Can the Use of Computer Navigation Reduce Revision Rates for THA?
A retrospective review of data from the Australian Orthopaedic Association National Joint Replacement Registry suggests that the answer is yes, at least for revision total hip arthroplasty due to dislocation.
Brittany DeClouette, MD, and Ajit Deshmukh, MD
Agarwal S, Eckhard L, Walter WL, et al. The use of computer navigation in total hip arthroplasty is associated with a reduced rate of revision for dislocation: a study of 6,912 navigated THA procedures from the Australian Orthopaedic Association National Joint Replacement Registry. J Bone Joint Surg Am. 2021 Jun 18. doi: 10.2106/jbjs.20.00950. Online ahead of print.
Malpositioning of the acetabular component in total hip arthroplasty (THA) has been identified as a major risk factor for dislocation. Over the past 20 years, computer navigation has been used with increasing frequency as a means of combatting this problem in primary THA, and it has been shown to improve the reproducibility of acetabular cup positioning. However, few studies have demonstrated the clinical benefit of this effect for prosthesis survival.
Via a retrospective review of data from the Australian Orthopedic Association National Joint Replacement Registry, Agarwal et al sought to determine whether there were differences in the rates of all-cause revision and revision specifically for dislocation for navigated versus non-navigated THAs.
The Australian registry captures data on nearly all THAs performed for osteoarthritis in the country. Agarwal et al included more than 269,000 THAs performed between 2009 and 2019, 6912 navigated (2.6%) and 262,936 non-navigated (97.4%). They excluded THAs with metal-on-metal bearing surfaces, dual-mobility liners, or constrained liners due to known high rate of revision with these implants.
For the navigated and non-navigated groups, Agarwal et al assessed:
- Cumulative percent revision rate
- Head size
- Surgical approach
- Surgical experience
- Reason for revision
- Type of revision
A sub-analysis further examined the 5 most commonly used femoral and acetabular component combinations implanted in the navigated and non-navigated THA groups.
When adjusted for age, sex, and femoral head size, no difference was observed in the rate of all-cause revision between navigated and non-navigated THAs. However, patients in the navigated THA group had a statistically significant lower rate of revision for dislocation: 0.4% vs 0.8%. In addition, no significant difference in rate of revision was observed when comparing the 3 surgical approaches used: posterior, lateral, and anterior.
In the sub-analysis, the rate of revision for dislocation and all-cause revision was significantly lower among the 5 acetabular and femoral component combinations most commonly used with a navigated THA: 0.3% vs 0.9%.
Computer navigation has evolved greatly since surgeons began using it for joint arthroplasty in the 1990s, with data now showing better accuracy and precision of acetabular component placement with navigation.
Although many studies have demonstrated that navigation improves reproducibility of cup placement, a limited number of studies have discussed the clinical outcomes associated with its use. Prior studies were either too poorly powered to show significant differences between navigated and non-navigated hips or they did not directly evaluate revision or dislocation rates.
The study by Agarwal et al is both the second-largest study on computer navigation and has the longest mean follow-up compared with similar studies. The results suggest that navigation for THA is associated with a lower rate of revision specifically for dislocation. The authors also considered prosthesis-specific variation in revision rates in this study. By selecting the 5 implant combinations used most commonly with and without navigation, revision rate variation among different implant types was eliminated. Lower rates of all-cause revision were found with the implants most commonly used in navigated THA.
The study has a few limitations that must be considered:
- Surgeon and hospital volume of THAs performed were not accounted for in the study. This can add confounders, as surgeons using navigation are more often high-volume surgeons who likely have fewer revisions overall.
- The registry data did not include closed reductions for dislocations as those patients were not taken to the OR.
- The registry data did not include implant position. Therefore, it is impossible to infer correlation between improved cup position secondary to navigation and reduced dislocation rate.
Although the results of the study by Agarwal et al do not necessarily imply causation, the association alone suggests that using navigation in primary THA is beneficial for avoiding revisions specifically for dislocations. Larger randomized clinical trials investigating navigated versus non-navigated THA will be necessary to prove causation.
Brittany DeClouette, MD, is an orthopaedic surgery resident at the NYU Grossman School of Medicine, NYU Langone Health, New York, New York. Ajit Deshmukh, MD, is a Clinical Associate Professor in the Department of Orthopaedic Surgery, NYU Grossman School of Medicine, NYU Langone Health, New York, New York.
Disclosures: The authors have no disclosures relevant to this article.