Durable Mid-Term Outcomes and High Rates of Meaningful Improvement After Hip Arthroscopy With Concomitant Periacetabular Osteotomy

Purpose

To evaluate 5-year outcomes following combined hip arthroscopy and periacetabular osteotomy (PAO) for the treatment of acetabular dysplasia and intra-articular pathology, with a focus on the rates of achieving clinically meaningful outcome thresholds.

Methods

Minimum 5-year outcome data from a prospectively maintained database were queried to identify patients who underwent concomitant primary hip arthroscopy and PAO between October 2010 and July 2019. Patient-reported outcomes evaluated included the modified Harris Hip Score (mHHS), non-arthritic hip score (NAHS), hip outcome score sport-specific subscale (HOS-SSS), and international hip outcome tool 12 (iHOT12). Clinically meaningful thresholds were also assessed, including minimal clinically important difference (MCID), patient-acceptable symptom state (PASS), and substantial clinical benefit (SCB).

Results

A total of 32 hips were included in this study. All PROs demonstrated significant improvement from the preoperative baseline to the 5-year follow-up ( P <.001). Clinical outcomes remained durable, with no significant decline observed between 2-year and 5-year follow-ups (mHHS P = 0.612; NAHS P = 0.701; iHOT-12 P = 0.284; HOS-SSS P = 0.158). Similarly, achievement rates for MCID, PASS, and SCB thresholds were sustained over time ( P = 0.105 to >0.999). Two hips (5.7%) converted to total hip arthroplasty (THA).

Conclusions

Concomitant hip arthroscopy and PAO are an effective procedure with durable 5-year outcomes. Patients demonstrated sustained improvements and a high rate of clinically meaningful success, supporting the value of this combined approach in appropriately selected cases.

Level of Evidence

Level IV: Retrospective therapeutic case series

Hip dysplasia is a common hip pathology that is associated with activity-limiting hip pain, as well as premature osteoarthritis. The periacetabular osteotomy (PAO) , has become a widely embraced surgical procedure for addressing symptomatic hip dysplasia. This technique primarily targets the underlying bony abnormalities with the goal of restoring normal hip anatomy, as well as delaying or preventing the onset of arthritis. This technique has demonstrated favorable long-term outcomes in delaying osteoarthritis with survivorship greater than 80% at 10 years, 60% at 20 years and 29% at 30 years. ,,,,,,,

Given the high prevalence of labral tears, cartilage lesions, and soft-tissue disorders in dysplastic hips, our institution began performing concomitant hip arthroscopy and PAO in 2014, consistent with a broader trend toward addressing intra-articular pathology during PAO. Since then, there has been a trend toward simultaneous or staged hip arthroscopy to address intra-articular pathology that is not treated with PAO. ,,,,,,,,, Preliminary investigations have yielded promising short-term results with concomitant hip arthroscopy, demonstrating similar outcomes and no increased complication rates when compared to isolated PAO. , To date, few studies have reported mid-term, follow-up outcomes of combined hip arthroscopy and PAO, particularly with regard to clinically relevant outcomes, such as minimal clinically important difference (MCID), patient-acceptable symptom state (PASS), and substantial clinical benefit (SCB). ,,

The purpose of this study is to evaluate 5-year outcomes following combined hip arthroscopy and periacetabular osteotomy (PAO) for the treatment of acetabular dysplasia and intra-articular pathology, with a focus on the rates of achieving clinically meaningful outcome thresholds. We hypothesized that there would be significant improvements in functional status at short-term follow-up, and that these would prove to be durable at mid-term follow-up.

Methods

This study was performed in accordance with the ethical standards in the 1964 Declaration of Helsinki. This study was carried out in accordance with relevant regulations of the U.S. Health Insurance Portability and Accountability Act (HIPAA). Details that might disclose the identity of the subjects under study have been omitted. This study was approved by the Institutional Review Board (IRB ID: 20242189) of the American Hip Institute Foundation, where the study was performed. All patients included in this study participated in the American Hip Institute Preservation Registry. Data on some of these patients may have been reported in other studies; however, the present study is a unique analysis. All data collection and reviews retrospectively received institutional review board approval.

