Computer Navigation Helps Reduce the Incidence of Noise After Ceramic-on-Ceramic Total Hip Arthroplasty
- S.M. Shah, K. Deep, C. Siramanakul, V. Mahajan, F. Picard, D.J. Allen
Department of Orthopaedics, Golden Jubilee National Hospital, Clydebank, UK
- The Journal of Arthroplasty 2017, Online May 2017.
- Level of Evidence
- Level III (Retrospective comparative study)
Shah et al. evaluated 375 ceramic-on-ceramic (CoC) total hip arthroplasties (THA) with mostly 32 mm head size, comparing 173 conventional versus 202 computer navigated implantations. Three surgeons performed the conventional procedures, and all navigated procedures were performed by a single, different surgeon. All patients received the same implant type with a BIOLOX®delta head and liner. They were interviewed about noise occurrence, and if yes what kind, onset, activities causing it and association with pain.
No patient in either group required revision for noise. Noise was reported in 14.7 % THAs, of which 7% were non squeaking noise such as click, grunt, grind or crunch. In the navigated group, noise was not associated with pain and only noises other than squeaking were associated with pain in the conventional THA group (5 patients). Activities reportedly associated with noise were 61 % bending, 15 % climbing stairs and 14 % rising from a chair. Gender, BMI and head size were not significantly different between silent and noisy THAs.
Patients aged < 65 years had a significant greater incidence of self-reported noise. A subgroup was analyzed for further comparison between 118 conventional and 68 navigated THAs. Subgroup analysis suggested that navigated CoC THAs have a significant 2.7 x lower risk for reported noise and 5.8 x lower for noises other than squeaking, not significantly different in the conventional vs. the navigated group (p = 0.2). Radiographic comparison showed that cup anteversion was significantly lower for squeaking hips compared with silent hips but cup inclination, femoral offset and total offset were similar.
The authors inferred that computer navigation helped to position implants appropriately and this leads to a significantly reduced incidence of noise for CoC bearings. However, the confounding between surgeon and treatment group, as well as unmatched patient factors, greatly complicate the association of navigation with reduced noise.
- Possible selection bias regarding age receiving CoC bearings
- Confounding by surgeon (no overlap in surgeons between two study groups, all navigated procedures performed by a single surgeon)
- Information on noise based on patient perception and subject to recall bias (subjective)
- Overall incidence of noise in THA with CoC bearings was 14.7 %; 7.7 % squeaking
- Computer navigated CoC THAs were associated with less self-reported bearing noise, but not lower incidence of reported squeaking
- Cup anteversion was significantly lower in squeaking hips compared with silent hips
- Squeaking was not associated with pain
- No revisions for noise
To appropriately restore 3D hip anatomy, computer navigation was used as a tool to control cup orientation, center of rotation, stem anteversion, offset and leg length during surgery. Additionally computer simulation may help estimating the risk of impingement of the implant during ambulation. However, structural limitations in this study design limit the association between surgical navigation and patients’ self-reported noise. Patients reported that movements like bending down or climbing stairs were associated with noise emission, thus it seems appropriate implant positioning based on patient specific anatomy can help to reduce the risk of its occurrence. Higher cup anteversion seems to reduce the risk for noise occurrence, especially squeaking. Because of the confounding in the present study, it remains unclear whether appropriate placement, or the use of navigation, is most likely responsible for reduction in bearing noise. Ideally a prospective randomized trial would be the best way to answer this question, rather than by comparing case series from different surgeons using different component placement strategies.