Retaining Severely Damaged Talar Body and Medial Malleolar Cartilage for Diabetic Ankle/Hindfoot Charcot Arthrodesis Using Intramedullary Nail: A Short Report

Abstract

Background:

The tibiotalocalcaneal (TTC) arthrodesis using an intramedullary nail (IMN) is a common method used to treat advanced diabetic ankle/hindfoot Charcot deformity. The talus is usually resected when severe loss of its body is present and the medial malleolar cartilage excised. We report our initial results with talar retention and absence of medial ankle gutter cartilage debridement.

Methods:

Four patients with type 2/3A Brodsky classification and stage 2/3 as Eichenholtz classification, presenting with a hindfoot varus deformity were treated with TTC using IMN. The talus was retained after excision of its proximal and distal cartilages while the medial malleolus cartilage was not touched. Bone union was the primary outcome. The minimum follow-up period was 12 months.

Results:

Bone union was achieved radiologically in all 4 cases within 6 months. No signs of postoperative infection was noted. The mean limb length difference between the pre- and postoperative values was 0.5 ± 0.2 cm. At the final follow-up, all patients were able to walk pain-free with full weightbearing. All 4 patients were very satisfied at 12 months with a mean American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score of 87 ± 3.1.

Conclusion:

When performing TTC arthrodesis for diabetic Charcot, preserving the talus even when the body is severely damaged could add to the stability of the construct resulting in bone healing and some leg length preservation. Including the medial malleolus in the fusion surgery might not be necessary.

Level of Evidence:

Level IV, case series.

Visual Abstract

This is a visual representation of the abstract.

Introduction

Diabetic Charcot osteoarthropathy of the foot and ankle constitutes a great clinical and therapeutic challenge with high rates of amputation and mortality.^3,9 Surgery based on joint fusion is usually indicated when the destruction is severe and progressive, often leading to an unstable deformity of the hindfoot/ankle. ⁴ A recent meta-analysis showed that the IMN method seems to offer quicker and better fusion rate when compared to external fixation with significantly lower postoperative infection rates. ⁸ In cases with severe talus body loss, most authors advocate its excision to achieve a talocalcaneal (TC) arthrodesis. However, some articles reported worse outcomes compared to TTC arthrodesis ⁷ along with limb shortening up to 3 cm. ⁵ This preliminary study reports the technique and outcomes of patients having advanced hindfoot/ankle Charcot deformity with severe talar body loss treated with IM nailing while retaining the talus. Additionally, in all cases the cartilage of the medial aspect of the tibiotalar joint was left intact.

Methods

Study Sample

This is a case series of 4 patients (3 females and 1 male) with noninfected ulcer-free advanced diabetic hindfoot and ankle Charcot treated with TTC using a Charcot-specific IMN. The age range was between 54 and 62 years. The mean HbA1c value was 7.1 ± 1.2. The mean preoperative limb length difference was 0.8 ± 0.4 cm. Patients were followed for a minimum period of 12 months.

Charcot Classification and Associated Deformities

The included cases were categorized as type 2/3A as per Brodsky classification. Based on Eichenholtz classification, cases were labeled as late stage 2 or stage 3. All cases were associated with a varus deformity of the hindfoot but none presented with ulcerations. The talus was severely damaged in all 4 cases, with more than 75% of its body being missing.

Surgical Technique

A lateral approach was used and the distal 7-8 cm of the fibula was excised and prepared into morselized bone graft. Debridement of both joints was undertaken while preserving the existing talar cancellous bone. The cartilage of the tibiotalar and subtalar joints was excised. On the medial side of the tibiotalar joint, only the shoulder segment was debrided whereas the cartilage of both facets of the remaining medial tibiotalar joint was left untouched. The hindfoot varus was corrected in the subtalar joint, mainly on the calcaneal side. A Charcot-specific IM nail was introduced. The entry point was located using the method described by Belczyk et al. ² After proper reaming, the guidewire was left and the medial aspect of both joints were filled with fibular autograft with no attempt to overfill, so as not to affect the coronal alignment. The nail was then inserted and the remaining space around the nail and the lateral aspect of both joints was filled with morselized fibular graft. Distal and tibial screws were inserted. A double plaster splint (posterior and coronal) was applied. Figures 1 and 2 show 2 clinical cases.

Figure 1.

Case 1. Ankle/hindfoot Charcot. (A) Preoperative anteroposterior view. (B) Preoperative lateral view. (C) Postoperative anteroposterior view. (D) Postoperative lateral view.

Figure 2.

Case 2. Ankle/hindfoot Charcot 2 years following midshaft tibia fracture. (A) Preoperative anteroposterior view. (B) Preoperative lateral view. (C) Postoperative anteroposterior view. (D) Postoperative lateral view. (E) Postoperative oblique view.

