Anatomical Structures at Risk in Percutaneous Preparation Talonavicular Fusion

BACKGROUND

The stability of the hindfoot greatly relies on the integrity of the talonavicular joint. Pathologies affecting this joint often necessitate fusion. Our study explores the risks posed to neurovascular and tendon structures during simulated percutaneous talonavicular joint preparation for fusion.

METHODS

In 9 fresh cadaver specimens, the talonavicular joint was accessed through two portals. A 2-mm Shannon burr was employed for joint surface preparation with distraction provided by a pin-based distractor. Dissections were performed to assess potential damage to critical structures, including the dorsalis pedis artery, superficial and deep peroneal nerves, extensor hallucis longus (EHL), and tibialis anterior (TA) tendons.

RESULTS

The dorsal portal site was found to be significantly closer to important structures compared to the medial portal site. The Shannon burr made contact with various structures, with a single transection identified for both deep and superficial peroneal nerve branches. During the dorsal portal site approach, potential injury to the EHL tendon was identified as concern.

CONCLUSION

This study sheds light on the potential risks associated with percutaneous dorsal and medial joint preparation approaches using a Shannon burr.Level of Evidence:Level V, mechanism-based reasoning..

Isolated Talonavicular Arthrodesis as Treatment for Flexible Progressive Collapsing Foot Deformity: A Case Series

Background

For the younger, more active patient with flexible symptomatic progressive collapsing foot deformity (PCFD), joint-sparing procedures may be preferred to preserve functional motion. Isolated talonavicular (TN) arthrodesis has been described for treatment of rigid and flexible PCFD for patients that are older and less active whose deformity is still correctable through the TN joint. The purpose of this study was to evaluate radiographic and clinical outcomes in patients with PCFD treated with isolated triplanar correction with a TN joint arthrodesis.

Methods

Forty-nine patients (53 feet) with flexible PCFD underwent isolated TN arthrodesis. Weightbearing radiographs were performed pre- and postoperatively, and measurements included lateral talar-first metatarsal angle, calcaneal pitch, TN coverage angle, and the anteroposterior (AP) talar-first metatarsal angle. The Foot and Ankle Ability Measure (FAAM) and Veterans-Rand 12-Item Health Survey (VR-12) scores were also collected.

Results

Thirty-five females and 14 males were evaluated with a mean age of 63 years, at an average follow-up of 41.3 months. Significant improvements were found radiographically. Lateral radiographs demonstrated improvements in lateral talar-first metatarsal angle from 25.2 degrees preoperatively to 9.5 degrees postoperatively (P < .001) and calcaneal pitch from 14.9 degrees preoperatively to 17.5 degrees postoperatively (P < .001). AP radiographs showed the TN coverage angle improving from 35.0 degrees to 4.9 degrees postoperatively (P  < .001) and AP talar-first metatarsal angle improving from 17.3 degrees to 5.9 degrees postoperatively (P < .001). Clinical outcomes were improved in the FAAM pain score (48.6 to 39.2, P = .130), FAAM ADL score (53.8 to 69.2, P = .002), FAAM Sport score (29.5 to 40.7, P = .099), and the overall FAAM score (47.7 to 63.1, P = .006). Patient satisfaction with medical care was 85.2/100 postoperatively.

Conclusion

Isolated TN arthrodesis is a viable surgical option for older, lower-demand patients with flexible PCFD. This study demonstrated significant improvements in radiographic alignment and FAAM scores. Comparative studies with other surgical procedures should be performed to determine which is the best technique for older, lower-demand patients with flexible PCFD.

Level of Evidence

Level III, retrospective cohort study.

Surgical Construct Type Is Associated With Time to Fusion and Reoperation Rate in Double and Isolated Talonavicular Arthrodeses

BACKGROUND

This study evaluates the effect of surgical construct on postoperative outcomes in patients undergoing isolated talonavicular (TN) or double (TN and subtalar ST) arthrodesis. TN constructs included plate and screw, screw and staple, and isolated staple constructs. Subtalar constructs included 1- and 2-screw constructs.

METHODS

Retrospective chart review identified 52 patients who underwent double or isolated TN arthrodesis between 2016 and 2021 by a single fellowship-trained foot and ankle surgeon with minimum 6 months of follow-up (mean = 1.62 years, range = 0.50-4.39 years). Data collected included demographics, medical history, surgical indication, surgical constructs used, complications, reoperations, patient-reported outcome measures, and radiographic measures.

