Innovations in Joint Preservation Procedures for the Dysplastic Hip "The Periacetabular Osteotomy"

Bernese periacetabular osteotomy (PAO): from its local inception to its worldwide adoption

The development of the Bernese periacetabular osteotomy (PAO) is based on a structured approach starting with an analysis of the preexisting procedures to improve the coverage of the femoral head and was followed by a list of additional goals and improvements. Cadaveric dissections with a detailed description of the vascular supply of acetabulum and periacetabular bone set the stage for an intrapelvic approach, which offered the largest acetabular correction possible combined with safe intracapsular access. The final composition of osteotomies required the development of several instruments and cutting devices before the feasibility could be tested on a series of cadaveric hips.While the sequence of the osteotomies remained largely unchanged over time (except for the pubic and ischial osteotomies), several propositions for an easier/less invasive approach have been discussed; some made it into standard practice. Efforts were undertaken to optimize the learning curve and minimize failures using video-clips, hands-on courses, fellowships, publications, and ongoing mentoring programs. In retrospect, with almost 40 years of experience, such efforts have promoted a worldwide adoption of the Bernese periacetabular osteotomy.

Top 100 cited studies in periacetabular osteotomy for acetabular dysplasia: do lower levels of evidence guide clinical practice?

As no prior study has examined the citations profile of key articles related to periacetabular osteotomy (PAO), our analysis utilized the Web of Science database to (1) identify the most-cited clinical studies relating to PAO in the management of acetabular dysplasia and (2) assess any trends over time with respect to the quality of literature. The top 100 highest-cited studies related to PAO had a mean of 49 citations (range, 6-666 per study). With respect to the level of evidence, most studies had level IV evidence (58%); 1% level I, 16% level II, 28% level III and 2% level V. Most studies were retrospective ( n  = 86); there were 14 prospective studies (including one randomized study). The most common study designs were case series ( n  = 58) and cohort ( n  = 16), followed by matched-cohort ( n  = 13) and case-control ( n  = 6). The mean ± SD Newcastle-Ottawa Scale score was 6.48 ± 1.31. A total of 59 and 41 of the included articles were classified as high risk and high quality, respectively. No studies were classified as very high risk. As a whole, our analysis demonstrated that currently available PAO literature is still of low quality and of low level of evidence. While PAO has been well-documented as a durable procedure for addressing acetabular dysplasia, future research must focus on higher quality, randomized and prospective data to answer key clinical or technique-related topics.

Athletes Undergoing Concomitant Hip Arthroscopy and Periacetabular Osteotomy Demonstrate Greater Than 80% Return-to-Sport Rate at 2-Year Minimum Follow-Up

PURPOSE

To report minimum 2-year follow-up patient-reported outcomes and return-to-sport (RTS) rates in athletes undergoing concomitant hip arthroscopy and periacetabular osteotomy (PAO) to treat acetabular dysplasia and intra-articular pathologies such as cam deformity and labral tears.

METHODS

We reviewed the data of consecutive athletes undergoing concomitant primary hip arthroscopy and PAO for acetabular dysplasia and cam deformity from November 2010 to December 2018. Patients were included in the study if they had the following preoperative and minimum 2-year postoperative scores: modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), and Hip Outcome Score-Sport-Specific Subscale (HOS-SSS). The percentage of patients who achieved the minimal clinically important difference was recorded, in addition to RTS status.

RESULTS

A total of 29 athletes (29 hips) were included, with a mean follow-up time of 34.1 ± 7.9 months, mean age of 26.0 ± 8.7 years, and mean body mass index of 23.7 ± 3.4. These athletes showed significant improvements in the mHHS, NAHS, and HOS-SSS from baseline to latest follow-up (P < .001). The minimal clinically important difference was achieved at high rates for the mHHS (82.8%), NAHS (86.2%), and HOS-SSS (79.3%). Athletes who attempted to RTS successfully returned at a rate of 81.8%.