Patient Selection

We retrospectively reviewed for patients who received simultaneous hip arthroscopy and PAO between October 2010 and July 2019. Patients were considered for this study if they had undergone a primary hip arthroscopy with concomitant PAO without prior ipsilateral hip surgery. Patients were excluded from this study if they had a prior ipsilateral hip condition (femoral head osteonecrosis, rheumatoid arthritis, septic arthritis) preoperative Tönnis osteoarthritis grade >1, or workers compensation claims ( Fig 1 ).

Fig. 1

CONSORT-style flow diagram of patient selection for inclusion in the study. WC, Worker’s Compensation.

Preoperative Evaluation, Surgical Indications, and Imaging Protocol

All patients underwent a minimum of 3 months of conservative treatment measures, such as physical therapy, medications, and activity modification, before proceeding to surgery. Preoperative use of detailed patient history, physical examination, and radiographic analysis by the senior authors (B.G.D. and J.M.L.) determined candidates for hip arthroscopy with concomitant PAO. All patients with frank dysplasia (defined as LCEA <18°) underwent PAO as part of their surgical management. In patients with borderline hip dysplasia (LCEA 18–25°), surgical decision-making was based on a combination of radiographic and clinical factors. Patients with additional high-risk features—including a Beighton score ≥4 and Tönnis angle >10—were considered appropriate candidates for combined PAO and hip arthroscopy, given the increased risk of failure with arthroscopy alone. Hip arthroscopy was added to the procedure when preoperative MRI revealed intra-articular pathology—such as labral tears or chondral damage—that was amenable to arthroscopic treatment. Patient preoperative demographics were collected at the preoperative visit. Other characteristics recorded during initial consultation and subsequent re-evaluation visits include gait, range of motion, strength, points of tenderness, signs of femoral acetabular impingement (FAI), and mechanical symptoms (snapping, catching, locking) during the physical examination.

Preoperative and postoperative radiographs were obtained and assessed by the senior authors (B.G.D. and J.M.L). Supine and standing anteroposterior pelvis, Dunn 45°, and false-profile views were used to evaluate acetabular and femoral morphology. Radiographic measurements included the lateral center edge angle (LCEA), anterior center edge angle (ACEA), alpha angle, Tönnis angle, and Tönnis grade. Magnetic resonance arthrography was obtained on all patients before surgery to identify interarticular pathology. Postoperative radiographs were obtained immediately after surgery, 2-week, 4-week, 6-week, 3-months, 1-, 2-, and 5-years postoperatively. The same standardized radiographic views were used at each timepoint to ensure consistency across assessments. Acetabular dysplasia was defined as an LCEA of less than 18° with borderline hip dysplasia with an LCEA between 19° and 25°. ,

Surgical Technique

All surgeries were performed with a combination of epidural and general anesthesia in the modified supine position on a traction table. In all cases hip arthroscopy was performed first by a single surgeon (B.G.D.) through the anterolateral, mid-anterior, and distal anterolateral accessory portals. These portals were routinely used to allow comprehensive access to both the central and peripheral compartments of the hip, facilitating thorough diagnostic evaluation and treatment. A comprehensive diagnostic arthroscopy ensued, systematically assessing the central compartment (acetabular fossa and femoral head articular surfaces, ligamentum teres, acetabular rim and labrum), as well as the peripheral compartment (femoral head-neck junction, capsule, and iliopsoas tendon). Looped labral tears were repaired with the use of Knotless 1.8-mm FiberTak anchors (Arthrex, Naples, FL) or Knotless SutureTak anchors (Arthrex), base labral tears were repaired with the use of 2.9 mm Hip PushLock anchors (Arthrex), or selectively debrided to maximize stability. Treatment of any intra-articular pathology was carried out when indicated. Minimal acetabuloplasty (<0.5 mm) was performed in cases requiring preparation of the acetabular rim to create a suitable bony bed for labral refixation. This was never done with the intent to reduce acetabular coverage or alter LCEA. Femoroplasty was performed in patients with radiographic evidence of cam morphology, defined as a preoperative alpha angle >55°, or when intraoperative inspection confirmed reduced femoral head-neck offset or an aspherical junction. These interventions were intended to address residual impingement and optimize femoral clearance following PAO.

