Issue: July 2013
July 01, 2013
13 min read

Panel discusses the emerging techniques and current controversies in hip dysplasia

Issue: July 2013
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With the rapid growth of hip arthroscopy and the attractiveness of less invasive surgery, some young adult patients with dysplasia opt for hip arthroscopy, refusing recommended open periacetabular osteotomy. Despite avoidance of rim trimming, which would make a shallow hip even shallower, and the avoidance of labral debridement (the hypertrophic labrum may play a critical functional role in dysplasia) with labral repair, poor outcomes with rapidly progressive arthritis may occur, precluding a later periacetabular osteotomy. Some early studies demonstrate good outcomes with isolated hip arthroscopy; others do not. Isolated periacetabular osteotomy has yielded successful outcomes in the past, but there seems to be a relatively high prevalence of coexisting cam femoroacetabular impingement. These findings have stimulated controversy as to the indications, procedures, timing, sequence and approach to the treatment of adult hip dysplasia.

In this month’s Orthopedics Today Round Table, panelists share their insights on this timely hip preservation topic.

Dean K. Matsuda, MD

Roundtable Participants

  • Moderator

  • Dean K. Matsuda, MD
  • Los Angeles
  • Omer Mei-Dan, MD
  • Denver
  • Javad Parvizi, MD, FRCS
  • Philadelphia
  • Christopher L. Peters, MD
  • Salt Lake City
  • Kjeld Søballe, MD, DMSc
  • Aarhus, Denmark
  • Richard N. Villar, MD
  • Cambridge, United Kingdom

Dean K. Matsuda, MD: With the rapid growth of hip arthroscopy for conditions such as femoroacetabular impingement (FAI), what is its role with dysplasia?

Richard N. Villar, MD: The prevalence of dysplasia (even mild) with FAI has been established at 47%. Of course, this finding is a reflection of the nature of my practice as well as the association of developmental dysplasia of the hip (DDH) with FAI. The key issue with all these studies is to clearly define what we mean by dysplasia. The use of the word “borderline” is not helpful, but I guess most of us would regard center edge angles (CEA) of 20° to 25° as being borderline. Until we agree, it is going to be difficult to truly understand when hip arthroscopy may or may not be useful.

We need to understand why some cases of DDH relapse so fast and others do not. Is it anything to do with hip arthroscopy at all? Could it be the integrity of the ligamentum teres? Personally, I strongly suspect the ligamentum is key. In my view, DDH in hips that relapse have a higher chance of having an incompetent or ruptured ligamentum than those that stand the test of time.

It is perhaps supposition for us to say the FAI is more important than the dysplasia. All we do know is the two can coexist. Byrd and McCarthy have published studies prior to the FAI and labral repair/reconstruction era that show some successful outcomes with isolated hip arthroscopy in dysplasia.

The problem is hips can certainly be made to feel better after hip arthroscopy in the presence of DDH. There is no doubt and data exist to prove it. However, the problem is that some hips then may relapse but we have no idea which ones as we do not understand the true mechanism behind a relapse. Furthermore, we have no evidence as to what might have happened if the hip had been left alone, without a hip arthroscopy. It is supposition to say that hip arthroscopy caused a relapse when such an event might have happened anyway, even if the association may seem clear. The evidence still does not exist to prove it. The key points to consider are:

  • Dysplasia is prevalent and commonly coexists with cam FAI (and perhaps vice versa), so we need to look for this.
  • It is important to treat the cam deformity, which may be done nicely with arthroscopy.

At a practical level, I simply do not touch the acetabular rim in a DDH case. It is a “no-go” area. I reconstruct any labral pathology as best I can and graft if I have to do so. I focus totally on the femoral side. I believe it is important to treat the cam deformity. In any event, for most DDH cases, removing the cam is not difficult technically.


Javad Parvizi, MD, FRCS: Hip surgeons are aware that patients with DDH have a mechanical issue that cannot be addressed by arthroscopy alone. Osteotomy of the pelvis and/or femur is usually indicated in patients with symptomatic DDH. Hip arthroscopy, however, may be used to evaluate the status of the articular cartilage in patients who require periacetabular osteotomy (PAO). In rare circumstances and when DDH is mild, labral repair using arthroscopy may be indicated. It is critical that anyone treating these patients be aware of the importance of labrum. Labral debridement in patients with DDH will lead to accelerated demise of the articular cartilage.

Omer Mei-Dan, MD: Whether hip arthroscopy is done concurrently with a PAO or staged (1 week to 2 weeks or a few months apart), proper management of soft tissue around the joint is mandatory due to the inherent instability. This instability will be increased by even the most minimal capsulotomy, trimming down of partially torn ligamentum teres or labral debridement. When the patient shows signs of hyper laxity, instability can become even more significant.

