8 out of 10 patients do well after surgery for tarsal coalitions: A systematic review on 1284 coalitions

Tarsal coalition in adults

Adult tarsal coalition consists in abnormal union of two or more tarsal bones. Reported incidence ranges between 1 and 13%. It is generally a congenital condition, due to dominant autosomal chromosome disorder, but with some acquired forms following trauma or inflammatory pathology. Poorly specific clinical signs and the difficulty of screening on conventional X-ray may lead to diagnostic failure. The present review of tarsal coalition addresses the following questions: how to define tarsal coalition? How to diagnose it? How to treat it? And what results can be expected? There are 3 types of tarsal coalition, according to the type of tissue between the united bones: bony in pure synostosis, cartilaginous in synchondrosis, and fibrous in syndesmosis. Location varies; the most frequent forms are talocalcaneal (TC) and calcaneonavicular (CN), accounting for more than 90% of cases. Cuneonavicular, intercuneal and cuboideonavicular locations are much rarer, at less than 10%. Tarsal coalition is classically painful, often with valgus spastic flatfoot in young adults. The pain is caused by the biomechanical disturbance induced by the bone, cartilage or fibrous bridges which partially or completely hinder hindfoot and/or midfoot motion. Conventional imaging, with weight-bearing X-ray and CT, is standard practice. Weight-bearing CT is increasingly the gold standard, displaying abnormalities in 3 dimensions. Functional imaging on MRI and tomoscintigraphy assess direct and indirect joint impact at the affected and neighboring joint lines. Non-operative treatment can be proposed, with orthoses, rehabilitation and/or injections. But surgery is the most frequent option: either resection of the bony, cartilaginous or fibrous constructs to restore optimally normal anatomy, or arthrodesis in the affected joint line or the entire joint. Surgery can be open, arthroscopic or percutaneous, depending on the severity of the biomechanical impact on the affected and neighboring joints. Resecting the abnormality is the standard practice in all locations if it affects less than 50% of the talocalcaneal joint line and there is no osteoarthritis to impair the functional outcome. Otherwise, fusion is required. Level of evidence: V; expert opinion.

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.

Cavus Foot Deformity with Calcaneonavicular and Medial Cuneiform-Navicular Coalition: A Case Series

Tarsal coalitions have only very infrequently been observed in the context of cavus foot abnormalities. Recognizing this diagnosis could be crucial to effective cavus repair. We report tarsal coalitions observed in cavus deformity here. Between 2022 and 2023, the records of every patient treated by one of the authors for a varus deformity who was later determined to have either a unilateral or bilateral tarsal coalition were examined. Two patients with cavus deformities who were treated by one of the authors have either a unilateral or bilateral tarsal coalition. Three foot (medial cuneiform-navicular n = 1 and calcaneonavicular n = 2) with tarsal coalition were examined. All of these cases occurred in patients with idiopathic cavus deformity. Computed tomography scans were used to make a firm diagnosis for each patient. We advise surgeons to keep an awareness for this potential comorbid issue in all cavus foot abnormalities and to take advanced imaging into consideration. In these uncommon cases, the medial cuneiform-navicular and calcaneonavicular joints formed an osseous coalition with pes cavus deformity, which successfully resolved with conservative and surgical treatment, respectively. Level of Clinical Evidence: IV.

Classification of the Os Calcis Subtalar Morphology in Symptomatic Flexible Pediatric Pes Planus Deformity Using Weightbearing CT and Distance Mapping

BACKGROUND

The etiology of symptomatic pediatric pes planus (PP) deformity is unclear. Reduced os calcis subtalar joint (OCST) anterior facet morphology has been suggested to result in less support to the talar head and a higher propensity to develop PP deformity. Weightbearing computed tomography (WBCT) and distance mapping (DM) offer new opportunities to investigate PP deformity in general and the OCST specifically. The purpose of this study is to investigate the OCST morphology using DM and to classify PP subtalar subtypes with DM using Bruckner's A-D classification system.

METHODS

Forty feet in 25 patients in a national referral center were evaluated for symptomatic PP deformity that failed nonoperative treatment. A WBCT scan was performed as part of the preoperative evaluation. Visualization of the distance distribution between the articulating surfaces of the subtalar joint was based on a DM technique. Intra- and interobserver agreement of the subtalar morphology was assessed using Bruckner's classification system.

RESULTS

The mean age was 10.7 ± 1.4 years. The following mean ± SD and median ± ranges were semiautomatically measured for this group: Meary angle -21 ± 8, calcaneal inclination 15 ± 4 degrees, talar coverage angle 39 (range 32.6-49) degrees, and hindfoot moment-arm 16 ± 5 mm. Classifying subtalar morphology using DM yielded an excellent intra- and interobserver agreement. The individual percentages of each individual subtype were calculated: type A 5%, type B 48%, type C 4%, and type D in 44%.

CONCLUSION

This study demonstrated excellent intraobserver and interobserver agreement in classifying the OCST using DM. A higher prevalence of types B and D was observed compared to types A and C in this PP cohort.

LEVEL OF EVIDENCE

Level III, retrospective study.