Conventional vs Augmented Reality-Guided Lateral Calcaneal Lengthening Simulated in a Foot Bone Model

BACKGROUND

Acquired adult flatfoot deformity (AAFD) results in a loss of the medial longitudinal arch of the foot and dysfunction of the posteromedial soft tissues. Hintermann osteotomy (H-O) is often used to treat stage II AAFD. The procedure is challenging because of variations in the subtalar facets and limited intraoperative visibility. We aimed to assess the impact of augmented reality (AR) guidance on surgical accuracy and the facet violation rate.

METHODS

Sixty AR-guided and 60 conventional osteotomies were performed on foot bone models. For AR osteotomies, the ideal osteotomy plane was uploaded to a Microsoft HoloLens 1 headset and carried out in strict accordance with the superimposed holographic plane. The conventional osteotomies were performed relying solely on the anatomy of the calcaneal lateral column. The rate and severity of facet joint violation was measured, as well as accuracy of entry and exit points. The results were compared across AR-guided and conventional osteotomies, and between experienced and inexperienced surgeons.

RESULTS

Experienced surgeons showed significantly greater accuracy for the osteotomy entry point using AR, with the mean deviation of 1.6 ± 0.9 mm (95% CI 1.26, 1.93) compared to 2.3 ± 1.3 mm (95% CI 1.87, 2.79) in the conventional method (P = .035). The inexperienced had improved accuracy, although not statistically significant (P = .064), with the mean deviation of 2.0 ± 1.5 mm (95% CI 1.47, 2.55) using AR compared with 2.7 ± 1.6 mm (95% CI 2.18, 3.32) in the conventional method. AR helped the experienced surgeons avoid full violation of the posterior facet (P = .011). Inexperienced surgeons had a higher rate of middle and posterior facet injury with both methods (P = .005 and .021).

CONCLUSION

Application of AR guidance during H-O was associated with improved accuracy for experienced surgeons, demonstrated by a better accuracy of the osteotomy entry point. More crucially, AR guidance prevented full violation of the posterior facet in the experienced group. Further research is needed to address limitations and test this technology on cadaver feet. Ultimately, the use of AR in surgery has the potential to improve patient and surgeon safety while minimizing radiation exposure.

CLINICAL RELEVANCE

Subtalar facet injury during lateral column lengthening osteotomy represents a real problem in clinical orthopaedic practice. Because of limited intraoperative visibility and variable anatomy, it is hard to resolve this issue with conventional means. This study suggests the potential of augmented reality to improve the osteotomy accuracy.

Outcomes of surgical management for tarsal coalitions: a systematic review

PURPOSE

To analyze the outcome of surgical treatment of tarsal coalition, assess the role of the surgical technique, as well as of coalition size and type on outcomes.

METHODS

The search followed the Preferred Reporting Items of Systematic Review and Meta-Analysis and was performed in four databases: MEDLINE, Central, Scopus and Web of Science. The protocol has been registered in the international prospective register of systematic reviews. Patient-reported outcomes (PROMs), complications, revisions and radiographic recurrence were collected. Risk of bias was assessed using MINORS criteria. A random-effects model for meta-analysis was applied for analysis of data heterogeneity.

RESULTS

Twenty-five studies including 760 tarsal coalitions were included and had a weighted average follow-up of 44 months. Studies scored fair to poor on the risk of bias assessment with a mean MINORS score of 67% (44-81%). In 77.8% (37.5-100%) of surgically treated tarsal coalitions, good/excellent/non-limiting or improved PROMs were reported. Calculated data heterogeneity was moderate (I2 = 57%). Open bar resection with material interposition had a clinical success rate of 78.8% (50-100%). Complications occurred in 4.96% of cases. Coalition size did not prove to be a determining factor in postoperative outcome. The influence of the coalition type was not investigated by any of the studies.

CONCLUSION

Data on outcomes of surgical management for tarsal coalitions is limited to retrospective case series with high risk of bias and moderate data heterogeneity. In about ¾ of cases, open resection and interposition of material results in improved PROMs. The arbitrary margin of ≥ 50% of TC coalition size in relation to the posterior facet has little importance in surgical decision-making. None of the studies reported on the influence of the coalition type on postoperative clinical success.