Patients remain in the supine position to undergo the PAO by two surgeons (J.M.L and B.G.D.) using a modified Ganz technique with a rectus-sparing approach under fluoroscopic guidance. , Following completion of the osteotomy, the acetabular fragment was reoriented under fluoroscopic guidance to optimize femoral head coverage and acetabular version, with the goal of improving lateral and anterior coverage while maintaining joint congruency. Particular care was taken to avoid overcorrection or the creation of impingement. Dynamic fluoroscopy and intraoperative range of motion assessment were used to confirm adequate clearance and identify any subspine impingement. Once optimal orientation was achieved, the fragment was secured using four 4.5-mm fully threaded cortical screws.

Rehabilitation Protocol

Postoperative pain management involved the use of an epidural catheter for the initial 24 to 48 hours. The duration of epidural use was determined based on patient-reported pain levels, hemodynamic stability, and mobility progression. In patients with well-controlled pain and stable vital signs, the catheter was typically removed at 24 hours; for those requiring extended analgesia or demonstrating slower early recovery, it was maintained for up to 48 hours. Patient’s operative leg is subjected to a continuous passive motion machine, which starts the day after surgery and continues for 4 weeks. During the first 6 to 8 weeks, weight-bearing was limited to 20% of the patient’s body weight. All patients took part in supervised physical therapy sessions aimed at enhancing range of motion, strengthening the hip stabilizers, and strengthening core muscles. Prophylactic celecoxib (200 mg once daily) and low-molecular-weight heparin (enoxaparin 40 mg subcutaneously once daily) were administered for 4 weeks to prevent heterotopic ossification and thrombosis, respectively. Standard dosing was used for all patients unless contraindicated, in which case adjustments were made based on renal function or bleeding risk.

Patient-Reported Outcomes

PROs recorded for the study included the modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), Hip Outcome Score Sports-Specific Subscale (HOS-SSS), visual analog scale for pain (VAS), and patient satisfaction. These outcomes were collected at a 2-year follow-up and at a 5-year follow-up. The use of both timepoints allowed for analysis of the durability of surgical outcomes over time. Patients who met an endpoint—defined as a secondary revision surgery or conversion to THA—were not included in the PRO analyses, as their outcomes would reflect the secondary procedure rather than the index surgery. However, these patients were accounted for in the secondary surgery analysis section. Previously defined patient-acceptable symptomatic state (PASS) and substantial clinical benefit (SCB) were used. , Minimal clinically important difference (MCID) was calculated via the distribution method using preoperative PROs. For mHHS, PASS was defined as 83.3 for short-term and 83.6 for mid-term outcomes; SCB was defined as 85.8 for short-term and 94.4 for mid-term outcomes; and MCID was calculated as 5.4. For NAHS, PASS was defined as 85.6 for short-term and 81.9 for mid-term outcomes; SCB was defined as 94.4 for short-term and 93.1 for mid-term outcomes; and MCID was calculated as 7.2. For HOS-SSS, PASS was defined as 81.9 for short-term and 80.9 for mid-term terms; SCB was defined as 77.9 for short-term and 85.8 for mid-term outcomes; and MCID was calculated as 10.1. For iHOT12, PASS was defined as 72.2 for short-term and 74.3 for mid-term outcomes; and SCB was defined as 76.8 for short-term and 87.5 for mid-term outcomes.

Statistical Analysis

Statistical analyses were performed in Microsoft Excel with the RealStats Add-In Function and GraphPad. An a priori power analysis found that 26 subjects were needed to detect a mean difference of 8 points in mHHS, while achieving 80% power with an α-value of 0.05 and a standard deviation of 10 (G∗Power, Dusseldorf). , Mean substitution was utilized for patients when they were missing one of the PROs analyzed in the study. Categorical data were reported as percentages and analyzed with a χ 2-test. Continuous data were reported as means with ranges and standard deviation. The Shapiro–Wilk Test was utilized to determine normality of continuous data. Nonparametric continuous data were analyzed using a two-tailed Wilcoxon Signed-Rank Test for paired samples. A two-tailed paired t -test was used to analyze parametric continuous data. The threshold for statistical significance for all analyses was set at P <.05.