CONCLUSIONS

Athletes undergoing concomitant hip arthroscopy and PAO showed significant improvements in patient-reported outcomes at minimum 2-year follow-up and had an RTS rate of 81.8%.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Treatment decisions after interdisciplinary evaluation for nonarthritic hip pain: A randomized controlled trial

BACKGROUND

Physical therapy and hip arthroscopy are two viable treatment options for patients with nonarthritic hip pain (NAHP); however, patients may experience considerable decisional conflict when making a treatment decision. Interdisciplinary evaluation with a physical therapist and surgeon may better inform the decision-making process and reduce decisional conflict.

OBJECTIVE

To identify the extent to which an interdisciplinary evaluation between a surgeon, physical therapist, and patient influences treatment plans and decisional conflict of persons with NAHP.

DESIGN

Randomized controlled trial.

SETTING

Hip preservation clinic.

PARTICIPANTS

Adults with primary NAHP.

INTERVENTIONS

Participants were randomized to receive a standard (surgeon) or interdisciplinary (surgeon+physical therapist) evaluation. Surgeon evaluations included patient interview, strength and range-of-motion examination, palpation, gross motor observation, and special testing. Interdisciplinary evaluations started with the surgeon evaluation, then a physical therapist evaluated movement impairments during sitting, sit-to-stand, standing, single-leg stance, single-leg squat, and walking. All evaluations concluded with treatment planning with the respective provider(s).

OUTCOME MEASURES

Treatment plan and decisional conflict were collected pre- and postevaluation. Inclusion of physical therapy in participants' postevaluation treatment plans and postevaluation decisional conflict were compared between groups using chi-square tests and Mann-Whitney U tests, respectively.

RESULTS

Seventy-eight participants (39 in each group) met all eligibility criteria and were included in all analyses. Sixty-six percent of participants who received an interdisciplinary evaluation included physical therapy in their postevaluation treatment plan, compared to 48% of participants who received a standard evaluation (p = .10). Participants who received an interdisciplinary evaluation reported 6.3 points lower decisional conflict regarding their postevaluation plan (100-point scale; p = .04). The interdisciplinary and standard groups reduced decisional conflict on average 24.8 ± 18.9 and 23.6 ± 14.6 points, respectively.

CONCLUSIONS

Adding a physical therapist to a surgical clinic increased interest in physical therapy treatment, but this increase was not statistically significant. The interdisciplinary group displayed lower postevaluation decisional conflict; however, both groups displayed similar reductions in decisional conflict from pre- to postevaluation. This study also demonstrated the feasibility of an interdisciplinary evaluation in a hip preservation clinic.

A comparison of 6-month outcomes between periacetabular osteotomy with concomitant hip arthroscopy to isolated hip arthroscopy for femoroacetabular impingement

PURPOSE

To compare early outcomes of periacetabular osteotomy (PAO) with concomitant hip arthroscopy to isolated hip arthroscopy for femoroacetabular impingement (FAI) and chondrolabral pathology using patient-reported outcomes measurement information system (PROMIS).

MATERIALS AND METHODS

Consecutive patients scheduled for PAO with concomitant hip arthroscopy (PAO + HA) or isolated hip arthroscopy (HA) between the ages of 15 and 30 years old were prospectively included in the study. Based on power analysis, subjects were recruited until there were 22 subjects in the PAO + HA group. These subjects were then gender matched to the HA group. The PROMIS, with six subscales and two global health measures, were completed during preoperative and 6-month follow-up visits. One-way ANOVA was performed to compare intake information of age, symptom duration, body mass index, and Beighton scores as well as preoperative and 6-month postoperative PROMIS scores between the PAO + HA and HA.

