➢ The most common complications that have been described in association with periacetabular osteotomy include, in decreasing order of cumulative frequency, superficial wound complications, heterotopic ossification, lateral femoral cutaneous nerve dysesthesias, delayed union or nonunion of the osteotomy site, deep hematoma, and postoperative fracture of the posterior column, ischium, or pubis.
➢ Preoperative measures to reduce complication rates for periacetabular osteotomy include appropriate patient selection, surgical mentoring during the learning curve, and optimization of modifiable risk factors.
➢ Intraoperative measures to reduce complication rates include meticulous soft-tissue handling, appropriate lower-limb positioning and protection of neurovascular structures when performing osteotomy cuts, intraoperative fluoroscopy to evaluate osteotomy fragment positioning and to visualize osteotomies in relation to the hip joint, and consideration of using blood conservation strategies to reduce blood loss and need for transfusion.
➢ Postoperative measures include protected weight-bearing in the postoperative period until evidence of osteotomy healing is seen on radiographs and prophylaxis for deep venous thrombosis and heterotopic ossification.
The Bernese periacetabular osteotomy is a surgical procedure used to reorient the acetabulum while preserving posterior column pelvic continuity, retaining the shape of the true pelvis, and allowing for large manipulations in multiple planes1. This procedure has been used in skeletally mature patients with acetabular dysplasia and acetabular version abnormalities to improve femoral head coverage, to translate the hip joint medially, and to redistribute weight-bearing forces more evenly across the acetabulum2,3. Long-term follow-up has shown improvement in hip pain and function after periacetabular osteotomy in patients with acetabular dysplasia4.
When performing a periacetabular osteotomy, it is necessary to have a firm understanding of surgical anatomy and technique, meticulous preoperative planning, and regular postoperative follow-up. Given the complexity and steep learning curve associated with periacetabular osteotomy, there is the potential for several complications in the perioperative period2,5-10. Retrospective and prospective studies have categorized and have defined these complications, and cumulative rates of common complications have been summarized in Table I.
Complication Rates in Periacetabular Osteotomy
In a report of sixty cases, Biedermann et al.7 noted minor complications in twenty-five cases (42%), with dysfunction of the lateral femoral cutaneous nerve as the most common among these patients (30%), and major complications in twenty-two patients (37%), with delayed union or nonunion of the osteotomy as the most common among these patients (13%).
Sierra et al. reviewed the prevalence of major nerve injury after periacetabular osteotomy across a number of high-volume centers11. Femoral and sciatic nerve deficits were reported with a prevalence of approximately 2.1% in patients undergoing periacetabular osteotomy, with combined motor and sensory deficits of the sciatic and peroneal nerves being most common11. The majority of these nerve injuries were transient and resolved over the postoperative period without further intervention11.
In a large retrospective study of eighty-three hips by Thawrani et al.3, there were three major complications (4%) and eighteen minor complications (22%). Major complications included excessive arterial bleeding requiring embolization, osteonecrosis of the acetabular fragment, and osteonecrosis of the femoral head. Minor complications included superior pubic ramus nonunion in five patients, superficial stitch abscesses in four patients, and lateral femoral cutaneous nerve palsy in four patients. Major complications were associated with longer operative time, greater blood loss, and proximal femoral osteotomy, and minor complications were associated with surgical procedures for diagnoses other than developmental dysplasia.
Expanding on these smaller studies, a recent large, prospective study of 205 patients by Zaltz et al.2 showed that minor complications occurred in sixty patients (29%) and major complications occurred in twelve patients (6%) at one year after the surgical procedure. The investigators used the modified Clavien-Dindo grading scale to classify complications as either minor (grades I and II) or major (grades III and IV)12. Minor complications resolve with no or minimal deviation from a typical postoperative course12. Major complications require repeat surgical intervention or result in permanent injury or death12. At the ten-week follow-up of 201 patients, there were twenty-three patients with minor complications (11.4%), most commonly wound complications (five patients) and persistent lateral femoral cutaneous nerve dysesthesia (four patients). At the same time point, an additional seven patients (3.5%) developed major complications, such as acetabular migration (one patient), deep infection (two patients), peroneal nerve palsy (one patient), and, most commonly, venous thromboembolic disease (three patients with deep venous thrombosis, one of whom had a non-fatal pulmonary embolism). At the second postoperative visit (mean time, fourteen months postoperatively) of 177 patients in this same cohort, there were thirty-seven new minor complications, most commonly asymptomatic heterotopic ossification (thirty-three patients: twenty-one with Brooker grade I, seven with Brooker grade II, three with Brooker grade III, and two with Brooker grade IV). At the second follow-up visit, five patients had major complications including symptomatic grade-III heterotopic ossification, acetabular migration, intra-articular screw placement, and posterior column nonunion requiring open reduction and internal fixation2.
