Indications and techniques for hip arthroscopy continue to evolve
Although the concept of hip arthroscopy was introduced in 1931, the procedure remained unpopular until the late 1980s due to technical challenges, poor instrumentation and few indications to merit widespread use. Now, increased knowledge and improved techniques and equipment in recent years have lead to a surge in the use of this procedure.
"Hip arthroscopy is an evolving science," Charles A. Bush-Joseph, MD, of Midwest Orthopaedics at Rush in Chicago, told Orthopedics Today. "We are clearly better able to more accurately diagnose hip and groin conditions. Industry is catching up. There has been dramatic innovation in the equipment surgeons use to perform these types of procedures, making them more reliable and reproducible."
Initially, the indication for hip arthroscopy was simple.
"When we started out, the clearest indication was taking out loose bodies because in years gone by, that was the only thing we were good at diagnosing," J.W. Thomas Byrd, MD, of Nashville Sports Medicine and Orthopaedic Center, Nashville, Tenn., told Orthopedics Today.
Over time, Byrd said, surgeons realized that arthroscopy had many uses in the hip, including the identification and treatment of labral tears — the most common hip pathology addressed with arthroscopy.
The hip labrum acts like a stabilizer and shock absorber for the acetabulum, John P. Salvo Jr., MD, of the Rothman Institute in Marlton, NJ, told Orthopedics Today. Its other critical function is to provide a suction seal around the femoral head, locking in the synovial fluid. Labral tears disrupt this function.
"When we are able to anchor it back to the acetabulum arthroscopically, we can restore that function — that suction seal function of the labrum — and that is something we can see arthroscopically," Salvo said.
Another indication is to use hip arthroscopy for peritrochanteric area problems, specifically for patients who have injuries to the hip abductor muscles, such as the gluteus medius and minimus, Bush-Joseph said.
- "You basically have two groups of surgeons: people who treat femoroacetabular impingement arthroscopically and people who treat through an open procedure."
- — John P. Salvo Jr., MD
"Most surgeons would call the peritrochanteric surgery the ‘rotator cuff of the hip,’" he said. "We are seeing more attention to that in the last 3 to 5 years than we have seen prior to that time."
A more recent indication is for the treatment of femoroacetabular impingement (FAI).
"Femoroacetabular impingement deals with what is felt to be either a developmental or congenital boney abnormality of the hip socket," Bush-Joseph said. "Our challenge is to define what is truly abnormal vs. what is a variation of normal. Certainly, patients with truly abnormal boney anatomy are at a greater risk for soft tissue injury, labral tears and eventual hip degeneration."
Arthroscopy has allowed less invasive treatment of more severe FAI deformities, Dean K. Matsuda, MD, of Kaiser West Los Angeles, told Orthopedics Today. "Specifically with regard to impingement, we are now able to treat some severe deformities such as global pincer impingement, i.e., coxa profunda and acetabuli protrusio, completely arthroscopically, whereas, perhaps a year or so ago, many felt that these were only treatable via a more invasive open dislocation-type surgery," he said. "We have started to perform minimally invasive derotational femoral osteotomies with adjunctive hip arthroscopy for cam FAI from severe femoral retroversion. Open dislocation surgery will still be needed in the treatment of some major deformities, but gravitation toward arthroscopic procedures will continue."
FAI is a controversial subject for several reasons. First, surgeons are divided on the best way to treat it.
"You basically have two groups of surgeons: people who treat femoroacetabular impingement arthroscopically and people who treat through an open procedure," Salvo said. "But the goals are the same: to get rid of the impingement, fix the labrum and take care of any other injuries that you see, such as cartilage wear or articular cartilage damage."
Second, the role of intervention remains ill-defined, Bush-Joseph said.
"The mere presence of a bony deformity does not define actual pathology that requires treatment," he said.
Byrd agreed, "We are getting so good at diagnosing impingement," he said. "We need to be careful that we are not overshooting the target and over-diagnosing cases that might not need the surgery."
Third, when the surgeon correctly identifies a patient with FAI, there are no guidelines on how much bone to remove.
"Many surgeons just go by visual cues without any hard and fast rules," Bush-Joseph said.
Potential trauma applications
Hip arthroscopy is also applicable when treating trauma patients, Bush-Joseph said.
"The best example is the patient who suffers a hip dislocation," he said. "When the hip is reduced, there is a boney, cartilaginous or soft tissue body that prevents concentric reduction of the hip. In past years, the only way to remedy that would be to do an open hip dislocation, remove the loose bodies and repair it." Now, he said that repair can be performed arthroscopically, which allows the patient to recover more rapidly and with less risk.
In addition, the procedure may be applied to reducing and fixating posterior wall fragment fractures, removing loose bodies and soft tissue injury repair, Bush-Joseph said.