RESULTS

22 consecutive subjects undergoing PAO + HA were all females (average age 20.0 years) and matched to 22 consecutive females (average age 22.6) in the HA group. ANOVA did not find a significant difference between the two groups when comparing intact information, with exception of age (p = 0.04). A significant difference was also not identified (p ≥ 0.05) between the two groups on preoperative or 6-month postoperative PROMIS scores. The largest difference in 6-month postoperative scores between the two groups was 4.4 points on physical function subscale.

CONCLUSION

Outcomes at 6 months were not significantly different when comparing PAO + HA to HA for FAI and chondrolabral pathology in females under 30 years of age. The more extensive surgery with a prolonged protective period associated with PAO do not seem to negatively impact outcomes at 6 months when compared to HA. These finding support the use of PAO + HA, particularly if the patient and/or surgeon were concerned about prolonged disability, metal health issues, and/or higher pain levels that might be associated with the PAO procedure.

Femoral version deformities alter joint reaction forces in dysplastic hips during gait

Developmental dysplasia of the hip (DDH) causes hip instability and early-onset osteoarthritis. The focus on pathomechanics in DDH has centered on the shallow acetabulum, however there is growing awareness of the role of femoral deformities in joint damage. The objective of this study was to determine the influence of femoral version (FV) on the muscle and joint reaction forces (JRFs) of dysplastic hips during gait. Magnetic resonance images, in-vivo gait data, and musculoskeletal models were used to calculate JRFs and simulate changes due to varying FV deformities. Rotation about the long axis of the femur was added in the musculoskeletal models to simulate FV values from -5° (relative retroversion) to + 35° (increased anteversion). In our simulations, FV deformities caused the largest changes to the anteroposterior and resultant JRFs. From a normal FV of 15°, a 15° increase in femoral anteversion caused JRFs to be less posterior in early stance (Δ = 0.43 ± 0.22 xbodyweight) and more anterior in late stance (Δ = 0.60 ± 14 xbodyweight). Relative retroversion caused anteroposterior changes that were similar to anteversion in early stance but opposite in late stance. Resultant JRFs experienced the largest changes during late stance where anteversion raised the peak by 0.48 ± 0.15 xbodyweight and relative retroversion lowered the peak by 0.32 ± 0.30 xbodyweight. Increasing anteversion increased hip flexor and abductor muscle forces, which caused the changes in JRFs. Identifying how FV deformities influence hip joint loading can elucidate their role in the mechanisms of hip degeneration in patients with DDH.

Influence of shelf acetabuloplasty on the outcomes of total hip arthroplasty in hips with dysplasia: a case-control study

INTRODUCTION

Total hip arthroplasty (THA) in young adults, especially in those with hip dysplasia, is affected by wear and acetabular fixation problems. Shelf acetabuloplasty is performed to delay THA in patients with acetabular dysplasia. Thus, we conducted a retrospective, continuous case-control study at a single healthcare facility to analyze (1) the influence of prior shelf acetabuloplasty on the survival of a subsequent THA and (2) the functional outcomes.

MATERIALS AND METHODS

We evaluated 105 patients (124 THA) who underwent THA due to hip dysplasia: 54 patients (61 THA) were included in the THA post-shelf acetabuloplasty group (case group) and 51 patients (63 THA) in the THA for dysplasia group (control group).

RESULTS

At 15 years' follow-up, 89% of patients (95% CI: 84-91%) in the shelf group and 83% (95% CI: 81-90%) in the dysplasia group had not undergone surgical revision. This difference between groups was not statistically significant (p = 0.566). The functional outcomes were satisfactory in both groups; however, they were significantly better in the dysplasia group than in the shelf group based on the Merle d'Aubigne and Postel score (16.9 vs 16.0 min-max: 14-18 vs 3-18) (p = 0.01), Harris Hip score (90.0 vs 84.7, min-max: 62-100 vs 22-100) (p = 0.017), and the Oxford-12 (18/60 vs 21/60, min-max: 45-12 vs 51-12) (p = 0.04).

