Comparison of Limb-length Discrepancy After THA: With and Without Computer Navigation

Abstract

Limb-length discrepancy following total hip arthroplasty (THA) is often cited as a reason for patient dissatisfaction and for hip instability. Various intraoperative techniques have been described to help restore normal limb length after THA. The purpose of this study was to assess whether a computer-navigated surgical technique would help restore limb-length equality following THA.A retrospective study of 150 consecutive patients compared a free-hand (non-navigated) THA technique vs a computer-navigated THA technique. Each group contained 75 patients. The primary outcome measurement was limb-length discrepancy, which was evaluated using a digital anteroposterior pelvic radiograph. Secondary outcome measurements included a Harris Hip Score questionnaire and a single question evaluating the subjective feeling of the operative limb (longer, shorter, or equal). At a minimum 1-year follow-up, results showed that computer-navigated THA helped restore limb-length equality. An average leg-length difference of 0.3 mm (SD=0.3 mm) was found with computer-navigated THA compared with a leg-length difference of 1.8 mm (SD=0.7 mm) when a non-navigated THA was used. This was statistically significant. Both groups had similar Harris Hip Scores (computer-navigated group, 84.8; non-navigated group, 84.2; P=.835), and no difference was found between the 2 groups regarding the patient's perception of the operative limb length.This study demonstrated that computer-navigated THA resulted in improved restoration of normal limb length and limited significant outliers but did not show improvement in Harris Hip Scores or patient's perception of limb-length equality.

Does haptic robot-assisted total hip arthroplasty better restore native acetabular and femoral anatomy?

“…A similar percentage of native acetabular anteversions were within the Lewinnek safe zone, while a higher percentage of native acetabular inclinations were within the safe zone than in previous data . Consistent with the literature , robot‐assisted THA showed higher accuracy and precision in positioning the cup within the safe zone than free‐hand THA (75% vs 36%), leading to a smaller number of outliers outside the safe zone in robot‐assisted THAs.…”

“…Component positioning in THA is critical in optimizing satisfactory clinical outcomes. Navigation THA has been reported to provide higher precision in component positioning than the conventional free‐hand THA . However, whether robot‐assisted THA better restores the 3D orientations and positions of the hip geometry remains unknown.…”

“…In order to optimize the acetabular cup and femoral stem placement, various navigation surgeries have been used to provide higher precision in component positioning than the conventional free‐hand alignment method . Navigation THA successfully reduced the number of cases outside those safe zones ; however, several studies reported that there was no significant improvement in the clinical outcomes of THA patients receiving computer‐assisted implantation relative to conventional free‐hand THA .…”

Does stem design influence component positioning in total hip arthroplasty using a minimal invasive posterolateral approach?

“…For standard length stems, several studies have demonstrated that using a MIS approach does not compromise the long-term clinical and radiographic outcome when compared with conventional incision techniques [23,24]. With regard to the reconstruction of leg length, our results compare favorably with a report of Licini et al [25] who described 0.3-mm leg lengthening using navigation. This is the first study to describe the cup position with reference to the reported target orientation for inclination and anteversion using a MIS posterolateral approach in a large number of patients.…”

No Benefit After THA Performed With Computer-assisted Cup Placement: 10-year Results of a Randomized Controlled Study

“…At 10 years, the clinical outcomes including the HSS, the HOOS, and the SF-12 were comparable in the two groups. In two previous studies (comparison of limb length discrepancy after THA: with and without computer navigation), no clinical difference was observed for the HHS or the Postel-Merle score between the CAS group and standard groups at, respectively, 1 year and 13 years [13,21]. To our knowledge, only one previous study used the HOOS as a specific hip quality-of-life questionnaire to compare the two techniques with no difference observed between the two groups at 5 to 7 years after surgery.…”