"Open dislocation surgery will still be needed in the treatment of some major deformities, but gravitation toward arthroscopic procedures will continue."
- — Dean K. Matsuda, MD
Arthroscopy may be used to repair acetabular fractures, although surgeons should use caution. During these surgeries, saline is pumped into the patient’s body during arthroscopy and the fluid will follow the path of least resistance, possibly causing fluid to fill the retroperitoneal space.
"That is something you have to be cautious about both with the pressure you use and the length of time you are pumping fluid in because it does cause problems," Salvo said.
There are emerging indications for hip arthroscopy.
"We are going to see progress in the use of the arthroscope around the central pubic area for athletic pubalgia and are already using it for endoscopic pubic symphysectomy, often in athletes that also suffer from FAI," Matsuda, an Orthopedics Today Editorial Board member, said. "[Hip arthroscopy is] going to grow in use in the field of fracture fixation of select femoral head and acetabular fractures. We have even successfully used arthroscopic internal fixation in the treatment of osteochondritis dissecans of the femoral head."
Furthermore, use of the arthroscope may expand into the subgluteal space, including endoscopic treatment of sciatic nerve entrapment, ischiofemoral impingement and repair of proximal hamstring avulsion injuries, Matsuda said.
Hip arthroscopy can be a useful tool in pediatric cases, James J. McCarthy, MD, of Cincinnati Children’s Hospital, told Orthopedics Today, and can be used to treat some of the sequelae of Legg-Calve-Perthes disease.
"A small percentage [of children with this disease], approximately 3%, will have intra-articular issues that cause pain," he said. "It could be a chondral flap, labral tear, or be different forms of acetabular impingement. Some of those can be treated arthroscopically."
When McCarthy and colleagues studied the results of hip arthroscopy in Legg-Calve-Perthes disease, they found that two-thirds of their patients did well at a year and one-third did not show much improvement.
Byrd also found good results in his study of 20 consecutive pediatric patients. At 2 years, all were improved, although the improvement was negligible in two patients.
Hip arthroscopy can be used to treat pediatric hip dysplasia, although research is in the early stages, McCarthy said. Operating on children aged 1 year or 2 years "is an out-of-the-box type of use," he said.
McCarthy’s results showed that the surgeries have been successful and result in stable hips. Three patients did well; however, one child developed avascular necrosis (AVN).
"It is unclear if the arthroscopy was the cause of the AVN, but it is concerning," he said.
Steep learning curve
Hip arthroscopy is a challenging operation.
"It is not like the shoulder, knee, elbow or ankle," Thomas G. Sampson, MD, of Post Street Orthopaedics and Sports Medicine in San Francisco, told Orthopedics Today. "You have to go through a lot of muscle and structures that are quite deep. There are also various vital structures: the femoral artery, the femoral vein and nerves in the front and the sciatic nerves on the side. It is a bit scary with all of the vital structures you could potentially damage."
Byrd noted other reasons that make the procedure challenging. The hip anatomy and geometry can be an obstacle.
"The hip is the closest to being a true ball-and-socket constrained joint; that limits maneuverability," he said. The surgeon must get through the thick soft tissue envelope that covers the hip, and the capsule is tight, which limits how much the surgeon can separate the joint surfaces.
Many orthopedic surgeons do not understand hip joint pathology and the pathomechanics, Byrd added.
"Just because you are facile with an arthroscope, does not necessarily mean that you are knowledgeable on how to interpret and decipher the numerous types of hip pathology that we encounter," he said.
Surgeons noted that learning to perform the operation takes time.
"People ask, ‘How many cases do you need to do before you feel comfortable with hip arthroscopy?’" Byrd said. "I guess I am still looking for that number. Every case is a challenge."
Surgeons also need time to adjust to the specialized instruments required for hip arthroscopy.
"We need specialized instruments, not only in length but also curved instruments, flexible instruments in order to safely work around the joint," Salvo said.
The standard equipment for shoulder or knee arthroscopy is a 30° arthroscope, whereas with the hip, surgeons generally use a 70° arthroscope. "It has a bigger angle so you can see around the corner," Salvo said.
Repetition is the key to mastering hip arthroscopy.
"To me, it is an operation that takes between at least 50 to 100 cases where physicians feel confident and comfortable moving around and performing routine procedures," Bush-Joseph said. "For complex cases, the learning curve is probably around 250 cases."
Once a surgeon grasps the surgical technique, the procedure often yields good outcomes. However, this was not always the case.
"I would say in the first 10 years, we did not do so well," Sampson, who is president if the International Society for Hip Arthroscopy said. Results improved throughout the 1990s until now, he said, when they are good.
Research has shown that the outcomes of hip arthroscopy are maintained over time. In a study of 50 patients (52 hips) with 10-years follow-up, Byrd and colleagues demonstrated the long-term effectiveness of hip arthroscopy as a treatment for labral pathology, chondral damage, synovitis and loose bodies.
