Abstract
Background
Periacetabular osteotomy (PAO) is a well-accepted treatment for acetabular dysplasia, but treatment success is not uniform. Concurrent hip arthroscopy has been proposed for select patients to address intraarticular abnormalities. The patient-reported outcomes, complications, and reoperations for concurrent arthroscopy and PAO to treat acetabular dysplasia remain unclear.
Questions/purposes
(1) What are the functional outcome scores among select patients treated with PAO plus concurrent hip arthroscopy at mid-term follow-up? (2) What factors are associated with conversion to THA or persistent symptoms (modified Harris hip score ≤ 70 or WOMAC pain subscore ≥ 10)? (3) What proportion of patients underwent further hip preservation surgery at mid-term follow-up? (4) What are the complications associated with the procedure?
Methods
Between November 2005 and December 2012, 78 patients (81 hips) who presented with symptomatic acetabular dysplasia—defined as a lateral center-edge angle less than 20° with hip pain for more than 3 months that interfered with daily function—had undergone unsuccessful nonsurgical treatment, had associated intraarticular abnormalities on MRI, and underwent combined hip arthroscopy and PAO. Eleven patients did not have minimum 4-year follow-up and were excluded, leaving 67 patients (70 hips) who met our inclusion criteria and had a mean follow-up duration of 6.5 ± 1.6 years. We retrospectively evaluated patient-reported outcomes at final follow-up using the University of California Los Angeles (UCLA) activity score, the modified Harris Hip Score (mHHS), and the WOMAC pain subscore. Conversion to THA or persistent symptoms were considered clinical endpoints. Repeat surgical procedures were drawn from a prospectively maintained database, and major complications were graded according to the validated Clavien-Dindo classification (Grade III or IV). Student t-tests, chi-square tests, and Fisher exact tests identified the association of patient factors, radiographic measures, and surgical details with clinical endpoints. For patients who underwent bilateral procedures, only the first hip was included in our analyses.
Results
At final follow-up, the mean mHHS for all patients improved from a mean ± SD of 55 ± 19 points to 85 ± 17 points (p < 0.001), the UCLA activity score improved from 6.5 ± 2.7 points to 7.5 ± 2.2 points (p = 0.01), and the WOMAC pain score improved from 9.1 ± 4.3 points to 3.2 ± 3.9 points (p < 0.001). Three percent (2 of 67) of patients underwent subsequent THA, while 21% (15 of 70) of hips were persistently symptomatic, defined as mHHS less than or equal to 70 or WOMAC pain subscore greater than or equal to 10. Univariate analyses indicated that no patient demographics, preoperative or postoperative radiographic metrics, or intraoperative findings or procedures were associated with subsequent THA or symptomatic hips. Worse baseline mHHS and WOMAC pain scores were associated with subsequent THA or 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 (Clavien-Dindo Grade III or IV).
Conclusion
This study demonstrated that concurrent hip arthroscopy and PAO to treat symptomatic acetabular dysplasia (with intraarticular abnormalities) has good clinical outcomes at mid-term follow-up in many patients; however, persistent symptoms or conversion to THA affected almost a quarter of the sample. We noted an acceptable complication profile. Further study is needed to directly compare this approach to more traditional techniques that do not involve arthroscopy. We do not use isolated hip arthroscopy to treat symptomatic acetabular dysplasia.
Level of Evidence
Level IV, therapeutic study.
Introduction
In acetabular dysplasia, structural instability from a shallow acetabulum may lead to abnormal joint contact pressure, hip pain and functional limitations, as well as accelerated development of secondary osteoarthritis [18, 29, 44]. Periacetabular osteotomy (PAO) is a surgical option for patients with symptomatic acetabular dysplasia that reorients the acetabulum to restore stability and improve the mechanical hip environment [18]. Studies of PAO have shown improvement in pain and function outcomes [7], with survival of the native hip continuing for decades after surgery in some series [26, 41, 43, 45, 46, 49]. Although the clinical results of PAO have been promising, such results are not uniform. To improve the predictability of clinical outcomes, there is increasing interest in addressing associated intraarticular abnormalities (labral tears, articular cartilage lesions, and ligamentum teres tears) at the time of PAO [1, 17, 38].
