Can computer-assisted surgery help restore leg length and offset during THA? A continuous series of 321 cases

• Published in: Orthopaedics & traumatology, surgery & research Vol. 101; no. 7; pp. 791 - 795
• Main Authors: Clavé, A, Sauleau, V, Cheval, D, Williams, T, Lefèvre, C, Stindel, E
• Format: Journal Article
• Language: English
• Published: France Elsevier Masson SAS 01-11-2015
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Arthroplasty, Replacement, Hip - methods; Computer-assisted orthopedic surgery; Female; Follow-Up Studies; Hip Joint - diagnostic imaging; Hip Joint - surgery; Humans; Leg Length Inequality - diagnostic imaging; Leg Length Inequality - surgery; Limb length discrepancy; Male; Middle Aged; Orthopedics; Radiography; Retrospective Studies; Surgery; Surgery, Computer-Assisted; Total hip arthroplasty; Young Adult; Computer-assisted orthopedic surgery; Limb length discrepancy; Total hip arthroplasty
• ISSN: 1877-0568; 1877-0568
• DOI: 10.1016/j.otsr.2015.08.003

Abstract Introduction Total hip arthroplasty (THA) can bring about complications – particularly leg length differences – that are becoming increasingly litigious. Computer-assisted orthopedic surgery (CAOS) can help optimize the procedure, but its ability to effectively restore leg length is controversial. As a consequence, we carried out a study to determine: (1) its contribution to meeting leg length and offset objectives, (2) its reliability, by evaluating the correlation between radiological and navigation data, (3) its safety, by evaluating navigation-specific and non-specific complications. Hypothesis CAOS will help to restore leg length within ± 5 mm in more than 80% of cases. Material and methods A series of 321 continuous cases of cementless THA implanted through the posterolateral approach using CAOS was analyzed retrospectively. With a minimum 1 year follow-up, we evaluated whether the leg length and offset goals were achieved, how well the navigation and radiology data were correlated and whether navigation-specific and non-specific complications occurred. Based on our hypothesis that 80% of patients would have less than 5 mm leg length difference and the null hypothesis (PA = P0) with an alpha of 0.05, 200 observations were required to achieve a power of 90%. Results The leg length and offset objectives were achieved in 83.3% and 88% of cases, respectively. Twenty-two patients required a heel wedge to compensate for leg length differences. The correlation between the radiology and surgical navigation data was satisfactory – the Pearson coefficient was 0.79 for length and 0.74 for offset. Intraoperative and postoperative complications or adverse events were found in 14.6% of cases; these were specific to CAOS in 12.1% of cases and non-specific in 2.5% of cases. Conclusion This study shows the relevance of CAOS for achieving preoperative leg length objectives, with good correlation between navigation and radiology data, and without major complications. Level of evidence IV – retrospective study.