Taken together, minor and major complications have been reported after periacetabular osteotomy at varying rates depending on the study reviewed. There are several strategies that can be employed to minimize these risks. In this review, we will describe preoperative, intraoperative, and postoperative measures that can be employed to avoid complications in patients undergoing periacetabular osteotomy based on both existing literature and experience from a high-volume center. These have been summarized in Table II. The purpose of this article is to provide an evidence-based review of reducing complication rates in periacetabular osteotomy and improving patient outcomes.
There are several preoperative measures that may help to avoid or to reduce the risk of complications after periacetabular osteotomy, including surgeon experience and volume, patient selection, and medical optimization.
Optimizing patient selection and surgical indications are necessary steps to reducing the postoperative complication rates and maximizing outcomes with any surgical intervention. The ideal candidate for periacetabular osteotomy is a patient under the age of thirty years with good or excellent hip joint congruency and minimal osteoarthritis. Older patient age, increased preoperative disability, a preoperative Trendelenburg gait, an incongruent hip joint, and evidence of osteoarthritis are described risk factors for poor outcomes at longer-term follow-up, with age and hip congruency being the most consistent independent predictors4,13-15. At a twenty-year follow-up, Steppacher et al. reported survivorship rates after periacetabular osteotomy of 75% in patients with preoperative Tönnis grade-0 or 1 osteoarthritis (no joint space narrowing) compared with 13% in patients with Tönnis grade-2 or 3 osteoarthritis14. Using decision analysis, Sharifi et al. found that periacetabular osteotomy for Tönnis grade-1 osteoarthritis was cost-saving and became cost-effective relative to total hip arthroplasty by 5.5 years15. For Tönnis grade-2 osteoarthritis, the cost-effectiveness of periacetabular osteotomy surpassed that of total hip arthroplasty at 18.5 years15. Periacetabular osteotomy requires a long recovery and carries the potential for substantial complications, and patients with risk factors for early conversion to total hip arthroplasty or poor functional outcomes should be counseled appropriately. Patients with these risk factors may receive greater benefit from total hip arthroplasty, and avoiding periacetabular osteotomy (and its potential complications) in patients with increased risk of periacetabular osteotomy failure can reduce the overall rates of total hip arthroplasty conversion and can optimize the overall treatment of patients with acetabular dysplasia.
Previous pelvic reconstructive surgery may be another nonmodifiable preoperative factor that may be associated with increased risk of complications. In particular, the rate of nerve injury was higher in the setting of periacetabular osteotomy after previous pelvic reconstruction (9% [six of sixty-seven hips]) relative to series including only primary surgical procedures16. The authors attributed this to the complex deformities that were encountered in their series. Further studies examining revision periacetabular osteotomy did not find an increased major or minor complication rate relative to primary periacetabular osteotomy; however, patients undergoing revision periacetabular osteotomy had smaller increases in patient-reported, disease-specific outcome scores17. Some measures used by previous investigators for revision pelvic surgical procedures include using three to four 4.5-mm cortical screws for osteotomy fixation, neuromonitoring, and using an amount of correction partially dictated by previous pelvic deformity and hip range of motion (minimum, 90° of hip flexion)16. Stambough et al. contraindicated patients for periacetabular osteotomy if they had severe hip joint incongruency or poor hip range of motion preoperatively17.