RESULTS

Overall complication and reoperation rates were 26.3% and 12.3%, respectively. Among TN constructs, time to ST (P = .026) and TN (P = .018) fusion was significantly slower among patients receiving a plate and screw construct. Complication rate did not differ, but reoperation rate was significantly higher for plate and screw TN constructs (P = .039). Postoperative Foot and Ankle Outcome Score (FAOS) Quality of Life (P = .028) and Total (P = .016) scores were significantly better among plate and screw TN constructs.

CONCLUSION

Utilization of screw and staple or isolated staple construct have significantly quicker time to fusion and lower reoperation rates than plate and screw constructs for the TN joint.

LEVEL OF EVIDENCE

Level III: Retrospective cohort study.

Surgical Construct Associated with Time to Fusion in Double and Isolated Talonavicular Arthrodeses

Category:

Hindfoot; Ankle Arthritis

Introduction/ Purpose:

Double arthrodesis of the subtalar (ST) and talonavicular (TN) joints, along with isolated TN arthrodesis, are commonly performed for hindfoot osteoarthritis and rigid hindfoot deformity. Few studies have examined the effects of the type of ST and TN fixation constructs on nonunion rate following double and isolated TN arthrodesis procedures. This study evaluates the effect of surgical construct on the union rate and time to fusion in patients undergoing double or isolated TN arthrodesis.

Methods:

Retrospective chart review identified 52 patients (52 feet) who underwent double or isolated TN arthrodesis between 2016 and 2021 by a fellowship-trained foot and ankle surgeon with at least six months of follow-up (mean=1.62 years, range=0.50- 4.39 years). Data collected included demographics, medical history, surgical indication, surgical constructs used, complications, reoperations, patient-reported outcome measures, and radiographic measures. ST constructs included one (n=4) or two (n=44; parallel=43, divergent=1) cannulated screws, while TN constructs included dorsal plate (n=2), dorsal plate and screw (n=10), isolated screws (n=3) screw and staple (n=29), or isolated staples (n=13). At the time of their surgery, the mean age was 60.39 (range, 17-80) years, mean body mass index (BMI) was 33.89 (range, 20.74-48.41) kg/m2, and most subjects were non-smokers (94.7%). Mean follow-up duration was 1.62 (range, 0.50-4.39) years.

Results:

Overall complication and reoperation rates were 26.3% and 12.3%, respectively. Among TN constructs, the time to ST (p=.026) and TN (p=.018) fusion was statistically significantly slower among patients receiving a plate and screw TN construct. Complication rate did not differ by construct, but reoperation rate was significantly higher for the plate and screw TN construct (p=.039). Postoperative Foot and Ankle Outcome Score (FAOS) Quality of Life (p=.028) and Total (p=.016) scores were significantly better among plate and screw TN constructs.

Conclusion:

The utilization of a screw and staple or isolated staple construct have a statistically significantly quicker time to fusion and lower reoperation rates than plate and screw constructs for the TN joint. These findings can be used to guide clinician decision-making while allowing physicians to take their personal construct preference into account, as well as serve as a useful starting point to other researchers interested in investigating the impact of surgical constructs on ST and TN fusions.

Structures at Risk During Percutaneous Screw Fixation for Talonavicular Fusion

BACKGROUND:

Talonavicular (TN) fusion using screws dorsomedially and dorsolaterally can cause neurovascular injury. The purpose of our cadaveric study was to evaluate the safety of percutaneous screw insertion in relation to dorsal neurovascular structures.

METHODS:

Ten fresh-frozen cadaver legs were used for this study. Percutaneous cannulated screws were inserted to perform isolated TN arthrodesis. The screws were inserted at 3 consistent sites: a "medial screw" at the dorsomedial navicular where it intersected at the medial plane of the first cuneiform, a "central screw" at the edge of the dorsal navicular between the medial and intermediate cuneiforms, and a "lateral screw" at the edge of the dorsal navicular between the intermediate and lateral cuneiforms. Superficial and deep dissections were carried out to identify any injured nerves, arteries, and/or tendons.

RESULTS:

The medial screw injured the anterior tibialis tendon in 2 cases (20%), the central screw injured the extensor hallucis longus tendon in 3 cases (30%), and the lateral screw injured the anterior branch of the superior peroneal nerve (SPN), the lateral branch of the SPN, and the medial branch of the distal peroneal nerve (DPN) once each in a total of 3 cases (30%). Despite no direct injury, the central screw indicated a potential risk of neurovascular injury: closest distance to the anterior SPN was 2 mm and to the medial DPN 2 mm.

CONCLUSION:

Although neurovascular injury risk exists for all of these screw placements, TN fusion with a central screw introduced a potentially decreased risk of neurovascular injury at the expense of increased risk of tendon injury compared to the lateral screw.

CLINICAL RELEVANCE:

Based on these results, we recommend a careful dissection be performed prior to percutaneous screw insertion.