Advances in hip arthroscopy evolve to include more restorative indications and procedures

The evolution of hip arthroscopy has been rapid, and recent advances in 3-D imaging, instrumentation and surgical techniques are making it possible for surgeons to now perform procedures that were once typically performed by “open techniques” through arthroscopy.

“The future of hip arthroscopy is bright, and the arthroscopic and endoscopic techniques will become more commonly used in more indications and applications of hip surgery,” said Dean K. Matsuda, MD, physicianlead of Hip Preservation and Hip Arthroscopy at Southern California Permanente Medical Group and Orthopedics Today Editorial Board member.

“Hip arthroscopy is exciting right now because there have been a lot of advances during the past 5 to 10 years that we have not seen in the hip,” said Shane Nho, MD, MS, assistant professor at the Hip Preservation Center in the Department of Orthopedic Surgery at Rush University Medical Center. “The hip is the most recent joint to be explored in terms of possible sources of pain, not just within the joint, but outside the joint.”

These sources of pain include greater trochanteric pain syndrome, gluteus medius and minimus tears, and pain in the posterior aspect of the hip, which includes gluteal space syndrome and proximal hamstring tears.

“We have also identified other extra-articular sources of pain, such as subspine impingement, ischiofemoral impingement, and trochanteric pelvic impingement,” Nho told Orthopedics Today. “We are diagnosing pathology that was previously poorly understood and making advances in response.”

“We have certainly evolved to doing more restorative procedures, especially with the labrum,” said J.W. Thomas Byrd, MD, of Nashville Sports Medicine and Orthopaedic Center and founder of the Sports Medicine Foundation. “The labrum is probably the most common pathology that we deal with, and a labral tear is probably the most painful to patients. We have gotten good at repairing the labrum, which has an excellent healing capacity.”

New techniques

Matsuda recently developed a procedure called labralization, which is a variant of labral reconstruction and involves restoring labral function by preserving a chondral-free margin after meticulous rim trimming.

“Labralization may be an alternative to labral reconstruction where a pseudolabrum is formed from the free margin of acetabular articular cartilage in nondysplastic hips after meticulous rim trimming, forming an immediate ‘healed and sealed’ labral construct,” he said.

Preliminary results published in 2012 on six patients with cam-pincer femoroacetabular impingement who underwent arthroscopic hip labralization and acetabulo-femoroplasty revealed a mean 38-point improvement on the Non-Arthritic Hip Score, high patient satisfaction and no complications or revision surgeries.

Chondral repair procedures are also being developed as an alternative to microfracture chondroplasty. Historically, surgeons have trimmed away the cartilage on the acetabulum and then performed microfracture on the remaining bony base of the acetabulum. However, Matsuda and others are trying to preserve the cartilage flap and repair it back down to the original bony foundation.

Expansion of arthroscopy for FAI

According to Matsuda, more surgeons are moving toward the use of arthroscopy for treating femoroacetabular impingement (FAI). “We and other groups have published data showing that the outcomes are as good if not better with arthroscopy than with open surgery, with fewer major complications,” he said.

In a systematic review, Matsuda and his colleagues found clinical success ranged from 65% to 95% with open dislocation and from 67% to 90% with arthroscopy. They also found major complication rates of up to 17% and 20%, respectively, with the mini-open procedure and open dislocation for FAI compared with a complication rate of up to 5% with arthroscopy. Botser and colleagues found overall complication rates of 1.7% for arthroscopy, 9.2% for open surgical dislocation and 16% for combined approaches. Their study also revealed a greater mean improvement in the Modified Harris Hip Score with arthroscopy — an increase of 26.4 compared with 20.5 for open surgical dislocation and 12.3 for the combined approach.

Some surgeons feel that there are limits to what arthroscopy can do for FAI. “Most of these limits are based on technical issues where the surgeon can’t see or reach the areas that need treatment on these severe deformities,” Matsuda, who is also chairperson of the American Academy of Orthopaedic Surgeons (AAOS) Sports Medicine and Arthroscopy Program Committee, said.