Optimizing Modifiable Risk Factors
Optimizing modifiable risk factors prior to periacetabular osteotomy can also help reduce the perioperative risk in these patients. Obesity has been identified as one risk factor that results in higher complication rates for patients undergoing periacetabular osteotomy18,19. Novais et al. reported that body mass index was the only variable that was associated with developing complications after periacetabular osteotomy in a multicenter study18. Major complications (grades III to V as described above) developed in 22.3% of a total of sixty-five obese patients (body mass index of >30 kg/m2) compared with 3.1% of a total of 215 non-obese patients18. Wound complications were particularly common, with deep infection requiring reoperation in 11% of obese patients and superficial infection, in 15%18. Additionally, excessive adipose tissue can obscure anatomic landmarks, resulting in difficulties with exposure and implant placement and in longer operative times18,19. Similarly, McKinley reported superficial wound dehiscence in seven of thirty-six cases, and all of these complications occurred in obese patients10. Additionally, it is the senior author’s (E.L.S.) experience that a large soft-tissue envelope makes positioning of the chisel for the osteotomies more challenging. To our knowledge, no studies examining perioperative risk reduction for obese patients undergoing periacetabular osteotomy have been performed; therefore, counseling recommendations on reducing complication rates in these patients remain speculative. In the total hip arthroplasty literature, obesity is an independent risk factor for increased postoperative complication rates, including wound complications20,21. One risk reduction strategy that has been examined in total hip arthroplasty is preoperative weight loss, including bariatric surgery if necessary in morbidly obese patients. The role of weight loss and bariatric surgery prior to total hip arthroplasty remains controversial, and many questions remain including the efficacy of risk reduction, the timing of interventions, and the effect on patient-reported outcomes22-24. Additional interventions such as meticulous wound closure, use of deep drains, avoidance of incisions crossing the abdominal pannus, and modifications of perioperative antibiotic administration may be potential interventions to reduce wound complications in these patients. To our knowledge, there are few publications in the total hip arthroplasty or periacetabular osteotomy literature to provide guidance on risk reduction strategies in obese patients undergoing major hip surgery, and further studies are necessary.
Optimization of other systemic modifiable risk factors prior to surgery may be important to reduce perioperative complication rates in periacetabular osteotomy. Patients undergoing periacetabular osteotomy tend to be young and have low rates of cardiac and pulmonary comorbidities. Zaltz et al. found that 1% of patients had coronary artery disease, 2.4% had hypertension, and 12.2% had asthma preoperatively2. One patient in 201 cases in the ten-week follow-up had a cardiac arrhythmia postoperatively2. Despite the low rate of systemic comorbidities, periacetabular osteotomy results in mean estimated blood loss of >500 mL, and these resulting fluid shifts can exacerbate any underlying cardiopulmonary disease. No standardized guidelines exist on perioperative testing needs in patients undergoing periacetabular osteotomy; however, optimization of all patients with systemic comorbidities by appropriate pediatric or medical consultations may help reduce unnecessary risks. Our institution requires a preoperative medical examination for all patients undergoing periacetabular osteotomy, which helps to provide perioperative guidance. Additional preoperative testing may be performed such as in patients with a family history of clotting disorders. Additional intraoperative measures including blood conservation, hypotensive anesthesia, and postoperative attention to deep venous thrombosis prophylaxis may help reduce systemic complications and will be discussed in more detail.
Minimizing Surgeons’ Learning Curves
The periacetabular osteotomy has a substantial learning curve and advanced training with appropriate mentorship can help reduce complication rates early on in a surgeon’s practice. In an initial series of sixty-three patients, Siebenrock et al. found that all major complications occurred in the first eighteen patients undergoing periacetabular osteotomy25. Complications included intra-articular osteotomy, acetabular fragment overcorrection, transient femoral nerve palsy, and femoral head subluxation25. Davey and Santore reported a 17% major complication rate in their initial thirty-five cases (major bleeding, reflex sympathetic dystrophy, transient sciatic nerve palsy, deep venous thrombosis or pulmonary embolism, and nonunion of the ilium), which decreased to 2.9% in their next thirty-five cases6. This learning curve was evident despite extensive preparation by the surgeons prior to performing periacetabular osteotomy, including performing cadaveric dissections and meeting with experts in the field for guidance6. Similarly, Peters et al. reported that the majority of complications occurred in their initial thirty cases (three transient femoral nerve palsies, one transient sciatic nerve palsy, four deep hematomas, and two deep infections)8. Only one complication occurred in the subsequent fifty-three hips (transient femoral nerve palsy)8. All of these reports of higher complications in the initial cases performed by surgeons suggest a substantial learning curve associated with periacetabular osteotomy and the attempts to mitigate or accelerate this learning curve are critical. In addition, consistent case volume over time is critical to remaining proficient. The exact number of cases necessary is not known at this time, but we suggest that at least fifteen to twenty cases per year would be optimal.
