At Issue: Arthroscopy of dysplastic hip

Question: When is hip arthroscopy the most effective course of treatment of the dysplastic hip?

Editor’s note: Orthopedics Today introduces the At Issue column. In this new feature, experts will delve deeper into specific topics of interest to orthopedic surgeons.

Patient selection is key

Arthroscopy may be useful as a stand-alone surgery in some instances and as an adjunctive and endoscopic assistive procedure in others, although patient selection is key. While definitive thresholds of dysplasia severity that best respond to specific surgical procedures have not been established, one study found an average lateral center edge (LCE) angle of 14.7°, acetabular inclination 16.3° and an anterior center edge angle (ACE) angle of 16.8° in patients who fail hip arthroscopy that required subsequent periacetabular osteotomy. I suggest even more conservative radiographic thresholds (ie, less severe dysplasia) for isolated hip arthroscopy to be considered a viable option.

Dean K. Matsuda
Dean K. Matsuda

Evidence is emerging that isolated hip arthroscopy may be sufficient to treat borderline or mild dysplasia. General principles include the preservation of acetabular rim, labrum and capsule. Although some degree of anterolateral insufficiency is present, some patients may exhibit a positive radiographic crossover sign. While classically suggestive of focal overcoverage in dysplasia, a positive radiographic crossover sign may be physiologic (increasing the deficient focal coverage) or indicate posterior wall insufficiency and should not be resected, as this would lead to an even shallower socket.

Although the labrum may or may not be hypertrophic, it should be repaired whenever possible and reconstructed when not. I prefer using a semitendinosis allograft, especially when arthroscopically reconstructing a hypertrophic labrum. Retention of capsular integrity appears to be important in arthroscopic surgery for dysplasia. I prefer a small oblique interportal capsulotomy connecting the anterolateral and modified midanterior portals, minimizing damage to the iliofemoral ligament, a significant hip stabilizer.

With regard to femoral deformities, dysplasia is commonly associated with cam deformity. Arthroscopic femoroplasty is performed by progressive positioning of the proximal femur, bringing small sequential sections of cam deformity into view through the small capsular window, followed by arthroscopic capsular repair.

For patients with moderate dysplasia who may require more static bony coverage, the endoscopic shelf acetabuloplasty has provided early-term successful outcomes in Japan with its high prevalence of dysplasia. An iliac crest graft is press-fit into a slot at the anterosuperior acetabular rim in intimate contact with the repaired capsule following central compartment arthroscopy and femoroplasty. The durability of these successful outcomes is unknown and probably depends upon possible physiologic metaplasia of the compressed capsule to fibrocartilage.

The periacetabular osteotomy (PAO) is a popular treatment for moderate and severe dysplasia. PAO is attractive due to its ability to reorient the acetabulum and articular cartilage into a more biomechanically sound position while preserving the functional integrity of the posterior column, facilitating early ambulation.

Hip arthroscopy is emerging as a viable adjunct to the PAO and may be concurrently performed. A significant prevalence of treatable intracapsular hip pathology has been demonstrated in patients undergoing PAO and may be better detected via arthroscopy than arthrotomy. In patients with more severe cartilage damage than appreciated on preoperative imaging, arthroscopy may indicate hip arthroplasty over an ill-advised PAO.

PAO has classically been performed as a major open surgery with varying rates of complications and prolonged postoperative rehabilitation. We recently performed endoscopy-assisted PAO with initial central compartment arthroscopy, endoscopic visualization of the posterior peritrochanteric space and inner pelvic table and PAO via mini-incisions with retraction of the arthroscopically visualized sciatic nerve during the critical ischial and posterior column cuts. Following endoscopy-assisted acetabular reorientation, arthroscopic femoroplasty was optimized to the new rim position. Arthroscopic capsular repair was then performed. Although it is premature to claim broad utility of this approach, further investigation is merited to establish whether endoscopy-assisted PAO will reduce complications or enhance outcomes.

A recent review revisits whether certain older augmental or pelvic osteotomies may still have a contemporary role in the treatment of select patients with dysplasia. In a recent cadaver lab, we performed an endoscopic Chiari osteotomy, a variant of the endoscopic shelf procedure and an endoscopy-guided Birmingham interlocking pelvic osteotomy (BIPO). Popular in Europe, the BIPO classically cuts the posterior column yet permits early ambulation due to a stable interlocking peri-acetabular interface after acetabular reorientation.

While it is yet unknown whether PAO or BIPO may be better suited for endoscopic guidance, the ultimate goal is a completely endoscopic osteotomy that appeals to the growing number of patients with marked dysplasia who prefer less invasive surgery but require acetabular reorientation. I see no value in using hip arthroscopy to treat dysplasia in patients with preoperative evidence of severe osteoarthritis or patients for which osteotomy is otherwise contraindicated.

