Conversion to Total Hip Arthroplasty After Hip Arthroscopy: A Cohort-Based Survivorship Study With a Minimum of 2-Year Follow-up

Patients Aged 40 Years and Older Demonstrate Durable and Comparable Results to Patients Aged Less Than 40 Years After Primary Hip Arthroscopy for Femoroacetabular Impingement Syndrome: A Propensity Matched Study at Minimum 10-Year Follow-Up

PURPOSE

To compare clinical outcomes and rates of secondary surgery, including revision hip arthroscopy and conversion to total hip arthroplasty (THA), after primary hip arthroscopy for femoroacetabular impingement syndrome (FAIS) in patients ≥40 years of age at minimum 10-year follow-up compared with a propensity-matched control group of patients <40 years.

METHODS

A retrospective cohort study was performed for patients who underwent primary hip arthroscopy for FAIS between January 2012 and February 2013. Patients ≥40 years old were propensity matched in a 1:1 ratio by sex and body mass index to patients <40 years old. Patient-reported outcomes (PROs) including Hip Outcome Score for Activities of Daily Living and Sports-Specific subscales, modified Harris Hip, International Hip Outcome Tool-12, and Visual Analog Scale for Pain and Satisfaction were collected. Rates of minimal clinically important difference (MCID) and patient-acceptable symptomatic state (PASS) achievement at 10 years were evaluated and compared between groups. Rates of secondary surgery including revision hip arthroscopy and conversion to THA were evaluated. Gross survivorship between cohorts was evaluated using a Kaplan-Meier curve.

RESULTS

Fifty-three patients aged ≥40 (age 48.3 ± 5.8 years) were successfully matched to 53 patients aged <40 (age: 28.9 ± 7.2, <0.001). There were no other preoperative group differences regarding patient demographics, characteristics, or radiographic findings. Both groups demonstrated significant improvement regarding all PROs at a minimum of 10 years' follow-up (P < .001 for all). No significant difference was noted between cohorts regarding any delta (preoperative to 10-year postoperative) scores (P > .05 for all). High rates of MCID and PASS achievement were achieved in both cohorts, with no significant differences in any PRO measure (P > .05 for all). No significant differences in rates of complications (age ≥40: 2.0%, age <40: 7.7%, P = .363), rates of revision (age ≥40: 7.5%, age <40: 9.4%, P = .999), or conversion to THA (age ≥40: 13.2%, age <40: 3.8%, P = .161) were identified. On Kaplan-Meier analysis, no significant difference (P = .321) was demonstrated in overall gross survivorship between cohorts.

CONCLUSIONS

Patients with age ≥40 with FAIS undergoing primary hip arthroscopy demonstrated durable and comparable 10-year PRO and rates of MCID and PASS achievement compared with a propensity-matched cohort of age <40 counterparts.

LEVEL OF EVIDENCE

Level III, retrospective comparative prognostic trial.

Injections prior to hip arthroscopy are associated with increased risk of repeat hip arthroscopy at 1 and 5 years

INTRODUCTION

Previous studies have shown that intra-articular hip injections prior to hip arthroscopy (HA) can be a helpful diagnostic tool. However, local anesthetic and corticosteroid injections can be chondrotoxic and corticosteroid injections have been shown to increase the risk of infection during subsequent surgical intervention. The purpose of this study was to evaluate whether preoperative injections adversely affect outcomes of HA using a national database.

MATERIALS AND METHODS

The TriNetX database was retrospectively queried. Patients undergoing HA for femoroacetabular impingement with at least 1 year of claims runout were included in the analysis. Patients were grouped by whether they had a hip injection within 1 year prior to HA. The rates of repeat HA, total hip arthroplasty (THA), infection, osteonecrosis, and new onset hip OA at 1- and 5-years postoperatively were compared between groups. Statistical significance was assessed at α = 0.05.