Deficiency in anterolateral acetabular coverage in patients with acetabular dysplasia is associated with overload of the acetabular rim complex [22, 25] and leads to a high incidence of associated pathologic abnormalities of the labrum and chondrolabral junction [19, 35]. Treating labral tears and associated conditions via an arthroscopic approach is well established for the nondysplastic hip; however, the role of arthroscopy in the setting of hip dysplasia remains controversial [6, 31]. To comprehensively correct hip pathologic conditions in a single setting, hip arthroscopy in conjunction with PAO has been described [15, 24, 34, 35]. This combined approach allows for improved access to the central compartment and more comprehensive correction of concurrent intraarticular abnormalities, when present. There are limited reports on hip arthroscopy with PAO, and several do not include patient-reported outcome data [14, 33, 35] or only include short-term follow-up [34]. As the use of PAO expands, a more nuanced understanding of the role of adjunctive procedures is needed [10]. In our practice, we introduced the combined procedure to treat patients with a high likelihood (history, examination findings, and imaging findings) of associated intraarticular damage because it seemed these patients would benefit the most from this surgical strategy.
Therefore, in this study, we assessed the mid-term (minimum 4 years, range 4-11) patient-reported outcomes, complications, and reoperations of concurrent arthroscopy and PAO to treat symptomatic acetabular dysplasia with associated intraarticular abnormalities.
We specifically asked (1) What are the functional outcome scores among select patients treated with PAO plus concurrent hip arthroscopy at mid-term follow-up? (2) What factors are associated with conversion to THA or persistent symptoms (modified Harris hip score ≤ 70 or WOMAC pain subscore ≥ 10)? (3) What proportion of patients underwent further hip preservation surgery at mid-term follow-up? (4) What are the complications associated with the procedure?
Patients and Methods
Study Overview and Indications
This was a retrospective study at 4-year minimum follow-up of patients undergoing combined hip arthroscopy and PAO for symptomatic acetabular dysplasia with associated intraarticular abnormalities. All patients were prospectively enrolled in our institutional hip preservation database. This study was approved by the institutional review board.
Patients who underwent concurrent arthroscopy and PAO were eligible for inclusion. Patients were excluded if they had diagnoses other than classic acetabular dysplasia, as defined by a lateral center-edge angle (LCEA) less than 20° (associated neuromuscular disease, Legg-Calvé-Perthes disease, slipped capital femoral epiphysis, posttraumatic deformity, and isolated acetabular retroversion).
Patients who presented to the clinic of the senior author (JCC) between November 2005 and December 2012 and met the appropriate criteria for PAO (hip pain that interfered with daily function that was persistent after 3 months of nonsurgical treatments, with radiographic evidence of acetabular dysplasia with an LCEA less 20° without degenerative changes) were offered PAO [8]. All such patients underwent MR arthrography (MRA) to evaluate the labrum and articular cartilage. If a labral detachment from the acetabular rim or a focal cartilage defect was visualized on MRA and the clinical history and examination findings were consistent with intraarticular symptoms (specifically, symptoms of intermittent sharp groin pain in combination with a positive anterior impingement test), then hip arthroscopy was recommended before PAO during the same operative setting. Hip arthroscopy was performed for symptoms in the central (iliofemoral) compartment only. A femoral head-neck offset deformity was not an indication for hip arthroscopy and, if present, was addressed via open arthrotomy through the PAO exposure. The decision to perform adjunctive femoral head-neck osteochondroplasty was based on a hip examination after completion of PAO, as previously reported [46]. If the hip had less than 15° of internal rotation at 90° flexion after PAO, then osteochondroplasty was performed. This protocol was followed consistently throughout the study period.
During the study period, 314 PAOs were performed (Fig. 1). Twenty-six percent (83 of 314 procedures in 80 patients) of these procedures were combined arthroscopy and PAO. Two patients were excluded because of a diagnosis other than developmental dysplasia of the hip, and 11 patients could not be reached for follow-up at a minimum of 4 years postoperatively. We included 70 procedures in 67 patients, resulting in an 86% follow-up proportion, and included only the first hip of the bilateral patients in the analyses (Table 1). The mean age ± SD at the time of surgery was 29 ± 10 years, and 93% (62 of 67) of patients were women. Sixty percent (42 of 70) of the surgeries were performed on the right hip, and the mean BMI was 24 ± 3.7 kg/m2.
