Miscellaneous Problems: Synovitis, Degenerative Joint Disease, and Tumors

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CHAPTER 6 Miscellaneous Problems: Synovitis, Degenerative Joint Disease, and Tumors

Thomas G. Sampson

GENERAL CONSIDERATIONS

Synovitis

Synovitis of the hip has many causes. In this chapter, we will discuss only five of the pathologic entities causing primary synovitis—rheumatoid arthritis (RA), calcium pyrophosphate dihydrate crystal deposition disease (CPPD), fatty deposition disease (hyperlipoproteinemia), hemachromatosis, and pyarthrosis—and their arthroscopic treatment.

The role of arthroscopic synovectomy in treating synovial diseases was apparent to the earliest arthroscopists. In almost all pathology of the hip, synovitis is present. Our group has had several undiagnosed cases of hip pain with effusions that were shown to be seronegative rheumatoid arthritis with synovial biopsy. In 1988, Ide and colleagues1 performed arthroscopic synovectomy for RA on six hips in three patients using mechanical shavers through a two-portal technique, with good results. With the advent of laser and radiofrequency (RF) ablation, there are now three modalities used to débride the synovium. It remains difficult to reach 100% of the joint but with newer, more effective medical management, debulking of the diseased synovium seems to be adequate.

CPPD has not been reported as frequently in the hip as it has in the ligamentum flavum and in the knee, associated with RA.2,3 Our group has performed synovectomy on two patients for CPPD associated with femoroacetabular impingement. Clearly, it is an entity that should be considered in the differential diagnosis of patients with refractory synovitis.

There are no reports in the arthroscopic literature on the treatment of hyperlipoproteinemia, hemachromatosis, or any of the metabolic arthropathies. Our group has performed partial synovectomy in a few patients thought to have fatty deposition and in one patient with hemachromatosis associated with arthritis. It is presented here only to make the arthroscopic surgeon aware that metabolic arthropathies exist.4 Metabolic arthropathy appears as white or yellowish plaques on the articular cartilage associated with a mild synovitic reaction. The plaque cannot be removed without destroying the articular cartilage and therefore should be treated with synovectomy only.

Arthroscopic débridement and lavage has become the treatment of choice for septic arthritis in children, adolescents, and adults. This modality has been associated with minimal morbidity and an excellent cure rate.5–8 McCarthy and associates9 have reported on successful treatment of septic total hips in two patients using arthroscopic débridement, lavage, and intravenous antibiotics Our group has successfully treated four patients with late hematogenous infections of their total hips arthroscopically. No recurrence has been noted, with the longest follow-up being 20 years, when one patient died from natural causes at the age of 93 years (Fig. 6-1).

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FIGURE 6-1 A, Pyarthrosis caused by Staphylococcus aureus in a total hip from a hand infection that occurred 1 year and 3 months after index replacement. Note the exudate between the metal head and acetabulum (arrow). B, Infected total hip. Note the exudate and synovitis (arrow). C, Insertion of drainage tube over slotted cannula (arrow).

Degenerative Joint Disease

The arthroscopic treatment of degenerative joint disease (DJD) of the hip remains controversial and most challenging and difficult. Even the most experienced hip arthroscopists avoid the procedure in DJD because there are few benchmarks to predict a successful outcome. Prior to 2001, DJD was treated with arthroscopic débridement, labrectomy, synovectomy, and abrasion chondroplasty. In 28 of 290 patients who had partial labrectomies in the presence of DJD, only 21% had a good result compared with a 71% good result rate in those without DJD.10 Subsequently, with the recognition of femoroacetabular impingement (FAI) and the added correction of the abnormal morphology, the modified Harris hip score improved significantly from 72 to 92 with an average 4-year follow-up.11–13

A residual head-neck deformity from femoral neck fractures has been a cause of FAI and DJD. Reshaping of the deformity has been done using an open surgical dislocation by Eijer and coworkers.14 Our group has treated the DJD and deformity with an arthroscopic head-neck osteoplasty and débridement, synovectomy, and abrasion chondroplasty with microfracture in three patients.

Tumors

Essentially all tumors that are amenable to arthroscopic treatment are benign. Pigmented villonodular synovitis (PVNS) and synovial chondromatosis may be considered synovial diseases instead of tumors, and are both difficult to eradicate unless a complete synovectomy can be performed. Frequent recurrences are seen, from inadequate removal of the tumors or inadequate synovectomy.15–17 Capsulotomy is recommended to expose all areas and recesses of the central and peripheral compartments to remove the loose and attached bodies and ablate the synovium, particularly where the lesions are forming.