Some techniques to reduce learning curve complications for surgeons performing periacetabular osteotomies include advanced fellowship training with a surgeon experienced in proper surgical technique, surgical mentoring by another experienced surgeon during fellowship training, and, as an early attending surgeon, independent learning with cadaveric dissections to optimize familiarity with the anatomy or working with a co-surgeon early in the primary surgeon’s experience2,26. Similar to other surgical procedures such as anterior total hip arthroplasty, it is important for surgeons performing periacetabular osteotomies to select an experienced surgical mentor to improve their ability to perform the procedure safely, to discuss challenging cases, and to monitor their progress26,27. For surgeons without a local mentor, remote mentoring with an experienced surgeon in the field may also reduce complications during the learning curve for periacetabular osteotomy26. In the experience of the senior author, it is also beneficial for periacetabular osteotomy surgeons to initially operate with another experienced co-surgeon to improve their comfort level with the procedure and to minimize the risk of complications.
Meticulous soft-tissue handling and obtaining an appropriate surgical exposure are critical. The surgical approach is typically performed as described by Ganz et al.1, with subsequent modifications to reduce soft-tissue dissection28. The patient is positioned supine with the lower limb draped free into the surgical field to allow for appropriate manipulation during the case. The modified Smith-Petersen approach to the hip is most commonly utilized for anterior exposure. In the superficial plane, it is important to avoid the lateral femoral cutaneous nerve, which commonly lies over the fascia of the sartorius muscle, and approaching the interval laterally over the tensor fasciae latae reduces risk to this nerve. Blunt dissection will then expose the deep medial border of the tensor fascia latae and the gluteus minimus tendon to expose the indirect head of the rectus femoris muscle. The anteroinferior hip capsule and pubis are then exposed with the hip in slight flexion and adduction. The sartorius is removed from the anterior superior iliac spine with a small wafer of bone to allow for repair at the conclusion of the case. The direct head of the rectus tendon was originally removed from its insertion on the anterior inferior iliac spine; however, some authors have described a rectus-sparing approach that leaves it intact to reduce soft-tissue dissection29,30. Preliminary studies have shown that the rectus-sparing approach is safe and does not compromise acetabular fragment correction; however, it is unclear at this time how it affects early recovery of hip flexion and patient-reported outcome scores29,30. It is our preference to open the lateral rectus fascia so that the rectus femoris can be mobilized medially. Proximal to the traversing vessels of the lateral femoral artery, the deep rectus fascia is incised to expose the lateral margin of the iliocapsularis muscle. The iliocapsularis is then carefully dissected under the rectus. The lateral aspects of the iliacus and iliocapsularis are mobilized medial to the rectus tendon until the iliopsoas bursa is seen. The bursa is then opened, which will allow access to the periosteum of the superior ramus and will allow for a plane to be opened between the medial hip capsule and the iliopsoas tendon sheath. We perform this exposure in a meticulous manner to lessen the risk of heterotopic ossification. For distal exposure, the iliocapsularis is dissected from its insertion on the hip capsule, allowing access to the ischium for performance of the distal limb of the posterior column osteotomy. Modifications are made to this exposure depending on the surgeon, as some surgeons will still detach the rectus from its insertion when more anterior capsule visualization is required.
Performing the Osteotomy
We have found fluoroscopy to be useful to avoid complications when performing a periacetabular osteotomy. Specifically, it has been found to be a reliable tool in preventing violation of the posterior column and avoiding an intra-articular osteotomy31. Fluoroscopy is utilized to confirm the ischial osteotomy starting point in the infracotyloid groove to avoid iatrogenic acetabular penetration (Fig. 1). The surgeon should confirm completion of this cut from the medial to the lateral aspect of the ischium to facilitate mobilization. Most critically, intraoperative fluoroscopy will assist with the orientation and direction of the posterior column osteotomy. Using a 50° false profile view will give the surgeon a landmark for the start of the posterior column cut and will assist the surgeon as the osteotome is directed distally between the acetabulum and sciatic notch. It is also helpful to have the osteotome perpendicular to the image to prevent inadvertent osteotomy in the lateral aspect of the acetabulum (Fig. 2). Leaving enough bone in the posterior column and ischium is important to avoid postoperative stress fracture. For the pubic osteotomy, circumferential subperiosteal exposure is critical to achieve good fragment mobility and to protect the obturator neurovascular structures in the obturator foramen. Good acetabular fragment mobility is critical to achieve full correction and to avoid iatrogenic acetabular retroversion. Fragment mobility can be one of the more challenging goals for surgeons in the initial learning curve. Our preferred steps are to first perform the pubic osteotomy followed by the ischial osteotomy. Then we mark the start of the posterior column cut, which is the end point of the supra-acetabular cut. When performing the supra-acetabular osteotomy, the saw blade is perpendicular to the patient, not to the iliac crest, to provide enough supra-acetabular bone. Once the medial portion of the posterior column cut is complete, we cut the lateral and superior portion of the posterior column. This will usually allow enough mobilization that the more lateral posterior column can be cut carefully until the fragment can be completely mobile.