CONCLUSION

Shelf acetabuloplasty before THA does not negatively affect THA survivorship. The functional outcomes appear to be better in the hips that did not undergo shelf acetabuloplasty, although the results were good in both groups.

[Mid-term effectiveness of periacetabular osteotomy through modified ilioinguinal approach for acetabular dysplasia in adults]

Objective

To investigate the mid-term effectiveness of periacetabular osteotomy (PAO) through modified ilioinguinal approach for acetabular dysplasia in adults.

Methods

Between January 2016 and December 2018, 39 patients (43 hips) with acetabular dysplasia who met the selection criteria were enrolled in the study and their clinical data were retrospectively analyzed. All patients were treated with PAO via modified ilioinguinal approach (firstly, the skin and superficial facia were cut via the traditional ilioinguinal approach, and the deep tissues were cut via the modified iliac-femoral approach). There were 3 males (3 hips) and 36 females (40 hips) with an average age of 36 years (range, 18-51 years). Among them, 35 cases of lesions involved single hip and 4 cases of lesions involved bilateral hips. The disease duration ranged from 4 to 96 months, with a median of 18 months. According to the modified Tönnis grading for osteoarthritis, 35 hips were classified as grade 0, 6 hips as grade Ⅰ, and 2 hips as grade Ⅱ. All patients had different degrees of hip pain. The preoperative visual analogue scale (VAS) score of pain was 4.7±0.8, and the modified Harris hip score was 78.5±8.6. The lateral centre-edge angle (LCEA) was (10.52±10.83)°, and the acetabular index (AI) was (26.89±9.07) °. The operation time, intraoperative blood loss, and the incidence of complications were recorded. LCEA, AI, and the progression of osteoarthritis were reviewed by X-ray films. The function and pain of hip joint were evaluated by modified Harris hip score and VAS score.

Results

All operations were successfully completed. The operation time was 90-150 minutes, with an average of 130 minutes. The volume of intraoperative blood loss was 350-600 mL, with an average of 500.6 mL. All patients were followed up 17-52 months, with an average of 32.7 months. Postoperative numbness of the lateral femoral cutaneous nerve occurred in 3 cases, and no other complications occurred. At last follow-up, the modified Harris hip score was 97.7±3.7 and VAS score was 0.9±1.1, both of which were better than those before operation ( P<0.05). At 1 year after operation, X-ray films showed that the all osteotomies healed. In term of the modified Tönnis grading for osteoarthritis, 1 hip downgraded from grade 1 to grade 0, while the remaining hips stayed unchanged. At last follow-up, LCEA and AI were (27.54±8.49) ° and (11.30±5.53) °, respectively, which were significantly different from those before operation ( P<0.05).

Conclusion

PAO through modified ilioinguinal approach is effective in relieving pain and restoring hip function in adults with acetabular dysplasia, which can overcome the disadvantages of the traditional ilioinguinal approach, and may delay the development of osteoarthritis.

Associations Between Movement Impairments and Function, Treatment Recommendations, and Treatment Plans for People With Femoroacetabular Impingement Syndrome

OBJECTIVE

The purpose of this study was to describe movement impairments for persons with femoroacetabular impingement syndrome and their association with function, treatment recommendations, and treatment plans.

METHODS

This report is a secondary, observational analysis of a clinical trial dataset in which participants received an interdisciplinary evaluation from a surgeon and physical therapist. The therapist documented frontal and sagittal plane movement impairments across 6 functional tasks. Associations between number of impairments in each plane and function (33-item International Hip Outcome Tool [iHOT33]) were evaluated using Pearson or Spearman correlations. Joint provider recommendations (physical therapist and surgeon) and participant-reported treatment plans were dichotomized based on the inclusion of physical therapy or not. Logistic regressions were used to examine the effects of (1) iHOT33, total movement impairments, and previous physical therapist treatment on joint provider recommendation and (2) these same variables along with joint provider recommendation on participant treatment plan; prevalence ratios and 95% CIs were reported for significant contributors.