Arthroscopic removal of osteoid osteoma of the hip has been described by Glick and colleagues18 in two cases in the central compartment. Our group has since removed an old, yet active osteoid osteoma from the head-neck junction associated with a cam impingement requiring excision, synovectomy, and head neck osteoplasty (Fig. 6-2).

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FIGURE 6-2 A, Radiograph of a 43-year-old woman with a 10-year history of a painful osteoid osteoma (arrow). B, Localization with fluoroscopy at surgery. C, The mass effect of the osteoid osteoma seen at arthroscopy (arrow). D, Removed osteoid osteoma, along with multiple loose bodies.

Heterotopic bone should be considered a pseudotumor of the hip and is most often a complication of trauma or hip surgery. There are no reports of its treatment using arthroscopic techniques; however, our group favors arthroscopic excision and follow surgery with a single dose of 700 rad of radiation or a strong dose of nonsteroidal anti-inflammatory drugs (NSAIDs) for 3 to 6 weeks. The recurrence rate is lower with the subsequent radiation.

ANATOMY AND PHYSICAL EXAMINATION

Synovitis of the hip may present with pain in the groin, buttock, and trochanter. The hallmarks of the presentation and examination are associated with an irritable hip. Much like an acute abdomen that is stiff and exquisitely painful on palpation and jarring, the irritable hip is very painful on palpation and rotational movements. Synovitic hips will have pain with all ranges of motion or at the extremes of motion when tested passively. Septic hips may vary as to the level of pain, depending on the organism type and the tenseness of the effusion.

Degenerative joint disease presents with or without a limp, and difficulty walking, sitting, and putting on shoes and socks because of restricted range of motion. With the loss of articular cartilage, a straight leg raise with the knee extended may cause pain in the groin because of the compressive forces of the opposing chondromalacic surfaces of the head and acetabulum. There may be popping and catching with rotation. Loss of internal rotation is almost always present. The Trendelenburg sign and test may be negative in milder cases. Our group has found that if there is at least 50% range of rotational movement when tested passively compared with the normal contralateral side, and if more than 50% of articular cartilage thickness on the anteroposterior (AP) x-ray is present, results show a more than 80% chance of significant improvement that continues for more than 2 years (Fig. 6-3).

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FIGURE 6-3 A, Fluororadiograph of a 55-year-old man with 3 years of left hip pain, DJD, and FAI. Note maintenance of the joint space (arrows). After arthroscopic synovectomy, débridement, microfracture, and removal of the cam bump, his modified Harris hip score was still 100 at 5 years postoperatively. B, Arthroscopic view of the fragmented acetabular articular cartilage being débrided by an RF probe. C, Microfracture of the exposed acetabular bone.

Tumors present with pain and, in many cases, popping and catching. There may be a limp if there is an effusion. Range of motion may be restricted if catching or locking is present. Most patients may present with entirely normal movement. Osteoid osteomas usually cause night pain that is relieved by aspirin or other NSAIDs.18,19

PREOPERATIVE IMAGING AND PLANNING

Routine radiographs are mandatory for preliminary imaging of the hip in all cases of hip symptoms. This should include an AP view of the pelvis, including both hips from the top of the iliac crest to below the lesser trochanters and frog-leg and cross-table lateral views. On the AP view, the tip of the coccyx should be 1 to 2 cm from the pubic symphysis to eliminate pelvic tilt. Magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA) with gadolinium should be done as an adjunct to the x-rays if clinically indicated.

The findings of synovitis on x-ray may be normal in the early stages may include subtle erosions and cyst formation. On MRI, the findings in RA may include subchondral erosions and hypertrophic synovium.20 DJD is easily detectable x-rays and MRI scans, with osteophyte formation and joint space narrowing. Because FAI may be the cause in many osteoarthritic hips, a metaplastic bump on the head-neck junction and a rim overgrowth or prominence may be seen. In many cases, a fibro-osseous cyst of varying size appears on the neck, typically within the bump. The MRI shows capsular thickening, chondral erosions, and usually some cysts.