Avoiding Nerve Injury
Neuromonitoring has also been described in the setting of periacetabular osteotomy and may help to predict postoperative neurologic deficit, although its utilization rates are variable11,16,32. In a series of 140 periacetabular osteotomies, abnormal electromyographic activity was noted in five of seven patients with postoperative neurologic deficits; however, electromyographic abnormalities were noted in a total of thirty-six patients32. The authors suggested that retractor repositioning at the time of signal abnormality may reduce further injury to the affected nerve32. Osteotomy fragment repositioning may reduce rates of nerve injury if neuromonitoring changes occur during correction. Sierra et al. found that age, body mass index, a previous pelvic surgical procedure, and the preoperative diagnosis were not associated with the risk of nerve injury11. Appropriate lower-limb positioning is critical during the osteotomy to help to minimize tension on neural structures and to avoid injury to the sciatic and obturator nerves. Positioning for the pubic cut consists of hip flexion and adduction to take tension off the psoas and adjacent femoral nerve11. We also recommend using medial retraction on the pubis for only as long as it takes to perform the osteotomy and to make sure the retractor is deep to the iliopsoas. For the lateral portion of the ischial osteotomy, abduction and hip extension are utilized to take tension off the sciatic nerve11. Additionally, care must be taken to avoid exiting laterally and posteriorly when performing the posterior column osteotomy because of proximity to the sciatic nerve11. Thus, the osteotome is directed medially, and the lateral portion of the osteotomy does not need to be deeper than cutting the cortex. The use of routine electromyography remains controversial and more studies are necessary to determine its role in reducing nerve injury during periacetabular osteotomy.
Osteotomy Fragment Positioning
Another intraoperative measure to improve patient outcomes is optimizing osteotomy fragment positioning. Poor acetabular fragment mobilization can lead to retroversion of the acetabular fragment, and studies have shown that excessive acetabular retroversion or anteversion may be associated with an increased risk of femoroacetabular impingement and failure13,33. The goal of surgery should be to recreate proper acetabular orientation and a spherical femoral head and to avoid iatrogenic femoroacetabular impingement13. Additionally, excessive lateralization of the acetabular fragment or residual incongruence between the femoral head and acetabulum may negatively impact patient outcomes. Proper intraoperative radiographs are critical to optimize osteotomy fragment positioning prior to final fixation1,8. The sclerotic weight-bearing area of the acetabulum should balance over the femoral head on anteroposterior and false profile imaging. The anterior and lateral walls should meet at the lateral aspect of the sourcil, with the posterior wall crossing the center or just lateral to the center of the femoral head and the anterior wall crossing the superior medial portion of the femoral head.
Reducing Intraoperative Blood Loss
In the periacetabular osteotomy literature, transfusion rates have been reported to be as high as 58%, with substantial levels of estimated intraoperative blood loss34,35. Meticulous soft-tissue handling and surgical dissection and appropriate hemostasis are important to reduce blood loss during periacetabular osteotomy. Additionally, various blood conservation strategies such as the use of cell salvage and antifibrinolytic agents are being used to decrease intraoperative blood loss and to reduce the need for postoperative blood transfusions. More specifically, hemostatic agents such as tranexamic acid have been shown in a retrospective study to decrease intraoperative blood loss and to reduce the rate and amount of blood transfusions after periacetabular osteotomy35. Both intravenous and topically administered tranexamic acid have been extensively studied to reduce blood loss in total hip arthroplasty, and both methods of administration have been found to reduce rates of blood transfusion, length of stay, and intraoperative blood loss36-38. For intravenous administration, 1 g of tranexamic acid given just prior to incision with an additional dose given six hours after surgery is one common regimen37. For topical administration, 1 g of tranexamic acid in 50 mL of saline solution is typically used intra-articularly prior to closure36. Other agents such as aminocaproic acid and local thrombotic agents are also being successfully used in total hip arthroplasty and may have a role in periacetabular osteotomies39,40. Neuraxial analgesia has been shown to reduce blood loss in total hip arthroplasty and may reduce rates of transfusion in periacetabular osteotomy; however, more studies are necessary to compare general anesthesia outcomes with regional anesthesia outcomes in periacetabular osteotomy41,42.