Fig. 1.
Flow diagram showing the patients who were included in the study. DDH = developmental dysplasia of the hip.
Table 1.
Patient demographics
| Characteristic | Study patients (n = 67) |
| Age in years | 29 ± 10 |
| Women, % (n) | 93 (62) |
| Height in cm | 167 ± 8 |
| Weight in kg | 66 ± 12 |
| BMI in kg/m2 | 24 ± 4 |
All values are given as the mean ± SD, except where noted.
Surgical Protocol
Hip arthroscopy was performed first, using previously described techniques, through the mid-anterior and anterolateral portals [5, 35]. A full diagnostic arthroscopy was performed. The articular cartilage and labrum were graded according to the modified Beck classification [2, 3, 30]. The labral condition was classified as normal, degeneration, full-thickness tear, detachment, or ossification; articular cartilage was classified as normal, malacia, debonding, cleavage, or defect. After arthroscopy, PAO was performed as described [8]. During the open portion of the procedure, adjunctive procedures included 89% (62 of 70) open femoral head-neck osteochondroplasty as described and 1% (1 of 70) anterior inferior iliac spine decompression with greater trochanteric osteoplasty.
Labral and acetabular articular cartilage abnormalities were common and were observed in 84% (59 of 70) and 83% (58 of 70) of hips, respectively (Table 2). During central compartment arthroscopy, procedures included 23% (16 of 70) acetabular chondroplasty, 9% (6 of 70) acetabular microfracture, 41% (29 of 70) labral debridement, 24% (17 of 70) labral refixation, 13% (9 of 70) ligamentum teres debridement, and 1% (1 of 70) acetabular rim osteoplasty for labral ossification. The mean operative time was 204 ± 41 minutes.
Table 2.
Central compartment arthroscopic findings (n = 70 hips in 67 patients)
Comparison of preoperative and postoperative radiographs showed significant changes in the LCEA (from 15° ± 5° to 29° ± 5°; mean difference 14° [95% confidence interval 13° to 16°]; p < 0.001), the Tönnis angle (from 16° ± 4° to 4° ± 4°; mean difference 12° [95% CI 10° to 13°]; p < 0.001), and the anterior center-edge angle (ACEA) (from 17° ± 7° to 31° ± 7°; mean difference 14° [95% CI 12° to 16°]; p < 0.001).
Primary and Secondary Study Endpoints
One author (CWG) retrieved and analyzed data from a prospectively maintained clinical database, and study endpoints were determined according to our defined criteria. Collected patient-reported outcome measures included the modified Harris Hip Score (mHHS), WOMAC score, and University of California Los Angeles (UCLA) activity score. Endpoints were conversion to THA or hips designated as clinically symptomatic if at final follow-up the mHHS was ≤ 70 or WOMAC pain score was ≥ 10, as described elsewhere [16, 46]. If a hip did not undergo arthroplasty or meet the criteria for being symptomatic, we classified it as preserved. We compiled radiographic metrics from standing AP pelvic radiographs from preoperative and final follow-up postoperative clinic visits. Metrics assessed included the LCEA, Tönnis angle, joint space, joint congruency [47], alpha angle, and Tönnis grade [42]. Additionally, the alpha angle was assessed on Dunn and frog-leg lateral views, and the ACEA was assessed on false-profile views. The radiographic metrics are recorded prospectively in the institutional hip preservation database by research staff trained by the senior author (JCC). Interobserver reliability was assessed with intraclass coefficients for continuous variables and Cohen’s kappa for categorial variables. Agreement ranged from moderate to very high as follows: LCEA = 0.89; Tönnis angle = 0.95; ACEA = 0.91; alpha angle = 0.65. Complications and reoperations occurring at any point throughout the follow-up period were recorded. Complications were classified with the Clavien-Dindo classification scheme, which has been validated in hip preservation surgery [13, 39]. Minor, asymptomatic heterotopic ossification (Brooker Grade I and II) occurs frequently after PAO and does not affect the clinical outcome; therefore, it was not considered a complication. Major heterotopic ossification (Brooker Grade III and IV) was counted as a complication [4]. We also did not consider decreased sensation in the distribution of the lateral femoral cutaneous nerve as a complication [48].
