Long-term outcomes of the mayo conservative hip system in patients aged 30 years or less with osteonecrosis of the femoral head: mean follow-up of more than 10 years

Masanori Nishi; Takashi Atsumi; Yasushi Yoshikawa; Ryosuke Nakanishi; Minoru Watanabe; Yoshifumi Kudo

doi:10.1007/s00402-024-05339-w

Long-term outcomes of the mayo conservative hip system in patients aged 30 years or less with osteonecrosis of the femoral head: mean follow-up of more than 10 years

Arch Orthop Trauma Surg. 2024 May 6. doi: 10.1007/s00402-024-05339-w. Online ahead of print.

Authors

Masanori Nishi^{1

2}, Takashi Atsumi^{3

4}, Yasushi Yoshikawa³, Ryosuke Nakanishi^{4

5}, Minoru Watanabe⁵, Yoshifumi Kudo³

Affiliations

¹ Department of Orthopaedic Surgery, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8666, Japan. m.nishi83@gmail.com.
² Department of Orthopaedic Surgery, Sassa General Hospital, 4-24-15 Tanashicyo, Nishitokyo-shi, Tokyo, 188-0011, Japan. m.nishi83@gmail.com.
³ Department of Orthopaedic Surgery, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8666, Japan.
⁴ Department of Orthopaedic Surgery, Sassa General Hospital, 4-24-15 Tanashicyo, Nishitokyo-shi, Tokyo, 188-0011, Japan.
⁵ Department of Orthopaedic Surgery, Showa University Fujigaoka Hospital, 1-30 Fujigaoka Aoba-ku, Yokohama City, Kanagawa, 227-8501, Japan.

PMID: 38709289
DOI: 10.1007/s00402-024-05339-w

Abstract

Introduction: Historically, total hip arthroplasty (THA) in very young patients has been associated with lower survivorship. However, the long-term outcomes of THA using short stems for osteonecrosis of the femoral head (ONFH) in very young patients remain unclear. Therefore, this study aimed to investigate the long-term outcomes of the Mayo conservative hip system, a short metaphyseal stabilised stem, in patients with ONFH aged ≦30 years.

Materials and methods: We retrospectively reviewed 104 joints in 76 patients with ONFH who underwent THA using the Mayo conservative hip system with a minimum follow-up of 8 years. The mean follow-up period was 12.5 (range, 8-19) years. Patients were categorised into two age groups (≦30 years, n = 21 and > 30 years, n = 83). Radiographic evaluation was used to assess stem sinking, stress shielding, and spot welds. The clinical evaluations were performed using the Japanese Orthopedic Association (JOA) hip score. Postoperative major complication and revision surgery rates were also assessed.

Results: The patient characteristics were similar between the two groups, except for the age. Revision surgeries were performed in five cases, with similar implant survival rates between the groups. Dislocations occurred in the older age group alone (four joints). One case of intra-operative periprosthetic femoral fracture was found in the younger age group. Stem sinking of > 3 mm occurred in one and seven joints in the younger and older age groups, respectively. Spot welds were observed in most joints (93.2%) in modified Gruen zones 2 and 6 without significant differences between the groups. Stress shielding showed no significant differences in the frequency of occurrence or location between the two groups. Furthermore,the JOA score showed no significant difference between the two groups.

Conclusion: The use of short stems in patients aged ≤ 30 years with ONFH showed favourable long-term outcomes.

Keywords: Long-term outcomes; Osteonecrosis of the femoral head; Short stem; Total hip arthroplasty; Young patients.