time, Harris hip score, hip loosening signs, and overall clinical outcomes.
RESULTS: The mean operating time for groups I and II was determined to be 116.5 ± 12.8 min and 137.7 ± 14 min, respectively (p < 0.05), while the average union time was 113 ± 51 days for group I and 152 ± 37 days for group II (p < 0.05). Fixation of the femur with a cable (group I) is therefore faster and results in more rapid union time when compared to plate osteosynthesis at the osteotomy site (group II). We observed only one non-union in group I compared with three in group II (p = 0.49). Harris hip scores at the final patient follow-up were 82.8 ± 7.8 and 80.8 ± 6.7 for groups I and II, respectively (p = 0.23). Thus, notably no significant differences were observed between the groups with regard to clinical outcomes such as the Harris hip score or loosening of the replacement components.
CONCLUSION: Fixation of the removed femoral segment with a cable provided adequate rotational stability and decreased the operating time, leading to early union at the osteotomy site.