Application of intraoperative limb-length measurement by a new osteotomy device in hemiarthroplasty for treating femoral neck fracture

BACKGROUND Limb length discrepancy is one of the most common complications after hip arthroplasty. We developed a device - intraoperative limb-length measurement and osteotomy device (ILMOD), and applied it to patients who were treated with hemiarthroplasty for femoral neck fracture to improve limb length discrepancy by providing an accurate osteotomy during hemi-arthroplasty. METHODS Between April 2012 and October 2013, 65 patients were treated with hip hemiarthroplasty for femoral neck fracture at our trauma center. 31 patients met the inclusion criteria and were randomly enrolled into two groups ILMOD group and control group. Hemiarthroplasty in this study was performed with cement fixation. Treatment-related measurements such as the operation time, attempts of osteotomy, and the volume of intra-operative blood loss were collected. In both groups, postoperative (1 month) radiologic analysis on anteroposterior weight-bearing pelvic view was performed to evaluate limb length discrepancy. RESULTS The results showed significant improvement in limb length discrepancy in ILMOD group, and analysis of postoperative radiographs found the mean length difference is 2.1 ± 1.9 mm in ILMOD group compared to 8.8 ± 5.1 mm in control group (P < 0.0001). No complications associated with the use of the device were reported, and none of the patients complained of the discomfort related to limb-length discrepancy after surgery. The average intra-operative time was significantly longer in ILMOD group (84.9 ± 9.2 min) compared to that in control group (70.9 ± 10.2 min) (P = 0.0004). CONCLUSIONS The ILMOD is an effective device that can be used easily for intraoperative limb length measurement and osteotomy during hemiarthroplasty. This method is applicable with Kocher-Langenbeck approach, and the technique could also be used in total hip arthroplasty. TRIAL REGISTRATION Chinese Clinical Trial Registry ChiCTR-OOC-15005904 . Registered 30 Junuary 2015.