RESULTS

6511 HA patients with previous injection and 1178 HA patients without previous injection were included. Patients with a previous injection were overall younger (32.3 vs. 34.7 years, p < 0.001), more likely to be female (69 vs. 48%, p < 0.001) and had a higher BMI (26.3 vs. 25.7 kg/m2, p = 0.043). At 1 and 5-years postoperatively, patients with any injection were 1.43 (p < 0.001) and 1.89 (p < 0.001) times more likely to undergo repeat HA, respectively. At 1 and 5-years postoperatively, patients who underwent a corticosteroid injection were 2.29 (p < 0.001) and 1.89 (p < 0.001) times more likely to undergo repeat HA than patients with local anesthetic injection only and 1.56 (p < 0.001) and 2.08 (p < 0.001) times more likely to undergo repeat HA than patients with no injection.

CONCLUSIONS

Intraarticular hip injections prior to hip arthroscopy, particularly corticosteroid injections, are associated with increased risk of repeat hip arthroscopy at 1 and 5 years. Additional studies are needed to elucidate this risk.

Assessment of Risk Factors and Rate of Conversion to Total Hip Arthroplasty Within 2 Years After Hip Arthroscopy Utilizing a Large Database of Commercially Insured Patients in the United States

Background

The conversion rate of hip arthroscopy (HA) to total hip arthroplasty (THA) has been reported to be as high as 10%. Despite identifying factors that increase the risk of conversion, current studies do not stratify patients by type of arthroscopic procedure.

Purpose/Hypothesis

To analyze the rate and predictors of conversion to THA within 2 years after HA. It was hypothesized that osteoarthritis (OA) and increased patient age would negatively affect the survivorship of HA.

Study Design

Cohort study; Evidence level, 3.

Methods

The IBM MarketScan database was utilized to identify patients who underwent HA and converted to THA within 2 years at inpatient and outpatient facilities between 2013 and 2017. Patients were split into 3 procedure cohorts as follows: (1) femoroacetabular osteoplasty (FAO), which included treatment for femoroacetabular impingement; (2) isolated debridement; and (3) isolated labral repair. Cohort characteristics were compared using standardized differences. Conversion rates between the 3 cohorts were compared using chi-square tests. The relationship between age and conversion was assessed using linear regression. Predictors of conversion were analyzed using multivariable logistic regression. The median time to conversion was estimated using Kaplan-Meier tests.

Results

A total of 5048 patients were identified, and the rates of conversion to THA were 12.86% for isolated debridement, 8.67% for isolated labral repair, and 6.76% for FAO (standardized difference, 0.138). The isolated labral repair cohort had the shortest median time to conversion (isolated labral repair, 10.88 months; isolated debridement, 10.98 months; and FAO, 11.9 months [P = .034). For patients >50 years, isolated debridement had the highest rate of conversion at 18.8%. The conversion rate increased linearly with age. Factors that increased the odds of conversion to THA were OA, having an isolated debridement procedure, and older patient age (P < .05).

Conclusion

Older patients and those with preexisting OA of the hip were at a significantly increased risk of failing HA and requiring a total hip replacement within 2 years of the index procedure. Younger patients were at low risk of requiring a conversion procedure no matter which arthroscopic procedure was performed.

Hip Arthroscopic Surgery With Chondrolabral Refixation, Osteochondroplasty, and Routine Capsular Closure for Femoroacetabular Impingement Syndrome: Clinical Outcomes at a Minimum 10-Year Follow-up

BACKGROUND

Hip arthroscopic surgery for femoroacetabular impingement syndrome (FAIS) has proven to be an effective surgical intervention, with high rates of return to sport and work as well as favorable outcomes at short- and midterm follow-up. However, limited data exist on outcomes at long-term follow-up.

PURPOSE

To evaluate patient-reported outcomes (PROs) at a minimum 10-year follow-up after primary hip arthroscopic surgery including labral repair, femoral osteochondroplasty, acetabular osteochondroplasty, and capsular closure for FAIS.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Patients who underwent primary hip arthroscopic surgery for FAIS between June 2012 and January 2013 were identified. PROs were collected preoperatively and at a minimum of 10 years postoperatively, including the Hip Outcome Score-Activities of Daily Living (HOS-ADL), Hip Outcome Score-Sports Subscale (HOS-SS), modified Harris Hip Score (mHHS), International Hip Outcome Tool-12 (iHOT-12), and visual analog scale (VAS) for pain and satisfaction. Unique minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) thresholds were calculated, and their rates of achievement were analyzed. An alpha level of <.05 was used to determine statistical significance.

