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01241398-201307001-0001401241398_2013_33_s70_sucato_skeletally_miscellaneous-article< 68_0_8_6 >Journal of Pediatric Orthopaedics© 2013 by Lippincott Williams & WilkinsVolume 33 Supplement 1 SupplementJuly/August 2013p S70–S75Role of Femoral Head Surgery in Skeletally Mature Perthes Disease[Hip Disorders Supplement]Sucato, Daniel J. MD, MSDepartment of Orthopaedic Surgery, Texas Scottish Rite Hospital for Children, Dallas, TXThe author did not receive financial support for this study.The author declares no conflict of interest.Reprints: Daniel J. Sucato, MD, MS, Department of Orthopaedic Surgery, Texas Scottish Rite Hospital for Children, 2222 Welborn St., Dallas, TX 75219. E-mail: dan.sucato@tsrh.org .AbstractLegg-Calve-Perthes disease (LCPD) nearly always results in femoral deformity at skeletal maturity that may lead to symptoms due principally to femoroacetabular impingement. Treatment for the skeletally mature patient with LCPD varies from observation with activity modifications to surgical procedures which range from isolated femoral or acetabular-sided surgery to the more common combined surgery. On the femoral side, the traditional procedures have been proximal varus and valgus osteotomies (with some component of flexion) to reorient the femoral head and allow better femoral head weight-bearing cartilage across the hip joint. Acetabular procedures have been used less frequently including reorientation or shelf procedures to provide improved femoral head coverage. The challenge in the skeletally mature hip patient is to determine which of these components require addressing at the time of surgical treatment. More recently, procedures to the femoral head itself have been developed to reshape the femoral head and assist in matching the size of the femoral head to the acetabulum, prevent impingement and restore more normal articular cartilage in the weightbearing zone. This review will focus on these surgical treatments specific to the femoral head in skeletally mature LCPD.Legg-Calve-Perthes disease (LCPD) nearly always results in femoral deformity at skeletal maturity that may lead to symptoms due principally to femoroacetabular impingement (FAI). The pathology of the hip varies from a nearly-normal hip (Stulberg 1) to severe femoral head deformity associated with significant acetabular morphology changes and an incongruent joint (Stulberg 5). The FAI may be on the femoral side alone and often is on both the femoral and acetabular side with some patients demonstrating some component of acetabular dysplasia. Long-term outcomes studies for patients with LCPD have relied on the Stulberg classification to serve as a predictor for symptoms and function with time. Previously, the outcomes from LCPD have demonstrated overall good results especially for the Stulberg I and II hips with variable results for the Stulberg III hips and relatively poor results for IV and V hips.1 However, we recently reported the 20-year follow-up of LCPD patients treated nonoperatively (range-of-motion exercises and bracing) demonstrating that 44% of patients had moderate or severe radiographic osteoarthritis while 30% had mild radiographic arthritis.2 These data differ with older studies which report better long-term results and may be a reflection of higher expectations and greater interest in more strenuous activities in currently than in the past.Treatment for the skeletally mature patient with LCPD varies from observation with activity modifications to surgical procedures which range from isolated femoral or acetabular-sided surgery to combined surgery. On the femoral side, the traditional procedures have been proximal varus and valgus osteotomies (with some component of flexion) to reorient the femoral head and allow better femoral head weight-bearing cartilage across the hip joint. Acetabular procedures have been used less frequently including reorientation or shelf procedures to provide improved femoral head coverage. Overall, the success of previous hip preservation surgery for skeletally mature LCPD is less than ideal and leads one to look to other options to yield improved results.3 With better understating of FAI, through the work of Ganz and colleagues, newer procedures have been developed to create strategies to improve the outcome of these patients. The ability to gain full access to the hip including the femoral head and acetabulum, through the surgical hip dislocation (SHD) approach has provided opportunities to perform procedures directly to the femoral head in a safe manner—the focus of this article.The femoral head in a patient with LCPD at skeletal maturity generally is more oval than round and can include saddle-type deformities with the best articular cartilage located on the medial and lateral aspects of the femoral head (Fig. 1). The femoral head is misshapen so that its width and depth are 15% to 20% greater than the opposite normal femoral head.4,5 The central aspect of the femoral head has soft areas of cartilage with a central osteochondral lesion which is poorly perfused and has thinned and abnormal articular cartilage.6 The increased size and shape of the femoral head can produce intra-articular impingement, whereas the high-riding greater trochanter can result in extra-articular impingement.7 In general, there is nearly always a component of FAI, which can be a cam or pincer, or a combination of both. Finally, hip instability with uncovering of the femoral head laterally and anteriorly can also be seen and may be a primary cause of