Problem to be addressed
In the fiscal years 2017–2018, 58,492 hip replacements were performed in Canada, which reflects a 17.4% increase over the preceding 5 years [
1]. More than $1 billion is currently spent annually performing joint replacement surgeries as a result of secondary osteoarthritis (OA) [
1]. The prevalence of hip dysplasia in the general population ranges from 4.0 to 12.8% [
2,
3]. Research shows that patients with hip dysplasia are 5 times more likely to develop OA than patients with normal hip morphology, eventually requiring a hip replacement [
4]. More broadly, hip dysplasia has a long history of association with OA [
5] and is considered the leading precursor to OA across North America [
6‐
8] and Europe [
9,
10]. Wylie and Peters have established a clear relationship between the severity of deformity (as per radiological findings) and risk for OA development [
5]. The more shallow acetabulum results in a smaller surface area of cartilage for weight bearing and leads to overload of the acetabular rim and labrum [
11]. This leads to progressive damage of the cartilage in the hip joint and eventually causes arthritic changes [
6], as demonstrated by Kim et al.’s correlation between lack of proteoglycan content and severity of arthritic symptoms [
12]. Prior to the development of advanced OA, patients often have a prolonged phase of painful hip symptoms that interfere with activity and quality of life [
13,
14]. These symptoms usually affect younger adult patients, who will require a hip replacement surgery if not treated for their dysplasia [
13]. Fortunately, hip dysplasia can be diagnosed before more severe damage occurs and treated through hip preservation surgery (including periacetabular osteotomy) [
6].
The Bernese periacetabular osteotomy (PAO) reorients the more shallow and vertically oriented acetabulum and has been used successfully for over 30 years as the standard of care for hip dysplasia [
15]. Garbuz et al. showed that hip dysplasia significantly affects quality of life and that surgical correction with PAO leads to a significant improvement [
14]. In addition, PAO has been shown to limit radiographic changes in 88% and 75% of hips at 10- and 20-year follow-ups respectively [
16,
17]. The optimization of joint surface area in the weight-bearing region of the hip and improvements in the mechanical advantage of the abductor musculature are thought to provide most of the symptomatic improvement post-operatively. PAO outcomes have shown good symptomatic improvements, low complication rates, and an 18-year hip joint survival of 74% [
18], whereas patients with untreated hip dysplasia have shown a 20-year hip joint survival of 33% [
4]. More recently, Wyles et al. showed that for patients undergoing a PAO for symptomatic dysplasia, the rate and pattern of progression approximated those for patients with normal morphology from the historical cohort as well as significantly improved when compared with patients with unmanaged DDH. Similarly, in patients with Tönnis grade 1, the probability of progression to total hip arthroplasty at 5 and 10 years was 2% and 11%, respectively, compared with 23% and 53%.
A PAO is not only recommended to
delay or prevent the need for joint replacement surgery later on in life [
10,
19], but
positively impact the quality of life in patients with hip dysplasia. By doing a PAO, we can offset the need for a future hip replacement, which also saves money, as a PAO has been demonstrated as a more cost-effective procedure than a total hip replacement [
20].
Despite the breadth and depth of evidence highlighting the benefits following a PAO, 60–85% of patients have concomitant intraarticular pathology (cartilage damage) that cannot be corrected with a PAO [
21,
22] and 11% continue to exhibit symptoms post-surgery [
23]. Patients with hip dysplasia commonly have concomitant labral tears [
24‐
26], which has been suggested to be responsible for residual symptoms after PAO [
27]. Although MRIs have been routinely used to identify intraarticular pathology, they have been shown to be unreliable to appropriately detect them and quantify their severity [
28]. A hip arthroscopy, performed using a small camera, allows surgeons to address the intraarticular pathology inside the hip joint. As a result, some have advocated combining arthroscopic labral re-fixation/debridement and PAO [
29‐
31]. Between 2006 and 2010, there has been a 600% increase in hip arthroscopies in the USA [
32], with similar trends in Canada, demonstrating its high uptake since the mid-2000s. Although hip arthroscopy allows the surgeon to potentially address other intraarticular pathologies (i.e., ligamentum teres, chondral injuries), the effect of arthroscopic management of these injuries concomitantly with PAO is unknown. Furthermore, it is unknown whether cartilage damage can be mitigated with the addition of an arthroscopic procedure [
33]. Due to additional operative time, equipment, and human resources, costs are substantially increased by adding an arthroscopy to a PAO [
34,
35]. In Ontario, the addition of hip arthroscopy to the PAO represents a 125% increase in cost just in the OR [
36]. While the cost-effectiveness of a PAO has been established in the US healthcare (cost-effectiveness of $7856 per quality-adjusted life year and an average incremental effectiveness of 0.15) [
20], a true cost-utility benefit must be demonstrated if arthroscopic management of labral and other intraarticular pathologies can be justified in these patients.