Statistical Analysis
The primary clinical endpoint was a composite endpoint measure including conversion to THA or designation as a symptomatic hip. Comparisons were made between the preserved group and the composite endpoint group using the Fisher exact test and a chi-square test, where appropriate. For comparison between groups, we collapsed continuous variables into categorical variables as described previously, except for baseline hip scores, for which we conducted two-sample t-tests [46]. We performed only univariate analyses, which did not control for potential confounding, due to the small sample size. For the analyses, in patients who had bilateral procedures, we included only the first hip to undergo PAO. Preoperative and postoperative radiographic metrics were compared using paired t-tests. Analyses were performed using SAS version 9.4 (SAS Institute, Cary, NC, USA), and the level of significance was set at p ≤ 0.05.
Results
Functional Outcome Scores
At a mean follow-up interval of 6.5 years, all patients reported a mean improvement in the mHHS from 55 ± 19 points to 85 ± 17 points (mean difference 29 [95% CI 24 to 35]; p < 0.001), mean improvement in UCLA score from 6.5 ± 2.7 points to 7.5 ± 2.2 points (mean difference 0.9 [95% CI 0.21 to 1.60]; p = 0.01), and mean improvement in the WOMAC pain score from 9.1 ± 4.3 points to 3.2 ± 3.9 points (mean difference 5.7 [95% CI 4.43 to 7.00]; p < 0.001). These differences are greater than published minimum clinically important differences (MCIDs) [27, 40]. Seventy-six percent (53 of 70) of hips were preserved at the final follow-up interval, meaning they were not converted to THA and did not meet our established criteria for persistent symptoms. The group of preserved hips had a mean mHHS of 92 ± 9 points, UCLA score of 7.8 ± 2.1 points, and WOMAC pain subscore of 1.8 ± 2.4 points at the final follow-up examination. Twenty-one percent (15 of 70) of hips were deemed symptomatic (WOMAC pain score ≥ 10 or mHHS ≤ 70), and 3% (2 of 70) of the hips underwent THA at 21 and 45 months after PAO.
Factors Associated with Hip Preservation
Progression to THA or symptomatic hip status was associated with a lower baseline mHHS (57 ± 19 points for preserved versus 47 ± 17 points for THA and symptomatic; p = 0.05) and WOMAC pain scores (8.1 ± 4.1 points for preserved versus 12.4 ± 3.5 points for THA and symptomatic; p < 0.001). We found no differences with the numbers available between the THA and symptomatic hip group and preserved hip groups with respect to patient demographics, articular cartilage status or treatment, labral status or treatment, performance of femoral head-neck osteochondroplasty, or radiographic metrics (Table 3).
Table 3.
Analysis of patient and hip characteristics by outcome
| Variable | Category | Preserved hips (n = 52) | Symptomatic or THA progression (n = 15) | p value |
| Age in years | ≤ 25 | 38 (20) | 40 (6) | 0.91 |
| > 25 | 62 (32) | 60 (9) | ||
| BMI in kg/m2 | < 30 | 88 (46) | 87 (13) | > 0.99 |
| ≥ 30 | 12 (6) | 13 (2) | ||
| Gender | Women | 90 (47) | 100 (15) | 0.58 |
| Men | 10 (5) | 0 (0) | ||
| Pain chronicity | < 6 months | 4 (2) | 0 (0) | 0.54 |
| 6-12 months | 21 (10) | 7 (1) | ||
| 1-3 years | 52 (25) | 50 (7) | ||
| 3-5 years | 13 (6) | 21 (3) | ||
| > 5 years | 10 (5) | 21 (3) | ||
| Prior ipsilateral hip operation | No | 86 (44) | 86 (12) | > 0.99 |
| Yes | 14 (7) | 14 (2) | ||
| Postoperative joint congruency | Fair | 6 (3) | 7 (1) | > 0.99 |
| Good | 70 (35) | 73 (11) | ||
| Excellent | 24 (12) | 20 (3) | ||
| Preoperative LCEA in ° | < 20 | 83 (43) | 93 (14) | 0.44 |
| 20-38 | 17 (9) | 7 (1) | ||
| Postoperative LCEA in ° | < 20 | 6 (3) | 0 (0) | 0.8 |
| 20-38 | 90 (46) | 93 (14) | ||
| > 38 | 4 (2) | 7 (1) | ||
| Preoperative Tönnis grade | 0 | 48 (25) | 53 (8) | 0.72 |
| 1 | 52 (27) | 47 (7) | ||
| Acetabular cartilage grade | Normal | 15 (8) | 13 (2) | 0.27 |
| Malacia | 17 (9) | 40 (6) | ||
| Debonding | 33 (17) | 33 (5) | ||
| Cleavage | 19 (10) | 13 (2) | ||
| Defect | 15 (8) | 0 (0) | ||
| Acetabular cartilage treatment | None | 69 (36) | 67 (10) | 0.89 |
| Chondroplasty | 21 (11) | 27 (4) | ||