A large part of the success has been patient selection. Ideally, the patient should be younger — anywhere from their teens to their 40s, Sampson said.
"The healthier, younger [people] with the least amount of cartilage damage are the optimal patients," he said.
Ensuring that the patient has reasonable expectations has also been critical, Byrd said.
"If they have early arthritic changes, and they are thinking they are going to run their first marathon, that is not likely to happen," he said. "Sometimes as a surgeon, you have to help the patient adjust their goals and expectations before you think about surgery."
Low complication rate
Hip arthroscopy boasts a low complication rate.
"Most of the published literature over the past 12 to 14 years has been relatively consistent at around 1% to 1.5% of procedures suffering some kind of complication, usually minor," Bush-Joseph said. The major complication rate is lower, with anecdotal cases of fracture, avascular necrosis or neurovascular compromise, he said.
In addition, the complication rate decreases as surgeon experience increases.
"In the first 60 patients that we did, we had a 16% complication rate," Sampson said. "In the next 550 patients, we had about 4.5% complication rate. In the first 1,000 patients, the complication rate went down to 0.6%. Currently, the complication rate is 0.4%."
The risk of venous thromboembolic disease is minimal.
"In my personal experience, I have had one case, and I average between 60 and 80 hip arthroscopies a year," Bush-Joseph said. "That is one case in 10 years."
The incidence is similar to any other lower extremity surgery.
"I do not believe it is anywhere near what it is with hip replacement, where there is much greater manipulation of the limb and the joint," he said.
In patients with a family history of deep vein thrombosis (DVT), Bush-Joseph recommended high levels of DVT prophylaxis, including aspirin, compression stockings or other measures.
There are some occasional nerve injuries, Salvo said.
"Because we are using traction, the most common ones would be numbness with the lateral femoral cutaneous nerve, which could be a stretch injury from where our portals are," he said. There have been some reports of perineal nerve injuries and some numbness in the foot because of the boots used for traction.
"It is rare that this is permanent," Salvo said.
As with any surgical procedure, there are contraindications.
"If you have patients with significant end-stage arthritic wear, you are probably not going to improve their condition," Bush-Joseph said. "Most of the recent literature suggests that if patients have less than 2 mm of joint space remaining, the likelihood of a hip arthroscopy improving their quality of life is relatively small," he said.
The procedure is also contraindicated in obese patients, in those with active infections and in patients with regional pain disorders, like reflex sympathetic dystrophy or some degree of fibromyalgia.
In addition, Matsuda clarified that hip arthroscopy appears to be useful in the treatment of the septic hip.
"It may not be the pathology of the hip that is causing their problem," Salvo said.
Despite the ways hip arthroscopy has improved, there are still opportunities for growth.
"Indications and applications for hip arthroscopy will continue to expand and grow," Matsuda said. "But I temper that with what I believe is a healthy appreciation for critically reviewing our outcomes and refining the indications. Just because we can do something, does not necessarily mean we should. That said, if a safe and less invasive equivalent can be performed, it may prudent to develop and implement these procedures."
"We are still barely scratching the surface in the hip," Byrd said. "We still do not understand hip pathology. As our clinical assessment improves, as well as the technical and technological advancements, we are will be able to do many more things in the hip joint, especially as we are now going outside the hip into the endoscopic methods of the peritrochanteric space and the subgluteal space. We are developing less invasive methods for addressing some of the traditionally known forms of pathology, but we are also recognizing new problems that are amenable to endoscopic approaches." – by Colleen Owens
Burman M. Arthroscopy or the direct visualization of joints: An experimental cadaver study. J Bone Joint Surg Am. 1931;4:669-695.
Byrd JWT, Freeman CR, Jones KS. Hip arthroscopy for legg-calve-perthes disease: Minimum two-year follow-up. Arthroscopy. 2011;5:e52.
Byrd JWT, Jones KS. Prospective analysis of hip arthroscopy with 10-year follow-up. Clin Orthop Relat Res. 2010;468:741-746.
Matsuda DK. AAOS Now. 2011. www.aaos.org/news/aaosnow/aug11/clinical5.asp. Accessed April 19, 2012.
For more information:
Charles A. Bush-Joseph, MD, can be reached at 1611 W. Harrison St., Suite 300, Chicago, IL 60612; 312-432-2345; email: email@example.com.
J.W. Thomas Byrd, MD, can be reached at 2011 Church St., #100, Nashville, TN37203; 615-284-5800; email: firstname.lastname@example.org.
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; 323-857-4477; email: email@example.com.
James J. McCarthy, MD, can be reached at Cincinnati Children’s Hospital Medical Center, 3333 Burnett Avenue, Cincinnati, OH 45229; 513-446-0446; email: firstname.lastname@example.org.
