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Hip Preserving Surgical Techniques
 
Preserving rather than replacing the injured hip is an option in some instances of hip problems in dancers.
 
Here is how I learned about this area of orthopedics:
Shortly after I launched dancerhips.com I got a request from a young Canadian dancer. She had been experiencing increasing hip pain and had just been diagnosed with hip dysplasia and a torn labrum. Since her femoral head was still intact, and she was only 36, her surgeon suggested she have periacetabular osteotomy (PAO). After reading through dancerhips.com she wondered if I knew any dancers who had had PAO to whom she could speak. In truth, I did not. Furthermore, since I already had osteoarthritis (OA) requiring THR when my hip pain was initially diagnosed, I had never even looked into this type of surgery and was quite ignorant about it.
 
In response to her request, I contacted a number of prominent surgeons who specialized in PAO. I asked if they had ever operated on a dancer or athlete to whom the Canadian dancer could talk. I had a wonderful response from Dr. Michael Millis, Associate Professor of Orthopedic Surgery at Harvard Medical School. He had someone Anne could talk to, and he was very interested in supporting the dancerhips.com project.
 
Dr. Millis sent me some information about PAO, hip dysplasia, and other causes of so-called mechanical damage to the hip - damage caused by poor wear of poorly formed joints. I also was able to find some interesting information from Dr. Jeffrey Mast and Joel Matta on the Internet. The Hospital for Special Surgery (HSS) site is also helpful.(See Links below).
 
Why do dancers develop hip problems?
Some dancers have normal hip anatomy and develop hip problems because of trauma. Others are predisposed because of a developmental hip problem. This page addresses the latter group.
 
Hip Dysplasia
dyplastic hip (X-ray from HSS) The x-ray at left shows an example of developmental dysplasia of the hip, or DDH. This condition describes a shallow, steep socket that leaves the outer part of the femoral head uncovered or "unroofed." The uncovered portion cannot contribute to supporting the body's weight. Instead, all the load is concentrated in a small area, causing high local stress on the cartilage and underlying bone. Moreover, the steep slope of the socket creates a wobbly joint with high shear forces and high stress at the rim of the socket. Many hips with DDH also have associated deformities of the femoral neck - too short and too straight - and of the femoral head, which may be anything from slightly flat to bizarrely mushroomed.

The x-ray below shows severe developmental dysplasia with bone-on-bone arthritis on the left side (the patient's right hip, as she faces us).
DDH

Half of the deformed femoral head lies outside the socket. Dense "sclerotic" bone shows as bright white areas in the narrow region that bears all the load. The femur is abnormally narrow. This 48-year-old patient could walk very short distances with a pronounced limp. The other hip is more mildly dysplastic and shows a narrowing of the joint space, suggesting that erosion of cartilage already is underway.

All these "mechanical" problems cause uneven wear that leads to early osteoarthritis. This is the case for "civilians," but is even more likely for dancers. Dr. Millis says that dysplasia is clearly the most common cause of hip OA in women, and 80% of DDH patients are female. In Japan, dysplasia causes more than 90% of hip osteoarthritis! Further, shallow sockets allow for a big range of motion, so dancers are a self-selected group in which to find this problem.
 
It is easy to imagine how dancers also overload the hip: The continual external rotation demanded by the turn-out position of the legs further stresses the malformed weightbearing surfaces. Repetitive jumping increases the impact injury and over time accelerates the deterioration of the joint cartilage. Cracks or pits in the cartilage then allow joint fluid to enter the marrow, under the pressure of normal activity. The resultant "pseudocysts" full of joint fluid weaken the bone. The bone tries to repair itself, but the effort is uncoordinated. New bone tends to form in the wrong places - at the margins of the joint, as spurs. These spurs may cause a grinding pain and seriously limit the joint's range of motion.
 
In addition to bony deterioration, there may be stretching or tearing of the ligaments over the joint, the breakdown or "tearing" of the acetabular labrum (rim cartilage of the acetabulum) or a "fatigue" fracture of the bony rim of the acetabulum. Once the deterioration of cartilage is set in motion, there can be very rapid worsening of the hip integrity leading to osteoarthritis, even within a few months.
 
Femoral Acetabular Impingement (FAI)
As opposed to hip dysplasia, FAI generally refers to too much coverage of the ball by the socket. Often seen in high level athletes, this is a relatively new diagnosis with controversial treatment. To learn more, please visit this website maintained by the orthopedic surgeon, Allston J. Stubbs, M.D.
 
Labral tears
The acetabular socket has a rim of fibrocartilage called the labrum. Anatomically, it is analogous to the knee meniscus. This cartilage helps to seal in the joint fluid. When the acetabulum is shallow, the rim bears a heavy load, and the labrum can tear away.
 