Due to the above, every dysplastic or borderline dysplastic subject undergoing hip arthroscopy should be protected appropriately. This should start with meticulous capsular closure (or plication in overly lax patients) and 6 weeks of nonweight-bearing after hip arthroscopy. Patients also should avoid hip external rotation for 4 weeks to prevent excessive stress on the repaired capsule before the initial healing takes place.

Labral debridement should be avoided in these patients and a low threshold for labral reconstruction should be implemented, especially with non-functional labral tissue. If the labrum is reconstructed, it is advisable to use an oversized graft which will later serve as a bumper/shelf and increase anterolateral stability. Ligamentum teres reconstruction may be indicated in some unique cases.

Matsuda: What are the indications for PAO?

Christopher L. Peters MD: The primary indication for PAO is an adolescent or young adult patient with symptomatic hip dysplasia with radiographic findings of a congruent hip with minimal to no evidence of osteoarthritis (OA). The typical age range is mid-teens to 40 years, although ideal candidates are usually younger than 35 years. Women predominate over men approximately two to one. Most patients present with either activity-related anterior groin pain or laterally based muscle fatigue-type pain and a sensation of popping, clicking or instability is common. Patients have typically seen multiple health care providers prior to having a definitive diagnosis.

The radiographic work-up consists of an anteroposterior (AP) pelvis and a false profile lateral view. The lateral and anterior CEA are used to document acetabular dysplasia, an LCEA or ACEA less than 20° to 25° is consistent with acetabular dysplasia. The sourcil or roof obliquity is measured by the acetabular index, which should typically be less than 10° in a normal hip. An AP pelvis with the femora in maximum abduction and internal rotation is helpful to document hip congruency. The Tonnis grading system of OA is commonly used with grade 0 or I being the best indication for PAO. Advanced imaging usually includes a magnetic resonance arthrogram to document chondrolabral injury. Some surgeons also prefer to obtain a CT scan with 3-D reconstructions to further delineate the 3-D morphology of the proximal femur and acetabulum.

Matsuda: What are your thoughts on when isolated hip arthroscopy may be sufficient, how postoperative rehabilitation and monitoring detect early failure, and how PAO may still eventually be needed?

Mei-Dan: Hip arthroscopy can comprise the sole treatment in borderline dysplasia only, but never in frank dysplasia. Hip dysplasia should be appreciated and determined using X-ray and CT in all planes/views. Dysplasia is a 3-D pathology, involving both sides of the joint, and should be determined nor appreciated on the basis on LCE only.


An LCEA of 21° is considered by most as borderline dysplasia, and would many times be treated, if symptomatic, by arthroscopy only, but with anterior undercoverage due to acetabular anteversion, in conjunction with excessive femoral torsion, it likely has a poor chance of long-term good outcome. If all parameters, including those involving the acetabulum and femur, are close to normal and present with just borderline pathology, I would try hip arthroscopy first (sometimes in conjunction with femur derotation to correct femoral torsion) and assess symptoms and joint status 6 months to 12 months later to decide if PAO is still indicated. In this set-up, 6 full weeks of nonweight-bearing is mandatory.

The need for a future subsequent PAO should be assessed first and foremost clinically, but should be verified by X-ray and dGEMRIC imaging, confirming good cartilage quality. My experience is that in these scenarios clinical failure would precede X-ray signs.

Matsuda: Is there a threshold of dysplasia beyond which PAO should be performed with or without hip arthroscopy?

Parvizi: Any patient with symptomatic DDH who has failed nonoperative treatment is a candidate for PAO. I do not usually use one metric, like CEA, to determine whether a patient needs a PAO. CEA is a useful measurement that allows one to evaluate the severity of DDH or lateral coverage in this case.

Villar: Hip stability has for so long been regarded as a feature of its bony morphology alone and we have relied on CEA measurements as gospel for decades. Why is it that for every other joint in the body, stability is a balance between bony morphology and soft tissue support? Yet, for the hip this is rarely, if ever discussed. I think PAO surgeons have got it wrong. I am not saying PAO is a worthless procedure — far from it. However, I am saying for them to focus solely on the bony morphology means they are not addressing the full problem. What is most likely needed is a combination of both our skills — their osteotomy abilities and our arthroscopic ones.

Borderline or mild dysplasia may be a reasonable indication for isolated hip arthroscopy, but the labrum should be preserved, repaired or reconstructed and no rim trimming should be done. Patients may still need close postoperative monitoring and radiographs, and some patients may still need eventual PAO.