Pigmented villonodular synovitis may only be detected by MRI in the early stages and in late stages with periarticular erosion, effusion, and MR characteristics of hemosiderin deposition in the synovium. In these cases, it is important to examine the entire hip thoroughly, including the peripheral compartment, to ensure as thorough a resection as possible.

Synovial chondromatosis presents as cartilage type or osteocartilage type, with the latter visualized on plain radiographs. MRI images may range from loose bodies from small uniform-sized areas attached to the synovium to large, detached multiple bodies. In some cases, large aggregates and masses are also noted.

In all cases, radiography and MRI identify the diagnosis and location(s) of the lesions to be addressed arthroscopically. The standard techniques of hip arthroscopy are used to confirm the diagnosis. The use of a wide capsulotomy to expose the lesions is recommended. This allows for easier access of the instruments and facilitated removal of masses and loose bodies. The capsulotomy may be done from the central compartment by connecting the portals with an arthroscopic knife, or by an extracapsular method (see later). All peripheral compartment surgery may be done without distraction.

TECHNIQUE

Anesthesia Considerations

Most hip arthroscopy is done in an outpatient setting. It is difficult to predict the operative time in many of these cases, especially those with DJD and loose bodies from synovial chondromatosis. Our group performs the procedure with the patient in the lateral decubitus position. Awake patients under regional anesthesia may become uncomfortable lying on their side for the duration of the procedure. For this reason, as well as for relaxation and the need for paralysis, a general anesthetic is recommended.

Positioning

The supine or lateral position may be used to treat these conditions. The preference and skill of the hip arthroscopist will determine which to use. There are multiple series documenting good outcomes with both techniques.

Portals

In most arthroscopic procedures for the treatment for synovitis, DJD, and tumors, the standard three portals (anterior, anterolateral, and posterolateral) are used. When more peripheral areas need to be reached, the addition of an anterior and distal portal between 5 and 8 cm from the anterior portal is useful.

Procedure

The patient is placed in the supine or lateral decubitus position and the appropriate distractor is applied to the affected leg. A C-arm fluoroscope is brought in and, before prepping the patient, a series of four views is taken and recorded. These include AP views in neutral, internal, and external rotation as well as an AP 90-degree view to show the shape and interaction between the head-neck junction and the acetabulum, and to appreciate any loose bodies and their change in position.

Under fluoroscopic control, the long needle is placed through the anterolateral portal directed toward the capsular area at the head-neck junction. There should be about 1 cm of clearance with the greater trochanter. A Nitinol wire is placed through the needle and the skin is incised with a no. 11 blade. The arthroscope trocar sheath assembly is pushed over the wire and the sheath is used to sweep the muscle away from the capsule. The procedure is begun with a 30-degree arthroscope. The pump is started at 50 mm Hg pressure on low flow, allowing a view of the fat pad over the anterior hip capsule. The anterior portal is established with the same technique and a 4-mm switching stick is used to sweep the capsule and palpate the reflected head of the rectus femoris. The key to this approach is identifying the rectus femoris, because the capsule directly beneath covers the anterolateral portion of the labrum (Fig. 6-4).

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FIGURE 6-4 A, C-arm fluoroscopic view of the arthroscope and RF probe over the anterolateral capsule of a left hip before capsulotomy. B, Arthroscopic view external to the left anterolateral hip capsule. Note the reflected head of the rectus femoris (RRF), fat pad over the capsule (FP), and band of the iliofemoral ligament (BIFL). C, Arthroscopic view external to the left anterolateral hip capsule with the RF probe in place that matches the fluoroscopic view in A before capsulotomy. Note the RRF, capsule (C), and RF probe (P). D, Arthroscopic view of the cut capsule (CC), with the RF probe retracting the capsule before incising it over the labrum (L). Note the femoral head (H). E, Arthroscopic view of the completed capsulotomy exposing the femoral head (H), labrum (L), and acetabular rim (AR), much like what is seen in an arthrotomy. F, Illustration of the capsule being incised using the RF probe and exposure of the head-neck junction and labrum.

A 4-mm shaver is introduced and the fat is removed to expose the capsule. The capsulotomy is done with an RF probe, beginning at the base of the neck, toward the labrum. Capsular thickening is common and, in my experience, may vary from 2 or 3 mm to 2 cm. By lifting the capsule with the probe before cutting when near the articular cartilage and labrum, exposure may be done without damaging those structures. The capsulotomy is carried up and over the labrum and along the anterior and lateral acetabular rim, between the labrum and the bone.