Results

Demographics

Between October 2010 and July 2019, there were 33 hips who underwent primary hip arthroscopy with concomitant PAO who were eligible for inclusion. Of these, 32 hips (97.0%) had complete follow-up and were included in the study. There were 30 (93.8%) females and 2 males (6.2%) with an average age of 24.7 ± 7.6 years and body mass index of 23.9 ± 3.8 kg/m 2.

Radiographic Results

All preoperative and postoperative radiographs were Tönnis ≤ 1. The LCEA increased from 16.8 ± 4.9 preoperatively, with 53.6% of patients having frank dysplasia and 46.4% having borderline hip dysplasia, to 32.3 ± 5.4 postoperatively ( P <.001). The mean ACEA increased from a preoperative mean of 16.9 to a postoperative mean of 33.7 ( P <.001). Tönnis angle decreased from a preoperative mean of 14.2 to a postoperative mean of 2.9 ( P <.001), and α-angle decreased from a mean of 53.1 to a postoperative mean of 40.2 ( P <.001). Radiographic results are presented in Table 1 .

Table 1

Preoperative and Postoperative Radiographic Measurements of the Study Group

Radiographic Measurements Preoperative Δ Postoperative P Value
Tönnis Grade 0 26 (92.9%) – 25 (89.3%) .639
LCEA 16.8 ± 4.9 (1– 22.7) 15.5 ± 5.8 (6– 25.3) 32.3 ± 5.4 (21– 45) <.001
ACEA 16.9 ± 6.2 (4– 31.2) 16.8 ± 6.8 (6.7– 35) 33.7 ± 7.1 (16– 50.5) <.001
Tönnis angle 14.2 ± 5.3 (4.7– 25) −11.3 ± 8.2 (−25– 13.5) 2.9 ± 5.0 (−4.8– 18.9) <.001
Alpha angle 53.1 ± 10.9 (35.3– 87) −15.3 ± 13.3 (−55– −0.8) 40.2 ± 5.4 (32– 49) <.001

Values are presented as n (%) or mean ± SD (range). ACEA, anterior center edge angle; LCEA, lateral center edge angle.

Intraoperative Findings and Procedures

During surgery, hips were classified using the Seldes and acetabular labrum articular disruption scale to evaluate acetabular labrum tears and acetabular chondral damage, respectively. Nine hips had grade 1 Seldes tears, 10 hips had grade 2 Seldes tears, and 9 hips had both grade 1 and grade 2 Seldes tears. 10 hips were classified as grade 1, 10 hips were classified as grade 2, 5 hips were classified as grade 3, and 1 hip was classified as grade 4. Two hips were reported as not having acetabular chondral damage. Intraoperative observation of the ligamentum teres was categorized using the Villar Classification. One hip was recorded having type 1 complete tear, 18 hips were recoded having grade 2 partial tears, and 1 was recorded having hip grade 3 tears associated with degenerative changes. Acetabuloplasty was performed in 13 hips, and femoroplasty was performed in 23 hips. Femoral head microfractures were performed in 1 hip. Acetabular microfractures were performed in 2 hips. Twenty-seven hips underwent open capsular repair or plication. All intraoperative findings and procedures can be found in Tables 2 and 3 , respectively.

Table 2

Intraoperative Findings of the Study Group

Finding Hips
Seldes
I 9 (32.1%)
II 10 (35.7%)
I and II 9 (32.1%)
ALAD
0 2 (7.1%)
1 10 (35.7%)
2 10 (35.7%)
3 5 (17.9%)
4 1 (3.6%)
Outerbridge: acetabulum
0 1 (3.6%)
1 11 (39.3%)
2 10 (35.7%)
3 4 (14.3%)
4 2 (7.1%)
Outerbridge: femoral head
0 25 (89.3%)
1 0 (0.0%)
2 2 (7.1%)
3 0 (0.0%)
4 1 (3.6%)
Ligamentum teres tear (Villar classification)
0 6 (21.4%)
1 1 (3.6%)
2 20 (71.4%)
3 1 (3.6%)

Values are presented as n (%).

ALAD, acetabular labral articular disruption; LT, ligamentum teres.

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Jun 27, 2026 | Posted by in PHYSICAL MEDICINE & REHABILITATION | Comments Off on Durable Mid-Term Outcomes and High Rates of Meaningful Improvement After Hip Arthroscopy With Concomitant Periacetabular Osteotomy

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