Although arthroscopic techniques may not yet be able to treat the most severe deformities, according to Matsuda, surgeons have shown arthroscopy is feasible for posterior cam decompression, global acetabuloplasty and circumferential labral refixation or reconstruction. He and his colleagues recently presented a paper at the AAOS Annual Meeting that demonstrated comparable successful outcomes in the arthroscopic treatment of global and focal pincer impingement. They have also shown that they can treat posterior cam impingement arthroscopically and have published data on the “critical corner,” or the anteromedial region of the head-neck junction of the femur.

“We have shown in a clinical study that significant cam impingement may occur beyond the classic anterolateral quadrant,” Matsuda said. In patients who lack sufficient flexed-hip internal rotation after the anterolateral quadrant is decompressed, we have demonstrated improved range of motion with femoroplasty of the anteromedial critical corner.”

Osteosynthesis of fractures

Another evolving area in hip arthroscopy is arthroscopic osteosynthesis, or the arthroscopic reduction and internal fixation of acute fractures of the femoral head and select acetabular fractures. “In arthroscopy for trauma or fracture management, we can now fix fractures of the femoral head and certain acetabular fractures and can even treat malunited femoral head fractures,” Matsuda said.

In a case report on arthroscopic osteosynthesis of a femoral head malunion, Matsuda and colleagues reported 3-year results after arthroscopic malunion takedown, reduction, bone grafting and internal fixation. The patient had no postoperative complaints of pain or major complications.

Endoscopic-assisted procedures

Matsuda predicts that endoscopic-assisted periacetabular osteotomy (PAO) and closed proximal femoral osteotomy are on the horizon. PAO is currently done through an open procedure, but endoscopy would make it less invasive and potentially safer for patients, according to Matsuda. “The PAO is a procedure where you make bone cuts or osteotomies around the acetabulum and shift its position so that it better covers the femoral head,” he said. “It may offer more safety for patients via endoscopic visualization and retraction of the sciatic nerve during the ischial and posterior column cuts while minimizing iatrogenic violation of the joint.”

Another newer procedure is the endoscopic pubic symphysectomy for recalcitrant osteitis pubis, often associated with athletes with FAI. Matsuda and colleagues have demonstrated encouraging outcomes using this technique with up to 5-years follow-up. In the area of subgluteal surgery, endoscopy has been used for treating sciatic nerve entrapment and proximal hamstring repairs. Domb and colleagues performed endoscopic repair on 15 gluteus medius tears and reported that 14 patients showed an average 30-point postoperative improvement in hip-specific outcome scores.

Imaging and instrumentation

The field of hip arthroscopy has also seen advances in preoperative planning techniques and imaging, with 3-D dynamic imaging of the hip based on patients’ CT scans.

“This allows us to basically create 3-D models of a patient’s hip and dynamically move them to understand where the areas of impingement may occur and then direct our surgery specifically in those locations,” Nho said.

Recent software advances also facilitate precise decision making and preoperative planning.

“We have a better understanding of the complex 3-D mechanical problems that are associated with intra-articular damage patterns,” Bryan T. Kelly, MD, associate attending of orthopedic surgery at the Hospital for Special Surgery, associate professor of orthopedics at Cornell-Weill Medical Center and chief of the Hip Preservation Service, told Orthopedics Today. “A better preoperative plan allows for a more accurate surgical solution, which hopefully will lead to fewer failed surgeries. To see where mechanical impingement is occurring or static overload problems such as dysplasia are occurring can provide insight into the best treatment options.”

Smaller suture anchors are also now available for hip arthroscopy, which allows more precise placement of the anchors and therefore more anatomical joint labral repairs. “A lot of the initial instrumentation for the hip were shoulder implants and instrumentation that were made longer,” Nho said. “What we found is that the implants and instrumentation could be made better if they were designed specifically for the hip. A typical suture anchor for the shoulder are around 3 mm in diameter; the ones we use in the hip are around 1 mm to 1.5 mm.”

Success and limits

Hip arthroscopy offers the advantages of less invasive surgery including potential for less blood loss, quicker postoperative rehabilitation and improved cosmesis. “The arthroscopic technique compared with open techniques has shorter surgical recovery time and faster return to sport,” Kelly said.

