For young adults with borderline hip dysplasia (BHD), primary arthroscopy provides positive long-term outcomes, improving symptoms and function while avoiding the need for hip replacement surgery in most cases, according to a case series from Benjamin G. Domb, MD, and colleagues at the American Hip Institute in Chicago.
Their study was published online by The Journal of Bone & Joint Surgery.
Temporary or Definitive?
The best treatment for BHD is controversial. Periacetabular osteotomy is the standard treatment to reconstruct and reposition the hip joint. Arthroscopy has emerged as a less-invasive alternative procedure, with studies showing improvement in symptoms and hip function at short- to medium-term follow-up.
However, because of a lack of long-term follow-up data, it has been unclear whether arthroscopy is a “temporary or definitive solution,” according to the study authors.
To address this question, Dr. Domb and colleagues report their experience with primary arthroscopic surgery for BHD. Typical of patients requiring BHD treatment, the patients in their cohort were young (mean age of 31 years) and predominantly female (38 of 45 patients). All patients met standard radiographic criteria for BHD diagnosis: lateral center-edge angle between 18° and 25°.
Arthroscopic surgery included plication of the joint capsule and preservation of the cartilage lining the labrum. All patients had 10-year follow-up data to assess the need for conversion to total hip arthroplasty (THA), as well as patient-reported ratings of symptoms and hip function.
Who Might Need THA Conversion?
Eight of the 35 patients underwent THA during follow-up, performed at an average of 5.5 years after arthroscopy. On Kaplan-Meier analysis, estimated “survivorship” was 82.8% – roughly 4 out of 5 patients with BHD could expect to remain free of THA for at least 10 years after primary arthroscopy. This rate compared favorably with a matched control group of patients without BHD.
Patients who required THA were older and heavier than those who did not. After adjustment for other factors, the likelihood of THA was 4.4 times higher for patients with a body mass index of 23 kg/m2 or greater, and 7.1 times higher for those 42 years or older.
Primary arthroscopy for BHD was associated with significant improvement on standard patient-reported outcome measurements, including pain and hip function. For example, about 75% of patients met the minimum clinically important difference for improvement in pain score.
Adding to the Literature
Building on previous short- to medium-term studies, this study adds new evidence showing good long-term outcomes following primary arthroscopy for BHD. In addition to a low rate of conversion to THA over 10-year follow-up, less-invasive treatment with arthroscopy also avoids the longer recovery time required by standard surgery for BHD.
The authors point out some limitations of their case series: It was carried out at a highly specialized hip center, in a relatively small number of patients, with no comparison to standard surgery.
Dr. Domb and colleagues concluded that “BHD remains a challenging condition to treat successfully arthroscopically, and adequate capsular plication remains a highly technique-dependent procedure.”
Domb BG, Owens JS, Glein RM, Jimenez AE, Maldonado DR. Borderline dysplasia after primary hip arthroscopy with capsular plication and labral preservation: ten-year survivorship and patient-reported outcomes. J Bone Joint Surg Am. 2023 May 3;105(9):687-699. doi: 10.2106/JBJS.22.00340. Epub 2023 May 3.