John P. Salvo Jr., MD, can be reached at the Rothman Institute, 4 Greentree Center, Marlton, NJ 08053; 609-922-4249; email: email@example.com.
Thomas G. Sampson, MD, can be reached at Post Street Orthopaedics and Sports Medicine, 2299 Post St., Suite 107, San Francisco, CA 94115; 415-345-9400; email: firstname.lastname@example.org.
- Bush-Joseph is an unpaid consultant for The Foundry, a small start-up company. His institution, Rush University Medical Center, receives institutional support from Smith & Nephew and Arthrocare. Byrd is a consultant to and receives research support from Smith & Nephew Endoscopy and is a consultant to and has stock in A2 Surgical. Matsuda has intellectual property with Arthrocare and Smith & Nephew. McCarthy has no relevant financial disclosures. Salvo is a consultant to Smith & Nephew Endoscopy, specifically in the area of arthroscopy. Sampson is a consultant for ConMed and a review for the Journal of Bone and Joint Surgery (Br.), Clinical Orthopaedics and Related Research and Arthroscopy.
Does the steep learning curve associated with hip arthroscopy warrant subspecialty certification?
In favor of subspecialty certification
Christopher M. Larson
This is an important and timely question to pose to the orthopedic community. The goal of subspecialty certification should not be to limit the number of surgeons performing particular procedures, but instead to increase the surgeons’ fund of knowledge and improve their technical skills in a particular area that requires a unique subset of clinical and surgical skills. This would hopefully translate into better outcomes and a lower rate of complications and failures. Hip arthroscopy, periarticular hip endoscopy and hip preservation are rapidly evolving areas with an extremely steep learning curve for all surgeons, regardless of their experience and patient volume. This steep learning curve not only applies to the technical ability to perform these procedures, but also, more importantly, to the ability to make an accurate diagnosis and appropriately select patients for arthroscopic and open surgical procedures.
Hip disorders in the young adult and pediatric population are a unique area in orthopedics as it requires an expertise in the areas of adult and pediatric reconstructive surgery as well as sports medicine. There is limited opportunity for surgeons in residency programs to gain this experience, and for surgeons coming out of residency to acquire additional fellowship experience that covers each of these important areas. The surgeon is therefore required to do a number of fellowships and/or spend significant time gaining experience with various surgeons and in various educational lab settings. Surgeons do not need to perform open surgical dislocations and pelvic osteotomies in addition to arthroscopic and endoscopic hip procedures, but they do need to understand that there are limits for hip arthroscopy and when to refer these patients on for further evaluation.
We are seeing a significant increase in the number of failed hip arthroscopies as the number of surgeons performing them and procedures performed are increasing. We are at a critical time for hip preservation and endoscopic hip procedures with respect to understanding the variability in hip morphology, the various pathologies encountered about the hip and pelvis, and the optimal surgical and nonsurgical treatment approaches. I believe it is up to the leaders in this field to identify the most appropriate way to educate and train interested surgeons in this evolving subspecialty, and I believe it might be best achieved with a comprehensive subspecialty certification.
Christopher M. Larson, MD, is Program Director of the Minnesota Orthopedic Sports Medicine Institute Sports Fellowship Program at Twin Cities Orthopedics in Edina, Minn.
Disclosure: Larson is a consultant for Smith & Nephew and A3 Surgical. He has stock options in A3 Surgical and is on the editorial board for the Journal of Arthroscopy and Related Research.
A certificate of added qualification
Carlos A. Guanche
I think hip arthroscopy should be part of the sports medicine certification. There is already a sports medicine certificate of added qualification (CAQ), which I think covers it. Hip arthroscopy in general is so new, that I do not know that people really understand that it is predominantly a sports medicine injury.
One of the big problems with hip arthroscopy in the beginning was that there were a lot of total joint replacement surgeons who tried to do the procedure. Hip arthroscopy is more difficult than knee arthroscopy, which they were doing historically for a long time. It is a tighter joint. We use a 70° arthroscope, so technically it is a little harder to do. They were trying to do a procedure that is challenging, at best, and they did not have the requisite skills in the beginning.
When we first started seeing hip arthroscopy patients, we were dealing with older patients who were candidates for hip replacement rather than an arthroscopic procedure. What I have seen during the last 5 years in my own practice is that my average patient that I actually do a hip arthroscopy on is much more likely to be a high school or collegiate athlete. During the last few years, as we have understood more of what causes these injuries, and we are seeing people who are hip arthroscopy candidates. I think that it being arthroscopy, it falls under the auspices of sports medicine, which is already covered by the CAQ.
Carlos A. Guanche, MD, is an orthopedic surgeon at Southern California Orthopaedic Institute in Van Nuys, Calif.
Disclosure: Guanche is a consultant for Smith & Nephew Inc. and Tornier Inc.