Bilateral Synchronous THA Can Successfully Treat Bony Ankylosis

New data suggests that bilateral synchronous total arthroplasty for bony ankylosis can be effective in patients with ankylosing spondylitis.

Total hip arthroplasty (THA) for bony ankyloses is a technically challenging procedure in patients with ankylosing spondylitis, but mid-term results in a new study offer good news, researchers say.

Ankylosing spondylitis is a chronic progressive autoimmune disease involving medial axis joints. It involves the sacroiliac joint, spinal process and soft tissues behind the spine and can cause spinal deformity and hip ankylosis.

“Hip joint ankylosis could influence the extent of surgical exposure. Contracture of muscle tissue and heterotopic ossification results in further trauma and difficulties during surgery, thereby limiting the choice of surgical approach,” they wrote.

In “Mid-term results of bilateral synchronous total hip arthroplasty for bony ankyloses in patients with ankylosing spondylitis,” published on February 2, 2021 in the Journal of Orthopaedic Surgery & Research, the researchers reported minimum complications in the 19 patients included in the study.

Seventeen of the patients were male and two were female. The mean age of the patients was 49.2 years.

All patients received cementless THA. Intraoperative blood loss, Visual Analog Scale (VAS) score, Harris Hip Scores, and complications were all recorded. The researchers followed the patients for 62 to 98 months.

Overall, VAS score decreased from 7.42 ±0.92 to 2.42 ± 0.83, Harris Hip Score improved from 21.8 ±7.2 to 80.3 ±6.5, and the flexion-extension range of the hip improved from 0 to 142.3 ±6.2˚.

There were no joint dislocation, acute infection or deep vein thrombosis reported. One patient with septum bronchiale experienced an intraoperative fracture that was treated with wire strapping. And one patient had a traction injury of the femoral nerve postoperatively but recovered a year after a surgery. Heterotopic bone formation occurred in three patients.

“Bilateral synchronous THA was effective for bony ankyloses of the hip in patients with ankylosing spondylitis because it improved patients’ quality of life and had satisfactory mid-term outcomes,” the researchers wrote.