| Microfracture | 10 (5) | 7 (1) | ||
| Femoral head cartilage grade | Normal | 85 (44) | 100 (15) | 0.57 |
| Malacia | 10 (5) | 0 (0) | ||
| Debonding | 0 (0) | 0 (0) | ||
| Cleavage | 2 (1) | 0 (0) | ||
| Defect | 4 (2) | 0 (0) | ||
| Femoral head-neck osteochondroplasty | No | 13 (7) | 7 (1) | 0.67 |
| Yes | 87 (45) | 93 (14) | ||
| Labral grade | Normal | 15 (8) | 20 (3) | 0.52 |
| Degeneration | 19 (10) | 33 (5) | ||
| Full-thickness tear | 1 (1) | 0 (0) | ||
| Detachment | 63 (33) | 47 (7) | ||
| Labral treatment | None | 35 (18) | 33 (5) | 0.59 |
| Debridement | 44 (23) | 33 (5) | ||
| Refixation | 21 (11) | 33 (5) | ||
| Preoperative UCLA score, median (IQR) | 6.7 (2.7) | 5.8 (2.7) | 0.27 | |
| Preoperative mHHS, mean ± SD | 57.3 ± 18.9 | 46.6 ± 16.7 | 0.05 | |
| Preoperative WOMAC pain score, mean ± SD | 8.1 ± 4.1 | 12.4 ± 3.5 | < 0.001 |
All data presented as % (n), unless otherwise noted; LCEA = lateral center-edge angle; UCLA = University of California Los Angeles; mHHS = modified Harris Hip Score.
Reoperations
Seven percent (5 of 70) of hips underwent a reoperation for recurrent or persistent symptoms at a mean of 2.8 years after arthroscopy and PAO. These included one open psoas release with ramus osteoplasty and four revision hip arthroscopies to address a recurrent labral tear, capsular adhesions, or secondary impingement. The subset of patients who underwent reoperation for recurrent symptoms had a mean baseline mHHS of 48 ± 13 points, which improved to 61 ± 23 points at the latest follow-up after reoperation. Three of these five patients were classified as symptomatic at the final follow-up examination.
Complications
There were three major complications associated with the index procedure for an overall complication percentage of 4% (3 of 70). These were all Clavien-Dindo Grade III complications and included a wound hematoma that was treated with operative irrigation and debridement, a deep infection treated with operative irrigation and debridement, and Brooker Grade III heterotopic ossification that underwent excision.
Discussion
Abnormalities of the acetabular labrum, articular cartilage, and ligamentum teres are common in patients with acetabular dysplasia [20, 23, 25]. Historically, the treatment of acetabular dysplasia focused on correcting structural instability through reorientation of the acetabulum, without directly addressing any associated intraarticular abnormalities [9]. Theoretically, unloading the acetabular rim would resolve symptoms associated with intraarticular labrochondral abnormalities, and in fact, the long-term clinical outcomes of isolated PAOs are good-to-excellent for most patients. Nevertheless, a subgroup of patients with PAO do not experience full pain relief and improved function. Newer approaches have combined acetabular reorientation with hip arthroscopy to enable the assessment and treatment of intraarticular disease [36]. It remains unclear whether the use of hip arthroscopy as an adjunct to PAO provides better clinical outcomes and negates the need for further surgery to address intraarticular symptoms. We reported the mid-term patient-reported outcomes, complications, and reoperations of combined arthroscopy and PAO in patients specifically selected for the combined procedure, representing 22% of our patients during the study period. We currently use the combined procedure to treat patients with a high likelihood, based on clinical and imaging evaluations, of intraarticular damage (labral tear, articular cartilage lesions, and ligamentum teres tears). Thus, our cohort represents a subgroup of patients with more advanced disease at the time of PAO. Our data indicate improvements in patient function and pain that appear durable up to a mean of 6.5 years of follow-up, with an acceptable surgical complication burden. As we could not control for several potentially important confounding variables, our findings about factors associated with persistent symptoms or conversion to THA must be considered preliminary and explored in future studies using multivariable analysis to control for factors such as depression or anxiety.
