Primary arthroscopy outcomes better overall, but revision patients also see improvement
At 2-year follow-up, patients who undergo revision hip arthroscopy may be twice as likely to have undergone either total hip arthroplasty (THA) or hip resurfacing (HR) than those who undergo a primary hip arthroscopy procedure. In addition, patients undergoing primary arthroscopy tend to see improved outcomes compared to those undergoing revision. Parth Lodhia, MD, FRCSC, presented these findings at the annual meeting of the Arthroscopy Association of North America.
Dr. Lodhia and his colleagues had two purposes for conducting this study: to analyze survival in a mixed cohort of patients undergoing hip arthroscopy with minimum 2-year follow-up, and to compare clinical outcomes of primary and revision hip arthroscopy.
"We hypothesized that, compared to revision patients, primary hip arthroscopy patients would have fewer conversions to THA or HR, and would have significantly better patient-reported outcome scores," he said.
Hip arthroscopy on the rise
There has been increasing use of hip arthroscopy in recent years, with prospective studies demonstrating good rates of satisfaction and patient-reported outcomes, and complication rates ranging from 0.58 percent to 7.5 percent, according to Dr. Lodhia. The rates and outcomes of revision arthroscopy are less well understood.
The research team reviewed data on all hip arthroscopies performed by a single surgeon, Benjamin G. Domb, MD, of the American Hip Institute and Hinsdale Orthopaedics in Chicago, between February 2008 and June 2012 in patients who had not been previously treated for hip conditions. In all, they analyzed the outcomes of 872 patients (1,038 procedures), of which 824 patients (931 procedures) underwent primary hip arthroscopy and 97 patients (107 procedures) underwent revision hip arthroscopy; 49 patients underwent both procedures.
"Our end points were revision hip arthroscopy, THA, or HR," explained Dr. Lodhia. "We used four different patient-reported outcome scores—the modified Harris Hip Score (mHHS), the Nonarthritic Hip Score, the visual analogue scale, and two subscales of the Hip Outcome Score—activities of daily living and the sports-specific subscale. We collected data preoperatively, and at 3 months, 1 year, and 2 years postoperatively."
Dr. Lodhia noted several statistically significant differences between the primary and revision cohorts.
" The primary hip arthroscopy group was older, and the average BMI [body mass index] was just slightly higher than the revision patients. In addition, patients in the revision group tended to have more acute symptoms. Finally, the conversion to THA was 5.59 percent in the primary group and 11.21 percent in the revision group."
At 2-year follow-up, the researchers found that all outcomes had improved significantly in both primary and revision cohorts; however, they noted significantly better outcomes at all time points for primary patients compared to revision patients. Similarly, in comparing the mean change in outcome scores, they identified a significantly higher incremental increase in improvement at all time points for primary compared to revision patients.
"Finally, we looked at the cumulative risk of either a revision arthroscopy or THA/HR following primary hip arthroscopy," said Dr. Lodhia. "At 24 months, we found the rate of conversion to THA/HR was approximately 2.8 percent, while the rate of revision hip arthroscopy was just over 6 percent."
This is the largest study with a minimum 2-year follow-up reported to date, noted Dr. Lodhia. He cited the use of multiple patient-reported outcome scores as one of the study's strengths, but also identified several limitations.
"We lacked a control group of patients that did not undergo surgery," he said. "We had a short-term follow-up of 2 years, and a heterogeneous population. In addition, we looked at all different hip pathologies that would be treated with hip arthroscopy."
According to Dr. Lodhia, a previous study by Palmer et al and another by Philippon et al report conversion rates of primary hip arthroscopy ranging from 6 percent to 8.2 percent, respectively. In addition, in 2014 Aprato et al reported significant increases in mHHS scores at 2-year follow-up for patients undergoing revision hip arthroscopy, although much of the improvement disappeared at 3 years. Aprato also reported an 8 percent conversion rate to THA and 8 percent to re-revision.
"We find that 2 years after primary arthroscopy, the cumulative risk of THA and revision arthroscopy are 2.6 and 5.8 percent respectively," Dr. Lodhia said. "The relative risk of THA was double after revision arthroscopy compared to primary. And there was a significant improvement in all patient-reported outcome scores at 2 years for primary and for revision arthroscopies. Finally, primary arthroscopy patients displayed improved patient-reported outcome scores compared to revision patients."
Dr. Lodhia's coauthors on "Clinical Outcomes of Hip Arthroscopy: A Prospective Survival Analysis of Primary and Revision Surgeries in a Large Mixed Cohort" are Chengcheng Gui, BSE; Mark R. Hutchinson, MD; Shane J. Nho, MD; Michael S. Terry, MD; and Dr. Domb.
Peter Pollack is the electronic content specialist for AAOS Now. He can be reached at firstname.lastname@example.org
- At 2-year follow-up after primary arthroscopy, cumulative risk of THA/HR or revision arthroscopy was 2.6 percent and 5.8, respectively.
- The relative risk of THA/HR was doubled following revision arthroscopy compared to primary arthroscopy.
- Both cohorts saw significant improvement in all patient-reported outcome scores at 2 years.
- Primary arthroscopy patients displayed improved patient-reported outcome scores compared to revision patients.
- Palmer DH, Ganesh V, Comfort T, Tatman P: Midterm outcomes in patients with cam femoroacetabular impingement treated arthroscopically. Arthroscopy 2012;28(11):1671–1681. doi: 10.1016/j.arthro.2012.04.154.
- Philippon MJ, Briggs KK, Yen YM, Kuppersmith DA: Outcomes following hip arthroscopy for femoroacetabular impingement with associated chondrolabral dysfunction: Minimum two-year follow-up. J Bone Joint Surg Br 2009 Jan;91(1):16–23. doi: 10.1302/0301-620X.91B1.21329.
- Aprato A, Jayasekera N, Villar RN: Revision hip arthroscopic surgery: Outcome at three years. Knee Surg Sports Traumatol Arthrosc 2014;22(4):932–937. doi: 10.1007/s00167-013-2373-7.