Outcome data published by Marc J. Philippon, MD, and colleagues on 28 National Hockey League players revealed that after arthroscopic labral repair and treatment for FAI, players returned to skating/hockey drills at an average of 3.4 months and reported a 25-point improvement on the Modified Harris Hip Score at 2-year follow-up. Among nonathletes at 2.3 years of follow-up, Philippon and colleagues reported a mean 24-point improvement on the Modified Harris Hip Score and patient satisfaction rating of nine out of 10 for 112 patients who underwent arthroscopy for FAI.

However, the arthroscopic procedure remains limited by a significant learning curve, limited instrumentation and limited correction of severe deformities, according to Matsuda. In addition, “open procedures allow you to do dynamic assessments intraoperatively so that you can get a complete assessment of the decompression and reconstructions that are done,” Kelly said. “This is much more difficult to do arthroscopically.”

The most common contraindication to hip arthroscopy is moderate-to-severe osteoarthritis. According to Byrd, a clear contraindication parameter for hip arthroscopy is significant joint space narrowing with less than 2 mm of joint space remaining.

Other contraindications include the ankylosed non-distractible hip, protrusio — which is the most extreme form of pincer impingement — dysplasia and posterior cam deformities on the femoral head-neck junction. Recently, though, some surgeons are working to overcome these contraindications. For example, Matsuda and colleagues have been able to successfully treat protrusio and posterior cam deformities on the femoral head-neck junction arthroscopically. Domb and colleagues have also shown favorable results and high patient satisfaction at 2-year follow-up with an arthrosopic approach that includes labral repair and capsular plication for patients with symptomatic intra-articular hip disorders and borderline hip dysplasia.

The recommended age range for patients eligible for hip arthroscopy is expanding. “Insurance companies tend to cover the procedure for people between the ages of 18 and 50 [years],” Byrd said. “We are presenting a paper at this year’s AAOS Annual Meeting looking at the results of arthroscopically treating FAI in adolescents and the results in adolescents are every bit as good as those in adults.”

Because of increased life expectancy, it is beneficial for a patient older than 50 years to undergo hip arthroscopy for underlying impingement to achieve successful and more durable results. “We can do it without seeing disastrous complications,” Byrd said. “What is noticed most about older people is that if they have got significant osteoarthritic changes, especially joint spacing, they do not do as well, but that is not unique to old people — it is true whether you are 22 or 62 [years].”

Byrd also suggested that surgeons discuss patients’ expectations and ensure that they match the potential outcomes of the procedure. “If their expectations of the operation are unreasonable, you do not want to jump in and do an operation because ultimately, the success of these operations is determined by the patient’s level of satisfaction,” he said.

Learning curve

Another limitation is translating the results from high-volume arthroscopy centers with expert arthroscopy surgeons to surgeons with less experience. “We are constantly evolving as we start to critically evaluate outcomes with the idea of hopefully getting to the point where our technique provides our patients with the best and most predictable results,” Nho said.

Because hip arthroscopy is relatively new and technically advanced, many residents and fellows are not receiving adequate training in this area. “There are courses being offered by our industry partners and some of the orthopedic societies to help fill the gap, so the next generation of trainees will make the most significant increase in terms of people who are being trained adequately in performing the procedure,” Nho said.

“The learning curve is a little more of a challenge than with other joints, such as the knee and the shoulder,” Byrd said. “One of the biggest challenges of hip arthroscopy is just accessing the joint because of the constraint of the ball-and-socket architecture, which can be challenging to safely hit. You have to be careful every time you enter the joint. You have to be on your ‘A game’ every time.”

Kelly added: “There is a significant challenge in the field with clinical diagnosis, surgical technique, postoperative rehabilitation and progression of return to play. Each one of these is in many ways more challenging than some of the analogous problems in other joints. The growth of the field is delayed compared with the growth of shoulder and knee arthroscopy, and we have to be cautious about making sure that the people who are performing the procedures are adequately trained and are being careful in terms of patient selection and surgical technique.”

The learning curve depends on surgeons’ motor skills as well as their experience with arthroscopy in general, according to Philippon. “An open surgeon who hasn’t done any arthroscopy may take as many as 50 cases with the supervision of an experienced surgeon,” said Philippon, who is a managing partner of the Steadman Clinic and co-chair and board member of the Steadman Philippon Research Institute. “It is important for surgeons to seek standards and learn from experienced surgeons regardless of their baseline experience.”