RESULTS

A total of 94 patients (55 female; mean age, 34.3 ± 12.4 years) were analyzed with a mean follow-up of 10.1 ± 0.3 years (range, 10.0-10.7 years). Patients demonstrated significant 10-year improvement across all PRO measures (P < .001). MCID and PASS thresholds were calculated as follows: HOS-ADL (10.4 and 85.3, respectively), HOS-SS (14.6 and 60.2, respectively), mHHS (8.8 and 76.0, respectively), VAS pain (14.6 and 27.5, respectively), and iHOT-12 (PASS: 71.4). The majority of patients achieved the MCID and PASS for each PRO measure: HOS-ADL (73.4% and 70.9%, respectively), HOS-SS (78.5% and 77.2%, respectively), mHHS (81.0% and 70.9%, respectively), VAS pain (88.6% and 70.9%, respectively), and iHOT-12 (PASS: 73.4%). Overall, 9 patients (9.6%) underwent subsequent revision hip arthroscopic surgery at a mean 4.9 ± 3.7 years (range, 1.1-10.1 years) postoperatively, and 6 patients (6.4%) underwent conversion to total hip arthroplasty at a mean 4.1 ± 3.1 years (range, 0.9-9.3 years) postoperatively.

CONCLUSION

Patients who underwent primary hip arthroscopic surgery for FAIS utilizing contemporary methods of labral repair, acetabular and/or femoral osteochondroplasty, and capsular closure commonly experienced sustained clinical improvement and reported high levels of satisfaction at a minimum 10-year follow-up with low rates of reoperation.

Functional Outcome Scores and Conversion to Total Hip Arthroplasty After Hip Arthroscopy for Femoroacetabular Impingement Syndrome in Patients With Tönnis Grade 1 Versus Grade 0 Arthritis: A Propensity-Matched Study at Minimum 10-Year Follow-up

BACKGROUND

Hip arthroscopy has become the mainstay surgical intervention for the treatment of femoroacetabular impingement syndrome (FAIS). However, postoperative outcomes and rates of secondary surgery are mixed in patients with differing levels of preoperative osteoarthritis (OA). Furthermore, there is a paucity of literature comparing patients with and without OA at long-term follow-up.

PURPOSE

To compare outcomes and rates of secondary surgery at minimum 10-year follow-up, including revision hip arthroscopy and conversion to total hip arthroplasty (THA), in patients with Tönnis grade 1 undergoing hip arthroscopy for FAIS compared with a propensity-matched control group of patients with Tönnis grade 0.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients who underwent primary hip arthroscopy for FAIS between January 2012 and February 2013 were identified. Patients with Tönnis grade 1 were propensity matched in a 1:2 ratio by age, sex, and body mass index (BMI) to patients with Tönnis grade 0. Patient-reported outcomes (PROs) were collected at varying timepoints including preoperatively and 1, 2, 5, and 10 years postoperatively and compared between the 2 cohorts. Rates of minimal clinically important difference (MCID) and Patient Acceptable Symptom State (PASS) achievement at 10 years were evaluated and compared between groups. Rates of secondary surgery including revision hip arthroscopy and conversion to total hip arthroplasty (THA) were evaluated. Gross survivorship between cohorts was evaluated using a Kaplan-Meier gross survivorship curve. A subanalysis was performed comparing patients with Tönnis grade 1 who converted to THA and those who did not.

