Clinical efficacy of the Ankle Spacer for the treatment of multiple secondary osteochondral lesions of the talus

Abstract

Background: The Ankle Spacer was developed as a joint-sparing alternative to invasive end-stage surgeries. Currently, there are no clinical studies on the Ankle Spacer.

Aim: To describe the operative technique and the clinical efficacy of the Ankle Spacer for the treatment of multiple, cystic osteochondral lesions of the talus in patients with failed prior operative treatment.

Methods: This is a prospective study during which patients were assessed preoperatively, at 2- and 6 wk, and at 3, 6, 12 and 24 mo postoperatively. Patients with multiple, cystic or large (≥ 15 mm) osteochondral lesions of the talus after failed prior surgery were included. The primary outcome measure was the numeric rating scale (NRS) for pain during walking at 2 years postoperatively. Secondary outcome measures included the NRS in rest and during stair climbing, the American Orthopaedic Foot and Ankle Society Hindfoot Score, the Foot and Ankle Outcome Score, the Short- Form 36 physical and mental component scale, and the Range of Motion (ROM). Radiographic evaluations were conducted to evaluate prosthetic loosening and subsidence. Revision rates and complications were also assessed.

Results: Two patients underwent an Ankle Spacer implantation on the talus. The NRS during walking improved from 6 and 7 preoperatively to 2 and 2 points postoperatively at 2 years, in patient 1 and 2, respectively. The other patient-reported outcome measures also improved substantially. There were no re-operations nor complications. Radiological imaging showed no loosening of the implant and no change of implant position.

Conclusion: The Ankle Spacer showed clinically relevant pain reduction during walking, improvement in clinical outcomes as assessed with PROMs, and no complications or re-operations. This treatment option may evolve as a joint-sparing alternative to invasive end-stage surgeries.

Keywords: Ankle Spacer; End-stage; Hemi-arthroplasty; Osteochondral lesions of the talus; Talar surface implant.

Figure 1

Flow-chart of the study design and main procedures participants will undergo during this study. CA: Complication assessment; CT: Computed tomography; PE: Physical examination; Q: Questionnaires; ROM: Range of motion; X: Mortise and lateral radiographs.

Figure 2

The Ankle Spacer Implant.

Figure 3

Preparation of cartilage and bone prior to insertion. A: Removal of the talar cartilage; B: Removal of the subchondral bone; C: Bone marrow stimulation of the subchondral bone.

Figure 4

After the insertion of the Ankle Spacer. A: End-result after the insertion of the Ankle Spacer; B: End-result after the insertion of the Ankle Spacer.

Figure 5

Pre-operative computed tomography scan of patient number 1: Upper part shows coronal slides with the images from left to right going into the posterior to anterior direction. The lower part shows sagittal slides with the images from left to right going from lateral to medial.

Figure 6

Pre-operative computed tomography scan of patient number 2: Upper part shows coronal slides with the images from left to right going into the posterior to anterior direction. The lower part shows sagittal slides with the images from left to right going from lateral to medial.

Figure 7

Pre-and postoperative Numeric Rating Scale scores of pain and satisfaction for patients 1 and 2.

Figure 8

Preoperative and postoperative radiographs. A and C: Preoperative mortise radiographs; B and D: Preoperative lateral radiograph; E and G: Postoperative mortise radiograph (2-years); F and H: Postoperative radiograph.