Postsurgical Protocol

At 4 weeks, stitches were removed and the splint was replaced with a pneumatic foam walker. No weightbearing was allowed for the first 3 months; this period was followed by partial weightbearing for another 3 months. Anticoagulation therapy was given for 6 months. Control radiographs were performed at 6 weeks, 3 months, 6 months, and 12 months postoperatively.

Outcome Definition

Bone union was assessed primarily using radiographs, in search for callus formation and in particular bone filling of tibiotalar and subtalar joint lines. The clinical assessment of bone union was established on pain scoring at last follow-up. Limb length shortening, postoperative complications, and the American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score were set as secondary outcomes. Limb length shortening was assessed based on the tibiocalcaneal distance measured between the highest point of the tibial surface to the plantar cortex of the calcaneus on a lateral radiograph (Figure 3).

Figure 3.

Limb length difference measurement.

Results

At 6 months, bone union was achieved radiologically in all 4 cases with a conserved postoperative ankle/hindfoot axis. All wounds but one healed uneventfully; one patient presented a wound healing delay of 8 weeks treated successfully with topical dressings. No clinical signs of postoperative infection were noted. At the final follow-up, all patients showed a pain score of zero on clinical examination and were able to walk pain-free with full weightbearing. The mean limb length difference between the pre- and postoperative values was 0.5 ± 0.2 cm. All 4 patients were very satisfied at 12 months. The mean AOFAS ankle-hindfoot score was 87 ± 3.1.

Discussion

Usually when the talus is resected in totality, a substantial void is noted along with loose tibial and calcaneal end parts. Keeping the small-volume residual talus could add internal stability to the construct by means of ligament attachment and could act as an autologous graft. To add, limb shortening was found to be minimal when the talus was preserved.

Furthermore, we believe that preparing the medial tibiotalar joint for fusion would not add stability to the fused ankle joint. Preserving the medial malleolar cartilage thickness might on the contrary support the stability of the construct, even when signs of degeneration are present. Additionally, this part of the joint constitutes a small region compared to the whole area of the ankle joint, and filling it with bone graft could be difficult to achieve even with an additional direct approach.

We did not encounter signs of substantial bone fusion before 3 months. Therefore, we do not advocate an earlier partial weightbearing following the arthrodesis before this period. It is of importance to note that radiologic signs of bone healing could be difficult to observe, especially cases with coalescence and consolidation phases.

We are aware of 2 studies reporting fusion outcomes in cases of severe talar loss. Moonot et al ⁶ reported the use of different surgical approaches, an external fixator prior to IM nailing in 2 of their 7 patients, and a total excision of the talus replaced with morselized fibula or tricortical autograft from the iliac crest. These authors reported radiologic bone healing in all patients with a mean postoperative AOFAS score 73.4 ± 3.36, vs 87 ± 3.1 in our series. The study by Aikawa et al ¹ reported radiologic bone union in 3 cases following talar excision and tibiotalar fusion with a humeral plate. Although these authors did not record pain, AOFAS scores, and postoperative limb length difference, their patients could walk without braces or walking aids.

We acknowledge that a small case series with no comparison arm could not infer evidence-based guidelines from any studied condition. We further acknowledge that pain is not a reliable outcome variable in this population. Nevertheless, this early report could constitute the basis for larger studies comparing this method with the standard surgical management of ankle/hindfoot Charcot associated with severe loss of the talar body. Computed tomographic scan could be more accurate in showing signs of bone union, but it is not used routinely and can be challenging to interpret given the issue of metal artifact obscuring fine local bony detail.

Conclusion

When performing TTC arthrodesis for diabetic Charcot, preserving the talus even when the body is severely damaged could add to construct stability and preservation of limb length. In our small initial case series, we found high rates of bone fusion by 6 months while avoiding further limb shortening. Including the medial malleolus in the fusion surgery might not be necessary for the arthrodesis healing outcome.

Supplemental Material

sj-pdf-1-fao-10.1177_24730114251315672 – Supplemental material for Retaining Severely Damaged Talar Body and Medial Malleolar Cartilage for Diabetic Ankle/Hindfoot Charcot Arthrodesis Using Intramedullary Nail: A Short Report

Supplemental material, sj-pdf-1-fao-10.1177_24730114251315672 for Retaining Severely Damaged Talar Body and Medial Malleolar Cartilage for Diabetic Ankle/Hindfoot Charcot Arthrodesis Using Intramedullary Nail: A Short Report by Kaissar Yammine, Camille Samaha and Chahine Assi in Foot & Ankle Orthopaedics