RESULTS

A total of 31 patients with Tönnis grade 1 (age, 42.6 ± 9.0 years; BMI, 28.0 ± 6.3) were successfully matched to 62 patients with Tönnis grade 0 (age, 42.1 ± 8.5, P = .805; BMI, 26.1 ± 3.9, P = .117). Both the Tönnis grade 1 and Tönnis grade 0 groups demonstrated significant improvements regarding all PROs at minimum 10 years (P < .05 for all), except for the Hip Outcome Score Activities of Daily Living subscale (HOS-ADL) (P = .066) in the Tönnis grade 1 cohort. No significant difference (P > .05 for all) was noted between cohorts regarding any 10-year PRO. When the authors evaluated comparisons between preoperative and 1-, 2-, 5-, and 10-year PRO measures, significant differences were noted between cohorts regarding 2-year HOS-ADL (P = .021), Hip Outcome Score Sports-Specific subscale (P = .016), and modified Harris Hip Score (P = .026); otherwise, differences did not reach significance. High rates of 10-year MCID and PASS achievement were seen, with no significant differences between groups. Patients with Tönnis grade 1 had significantly higher rates of conversion to THA compared with patients who had Tönnis grade 0 (25.8% vs 4.8%; P = .006). Patients with Tönnis grade 1 had significantly lower gross survivorship compared with those who had Tönnis grade 0 (71.0% vs 85.5%, respectively; P = .04).

CONCLUSION

Hip arthroscopy confers comparable postoperative clinical improvements to patients who have FAIS with and without mild OA; however, the benefits among patients with mild OA may be less durable. Patients with Tönnis grade 1 had significantly higher conversion to THA and reduced gross survivorship compared with patients with no evidence of preoperative OA, suggesting that patients with evidence of OA may need to be cautioned on the higher rate of conversion surgery.

A Matched Comparison of the Rates of Achieving the Minimal Clinically Important Difference Following Conversion and Primary Total Hip Arthroplasty

BACKGROUND

Patient-reported outcome measures (PROMs) are often lower following conversion total hip arthroplasty (cTHA) compared to matched primary total hip arthroplasty (THA) controls. However, the minimal clinically important differences (MCIDs) for any PROMs are yet to be analyzed for cTHA. This study aimed to (1) determine if patients undergoing cTHA achieve primary THA-specific 1-year PROM MCIDs at comparable rates to matched controls undergoing primary THA and (2) establish 1-year MCID values for specific PROMs following cTHA.

METHODS

A retrospective case-control study was conducted using 148 cases of cTHA which were matched 1:2 to 296 primary THA patients. Previously defined anchor values for 2 PROM measures in primary THA were used to compare cTHA to primary THA, while novel cTHA-specific MCID values for 2 PROMs were calculated through a distribution method. Predictors of achieving the MCID of PROMs were analyzed through multivariate logistic regressions.

RESULTS

Conversion THA was associated with decreased odds of achieving the primary THA-specific 1-year Hip dysfunction and Osteoarthritis Outcome Score for Joint Replacement PROM (Odds Ratio: 0.319, 95% Confidence Interval: 0.182-0.560, P < .001) and Patient Reported Outcomes Measurement Information System Physical Function Short-Form-10a PROM (Odds Ratio: 0.531, 95% Confidence Interval: 0.313-0.900, P = .019) MCIDs in reference to matched primary THA patients. Less than 60% of cTHA patients achieved an MCID. The 1-year MCID of the Hip dysfunction and Osteoarthritis Outcome Score for Joint Replacement and Patient Reported Outcomes Measurement Information System Physical Function Short-Form-10a specific to cTHA were +10.71 and +4.68, respectively.

CONCLUSION

While cTHA is within the same diagnosis-related group as primary THA, patients undergoing cTHA have decreased odds of achieving 1-year MCIDs of primary THA-specific PROMs.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Patients Undergoing Primary Hip Arthroscopy Report Favorable Outcomes at Minimum 10 Year Follow-Up: A Systematic Review

PURPOSE

(1) To evaluate minimum 10-year PROs (patient-reported outcomes) and survivorship after primary hip arthroscopy and (2) to identify predictors of failure for secondary arthroscopy and conversion to total hip arthroplasty (THA).

METHODS

A systematic review of the literature was conducted with the following key words: "hip arthroscopy," "long-term," "outcomes," "ten-year," "survivorship," "10-year," "15-year," "fifteen-year," 20-year," "twenty-year," and "femoroacetabular impingement" in PubMed and Embase in March 2022 using the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Level I to Level IV evidence was included and reported on minimum 10-year outcomes or greater after primary hip arthroscopy. Long-term studies were defined as minimum 10-year follow-up in accordance with established standards in the literature. Case reports, review articles, technique articles, and opinion articles were excluded. Articles not in English were excluded. Title, author, publication date, study design, demographic, number of hips, follow-up time, study period, indications for hip arthroscopy, PROs, predictors of failure for THA, and rates of secondary surgeries were recorded. Survivorship was defined as a nonconversion to THA. P < .05 was defined as statistical significance.