Synovitis, loose bodies, degenerative tissue, and normal and abnormal anatomy of the head-neck region are visualized similar to an open procedure with the addition of magnification (Fig. 6-5).

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FIGURE 6-5 A, Three-dimensional CT scan of the left hip with synovial chondromatosis. B, Arthroscopic view of a clump of synovial chondromata (SC) anterior to the femoral neck (N). C, Arthroscopic view of a clump of SC anterior to the femoral neck (N) being freed up before extraction with an RF probe (RF). Note the cut capsule (CC). D, Arthroscopic view anterior to N in which the mass has been removed, exposing the iliopsoas (IS); the RF is being used to do a synovectomy. Note the femoral head (H).

Once the peripheral pathology has been identified, the hip is then distracted to enter the central compartment. It may be necessary to create a posterolateral portal to work in all areas of the central compartment. The central compartment is then inspected for pathology methodically, first through the anterolateral portal using a probe from the anterior or posterolateral portal. Moving the scope to the other portals is necessary for complete assessment of the joint.

If loose bodies are present, they are removed with a shaver and graspers. Occasionally, the fat pad hides notch bodies or is fibrotic, and is removed with the shaver. If the notch is filled with a mat of chondromata, the mass is removed with a combination of curettes, picks, and shavers (Fig. 6-6). If the notch has encroaching osteophytes, osteophytectomy using a long 4-mm hip burr, curettes, and picks is preferable to restore the contact forces between the head and acetabular cartilage (Fig. 6-7).21

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FIGURE 6-6 View of matted mass of synovial chondromata (MSC) filling the acetabular fossa. Note the acetabulum (A) and femoral head (H).

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FIGURE 6-7 A, Arthroscopic views of the acetabular fossa from normal to arthritic. Note the head (H), ligamentum teres (LT), fat pad (FP), and anterior (A) and posterior (P) views. B, AP radiograph (A) of the fossa osteophyte, and CT (B) and MRI (C) scans. Note the notch osteophyte (arrows). C, Arthroscopic procedure for excision of a notch osteophyte. D, AP fluororadiographs before and after removal of the notch osteophyte (arrows).

The rim of the acetabulum may have an anterolateral osteophytic ridge. The osteophyte is exposed behind the labrum and removed with a 4-mm hip burr. If cysts are encountered, they are curetted and saucerized with the burr (Fig. 6-8).

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FIGURE 6-8 A, AP radiograph in a 46-year-old man with painful DJD. The right hip shows a large, multishaped anterior impingement osteophyte (arrow). B, Arthroscopic view of the multishaped anterior rim osteophyte (O), with the soft tissue being dissected away by the RF wand. Note the head (H), labrum (L) and capsule (C). C, Arthroscopic view of the osteophyte (O) being excised by the 5-mm burr (B). D, Arthroscopic view of an elevator (E) separating the remaining osteophyte (O) away from the rim. E, Arthroscopic view of acetabular rim (AR) trimming with the 5-mm burr (B). F, Postoperative fluororadiograph showing the correction and removal of the anterior rim osteophyte.

Labral degeneration, tears, or destruction by synovitis are treated with partial labrectomy with the shaver and/or an RF wand. In some cases, a labral repair or refixation is done by abrading the base of the anticipated acetabular attachment with a 4-mm burr, followed by drilling for the anchor of choice, and finally inserting the anchor. The suture is wrapped around the labrum or sewn through with a suture passer or suture relay technique. Finally, the labrum is tied down securing it. It is preferable to place anchors 1 cm apart, which will determine the number of anchors used.

Erosions of the articular cartilage of the head and acetabulum require excision of the delaminated tissue to stable cartilage with a shaver or curette, abrasion and removal of the calcific layer, and microfracture using the awls. Most areas can be reached on the acetabular surface except for zone 6, near the transverse ligament; however, on the femoral head, there is difficulty applying instruments to zones 2m, 3m, 4m, and 6.22

In the peripheral compartment, the capsulotomy makes it much easier to find and remove loose bodies. The search should be performed circumferentially around the head and neck, beneath the lateral and medial synovial folds, near the transverse ligament and the distal capsular reflection near the lesser trochanter. Once the loose bodies or PVNS lesions have been removed, a synovectomy using 4-mm straight and curved shavers and RF wands is recommended. A flexible wand may be needed to reach all the areas. By doing as complete a synovectomy as possible, the recurrence rate of the disease will be reduced.

