Percutaneous, intra-articular Chevron osteotomy (PICO) for the treatment of hallux valgus. A Cadaveric Study

Abstract

Category: Bunion Introduction/Purpose: Percutaneous or minimally invasive surgery (MIS) forefoot surgery has experienced a vertiginous and sustained growth especially in the last decade. This is supported by numerous studies among which can be mentioned: clinical series, comparative studies, technique reports, radiological validations. Two cadaveric studies considered percutaneous forefoot surgery safe and has reported minimal risk which is consistent with clinical studies. We can consider that MIS forefoot surgery is transiting a sustained and responsible experience based on Third generation (TG) techniques (Open Chevron like). The purpose of this cadaveric study was to investigate the risk of iatrogenic neurovascular and tendon injury in a TG technique. Particularly, this study evaluated the Percutaneous, Intraarticular, Chevron Osteotomy (PICO) for the correction of hallux valgus. Methods: Eight unpaired feet, from Caucasian fresh frozen voluntary donor specimens were carefully dissected. One surgeon (JJDV) performed all of the procedures. In each foot, the surgeon performed a PICO and a lateral release of the first metatarsophalangeal joint (MTPJ). To evaluate the safety of the procedure the following data was obtained: 1. Distance between (DB) PICO portal (PP) and lateral border of the extensor hallucis longus (EHLT); 2. DB PP and dorsomedial digital nerve (DMDN); 3. DB PP and MTPJ; 4. DB Osteosynthesis portal (OP) and MTPJ; 5. DB OP and lateral border of EHLT; 6. DB OP and DMDN. This anatomical study also assessed if any arterial plexus damage was present via an indirect method by examination of the capsule and soft tissue around the first metatarsal. In addition, the following measurements were taken: angulation of osteotomy in the sagittal plane (Reproducibility) and IMA and HV angles (Correction power). Results: Two independent observers made all the assessments. The results of the safety measurements were as follow: 1. Average: 17,64 (range: 12,72-21,31); 2. Average: 7,29 (range:1,62-10,41); 3. Average: 15,72 (range: 9,48-20,52); 4. Average: 25,55 (range: 22,06-30,44); 5. Average: 12,77 (range: 8,04-16,71); 6. Average: 4,14 (range:1,72-8,20). There were no iatrogenic injuries. Nevertheless, the DB OP and DMDN showed the lowest average distance. With respect of the osteotomy angulation in the sagittal plane (Reproducibility), the average was: 85,62º (range: 78-100). Mean preoperative intermetatarsal angle (IMA) was 9,75° (range: 8-18°), and postoperatively the mean IMA was 8° (range: 4-13°). Before surgery the mean hallux valgus angle (HVA) was 22° (range: 13-40°) and the average postoperative HVA was 13,5° (range: 6-34°). Conclusion: The “Third generation” (TG) techniques reliably mimics the open Chevron procedure with all its known virtues whilst does not reproduce its disadvantages and complications. Also, according to several studies, these surgeries are useful, effective and (maybe) easier than open procedures. The proposed surgery (PICO) has shown to be safe, reproducible and have effective correction power when performed by a single surgeon (Trained in MIS surgery). We emphasize that percutaneous surgery has an extensive learning curve and therefore it may be difficult to reproduce the results initially.