RESULTS

Twelve studies met the inclusion criteria. In total, 4 studies were Level III, and 8 studies were Level IV. A total of 1,344 hips were included, and follow-up ranged from 10 to 20 years. Femoroacetabular impingement syndrome was the most common indication for hip arthroscopy. Ten of the 12 studies reported on PROs, and 8 studies reported significant improvement after hip arthroscopy at long-term follow-up. The remaining 2 studies reported favorable outcomes that satisfied clinical benefit thresholds at minimum 10-year follow-up. Five studies reported clinical benefit where each patient cohort achieved 80% minimal clinically important difference and 75% patient acceptable symptomatic state for at least one PRO. Rates of secondary arthroscopy ranged from 4.5% to 24%, and rates of conversion to THA varied from 0% to 44.1%. Older age and chondral damage were the most commonly cited predictors for conversion to THA.

CONCLUSIONS

At long-term follow-up, patients who underwent primary hip arthroscopy demonstrated favorable outcomes and variable rates of secondary surgeries. Patients undergoing hip arthroscopy within the last 20 years with Tönnis grade <1 and labral repair experienced greater than 90% survivorship. Chondral damage and older age were the most cited predictors for conversion to THA.

LEVEL OF EVIDENCE

Level IV, systematic review of Level III and Level IV studies.

Ultrasound Demonstrates Potential in Identify Proximal Femoral Morphology Before and After Cam Resection: A Cadaveric Study

PURPOSE

(1) To compare alpha angles measured on fluoroscopy with those measured on ultrasound pre- and postosteoplasty and (2) to determine whether ultrasound can adequately assess cam deformity correction.

METHODS

Twelve full-body specimens (20 hips) were analyzed. Images using fluoroscopy and ultrasound were captured of the operative hip with the hip in 6 consistent positions: 3 views in hip extension (neutral [N], 30° internal rotation [IR], and 30° external rotation [ER]) and 3 views in hip flexion of 50° (neutral [F-N], 40° external rotation [F-ER40], and 60° external rotation [F-ER60]). A curved-array ultrasound transducer probe was used with the transducer placed in line with the femoral neck to evaluate the proximal femoral morphology. An open femoral osteoplasty using an anterior approach was performed. Fluoroscopy and ultrasound were again used to capture images with the hip in the same 6 positions. Bland-Altman plots were used to determine whether fluoroscopic and ultrasound alpha angles agreed at each position. Independent t-tests were used to compare the alpha angles between the 2 modalities at each position, and paired t-tests were used to compare preoperative and postoperative alpha angles at each position.

RESULTS

No significant differences between the alpha angle on fluoroscopy and ultrasound at all 6 positions were appreciated preosteoplasty. The mean preoperative alpha angle on ultrasound in each position was as follows: N (55.4° ± 5.9° vs 43.0° ± 2.1°), IR (55.1° ± 5.3° vs 43.9° ± 5.5°), ER (58.6° ± 5.6° vs 42.8° ± 3.0°), F-N (53.9° ± 5.5° vs 41.6° ± 3.3°), F-ER40 (55.5° ± 4.6° vs 41.5° ± 2.7°), and F-ER60 (57.9° ± 6.5° vs 41.2° ± 4.2°). The mean preoperative and postoperative alpha angle on fluoroscopy in each position were as follows: N (56.0 ± 12.8° vs 43.1 ± 2.1°), IR (54.1 ± 13.4° vs 41.9 ± 2.9°), ER (61.2 ± 11.0° vs 44.2 ± 1.9°), F-N (57.9 ± 10.6° vs 44.0 ± 2.3°), F-ER40 (59 ± 8.2° vs 42 ± 2.2°), and F-ER60 (55 ± 7.6° vs 41.1 ± 2.6°). Postosteoplasty, there was no significant difference between the mean alpha angle on fluoroscopy versus ultrasound in any position except F-N (44.0 ± 2.3 vs 41.6 ± 3.3, P = .015). Bland-Altman plots showed a high level of agreement between alpha angle values on fluoroscopy and ultrasound at all positions pre- and postosteoplasty. There was a significant reduction in alpha angle measured on ultrasound and fluoroscopy at each position following osteoplasty. There were no significant differences in the delta of the pre- and postosteoplasty alpha angle measurements between fluoroscopy and ultrasound.