Finally, in the case of DJD, the femoral head-neck junction may need to be reshaped in the same way as with FAI. The neck may have barnacle-like osteophytes that are removed with a shaver, burr, and curettes.

If the hip is arthritic and stiff, a generous capsulectomy is done with the 5-mm shaver, arthroscopic knife, and/or RF probe. In all other situations, the capsule is left open, because it will heal in most cases (Fig. 6-9).

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FIGURE 6-9 A, Arthroscopic view of a capsular closure of a left hip. The curved suture hook (arrow) is shown penetrating the lateral capsule (LC) with a no. 1 absorbable monofilament suture. Note the medial capsule (MC). B, Arthroscopic view of a capsular closure of a left hip showing the penetrator (P) grasper grabbing the suture. Note the head (H) and neck (N) of the femur. C, Arthroscopic view of a capsular closure of a left hip after a no. 3 suture has been passed before tying. D, Arthroscopic view of a capsular closure of a left hip after the sutures have been tied and the capsule closed.

The treatment of septic arthritis involves entering the central compartment first with distraction through an anterolateral portal and placing a shaver through the posterolateral portal to carry out débridement, lavage, and a synovectomy. The peripheral compartment may be reached by releasing traction and flexing the hip to create the space, or by the method of capsulotomy described earlier. Lavaging the hip with more than 3 L of saline is recommended. Drains are placed through a slotted cannula and sewn into the skin. Broad-spectrum intravenous antibiotics are started after adequate cultures are taken. The antibiotic is later changed, based on the results of culture and sensitivity testing. Consideration should always be given to the involvement of an infectious disease consultant.

PEARLS& PITFALLS

• Whether to enter the central compartment first or do a capsulotomy is determined by the preoperative plan and distractibility of the hip. It is preferable to perform a capsulotomy first because most of the work is done in the peripheral compartment and no distraction is needed.
• Once done with the central compartment, distraction should be released. This avoids unnecessary traction and complication.
• Repairing the capsule, leaving the capsule open, or performing a capsulectomy should be considered. If the patient has hypermobile joints or there is concern about instability, the capsule is repaired with side to side absorbable no. 1 monofilament suture using suture hooks and retriever graspers.

POSTOPERATIVE CARE

After wound closure, 30 mL of bupivacaine is administered to all patients. An NSAID such as ibuprofen, celecoxib, or diclofenac is prescribed to reduce the potential for heterotopic bone formation. On the day of surgery, weight bearing on two crutches is begun as tolerated and progressed to one crutch or a cane. When the patient is experiencing little pain on weight bearing, has no sensation of giving way, and has good hip stabilization, use of the crutches or cane can be discontinued. Beginning 1 day after surgery, or when tolerated, the patient is encouraged to ride a stationary bike with little to no resistance for 20 minutes three times daily. The time is increased along with the resistance as tolerated. Sutures are removed at 1 week and elliptical and weight-training exercises are begun, along with distance walking on a treadmill or outside. The patient is taught range of motion exercises and told not to hyperextend for 3 to 6 weeks. At 1 month, the patient is evaluated for symptoms, range of motion, and hip stability. Most patients continue with self-directed advancement of their exercises and activities. If the range of motion is not 80% of normal, physical therapy is advised. Symptoms may continue to some degree, even after successful surgery, for at least 1 year, and patients are advised not to be alarmed if the symptoms fluctuate in intensity and frequency. Most symptoms improve over months. If there is a significant decline, further investigation with a simple x-ray may lead to a diagnosis of failed surgery. Surgical failure in arthritic patients is demonstrated by further loss of joint space or widening of the medial clear space and superior lateral subluxation.

COMPLICATIONS

Complications may be avoided by paying attention to the length of distraction time and the location of the neurovascular bundles, and taking great care to avoid damage to the articular cartilage.

In our series of 1000 cases, we have found that continuous distraction lasting less than 2 hours results in no sciatic, femoral, or pudendal neuropraxias. We have had five cases of lateral cutaneous neuropraxia; however, all either resolved or the patient accommodated to the patch of numbness on the thigh. Approximately 1% of our cases developed heterotopic bone; in five patients, reoperation was required to alleviate symptoms. There was one nondisplaced femoral neck fracture in a patient treated for DJD and FAI, in which the treatment was placement of a single cannulated screw. This patient has had a final modified Harris hip score of 100 for the last 5 years. We have had no occurrence of deep infections.

