CORR Insights®: What Mid-term Patient-reported Outcome Measure Scores, Reoperations, and Complications Are Associated with Concurrent Hip Arthroscopy and Periacetabular Osteotomy to Treat Dysplasia with Associated Intraarticular Abnormalities?

Where Are We Now?

Acetabular dysplasia is well recognized as the most common cause of secondary osteoarthritis of the hip, with insufficient osseous coverage leading to the increased mechanical load on the acetabular rim, hip pain, and functional limitations. Periacetabular osteotomy (PAO), regardless of surgical approach, is an effective treatment for symptomatic acetabular dysplasia that redirects the acetabulum to improve the acetabular coverage and restore hip stability [2, 6]. Studies of PAO [1, 2, 4] have shown improvement in pain and functional outcomes, with survival of the affected hip continuing for several decades after surgery.

Intraarticular pathology is quite common in patients with symptomatic acetabular dysplasia, and the prevalence of cartilage degeneration and labral tear ranged from 60% to 92% and from 64% to 97%, respectively, in patients undergoing PAO [5, 7, 8]. These lesions contribute to mechanical symptoms and the progression of osteoarthritis. Due to the high prevalence of intraarticular lesions in hip dysplasia and postoperative femoroacetabular impingement (FAI), which can result in persistent pain and functional limitations following PAO, hip arthroscopy is increasingly used as an adjunctive procedure at the time of PAO. Hip arthroscopy allows for the identification of hips with severe arthritis, which are not good candidates for preservation surgery; it also enables the management of cartilage-, labral-, and FAI-related pathology [7-9]. However, at present, there are limited reports on PAO plus hip arthroscopy. Several studies comparing PAO alone and PAO plus arthroscopy (scope/PAO) showed comparable clinical results, although a few studies showed better patient-reported outcomes with use of the arthroscope at the time of PAO [10, 12]. However, these studies generally were limited to short-term follow-up and did not include patient-reported outcomes. Therefore, whether intraarticular procedures should be performed during PAO on all patients remains controversial.

In the current study, Edelstein and colleagues [3] retrospectively analyzed the mean 6.5-year follow-up of selected patients who underwent scope/PAO to treat symptomatic acetabular dysplasia with associated intraarticular damage. At this follow-up interval, 76% of the hips were functioning well, 21% had persistent symptoms, and 3% had progressed to conversion to hip arthroplasty. Worse baseline modified Harris hip scores and WOMAC pain scores were associated with subsequent THA or persistently symptomatic hips. Seven percent (5 of 67) of patients underwent repeat hip preservation surgery for recurrent symptoms, and 4% (3 of 67) of patients had major complications. The authors concluded that arthroscopy plus PAO to treat symptomatic acetabular dysplasia delivered improved hip-related and other outcomes scores, although persistent hip symptoms and early conversion to total hip arthroplasty affected the lives of nearly a quarter of their patients. Based on these findings, I think surgeons should take concomitant arthroscopy for patients with possible intra-articular pathology into consideration.

Where Do We Need To Go?

Despite long-term follow-up studies [1, 2], limited information is currently available on how the status of intraarticular lesions changes after PAO. Moreover, it is unclear whether correction of the underlying structural abnormality with osteotomy can alter the natural course of the progression of the intraarticular lesions. Knowing more about how intraarticular lesions may change over time after PAO and how such lesions might be associated with the risk of further hip degeneration would help us to refine our indications for PAO (with or without arthroscopic augmentation).

It is important to note that there are patients who undergo additional surgery for associated labral pathology, although PAO alone generally results in good clinical outcomes. One study [9] found that 8.3% of patients underwent subsequent hip arthroscopy within 3 years of PAO. Another reported that 26 hips (27%) underwent arthroscopy, including labral repair on 20 hips, within 2 years of PAO [7]. Those authors found that preoperative borderline dysplasia, acetabular retroversion, and complete labral detachment were associated with later arthroscopy [7]. In this subgroup of patients, surgeons should be mindful to not overcorrect in the sagittal plane because the excessive anterior coverage can lead to iatrogenic FAI after PAO. Additionally, in patients with cam-type deformity, even the appropriate amount and direction of acetabular correction can cause cam-type FAI after PAO. In this situation, intraarticular procedures such as labral repair and femoral head-neck offset restoration would be warranted. However, we still lack data regarding the role of labral treatment during PAO, and we need further studies to define the indications for intraarticular procedures (and arthroscopy) during PAO.

Additionally, we need to develop tools that help us to understand how patients are really doing after these interventions. While reoperation and conversion to THA are concrete, they also are insensitive to change, and they take years to discern; in addition, some patients may prefer to live with pain than undergo a reoperation. Since the addition of arthroscopy probably does not greatly add to the morbidity of a PAO, but it does increase that morbidity somewhat (as well as increasing cost and surgical time), it would be worthwhile to develop more-sensitive tools that can help us decide whether the addition of arthroscopy is worth the patient’s while.

How Do We Get There?

Edelstein and colleagues [3] noted that further study in the form of a randomized controlled trial is currently underway. Such a study, I hope, will clarify when the addition of arthroscopy to PAO is best indicated. Even if such data are difficult to obtain in a practical way, a large, retrospective analysis, or meta-analysis, would be valuable and maybe necessary to identify which patients benefit from the additional procedure. Large, multicenter registries like the Academic Network of Conservational Hip Outcomes Research (known as ANCHOR) could potentially address these clinical challenges.

Going forward, future clinical research should focus on those patients who have an unexpectedly poor prognosis because of intra-articular pathology discovered at the time of PAO performed without arthroscopy. Even with a well-preserved joint space on the plain radiograph, intraarticular lesions ranging from localized labral tears to severe chondral or labral degeneration can be present in patients with acetabular dysplasia [4, 5]. Currently available MRI images can show the presence of lesions, but they often do not show the extent of these lesions. Thus, it is difficult to weigh the risk-benefit equation of adding arthroscopy at the time the surgical decision is made. I believe that in the very near future, high-resolution imaging technology, which is rapidly being developed [11], will be helpful to select which patients should have hip arthroscopy at the time of PAO.