CONCLUSIONS

Ultrasound is a useful tool for assessing a cam deformity in patients with femoroacetabular impingement syndrome and for determining adequate resection of a cam deformity intraoperatively.

CLINICAL RELEVANCE

Due to the inherent limitations and risks of the fluoroscopy, it is worth evaluating other nonionizing imaging modalities. Ultrasound has potential to be an accessible, cost-effective, and safe imaging modality that lacks radiation and is commonly used for intra-articular hip injections and dynamic examination of the hip.

Effect of Anchor Density on Functional Outcomes After Arthroscopic Hip Labral Repair

BACKGROUND

While labral repair has been widely adopted as the first line treatment for labral injury during hip arthroscopy, there is no widespread consensus on the procedural technique, including the number of anchors that should be used to avoid recurrent instability and revision surgery.

PURPOSE

To determine if anchor density can predict patient-reported outcomes after arthroscopic labral repair in the hip.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients aged 18 to 50 years who underwent primary hip arthroscopic surgery with labral repair between January 2011 and December 2016 were identified from a prospectively collected database. Exclusion criteria consisted of previous ipsilateral surgery, osteoarthritis (Tönnis grade >1), and severe cartilage defects (Outerbridge grade III/IV) or concomitant labral reconstruction, capsular reconstruction, or microfracture. Minimum 2-year patient-reported outcomes (modified Harris Hip Score [mHHS], Hip Outcome Score [HOS]-Activities of Daily Living [ADL], HOS-Sport Specific Subscale [SSS], 12-Item Short Form Health Survey [SF-12]), rates of achieving the minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) for each score, revision surgery rate, and rate of conversion to total hip arthroplasty (THA) were compared based on anchor density (number of anchors per millimeter of labral tear).

RESULTS

A total of 634 hips (575 patients) with a mean age of 30.4 ± 9.5 years (range, 18.0-49.9 years) met inclusion criteria. The mean labral tear size was 31 ± 11 mm (range, 2-70 mm) with a median number of anchors used for labral repair of 3 (range, 1-7) and mean anchor density of 0.11 ± 0.08 anchors (range, 0.03-1.33) per millimeter of labral tear. Hips with a minimum 2-year follow-up (451/634 [71.1%]) had significant improvements on the mHHS, HOS-ADL, HOS-SSS, and SF-12 Physical Component Summary (P < .001 for all). There was no significant correlation detected between anchor density or number of anchors used and postoperative scores (correlation coefficient range, -0.05 to 0.17; P > .05 for all). The rate of revision surgery was 6.4% (28 patients), with 8 hips found to have labral tears and/or deficiency on revision. Additionally, 6 hips (1.3%) had to undergo THA at a mean of 3.6 ± 2.1 years (range, 2.0-5.5 years).

CONCLUSION

Anchor density did not have a correlation with postoperative outcomes, achieving the MCID or PASS, revision hip arthroscopic surgery, complications, or conversion to THA.

Ultrasound Can Determine Joint Distraction During Hip Arthroscopy but Fluoroscopic-Guided Portal Placement Is Superior

Purpose

To compare joint distraction measured on ultrasound (US) with joint space width (JSW) measured on fluoroscopy in hip arthroscopy and to determine whether ultrasound guidance is as safe and effective as fluoroscopy, the current gold standard, for establishing arthroscopic portals.

