Nontraumatic avascular necrosis of the femoral head : Arthroscopic and navigation-supported core decompression.

Objective: The aim is to address core decompression and pathologies of the femoral head, treating them during the same procedure. Furthermore, radiation exposure will be reduced.

Indications: Femoral head necrosis ARCO (Association Research Circulation Osseous) stages I-III.

Contraindications: Progressive femoral head necrosis as ARCO stages IIIC-IV.

Surgical Technique: Arthroscopically navigated core decompression of the femoral head using an established optoelectronic system with fluoro-free software module. First, hip joint arthroscopy was performed and further pathologies were treated. Second, core decompression was navigated by a navigation pointer and drill sleeve to reach the correct target point. After visualization, the procedure is repeated 3-5 times.

Postoperative Management: Limited weight bearing of the operated leg (20 kg) for 10-14 days. Active or passive continuous motion machine for 4 weeks. Adjuvant postoperative indomethacin therapy for 10 days to reduce pain and bone marrow edema.

Results: From May 2018 to January 2019, 7 patients (male = 4; 40 ± 9 years) underwent arthroscopically navigated core decompression with 2 (29%) and 5 (71%) patients being classified as ARCO II and III, respectively. Preoperatively, all patients reported load-dependent pain. In all cases, we could identify synovitis, which results in soft tissue release and synovectomy. Furthermore, 4 of 7 patients had an additional labrum lesion, which is addressed by refixation or shrinking.

Discussion: Compared to the conventional technique, this fluoro-free navigation procedure allows more precise drilling. Moreover, additional pathologies, as found in all our cases, could be simultaneously addressed. The intraoperative radiation exposure for the patient and surgical team could also be reduced. Although arthroscopically assisted core decompression requires more preparation time, there are advantages over conventional surgery.