RESULTS

Thirty-nine participants demonstrated an average iHOT33 of 35.0 (SD = 19.5) and presented with a median 5 frontal and 3 sagittal plane impairments. More frontal plane impairments were associated with worse iHOT33 scores. Twenty-seven participants received a joint provider recommendation that included physical therapy; no significant contributors to these recommendations were identified. Twenty-four of the 27 participants with a physical therapist recommendation included physical therapy in their treatment plan. Two additional participants did not receive a physical therapist recommendation but included physical therapy in their plan. Joint provider recommendation was the only significant contributor to the participant-reported plan (prevalence ratio = 7.06; 95% CI = 3.25-7.97).

CONCLUSION

Persons with femoroacetabular impingement syndrome displayed clinically observable movement impairments that were associated with worse function. Joint provider recommendations strongly influenced participants' treatment plans to pursue physical therapy.

IMPACT

Physical therapists contribute new information to surgical examinations regarding movement. Joint recommendations from the physical therapist and the surgeon can influence patients' decisions to pursue physical therapy.

Periacetabular Osteotomy and Femoral Head Allograft for Hip Dysplasia and Femoral Head Cyst: A Case Report

CASE

A 34-year-old woman with developmental dysplasia of the hip (DDH) presented with chronic left hip pain related to a femoral head cyst. The patient strongly preferred a joint-preserving option. Periacetabular osteotomy (PAO) has shown reliable options for managing DDH, and femoral head fresh osteochondral allograft (FOCA) can be performed for cysts. We performed these procedures concomitantly for the first time. At 1-year follow-up, the patient had functional, pain-free motion and high satisfaction.

CONCLUSION

PAO and femoral head FOCA can be performed concomitantly with a common, anterior hip approach. They are a viable, joint-preserving option for patients with DDH and osteochondral lesions.

Arthroscopic Hip Capsular Plication With Augmentation Using a Bioinductive Collagen Implant

With advancements in arthroscopic techniques and instrumentation, hip arthroscopy has become an increasingly used technique to treat soft-tissue and osseous pathologies about the hip. Patient predisposition to labral and capsular injuries can present as femoroacetabular impingement or hip dysplasia, sometimes in combination. Capsular management continues to be a topic of debate, with capsular repair becoming the standard of care in most cases. Furthermore, in cases of borderline dysplasia and microinstability, considerations for not only capsular repair but with plication has shown significant clinical success. Although plication in this setting has shown promise, given a 20% failure rate, we suggest capsular augmentation to bolster the repair. We present a technique of capsular augmentation using a bioinductive collagen implant (Smith & Nephew) to improve the capsular integrity following repair and plication. The benefits of this implant are easy delivery through standard arthroscopic portals and secure fixation to the capsular tissue. These implants have a proven track record in the shoulder and serve as a scaffold for improved tissue quality, and their application in hip arthroscopy has potential by increasing the integrity of the capsular repair. Future studies are needed to address the clinical outcomes of this technique.

Modified iliac spine wafer osteotomy for exposure during Bernese periacetabular osteotomy

The Bernese periacetabular osteotomy (PAO) is a well-established procedure for the management of symptomatic hip dysplasia. The associated Smith–Petersen exposure offers excellent visualization of the acetabulum and control of acetabular osteotomy and mobilization. The traditional exposure of the true pelvis involves osteotomy of the iliac wing in order to mobilize the sartorial and inguinal ligament insertion. However, full osteotomy of the iliac spine may necessitate screw fixation if a relatively large segment of bone is included. A known complication with screw fixation of the iliac wing osteotomy involves failure of fixation and screw back out. Moreover, the screw may irritate the patient even in the setting of adequate fixation. A larger osteotomy may also injure the lateral femoral cutaneous nerve (LFCN) as it travels near the anterior–superior spine. To minimize the risk of these potential complications, a wafer osteotomy may be used to develop a sleeve of tissue involving the sartorial insertion. This sleeve also mobilizes the entirety of the LFCN medially and affords protection throughout the procedure. Furthermore, the wafer osteotomy may be re-fixed to the stable pelvis during closure with simple heavy suture fixation alone, avoiding screw insertion or associated removal. Because only a wafer or bone is taken during the spine osteotomy, more bone is available at the anterior–superior iliac spine for fixation of the mobile fragment after repositioning. In this technical note, we describe the wafer osteotomy technique in further detail.