Methods

Cadaveric whole-body specimens were positioned supine and subjected to 60 lbs. of unilateral axial traction using a distal femoral Steinman pin. Joint distraction was measured via JSW on fluoroscopic and ultrasound images. A single, fellowship-trained orthopaedic surgeon established anterolateral arthroscopy portals via ultrasound or fluoroscopic guidance in a randomized sequence. Total procedure time, number of times the spinal needle pierced the capsule, and iatrogenic chondral or labral injury were recorded.

Results

Twelve full-body specimens (20 hips) underwent distraction, and 17 hips underwent portal placement with fluoroscopic (n = 8) or ultrasound (n = 9) guidance. JSW measured on ultrasound was significantly less laterally (13.0 vs 9.2 mm, P < .001), apically (16.7 vs 9.2 mm, P < .001), and medially (17.9 vs 9.2 mm, P < .001). Successful portal entry was achieved in every specimen. Average procedure time was 133 ± 51 seconds for the fluoroscopy group and 371 ± 260 seconds for the ultrasound group (P = .026). Fluoroscopic guidance required significantly less needle insertion attempts at 1.13 compared with 3.33 attempts for ultrasound (P = .022). Labral damage was greater in the ultrasound group at 66.67% compared with 12.50% for fluoroscopy (P = .0497).

Conclusions

Joint distraction measured on ultrasound can be used to subjectively determine if the joint is adequately distracted in hip arthroscopy. Ultrasound-guided portal placement was associated with more needle insertion attempts, iatrogenic injury of the labrum, and overall procedure time in comparison to fluoroscopic guidance.

Clinical Relevance

Fluoroscopy is the gold standard to confirm adequate joint distraction, aid in establishing arthroscopy portals, and evaluate resection of the femoral head during hip arthroscopy but exposes the patient to ionizing radiation, requires additional operators in the operating room, and involves the need for a heavy lead shield. Alternatives to fluoroscopy are needed, but ultrasound has not proven superior in our cadaveric model.

Personalized Medicine Using Predictive Analytics: A Machine Learning-Based Prognostic Model for Patients Undergoing Hip Arthroscopy

BACKGROUND

Personalized medicine models to predict outcomes of orthopaedic surgery are scarce. Many have required data that are only available postoperatively, mitigating their usefulness in preoperative decision making.

PURPOSE

To establish a method for predictive modeling to enable individualized prognostication and shared decision making based on preoperative patient factors using data from a prospective hip preservation registry.

STUDY DESIGN

Cohort study (Prognosis); Level of evidence, 2.

METHODS

Preoperative data of 2415 patients undergoing hip arthroscopy for femoroacetabular impingement syndrome between February 2008 and November 2017 were retrospectively analyzed. Two machine-learning analyses were evaluated: Tree-structured survival analysis (TSSA) and Cox proportional hazards modeling for predicting time to event and for computing hazard ratios for survivorship after hip arthroscopy. The Fine-Gray model was similarly used for repeat hip arthroscopy. Variables were selected for inclusion using the minimum Akaike Information Criterion (AIC). The stepwise selection was used for the Cox and Fine-Gray models. A web-based calculator was created based on the final models.

RESULTS

Prognostic models were successfully created using Cox proportional hazards modeling and Fine-Gray models for survivorship and repeat hip arthroscopy, respectively. The Harrell C-statistics of the Cox model calculators for survivorship after hip arthroscopy and the Fine-Gray model for repeat hip arthroscopy were 0.848 and 0.662, respectively. Using the AIC, 13 preoperative variables were identified as predictors of survivorship, and 6 variables were identified as predictors for repeat hip arthroscopy. In contrast, the TSSA model performed poorly, resulting in a Harrell C-statistic <0.6, rendering it inaccurate and not interpretable. A web-based calculator was created based on these models.

CONCLUSION

This study successfully created an institution-specific machine learning-based prognostic model for predictive analytics in patients undergoing hip arthroscopy. Prognostic models to predict survivorship and the need for repeat surgeries were both adapted into web-based tools to assist the physician with shared decision making. This prognostic model may be useful at other institutions after performing external validation. Additionally, this study may serve as proof of concept for a methodology for the development of patient-specific prognostic models. This methodology may be used to create other predictive analytics models in different realms of orthopaedic surgery, contributing to the evolution from evidence-based medicine to personalized medicine.