symptoms.8 The challenge in the skeletally mature hip patient is to determine which of these components require addressing at the time of surgical treatment. This review will focus on the surgical treatment of the femoral head in skeletally mature LCPD, however, the patient often requires additional surgery to address the acetabular side as well.FIGURE 1. Two different patients at the time of surgical hip dislocation with skeletally mature Perthes disease demonstrating the variation in the shape and status of the articular cartilage. A, The femoral head viewed from the posterolateral aspect demonstrating the oval-shaped head. There is some loss of femoral head cartilage posteriorly secondary to a contre-coup injury from pincer impingement. B, The femoral head viewed from the anterior superior position demonstrating a large osteochondral defect in the central posterior position with the best articular cartilage seen anteriorly.INDICATIONS AND DECISION MAKING FOR FEMORAL HEAD RESHAPINGThe challenge in the treatment of the femoral head in skeletally mature LCPD is to first determine the best method to reshape the head to better fit within the acetabulum. The 2 general approaches are first, an outside-in approach in which femoral head is removed from the periphery and second, an inside-out head-reshaping procedures in which a central portion of the femoral head is removed. The advantages of the outside-in approach are that it is the typical approach utilized for CAM lesions in all conditions and is the more straightforward technically.9–12 In addition, those osteochondral segments removed to create better clearance of the hip can serve as autograft for large areas of the femoral head devoid of articular cartilage. The disadvantage of this approach is that it is difficult to restore a normal-shaped femoral head when there is significant deformity of the femoral head, and the peripheral cartilage removed during the osteochondroplasty is often the best cartilage seen on the femoral head.The advantages of the inside-out technique is that the best articular cartilage of the femoral head remains to act as the weight-bearing cartilage and the overall shape of the femoral head becomes round and provides the most congruent joint of the hip. The disadvantages are it is a newer procedure that is technically demanding with significant risk to the femoral head blood supply, and other complications such as femoral neck fracture and instability secondary to a smaller head are potential complications. Finally, the exact indications have not been fully defined for this procedure.INDICATIONS FOR THE FEMORAL HEAD RESHAPING PROCEDURESThe outside-in approach removes the most common areas of impingement—the anterior and lateral aspect of the femoral head. During a SHD procedure, the areas of impingement are identified as the hip is put through a full range of motion including flexion (anterior impingement) and abduction (lateral impingement). This area of impingement can be as small as 5 mm or as large as 20 to 30 mm depending on the size of the femoral head and the area of impingement (Fig. 2). It is critical to remove the offending portion of the femoral head to prevent impingement without losing the seal of the labrum around the femoral head. When lateral impingement occurs, the osteochondroplasty can come in close proximity to the lateral retinacular vessels and so great care must be taken to ensure that these are preserved during this dissection. Development of the retinacular soft-tissue flap, described later, is occasionally necessary to perform safe removal.FIGURE 2. Outside-in osteochondroplasty. A, The femoral head viewed during surgical hip dislocation. The misshapen head is seen with overall good articular cartilage but a loss of offset anteriorly. B, The osteochondroplasty line is seen as the anterior aspect of the femoral head is being removed with an osteotome. C, The femoral has been placed back into the acetabulum and the degree of clearance is seen during hip flexion.Indications for the inside-out technique in which an intracapital osteotomy is performed to remove the central portion of the femoral head continue to evolve with time (Fig. 3). The indications, as described by Ganz and colleagues, are the “older patient who has abnormal femoral head morphology in which there are no other alternatives, that if left untreated, would deteriorate rapidly or the situation would be unacceptable due to the caused clinical limitations.”13 The author generally considers using this technique when the plain radiographic images demonstrate a widened head, with a depressed central area containing poor cartilage confirmed by magnetic resonance imaging, in a patient with good sagittal plane range of motion but limited abduction. The final operative decision is generally made at the time of the SHD procedure with inspection of the femoral head identifying the above criteria in which the central femoral head has deficient or poor articular cartilage, whereas the best articular cartilage is located on the lateral aspect of the femoral head.FIGURE 3. The intracapital osteotomy as described by Reinhold Ganz. A, The central aspect of the femoral head (shaded area) is removed and (B) the lateral column is brought to the medial column and secured with screws. A relative femoral neck lengthening is performed and the trochanter is secured with 2 screws.It is generally indicated only for the skeletally mature femoral head, however, Ganz and colleagues has utilized this procedure in the skeletally immature patient with a femoral head