Detailing postoperative pain and opioid utilization after periacetabular osteotomy with automated mobile messaging

In the setting of periacetabular osteotomy (PAO), this investigation sought to (i) describe patient-reported pain scores and opioid utilization in the first 6 weeks following surgery and (ii) evaluate the effectiveness of postoperative communication using a robotic mobile messaging platform. Subjects indicated for PAO were enrolled from a young adult hip clinic. For the first 2 weeks after surgery, subjects received daily mobile messages inquiring about pain level on a 0–10 scale and the number of opioid pain medication tablets they consumed in the previous 24 h. Messaging frequency decreased to 3 per week in Weeks 3–6. Pain scores, opioid utilization and response rates with our mobile messaging platform were quantified for the 6-week postoperative period. Twenty-nine subjects underwent PAO. Twenty-one had concurrent hip arthroscopy. Average daily pain scores decreased over the first four postoperative days. Average pain scores reported were 5.9 ± 1.9, 4.1 ± 3.3 and 3.0 ± 3.5 on Day 1, Day 14 and Week 6, respectively. Reported opioid tablet utilization was 5.0 ± 3.2, 2.2 ± 2.0 and 0.0 ± 0.0 on Days 1 and 14 and at 6 weeks. Response rate for participants completing the 6-week messaging protocol was 84.1%. Patient-reported pain scores decreased over the first two postoperative weeks following PAO before plateauing in weeks 3–6. Opioid pain medication utilization increased in the first postoperative week before gradually declining to no tabs consumed at 6 weeks after PAO. Automated mobile messaging is an effective method of perioperative communication for the collection of pain scores and opioid utilization in patients undergoing PAO.

Outcomes of Hip Arthroscopy With Concomitant Periacetabular Osteotomy, Minimum 5-Year Follow-Up

PURPOSE

To report minimum 5-year follow-up results of concomitant hip arthroscopy followed by periacetabular osteotomy (PAO) to treat acetabular dysplasia and intra-articular pathology, such as femoroacetabular impingement syndrome and labral tears.

METHODS

Data were prospectively collected from October 2010 to December 2012. Patients were included in this study if they underwent concomitant hip arthroscopy and PAO and if they had preoperative scores documented for the following measures: modified Harris Hip Score (mHHS), Nonarthritic Hip Score (NAHS), Hip Outcome Score-Sports-Specific Subscale (HOS-SSS), and pain on a visual analog scale (VAS). Patients who underwent reverse PAO to address acetabular retroversion were excluded. Follow-up was considered complete with these outcomes collected after surgery, as well as the abbreviated International Hip Outcome Tool and patient satisfaction on a 0-10 scale. Significance was set at P = .05.

RESULTS

Sixteen patients were eligible, all of whom had complete follow-up at a minimum of 5 years after surgery. There were 13 female subjects. The average age of the patients was 23.5 ± 6.8 years (range, 12.3-35.3 years), and the average body mass index was 24.3 ± 5.6 (range, 14.8-34.2). The mean lateral center-edge angle increased from 14.2° to 31.8° (P < .0001), and the anterior center-edge angle increased from 11.9° to 28.6° (P < .0001). The Tönnis angle of acetabular inclination decreased from 19.3° to 2.6° (P < .0001). The alpha angle decreased from 55.7° to 41.0° (P < .0001). All preoperative radiographs were Tönnis ≤1, and there was no progression of arthritis in radiographs taken at the latest clinical visit. All patient-reported outcomes scores demonstrated significant improvement from preoperative baseline to the minimum 5-year follow-up scores (mHHS, P < .001; NAHS, P < .001; HOS-SSS, P = .001). The VAS score decreased from a preoperative mean of 5.8 to 3.1 at the latest follow-up (P = .007). No conversion to total hip arthroplasty was reported.