Hip Arthroscopy Technology

Hip arthroscopy may be a standalone procedure in borderline or mild dysplasia and a valuable adjunctive procedure to enhance reorientation or augmental osteotomies. It can provide attractive, less invasive surgeries and potentially optimize outcomes via improved matching of patients to procedures.

Disclosure: Matsuda reports he receives royalties for intellectual property from Smith & Nephew and Zimmer Biomet.

Role of hip arthroscopy in treatment of hip dysplasia remains controversial

Our understanding and treatment of hip dysplasia has evolved tremendously during the last decade. This is due to both advanced imaging and improved surgical techniques. Techniques, such as the periacetabular osteotomy and hip arthroscopy are being practiced around the world, providing patients with safe and effective solutions for hip pain.

Paul E. Beaulé
Paul E. Beaulé

That said, the role of hip arthroscopy in the treatment of hip dysplasia remains controversial due to our lack of understanding of which clinical factors are the key drivers of patient outcome. In other words, if the intra-articular labral pathology is the main driver, then hip arthroscopy is best suited in regard to treatment and optimizing recovery while periacetabular osteotomy (PAO) would be the optimum choice if the structural abnormality is the main driver. In many cases, however, both procedures are required.

One of the main concerns within the orthopedic community is the increasing incidence of failed hip arthroscopy in patients presenting with persistent hip pain secondary to underlying hip dysplasia and requiring a subsequent PAO. Our goal should always be to provide a single intervention with the highest rate of success. Although hip arthroscopy is appealing in regard to faster recovery and outpatient setting, if it negatively affects the outcome of a subsequent procedure, at the very least, this should be discussed with the patient and weighed against the excellent results of PAO.

The question could be reframed by drawing an analogy to the current standard of treatment of cam femoro-acetabular impingement: Who of us would the treat the labral pathology without resecting the cam lesion?

As a stand-alone procedure, hip arthroscopy can be the most effective treatment option for dysplasia in patients where the outcome of PAO is less predictable, such as patients older than 35 years with a non-congruent joint, and as an adjunct to PAO in patients with increased alpha angle or other associated femoral head/neck abnormalities and predominant mechanical symptoms. More research is needed both from a finite element-modeling aspect of cartilage stresses as well as clinical outcomes to help define what a normal or highly functioning hip joint is and how to best achieve this surgically for our patients with a painful dysplastic hip.

Disclosure: Beaulé reports no relevant financial disclosures.

Editor’s note: Orthopedics Today introduces the At Issue column. In this new feature, experts will delve deeper into specific topics of interest to orthopedic surgeons.

Patient selection is key

Arthroscopy may be useful as a stand-alone surgery in some instances and as an adjunctive and endoscopic assistive procedure in others, although patient selection is key. While definitive thresholds of dysplasia severity that best respond to specific surgical procedures have not been established, one study found an average lateral center edge (LCE) angle of 14.7°, acetabular inclination 16.3° and an anterior center edge angle (ACE) angle of 16.8° in patients who fail hip arthroscopy that required subsequent periacetabular osteotomy. I suggest even more conservative radiographic thresholds (ie, less severe dysplasia) for isolated hip arthroscopy to be considered a viable option.

Dean K. Matsuda
Dean K. Matsuda

Evidence is emerging that isolated hip arthroscopy may be sufficient to treat borderline or mild dysplasia. General principles include the preservation of acetabular rim, labrum and capsule. Although some degree of anterolateral insufficiency is present, some patients may exhibit a positive radiographic crossover sign. While classically suggestive of focal overcoverage in dysplasia, a positive radiographic crossover sign may be physiologic (increasing the deficient focal coverage) or indicate posterior wall insufficiency and should not be resected, as this would lead to an even shallower socket.

Although the labrum may or may not be hypertrophic, it should be repaired whenever possible and reconstructed when not. I prefer using a semitendinosis allograft, especially when arthroscopically reconstructing a hypertrophic labrum. Retention of capsular integrity appears to be important in arthroscopic surgery for dysplasia. I prefer a small oblique interportal capsulotomy connecting the anterolateral and modified midanterior portals, minimizing damage to the iliofemoral ligament, a significant hip stabilizer.

With regard to femoral deformities, dysplasia is commonly associated with cam deformity. Arthroscopic femoroplasty is performed by progressive positioning of the proximal femur, bringing small sequential sections of cam deformity into view through the small capsular window, followed by arthroscopic capsular repair.

For patients with moderate dysplasia who may require more static bony coverage, the endoscopic shelf acetabuloplasty has provided early-term successful outcomes in Japan with its high prevalence of dysplasia. An iliac crest graft is press-fit into a slot at the anterosuperior acetabular rim in intimate contact with the repaired capsule following central compartment arthroscopy and femoroplasty. The durability of these successful outcomes is unknown and probably depends upon possible physiologic metaplasia of the compressed capsule to fibrocartilage.