In a recent systematic review of six studies, Hoppe and colleagues found significant reductions in operative time and complication rates when using 30 hip arthroscopy procedures as the cutoff to differentiate between early and late cases in a surgeon’s experience. However, the authors noted their findings should be interpreted with caution because of insufficient evidence to validate 30 — or any number — as the cutoff. Matsuda adds that the use of operative time and complication rates to assess learning needs to be considered from a broader perspective. As surgeons advance along the learning curve, they may begin performing more advanced and challenging procedures which may neutralize the improvement seen in these variables.

“From my experience, it is probably close to around 300 cases before people have seen enough of a variety to adequately address the different types of hip pathology that they will encounter,” Kelly said.

Remaining questions

More questions than answers remain in the area of hip arthroscopy, but Matsuda said this is a healthy situation. “We do not have 20- to 50-year follow-up on these patients because the procedures just have not been around that long, so the durability of our short-term generally encouraging outcomes merits long-term validation” he said.

According to Byrd, there are still several aspects of the hip that are not completely understood. “We are just barely scratching the surface,” he said. “Most hip disorders we treat are probably multifactorial. Some people can have radiographic features of impingement without necessarily developing secondary damage and pathological features.”

One of the most important questions is whether arthroscopy will lead to a change in the natural history of the hip regarding progressive cartilage deterioration. “If we are making the mechanics of the joint more congruent, we should be able to improve the wear characteristics of the cartilage and make the joint last longer and, in some cases, maybe prevent the progression of joint deterioration and eliminate the need for joint replacement,” Kelly said. “To determine this requires following our patients for the next 20 to 40 years.”

He added that solutions are needed for addressing cartilage lesions that are frequently present secondary to hip deformities. “If we get to these patients too late when there is already some permanent cartilage damage, we may not have successful outcomes,” he said. “The future is being able to better deal with the cartilage lesions on both the acetabulum and femoral head.”

Philippon called for more level 1 studies to compare intervention types and to determine which patients are ideal candidates for hip arthroscopy. “We also need more studies to better understand the microinstability of the hip in athletes especially,” he said.

Future of hip arthroscopy

According to Nho, having a dynamic 3-D evaluation of patients’ specific hip anatomy will be the way of the future. “As we understand not just their three-dimensional joint anatomy, but also the way that their hip moves, rotates and functions and where impingement may occur, this will help direct more individualized treatment our for patients,” he said.

These imaging techniques could also allow for more precise bony resections that may be automated and potentially robotic, Nho said. “It may take the individual surgeon skill out of the equation and bring the procedure to a level that is generalizable to general orthopedic surgeons,” he said.

“We are close to being able to perfect computer navigation to help us actually do the corrections in surgery,” Byrd said. “In FAI surgery, we have computer software that is basically our template to help us understand the amount of bone removal that needs to be done. I am convinced that in a few years, we will look back on where we are today and think of it as the ‘cowboy days’ when we were eyeballing and free-handing, and in the future, we will have more precision and accuracy.”

Going forward, although it is likely that many hip preservation procedures will eventually be performed using arthroscopic and/or endoscopic techniques, certain deformities, patients, and procedures will still require treatment with an open approach.

“Our goal should remain to provide the best outcomes possible within our experience, skill set, and current cost-effective technology,” Matsuda said. “Conversion to open procedures from initial attempted arthroscopic/endoscopic approaches should not necessarily be viewed as failures but rather as ongoing efforts to bring less invasive techniques to more established open procedures. We must critically report our outcomes including our complications so that the orthopedic community at large may learn from our experiences in this rapidly evolving and exciting field.” – by Tina DiMarcantonio

Are there hip procedures that are more appropriately performed through open methods and should not be done arthroscopically?

Yes, but the procedure is evolving rapidly

Hip arthroscopy is new, and as such, continues to evolve at a more rapid rate than arthroscopy for some of the other joints. The limitations of what can be done using an arthroscope in the hip that exist today, may not exist in the near future.