CONCLUSIONS

Concomitant hip arthroscopy and PAO appears to be a safe and effective procedure with favorable mid-term outcomes that are durable compared to the short-term.

LEVEL OF EVIDENCE

Level IV, case series.

Concurrent femoral head reduction and periacetabular osteotomies for the treatment of severe femoral head deformities

AIMS

The aims of this study were to review the surgical technique for a combined femoral head reduction osteotomy (FHRO) and periacetabular osteotomy (PAO), and to report the short-term clinical and radiological results of a combined FHRO/PAO for the treatment of selected severe femoral head deformities.

PATIENTS AND METHODS

Between 2011 and 2016, six female patients were treated with a combined FHRO and PAO. The mean patient age was 13.6 years (12.6 to 15.7). Clinical data, including patient demographics and patient-reported outcome scores, were collected prospectively. Radiologicalally, hip morphology was assessed evaluating the Tönnis angle, the lateral centre to edge angle, the medial offset distance, the extrusion index, and the alpha angle.

RESULTS

The mean follow-up was 3.3 years (2 to 4.6). The modified Harris Hip Score improved by 33.0 points from 53.5 preoperatively to 83.4 postoperatively (p = 0.03). The Western Ontario McMasters University Osteoarthritic Index score improved by 30 points from 62 preoperatively to 90 postoperatively (p = 0.029). All radiological parameters showed significant improvement. There were no long-term disabilities and none of the hips required early conversion to total hip arthroplasty.

CONCLUSION

FHRO combined with a PAO resulted in clinical and radiological improvement at short-term follow-up, suggesting it may serve as an appropriate salvage treatment option for selected young patients with severe symptomatic hip deformities.

Arthroscopic Capsular Plication in Patients With Labral Tears and Borderline Dysplasia of the Hip: Analysis of Risk Factors for Failure

BACKGROUND

Hip arthroscopy for the treatment of instability in the setting of borderline dysplasia is controversial. Capsular management in such cases is an important consideration, and plication has been described as a reliable technique, with good midterm outcomes reported when indications are appropriate.

HYPOTHESIS

Patients with borderline dysplasia who have a lower lateral center-edge angle (LCEA) and greater age will be at a higher risk of failure after arthroscopic capsular plication.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Data were retrospectively reviewed for all patients between 15 and 40 years of age who underwent hip arthroscopy from November 2008 to January 2015. Inclusion criteria were an LCEA between 18° and 25°, Tönnis grade ≤1, primary case with capsular plication, and minimum 2-year follow-up. Patients were excluded if they had any history of ipsilateral hip procedure or conditions such as Legg-Calve-Perthes disease, slipped capital femoral epiphysis, rheumatologic disease, and Tönnis grade ≥2. Age, sex, and body mass index data were retrieved for each patient. Patient-reported outcomes (PROs)-including modified Harris Hip Score (mHHS), Non-Arthritic Hip Score (NAHS), Hip Outcome Score-Sports Specific Subscale, and a visual analog scale (VAS) for pain (0-10)-were obtained preoperatively and at a minimum of 2 years postoperatively, in addition to the postoperative International Hip Outcome Tool-12. The "success" group consisted of all patients who achieved the patient acceptable symptomatic state of mHHS ≥74 and had no ipsilateral hip surgery subsequent to their index arthroscopy. The "failure" group was composed of patients who were below the patient acceptable symptomatic state at latest follow-up or required secondary arthroscopy or conversion to total hip arthroplasty. Patient satisfaction and minimal clinically important difference were also calculated. Mean age for the failure group was applied as a cutoff age for subanalysis, and relative risk for failure was determined.