The periacetabular osteotomy (PAO) is a popular treatment for moderate and severe dysplasia. PAO is attractive due to its ability to reorient the acetabulum and articular cartilage into a more biomechanically sound position while preserving the functional integrity of the posterior column, facilitating early ambulation.

Hip arthroscopy is emerging as a viable adjunct to the PAO and may be concurrently performed. A significant prevalence of treatable intracapsular hip pathology has been demonstrated in patients undergoing PAO and may be better detected via arthroscopy than arthrotomy. In patients with more severe cartilage damage than appreciated on preoperative imaging, arthroscopy may indicate hip arthroplasty over an ill-advised PAO.

PAO has classically been performed as a major open surgery with varying rates of complications and prolonged postoperative rehabilitation. We recently performed endoscopy-assisted PAO with initial central compartment arthroscopy, endoscopic visualization of the posterior peritrochanteric space and inner pelvic table and PAO via mini-incisions with retraction of the arthroscopically visualized sciatic nerve during the critical ischial and posterior column cuts. Following endoscopy-assisted acetabular reorientation, arthroscopic femoroplasty was optimized to the new rim position. Arthroscopic capsular repair was then performed. Although it is premature to claim broad utility of this approach, further investigation is merited to establish whether endoscopy-assisted PAO will reduce complications or enhance outcomes.

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A recent review revisits whether certain older augmental or pelvic osteotomies may still have a contemporary role in the treatment of select patients with dysplasia. In a recent cadaver lab, we performed an endoscopic Chiari osteotomy, a variant of the endoscopic shelf procedure and an endoscopy-guided Birmingham interlocking pelvic osteotomy (BIPO). Popular in Europe, the BIPO classically cuts the posterior column yet permits early ambulation due to a stable interlocking peri-acetabular interface after acetabular reorientation.

While it is yet unknown whether PAO or BIPO may be better suited for endoscopic guidance, the ultimate goal is a completely endoscopic osteotomy that appeals to the growing number of patients with marked dysplasia who prefer less invasive surgery but require acetabular reorientation. I see no value in using hip arthroscopy to treat dysplasia in patients with preoperative evidence of severe osteoarthritis or patients for which osteotomy is otherwise contraindicated.

Hip Arthroscopy Technology

Hip arthroscopy may be a standalone procedure in borderline or mild dysplasia and a valuable adjunctive procedure to enhance reorientation or augmental osteotomies. It can provide attractive, less invasive surgeries and potentially optimize outcomes via improved matching of patients to procedures.

Disclosure: Matsuda reports he receives royalties for intellectual property from Smith & Nephew and Zimmer Biomet.

Role of hip arthroscopy in treatment of hip dysplasia remains controversial

Our understanding and treatment of hip dysplasia has evolved tremendously during the last decade. This is due to both advanced imaging and improved surgical techniques. Techniques, such as the periacetabular osteotomy and hip arthroscopy are being practiced around the world, providing patients with safe and effective solutions for hip pain.

Paul E. Beaulé
Paul E. Beaulé

That said, the role of hip arthroscopy in the treatment of hip dysplasia remains controversial due to our lack of understanding of which clinical factors are the key drivers of patient outcome. In other words, if the intra-articular labral pathology is the main driver, then hip arthroscopy is best suited in regard to treatment and optimizing recovery while periacetabular osteotomy (PAO) would be the optimum choice if the structural abnormality is the main driver. In many cases, however, both procedures are required.

One of the main concerns within the orthopedic community is the increasing incidence of failed hip arthroscopy in patients presenting with persistent hip pain secondary to underlying hip dysplasia and requiring a subsequent PAO. Our goal should always be to provide a single intervention with the highest rate of success. Although hip arthroscopy is appealing in regard to faster recovery and outpatient setting, if it negatively affects the outcome of a subsequent procedure, at the very least, this should be discussed with the patient and weighed against the excellent results of PAO.

The question could be reframed by drawing an analogy to the current standard of treatment of cam femoro-acetabular impingement: Who of us would the treat the labral pathology without resecting the cam lesion?

As a stand-alone procedure, hip arthroscopy can be the most effective treatment option for dysplasia in patients where the outcome of PAO is less predictable, such as patients older than 35 years with a non-congruent joint, and as an adjunct to PAO in patients with increased alpha angle or other associated femoral head/neck abnormalities and predominant mechanical symptoms. More research is needed both from a finite element-modeling aspect of cartilage stresses as well as clinical outcomes to help define what a normal or highly functioning hip joint is and how to best achieve this surgically for our patients with a painful dysplastic hip.

Disclosure: Beaulé reports no relevant financial disclosures.