Matsuda: Historically, PAOs yielded outcomes similar to those of recent studies using PAO plus femoroplasty for cam decompression (when present) and hip arthroscopy. What are your thoughts about this, and does every patient who has a PAO also need hip arthroscopy?

Parvizi: Arthroscopy of the hip prior to PAO may allow the surgeon to evaluate the status of the labrum and the articular cartilage. Thus, arthroscopy combined with PAO may be a useful tool in addressing the FAI issue and labral pathology that can coexist with DDH.

Peters: Because we are a tertiary referral center for hip dysplasia, more patients are coming to us after having had a hip arthroscopy. It is understandable that from a patient’s perspective, there is some attractiveness to having a hip arthroscopy rather than a PAO. The question is, “Is this the right thing to do.” In my opinion, it has become clear that isolated hip arthroscopy for the treatment of symptomatic hip dysplasia, particularly when a labral debridement is performed, leads to poor outcomes and compromises a subsequent PAO. We have published on this with Javad Parvizi, MD, FRCS. We remain concerned about the increased use of isolated hip arthroscopy in the setting of symptomatic hip dysplasia.

The question that needs to be answered is whether the intra-articular pathology needs to be addressed every time or whether correcting the anatomy and biomechanics of the hip will be sufficient to provide a lasting functional hip joint. Nevertheless, some centers are investigating the use of hip arthroscopy in a staged or simultaneous manner with PAO. Given the advances in hip arthroscopy, this seems like a logical extension of the technique, assuming the key principals of labral preservation and correction of the underlying acetabular dysplasia are respected. Ideally, a randomized prospective study comparing PAO with and without intra-articular treatment (open or arthroscopic) is required.


Matsuda: If PAO and hip arthroscopy appear indicated, should they be performed concurrently or as staged procedures? If the latter, should hip arthroscopy precede PAO or vice versa? Why?

Peters: The use of hip arthroscopy as an adjunct to PAO for treatment of acetabular dysplasia brings up several questions including surgeon skill set and timing. First, not all hip arthroscopists are comfortable with PAO and vice versa. Increasingly, surgeons are focusing on one of these techniques. At present, in some centers, a hip arthroscopy is performed by one subspecialist and a PAO by another, although there are still some examples of one surgeon being comfortable with both operations. I think the key principle here is that both hip arthroscopy and PAO are technically demanding procedures with steep learning curves, and so it makes sense that surgical outcomes would be optimized when surgeons practice what they know best. For some, this may mean cross-discipline surgeon collaboration, and for others, intensive training to master both techniques.

In terms of timing, I do not believe there is data to recommend routine use of hip arthroscopy prior to performance of a PAO. Moreover, data from Millis and Soballe would suggest that approximately 15% of patients having undergone an isolated PAO may need a subsequent hip arthroscopy for treatment of new or residual intra-articular pathology. This information, together with the fact that simultaneous hip arthroscopy and PAO may make the open procedure more difficult because of disturbance of tissue planes, would question the need for routine simultaneous hip arthroscopy and PAO. Perhaps a more logical approach would be to use hip arthroscopy selectively prior to the PAO for clear cases of intra-articular pathology associated with mechanical symptoms or as a disease-staging tool in questionable candidates for PAO. Finally, the use of hip arthroscopy in patients who have undergone a well-performed PAO and develop mechanical symptoms or have persistent pain would also seem to be a well-reasoned approach.

Mei-Dan: I scope all of my patients before an indicated PAO as my experience shows that in 100% of these cases, pathology of some sort is found. Although at times this pathology is mild, most of the time it is extensive. The initial symptoms and presentation are usually due to this additional pathology and the damage associated with the dysplasia. Our current patient population is somehow different than the initial pediatric one, which had significant dysplasia and relatively early presentation. Now, we mainly treat adults who are involved with high level of activity and who have mostly damaged their joint (and became symptomatic) due to the combination of dysplasia/FAI/activity.

As my PAO circumvents the hip joint and does not involve arthrotomy, and due to the fact that in my hands, arthroscopy can diagnose and address the intra-articular pathology better, it makes sense to perform hip arthroscopy before heading to an extensive surgery like PAO.

Also, it is not unusual for me to reconstruct the labrum prior to the PAO due to poor labral characteristics or previously debrided labrum. The common protocol would involve hip arthroscopy with subsequent PAO 7 days to 10 days later, to minimize the nonweight-bearing time period, as after the PAO, patients are weight-bearing as tolerated.

If I am convinced that hip arthroscopy would require minimal surgical time and arthrosopic fluid would not accumulate excessively in the tissues, then I might perform both at a single session. Otherwise, I will let the soft tissue dry out prior to conducting an open procedure in that same region. The logic behind conducting hip arthroscopy before and not after the PAO (it cannot be performed for at least 6 month after) is to make sure post-PAO rehabilitation would not be compromised by a painful labral tear, cartilage damage or FAI pathology.