RESULTS

Ninety patients (97 hips; 79.5%) met criteria for the success group, and 25 patients (25 hips) met criteria for the failure group. No significant differences in preoperative baseline scores or VAS were found. However, there did appear to be a trend that the failure group had lower mean preoperative scores for all PRO measures and a higher VAS score. The differences in preoperative mHHS and NAHS closely approached significance ( P = .053). Postoperative PRO, VAS, and patient satisfaction scores of the success group were significantly higher than the failure group. The failure group was significantly older than the success group (28.5 ± 7.8 vs 23.5 ± 7.5 years, P = .005). Patients >35 years old were 2.25 times more likely to fail according to relative risk (95% CI, 1.10-4.60; P = .0266). LCEA did not differ between the groups, and no other risk factors for failure were identified.

CONCLUSION

Stringent criteria for patient selection and meticulous repair or augmentation of the static stabilizers of the hip yielded favorable clinical outcomes in this study cohort with borderline dysplasia. Within this carefully selected group, the analysis revealed that increased age was the main risk factor for failure in the management of borderline hip dysplasia via isolated primary arthroscopic hip surgery with capsular plication.

Canine hip dysplasia: A natural animal model for human developmental dysplasia of the hip

Developmental dysplasia of the hip (DDH) in humans is a common condition that is associated with hip pain, functional limitations, and secondary osteoarthritis (OA). Surgical treatment of DDH has improved in the last decade, allowing excellent outcomes at short- and mid-term follow-up. Still, the etiology, mechanobiology, and pathology underlying this disease are not well understood. A pre-clinical animal model of DDH could help advance the field with a deeper understanding of specific pathways that initiate hip joint degeneration secondary to abnormal biomechanics. An animal model would also facilitate different interventional treatments that could be tested in a rigorous and controlled environment. The dog model exhibits several important characteristics that make it valuable as a pre-clinical animal model for human DDH. Dogs are naturally prone to develop canine hip dysplasia (CHD), which is treated in a similar manner as in humans. Comparable to human DDH, CHD is considered a pre-OA disease; if left untreated it will progress to OA. However, progression to OA is significantly faster in dogs than humans, with progression to OA within 1-2 years of age, associated with their shorter life span compared to humans. Animal studies could potentially reveal the underlying biochemical pathway(s), which can inform refined treatment modalities and provide opportunities for new treatment and prevention targets. Herein, we review the similarities and differences between the two species and outline the argument supporting CHD as an appropriate pre-clinical model of human DDH. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1807-1817, 2018.

Modified Shelf Acetabuloplasty Endoscopic Procedure With Allograft for Developmental Hip Dysplasia Treatment

Hip dysplasia has been identified as one of the leading causes of osteoarthritis. However, hip arthroscopy alone, in the setting of hip dysplasia, remains controversial. In borderline hip dysplasia, with lateral center-edge angle (LCEA) between 18° and 25°, good outcomes have been reported with appropriate capsular and labral management. However, in severe hip dysplasia, with LCEA below 18°, there is an acetabular bony structural deficiency that must be addressed. Even with the potential benefit of hip arthroscopy in addressing intra-articular injuries related to the instability, it cannot be used for soft-tissue procedures. Periacetabular osteotomy remains the gold standard to address that matter; however, its invasive nature along with the long recovery time leaves some patients unwilling to undergo this procedure. New minimally invasive endoscopic procedures, derived from open techniques, describe acetabular autologous bone grafting as an alternative. Donor-side morbidity is always a concern when using autografts; we believe that the use of bone allograft will decrease this potential issue and make the procedure itself less invasive. This Technical Note will describe a type of endoscopic shelf acetabuloplasty using an allograft iliac bone graft.