Postoperative rehabilitation should consist of early mobilization with protected weight-bearing. Delayed union, nonunion, and acetabular migration are potential complications postoperatively, and protection of weight-bearing may reduce the risk of these complications (Table I). The most common postoperative care regimens reported include partial weight-bearing (ranging from toe-touch to 50% weight-bearing) for the first six weeks, with progression to full weight-bearing after six weeks or after evidence of osteotomy healing is radiographically visualized1,2,4,8,16. Early full weight-bearing has been associated with a higher rate of fractures of the ischial ramus, posterior column, and loss of reduction1,43.
Deep Venous Thrombosis Prophylaxis
Several major venous thromboembolic prophylactic agents are associated with bleeding complications after major joint reconstruction, and the risks and benefits should be considered on a patient-by-patient basis44. The cumulative rate of deep venous thrombosis or pulmonary embolism after periacetabular osteotomy in the literature was 1.8% (Table I). Prophylactic regimens vary depending on the investigators and include mechanical prophylaxis alone, aspirin, low-molecular weight heparins, and warfarin3,4,8,9,45,46. Polkowski et al. found no postoperative deep venous thrombosis using routine screening ultrasound prior to hospital discharge in more than 130 patients undergoing periacetabular osteotomy treated with 325 mg of aspirin twice daily for deep venous thrombosis prophylaxis45. In a large multi-institutional series, Zaltz et al. found that the cumulative prevalence of deep venous thrombosis or pulmonary embolism was lower than in primary total hip arthroplasty (0.93% overall for symptomatic deep venous thrombosis or pulmonary embolism in this series), and the risk of complications from chemoprophylaxis in this group of patients has to be weighed against their relative low likelihood of thromboembolic complications46. Assessment of patients at risk preoperatively and optimal anticoagulation regimens for potentially higher-risk patients (smokers, those taking oral contraceptives) should be examined further in the future.
Reducing Heterotopic Ossification
Heterotopic ossification is one of the most common complications after periacetabular osteotomy (Table I). It is seen most commonly anteriorly and anterolaterally in the vicinity of the gluteus medius and iliocapsularis, and most patients with radiographic heterotopic ossification are asymptomatic at early follow-up2. Meticulous soft-tissue handling and minimizing dissection around the abductors are practical methods to help to reduce heterotopic ossification. There are not adequate data to suggest for or against routine heterotopic ossification prophylaxis after periacetabular osteotomy. In the hip arthroscopy literature, routine nonsteroidal anti-inflammatory drug (NSAID) prophylaxis with naproxen has been found to reduce the absolute risk of heterotopic ossification from 25% to 5.6%, particularly in cases with combined osteochondroplasty and acetabuloplasty47. Complications from this therapy included acute renal failure, hematochezia (blood per rectum), and gastritis, and further studies are needed to define the role of routine heterotopic ossification prophylaxis in periacetabular osteotomy47.
Periacetabular osteotomy is a successful and effective procedure when performed by experienced surgeons with appropriate training. Most complications are minor and resolve without further intervention; however, careful attention to patient selection, meticulous surgical exposure and osteotomy techniques, and appropriate surgical training are critical to minimize more serious complications. Further studies are needed with regard to minimizing overall complications in higher-risk individuals and optimizing postoperative protocols for deep venous thrombosis and heterotopic ossification prophylaxis. Overall, periacetabular osteotomy provides substantial pain relief and improved function in patients with acetabular dysplasia, and an increased emphasis must be placed on minimizing complications and subsequently optimizing outcomes after surgery.
Source of Funding: No external funding sources were utilized for this manuscript.
Investigation performed at the Center for Hip Preservation, Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY
Disclosure: None of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of any aspect of this work. None of the authors, or their institution(s), have had any financial relationship, in the thirty-six months prior to submission of this work, with any entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. Also, no author has had any other relationships, or has engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.
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