Matsuda: While attempting to improve lateral coverage of the femoral head with PAO, iatrogenic acetabular retroversion may occur, causing unwanted pincer FAI. One conceptual advantage to hip arthroscopy following PAO is that this may be addressed with careful rim trimming and labral refixation or reconstruction. We have treated several patients in this manner, but believe the incidence of iatrogenic pincer FAI is decreasing. PAO surgeons are keenly aware of the need to avoid unwanted retroversion during acetabular fragment reorientation/fixation.

Matsuda: Which approach do you prefer and why?

Peters: I have always used a modification of the Smith-Petersen approach for PAO. From approximately 1996 to 2010 the approach was similar to the modified description by Ganz and colleagues, and included take-down of the rectus femoris, anterior hip arthrotomy, treatment of chondrolabral injury and decreased femoral head neck offset as needed. Influenced by the work of Soballe and others, in 2010, we began use of a rectus-sparing approach without a routine capsulotomy. Although we have reported good results with our early technique, like others, we are unsure if the intra-articular pathology needed treatment in every case. Our recent experience with rectus-sparing PAO has been favorable and we have observed an earlier functional recovery. The concern remains about residual mechanical symptoms, but to date, no patient has required subsequent surgical treatment for intra-articular pathology. In the event that mechanical symptoms develop in the setting of a morphologically-corrected hip, we would anticipate that arthroscopic treatment may be useful.

Kjeld Søballe, MD, DMSc: I prefer the minimally invasive transsartorial approach. I have performed about 800 cases with this approach and my patients are able to mobilize the same day and can be discharged the day after surgery (not to a nursing house but to their own home). Mean operating room time is about 1 hour and 10 minutes and mean blood loss is 250 mL. In a study from the Journal of Bone and Joint Surgery, the survival of the hip is 97%.

Matsuda: Is an endoscopic PAO on the near horizon?

Søballe: I do not think so.

Mei-Dan: I believe and work on partially endoscopic PAO but cannot see the entire procedure going endoscopic soon. We will be able to go more minimally invasive, which will most probably result in less postopertive pain and discomfort, but still will have to do some portion open, less due to visualization issues and more due to the nature of the cuts.

Parvizi: One of the main issues related to performing PAO and the point of anxiety for most surgeons, particularly those in early years of their practice, is the final cut of the posterior column. This cut if not performed properly can lead to intra-articular extension of the osteotomy and if over penetrated through the column can damage the sciatic nerve that lies in proximity. I believe there is a role for the use of arthroscopy (endoscopy) in guiding this cut. During a practice session recently at the Joint Preservation course, Drs. Matsuda, Martin and I “experimented” with this concept, and we found the use of endoscopy for this purpose to be fascinating. The tip of osteotome coming through the posterior column could be seen to be within a few millimeters of the main trunk of the sciatic nerve. I believe this concept requires further exploration in the future as it holds great promise to minimize the trauma of PAO and potentially improve its outcome.

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Matsuda DK. Arthroscopy. 2012;doi:10.1016/j.arthro.2012.07.004.
McCarthy JC. Hip arthroscopy for acetabular dysplasia: a pipe dream? Orthopedics. 1998;21(9):977-979.
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For more information:
Dean K. Matsuda, MD, can be reached at Southern California Permanente Medical Group, Kaiser West Los Angeles Medical Center, 6041 Cadillac Ave., Los Angeles, CA 90034; email:
Omer Mei-Dan, MD, can be reached at Department of Orthopaedics, Division of Sports Medicine, 12631 E. 17th Ave., Mail Stop B202, Aurora, CO 80045; email:
Javad Parvizi, MD, FRCS, can be reached at the Rothman Institute, 925 Chestnut St., 5th Floor, Philadelphia, PA 19107;
Christopher L. Peters, MD, can be reached at University Orthopaedic Center, 590 Wakara Way, Salt Lake City, UT 84108; email:
Kjeld Søballe, MD, DMSc, can be reached at Orthopaedic Research Unit, University Hospital of Aarhus, Building 1B, Tage-Hansens Gade 2, DK-8000 Aarhus, Denmark; email:
Richard N. Villar, MD, can be reached at Spire Cambridge Lea Hospital, 30 New Rd., Impington, Cambridge, CB24 United Kingdom; email:
Disclosures: Matsuda, Mei-Dan, Peters and Søballe have no relevant financial disclosures; Parvizi is a consultant to Zimmer, Smith and Nephew, 3M and Convatec; Villar is a consultant for Smith & Nephew.