Limitations
This study has limitations. First, our study lacked an appropriate comparison group of patients who did not undergo concurrent hip arthroscopy. This was not feasible because our study patients were specifically selected for the combined procedure and represented a distinct subgroup. As a result, we cannot definitively state that this subgroup would demonstrate different results without an arthroscopic procedure. It is possible that the arthroscopy did not provide any additional benefit to the patient beyond the PAO. Our results here do not allow us to determine the benefit, if any, of the arthroscopy. Second, this was a retrospective study of procedures performed by one surgeon with extensive experience in both arthroscopic and open hip preservation surgery. The results may not be generalizable to all centers where hip preservation surgery is performed. Third, this cohort represented a subset of symptomatic patients with acetabular dysplasia who had a high likelihood of substantial intraarticular symptoms identifiable through preoperative evaluations. Fourth, 14% (11 of 78) of patients were lost to follow-up, despite extensive efforts to contact them. We must assume that these patients may be doing worse than the patients we analyzed. Fifth, the symptomatic and THA group was relatively small, and unexamined confounders such as mental health issues might explain the lower preoperative patient-reported outcome measure scores in these patients because we were unable to perform a multivariate analysis. Lastly, our composite endpoint of conversion to THA or persistent symptoms was not compatible with formal survivorship analysis because we could not determine the timing of symptom onset, so crude proportions are provided instead of survivorship analysis. This approach to measuring event burden may underestimate the apparent frequency of the events in question [12], but with so few patients lost to follow-up, we believe the impact of this limitation is likely to have been low in the current study.
Functional Outcome Scores
We found mean improvement in mHHS, WOMAC pain, and UCLA scores that met the MCID for these patient-reported outcome measures in our subgroup. Our data corroborate prior reports of symptomatic improvement after concurrent hip arthroscopy and PAO. Ricciardi et al. [34] compared combined arthroscopic labral refixation and PAO in 24 hips with isolated PAO in 58 hips, with early 1-year follow-up. Arthroscopy was indicated for symptomatic labral tears, with MRA findings of repairable labral detachment. They found no differences in improvements in the mHHS, Hip Outcome Score (HOS)-ADL, or HOS-sport scores; however, they found greater improvement in International Hip Outcome Tool–33 scores in the arthroscopy with PAO group than in the PAO alone group. Another study [24] reported on 43 hips treated with concurrent hip arthroscopy and rotational acetabular osteotomy via a lateral approach with trochanteric osteotomy at a mean follow-up of 74 months. They found labral tears in 88% of hips and performed labral debridement or excision. They noted improvement in the mean mHHS from 72 points at baseline to 94 points at the final follow-up interval.
Factors Associated with Hip Preservation
We found that progression to THA or symptomatic hip status was associated with lower baseline mHHS and WOMAC pain scores. The association between lower baseline hip function and worse outcomes after hip preservation surgery has been previously identified [36, 41]. The size of our cohort did not allow for a more detailed examination of patient factors that may correlate with lower baseline score; there may be confounding factors, such as anxiety or depression, that could account for the lower scores both before and after surgery. The current cohort had lower baseline mHHS than did patients in a prior report from our institution on the mid-term outcomes of PAO without arthroscopy [46]. Baseline mHHS for this cohort were on the low end of the spectrum of previously reported baseline scores for patients undergoing PAO (Table 4) [11, 32]. This difference may stem from selection of these patients among all patients who underwent PAO based on signs and symptoms indicating intraarticular abnormalities. Ricciardi et al.’s [34] study found that the presence of intraarticular symptoms was associated with lower baseline hip scores as well. As mentioned, various confounding factors may have also contributed to lower baseline scores. In addition to lower baseline scores, the mean age of patients in this study was older than in our previously reported cohort [46], suggesting more advanced disease and symptoms in this subgroup.