Hip arthroscopy has evolved from initially just removing loose bodies and torn labra to repairing the labrum. Bony reshaping through femoral osteochondroplasty and acetabuloplasty have become commonplace, as our understanding of the pathophysiology of hip disease, particularly femoroacetabular impingement, has come to light relatively recently. Hip microinstability is now being recognized, with hip arthroscopy techniques including capsular plication. The field continues to evolve, with procedures such as labral reconstruction and ligamentum teres reconstruction now being performed. However, our ability to replace other tissues, like loss of articular cartilage, or manage bony deficiencies is limited.

Our ability to address hip arthritis, with loss of articular cartilage on both sides of the joint, is limited. Other than debridement, we cannot resurface the joint, biologically or with a durable synthetic, using arthroscopy. So hip arthroplasty, performed open, remains the procedure of choice because there is not a durable and reliable procedure that can be performed arthroscopically that approaches the outcomes of hip arthroplasty.

Furthermore, we are limited in our ability to address bony deformities that require redirection of forces, like excessive femoral anteversion or femoral neck excessive valgus deformity — those would benefit from a femoral osteotomy. In addition, our ability to address acetabular undercoverage, resulting in hip dysplasia, is quite limited. Although there are some investigators attempting to perform arthroscopic-assisted shelf procedures, at this point, a periacetabular osteotomy is the gold standard for the care of significant dysplasia. And at this time, a periacetabular osteotomy is performed open and beyond the capabilities of arthroscopy.

In the future, I think this will be arthroscopically assisted. Some people are starting to dabble, but we are not there yet.

Marc R. Safran, MD, is professor of orthopedic surgery and team physician at Stanford University, second vice president of the International Society for Hip Arthroscopy and second vice president of the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine.
Disclosure: Safran is a consultant for Biomimedica and ConMed Linvatec and receives fellowship support from ConMed Linvatec and Smith & Nephew.COU

Both arthroscopic and open procedures are critical tools

Hip preservation surgery has much of its roots in open procedures. These include the open surgical hip dislocation (SHD) approach for intra-articular pathology and extra-articular impingement, the extensile anterior approach for periacetabular osteotomy (PAO) and mini-open approaches for femoral osteotomies. The rapid progress of arthroscopic techniques in recent years has made many hip preservation procedures possible through a less invasive arthroscopic approach. Nonetheless, open surgery retains a critical place in the armamentarium of the hip preservation surgeon.

The SHD approach provides excellent visualization and circumferential access to the entirety of the hip joint, including the labrum, chondral surfaces, and femoral head-neck junction. While arthroscopy has largely replaced SHD in treatment of focal impingement and labral tears, SHD may remain advantageous for certain complex procedures. Among these are:

• osteochondral allograft or mosaicplasty for focal chondral defects, especially of the femoral head;
• relative femoral neck lengthening and trochanteric advancement for extra-articular impingement;
• circumferential pincer impingement due to global overcoverage (relative indication); and
• posterior cam impingement (relative indication).

PAO is the primary treatment of choice for the dysplastic acetabulum and is currently the only surgical procedure that corrects the underlying bony deformity. Arthroscopy with capsular plication has made possible successful arthroscopic treatment of certain patients with borderline dysplasia. However, for patients with a center-edge angle ≤20º, any arthroscopic treatment should generally be accompanied by PAO. We have found that concomitant arthroscopy and PAO allow us to address both the intra-articular pathology and the underlying deformity.

Complex femoral deformities may cause abnormal alignment and mechanics of the hip, extra-articular impingement, or intra-articular impingement. Although certain arthroscopic procedures may be beneficial in these contexts, concomitant correction of the underlying femoral deformity is accomplished through femoral osteotomy. At our institution, the most commonly encountered femoral deformities are femoral retroversion and excessive anteversion. We treat these hips by addressing the intra-articular pathology arthroscopically and performing concomitant subtrochanteric femoral rotational osteotomy. Because the osteotomy is fixed with a dynamized nail, this procedure does not affect the need to restrict weight-bearing.

Tremendous advances in treatment of hip disease have been made through advanced arthroscopic techniques. For the hip preservation specialist, both arthroscopic and open procedures are critical tools to treat complex pathology of the hip joint.

Benjamin B. Domb, MD, is medical director at the American Hip Institute, clinical assistant professor at Loyola University Chicago, and director of orthopedics at Adventist Hinsdale Hospital.
Disclosure: Domb is a consultant for Arthrex Inc. and Mako Surgical Corp.