The treatment of labral tears is under active investigation. The usual treatment is conservative non-surgical management with anti-inflammatory medicines and rest; but more aggressive measures are now being done. Arthroscopic surgery can trim away a torn labral flap but is advised only if the joint is otherwise healthy and well formed. My own surgeon, Douglas Padgett MD, has successfully treated tears for two principal NYCB dancers who were then able to return to the stage. He says that it commonly takes a professional dancer six months to achieve that level of recovery.
 
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Treatment
Periacetabular Osteotomy (PAO)
After decades of research, it is now clear that the development of arthritic symptoms parallels mechanical deterioration. Since the early 1990's, much focus has been on the acetabular rim for the earliest signs. The components of "acetabular rim syndrome" are pain, impaired function, and characteristic degenerative changes on x-ray and MRI. DDH patients who have few or no arthritic changes in the hip are the best candidates for surgical correction by PAO.
 
Since early intervention has the highest level of success, what symptoms might the dancer have to suggest dysplasia?
Aching at the outside of the thigh and limping after activity are common first signs. A feeling of the anterior (front) hip "giving way" (instability) is also a clue, as are locking or catching in the hip and sharp groin pain.
 
The orthopedist performs certain maneuvers in the physical exam to detect possible hip problems. The impingement test involves forcing internal rotation of the flexed hip, and the apprehension test is done by externally rotating the hyperextended hip. Pain or apprehension (tensing up) with either of these maneuvers means a positive test result and suggests the hip is definitely in trouble. The full range of motion is also evaluated.Click here to see a video of the hip examination. X-rays are done to confirm the physical findings. If cartilage problems are suspected, as in a labral tear, an MRI study may be ordered. If PAO is considered, a CT scan can provide important information about likely surgical outcome.
 
"Periacetabular" means around the acetabulum. "Osteotomy" means to cut bone. In PAO, the patient's own joint is surgically altered to create a broader load-bearing surface. During the surgery, the acetabulum is sawed apart from the rest of the pelvis, repositioned to cover the head of the femur, and secured with metal hardware. If necessary, the head of the femur is repositioned by surgery on the femoral neck. Recovery usually involves 3-4 months of toe-touch weightbearing on crutches, followed by a gradual resumption of normal walking and extensive physical therapy. The orthopedic hardware may be removed in a subsequent operation.
 
Surgical goals of PAO include pain relief, restoration of function and prolonging the life of the patient's own hip. Due to the unique ability of the bone to regenerate itself (compared to skin, for example, which will scar instead of rebuilding itself), a well done PAO may be satisfactory for 30 years (to quote Jeff Mast, MD). The hip is preserved, not replaced. Even with so-called poor results, that is, those cases in which the patient later needed THR, joint replacement may be delayed by several years and prove more straightforward, due to prior correction of the joint deformity.
 
Although PAO is radical surgery, it may ultimately be a more conservative approach for a young person. The service life of a hip replacement prosthesis is limited to about 10-20 years; and the need to replace the prosthesis, possibly multiple times, creates progressive muscle scarring and bone loss, over the course of a lifetime. As covered elsewhere in this website, replacement materials currently available have various limitations. Finally, the successful PAO patient may return to full activity without restriction, whereas the THR patient will have to moderate certain vigorous activities and will always have to worry about possible dislocation.
 
To read a young dancer's account of her experience with hip preserving surgery, click here.
 
Hip Arthroscopy
Hip Arthroscopy must be done under anesthesia, since strong leg traction is needed to open the space between the ball and socket. That space, about ½ inch, is just enough for the surgeon to work while aided by fluoroscopy (live x-ray). Arthroscopy can be used to treat a labral tear.
 
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To see Surgical Hip Replacement Options click here.
 
Reference:
A comprehensive review of the literature is offered in this overview article.
Millis MB, Kim YJ. Rationale of osteotomy and related procedures for hip preservation: a review. Clin Orthop. 2002 Dec;(405):108-21.
 
I am indebted to the science journalist, Elisabeth Thomas-Matej for her extensive and insightful editing. You can read more about PAO on her website, Hip Universe.
 
Other Links:
Dr. Millis in Boston
Dr. Paul Beaule in Los Angeles: This page has an excellent PDF file to download about hip solutions for young adults
Dr. Jeffrey Mast in Nevada
Dr. Joel M. Matta in Los Angeles
The Rothman Institute: has a good explanation of different types of congenital hip problems and treatments
Surgeons for PAO: a listing of orthopedists on Hip Universe
HSS: dysplasia
HSS: arthroscopy
 
For arthroscopy for dancers in the West, a dancer and physical therapist (Andrea Avruskin PT, DPT, ATC, NREMT-B of Las Vegas) recommends Dr. Marc Philippon. He is the surgeon who did arthroscopy on Tara Lipinski and Mario LeMieux (hockey player).
He is currently relocating to the Steadman Hawkins Clinic in Vail, Colorado.
 
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