Table 4.
Studies reporting baseline and final mHHS after isolated PAO or concurrent hip arthroscopy and PAO
| Study | Number of hips | Procedure | Mean follow-up in years | Mean age in years | Mean baseline mHHS | Mean final mHHS |
| Current | 70 | Arthroscopy/PAO | 6.5 | 29 | 54.9 | 84.5 |
| Kim et al. [24] | 43 | Arthroscopy/rotational osteotomy | 6.2 | 40 | 72 | 94 |
| Domb et al. [15] | 17 | Arthroscopy/PAO | 2.4 | 24 | 64 | 84 |
| Ricciardi et al. [34] | 24 | Arthroscopy/PAO | 1 | 27 | 58 | 83 |
| Lerch et al. [26] | 75 | PAO | 29 | 29 | 83 | 85 |
| Dahl et al. [11] | 52 of 127 with HHS data | PAO | 7 | 31 | 83 (72-86)a | 84 (76-95)a |
| Wells et al. [46]b | 154 | PAO | 10.3 | 26 | 66 | 86 |
| Ricciardi et al. [34] | 58 | PAO | 1 | 23 | 61 | 84 |
| Peters et al. [32] | 83 | PAO | 3.8 | 28 | 54 | 87 |
Presented as the median value with interquartile range.
Data from the same institution as the current study.
Reoperations
We found a 7% reoperation proportion with repeat hip preservation surgery for recurrent or persistent symptoms, including one open surgery and four revision arthroscopies. In a review of 135 PAOs, Matheney et al. [28] reported that 11% (15) of hips underwent arthroscopy after isolated PAO for persistent symptoms related to labral tears or a chondral defect. Another study reported that within 2 years of isolated PAO, 27% (26 of 95) of patients underwent hip arthroscopy for persistent symptoms [21]. Our proportion of repeat hip preservation surgery is lower than these other reports. It is possible that the arthroscopy at the time of PAO in our cohort mitigated the development of recurrent symptoms that may have led to repeat hip preservation surgery; however, the lack of a comparator group limits any definitive conclusions on this topic.
Complications
We had three major complications that resulted in operative treatment and subsequently resolved. Our proportion of complications was consistent with those of a prior report of complications after isolated PAO [48]. The potential risks of concurrent hip arthroscopy with PAO include prolonged operative time, fluid extravasation into the soft tissues from arthroscopy, and capsular adhesions [33]. However, a recent study analyzing complications associated with the combined hip arthroscopy and PAO procedure indicated no adverse events or increase in complications compared with isolated PAO surgery [37]. We believe that performing femoral head neck osteochondroplasty, when indicated, through an open arthrotomy and not arthroscopically helps to mitigate any increased risk of complications from a prolonged arthroscopy.
Conclusion
We analyzed the mean 6.5-year follow-up of a subgroup of patients who underwent concurrent hip arthroscopy and PAO to treat symptomatic acetabular dysplasia with associated intraarticular damage. At this follow-up interval, 76% of hips were functioning very well, 21% had persistent symptoms, and 3% had progressed to conversion to hip arthroplasty. With 14% of patients lost to follow-up, it is possible that these numbers may be less favorable. We believe that comprehensive surgical correction of dysplasia and intraarticular damage in a single setting is a treatment strategy worthy of further investigation for selected patients. Further study in the form of a randomized control trial (currently underway) is needed to directly compare this approach to more traditional techniques that do not involve arthroscopy. We do not use isolated hip arthroscopy to treat symptomatic acetabular dysplasia.
Footnotes
The institution of one or more of the authors (JCC) has received, during the study period, funding from Curing Hip Disease Fund and the Jacqueline and W. Randolph Baker Fund for research personnel salary support and biostatistical consultation.
All other authors certify that neither he nor she, nor any member of his or her immediate family, has funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article.
All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request.
Each author certifies that his or her institution approved the human protocol for this investigation and that all investigations were conducted in conformity with ethical principles of research.
This work was performed at Washington University School of Medicine, St. Louis, MO, USA.
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