REFERENCES

1. Ide T, Akamatsu N, Nakajima I. Arthroscopic surgery of the hip joint. Arthroscopy. 1991;7:204-211.

2. Ishida Y, Oki T, Ono Y, Nogami H. Coffin-Lowry syndrome associated with calcium pyrophosphate crystal deposition in the ligamenta flava. Clin Orthop Relat Res. 1992;275:144-151.

3. Gerster JC, Varisco PA, Kern J, et al. CPPD crystal deposition disease in patients with rheumatoid arthritis. Clin Rheumatol. 2006;25:468-469.

4. Timsit MA, Bardin T. Metabolic arthropathies. Curr Opin Rheumatol. 1994;6:448-453.

5. Broy SB, Schmid FR. A comparison of medical drainage (needle aspiration) and surgical drainage (arthrotomy or arthroscopy) in the initial treatment of infected joints. Clin Rheum Dis. 1986;12:501-522.

6. Ohl MD, Kean JR, Steensen RN. Arthroscopic treatment of septic arthritic knees in children and adolescents. Orthop Rev. 1991;20:894-896.

7. Blitzer CM. Arthroscopic management of septic arthritis of the hip. Arthroscopy. 1993;9:414-416.

8. Kim SJ, Choi NH, Ko SH, et al. Arthroscopic treatment of septic arthritis of the hip. Clin Orthop Relat Res. 2003;407:211-214.

9. McCarthy JC, Jibodh SR, Lee JA. The role of arthroscopy in evaluation of painful hip arthroplasty. Clin Orthop Relat Res. 2009;467:174-180.

10. Farjo LA, Glick JM, Sampson TG. Hip arthroscopy for acetabular labral tears. Arthroscopy. 1999;15:132-137.

11. Sampson T. Hip morphology and its relationship to pathology: dyplasia to impingement. Oper Tech Sports Med. 2005;13:37-45.

12. Sampson T. Arthroscopic treatment of femoroacetabular impingement. Techniques in Orthopaedics. 2005;20(1):56-62.

13. Sampson TG. Arthroscopic treatment of femoroacetabular impingement: a proposed technique with clinical experience. Instr Course Lect. 2006;55:337-346.

14. Eijer H, Myers SR, Ganz R. Anterior femoroacetabular impingement after femoral neck fractures. J Orthop Trauma. 2001;15:475-481.

15. Boyer T, Dorfmann H. Arthroscopy in primary synovial chondromatosis of the hip: description and outcome of treatment. J Bone Joint Surg Br. 2008;90:314-318.

16. Sim FH. Synovial proliferative disorders: role of synovectomy. Arthroscopy. 1985;1:198-204.

17. Yamamoto Y, Hamada Y, Ide T, Usui I. Arthroscopic surgery to treat intra-articular type snapping hip. Arthroscopy. 2005;21:1120-1125.

18. Khapchik V, O’Donnell RJ, Glick JM. Arthroscopically assisted excision of osteoid osteoma involving the hip. Arthroscopy. 2001;17:56-61.

19. Alvarez MS, Moneo PR, Palacios JA. Arthroscopic extirpation of an osteoid osteoma of the acetabulum. Arthroscopy. 2001;17:768-771.

20. Sampson T, Bredella M. The hip. In: Stoller DW, editor. Magnetic Resonance Imaging in Orthopaedics and Sports Medicine. Philadelphia: Lippincott Williams & Wilkins; 2007:41-304.

21. Daniel M, Iglic A, Kralj-Iglic V. The shape of acetabular cartilage optimizes hip contact stress distribution. J Anat. 2005;207:85-91.

22. Ilizaliturri VMJr, Byrd JW, Sampson TG, et al. A geographic zone method to describe intra-articular pathology in hip arthroscopy: cadaveric study and preliminary report. Arthroscopy. 2008;24:534-539.

SUGGESTED READINGS

Byrd JWT. Operative Hip Arthroscopy. New York: Thieme; 1998:153-170.

Canale ST, Beaty JH, eds. Vol 1, Campbell’s Operative Orthopaedics. 11th ed. Philadelphia: Mosby; 2008:736-942.

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