that is significantly wide with a central component that is poorly ossified. The size of the head creates impingement and most probably resembles the traditional concept of hinge abduction.A relative femoral neck lengthening is always performed with removal of the central aspect of the femoral head while it is not always necessary when performing an outside-in procedure. In general, the indications for performing a relative femoral neck lengthening are poor biomechanics of the hip with a significant abductor lurch and/or extra-articular impingement secondary to a high-riding greater trochanter. This technique is described elsewhere in this series.SURGICAL TECHNIQUE FOR FEMORAL HEAD SURGERY IN PERTHESThe hip joint in LCPD is best addressed through a SHD approach as it provides full access to these very challenging hips and allows one to perform any of the procedures described. Ganz and colleagues described this SHD approach reporting on 213 adult hips, primarily treated for anterior impingement due to residual LCPD, idiopathic impingement, pigmented villonodular synovitis, and synovial chondromatosis.14 This was the first time a surgical technique provided an opportunity for full exposure of the femoral head and acetabulum without placing the femoral head blood flow in jeopardy. The femoral head perfusion information was the result of the work Ganz and colleagues had carried out with latex injection studies on cadavers to understand the proximal femoral blood.15 The standard SHD procedure is utilized to gain access to the femoral head. Hip arthroscopy has taken on a greater role in the treatment of FAI with excellent results, however, the significant morphologic changes seen in Perthes hips may make this difficult and a less than ideal approach to these patients.The original description of the SHD approach nicely outlines the exact steps of the procedure and how these preserve the femoral head blood flow. The development of the retinacular flap is necessary only when performing the intracapital osteotomy or when removal of the lateral femoral head potentially places these vessels in jeopardy. The approach first utilizes a trochanteric osteotomy, performed at a level to allow a few millimeters of the gluteus medius muscle to remain attached to the stable trochanteric fragment, whereas the mobile segment has the remaining gluteus medius, gluteus minimus, and the vastus lateralis; second, the dissection occurs between the piriformis and the gluteus minimus tendon to avoid the ramus profundus artery as it penetrates into the capsule which also avoids the branches of the inferior gluteal artery running distal to the piriformis; third, the extended retinacular soft-tissue flap is created after removal of the proximal aspect of the stable trochanter and the soft-tissue dissection begins on the superior aspect of the femoral neck with continued dissection on the posterior neck leaving the connection to the proximal epiphysis. The creation of the retinacular flap is not necessary when performing the outside-in approach but is necessary when performing the inside-out resection of the central portion of the femoral head. We monitor the femoral head blood flow with a piezoelectric pressure monitor in which monitor is placed into the center of the femoral head and good flow is represented by a good waveform pattern (Fig. 4).16 Once the flap is created, it contains the deep branch of the medial femoral circumflex artery, the anastomoses with the inferior gluteal artery and the retinacular vessels.13FIGURE 4. The femoral head in a patient with severe Perthes who has a central femoral head osteochondral defect undergoing an intracapital osteotomy. The pressure monitor is seen entering into the anterior aspect of the femoral neck and travels into the femoral head.Outside-In Approach to the Femoral HeadThe outside-in approach creates offset on the femoral side by removing an osteochondroplasty segment of the offending area on the femoral head. This is a fairly straightforward approach which allows one to trim the femoral head under direct visualization and the open approach provides an opportunity to test the clearance of the femoral head by the acetabulum by flexing the hip under direct visualization before and after the osteochondroplasty. The technique of removal is first done with an osteotome starting on the femoral head and removing the planned area in 1 sleeve of tissue. Rongeurs and a burr can be used to help shape the femoral offset to the desired level. It is important to remove only those sections of the articular cartilage to resolve the issue of impingement while preserving the ability to maintain the seal between the femoral head and the labrum. The exposed bone is covered with a thin layer of bone wax to prevent excess bleeding in the joint and in hopes of preventing return of the osteochondral bump. The results of this technique are varied and most probably depend on the status of the articular cartilage of the remaining femoral head and cartilage. Eijer et al17 reported that 50% of patients were pain-free while all patients had improvement at 33 months of follow-up.Inside-Out Approach to the Femoral HeadWhen a central aspect of the femoral head has significant deficiency of cartilage, the osteochondroplasty fragment removed from the anterior aspect of the head can be used as a graft, placed into the defect after it has been contoured (Fig. 5). The early results of this technique have been promising. Anderson et al18 reported on 14 skeletally mature patients with LCPD undergoing a surgical dislocation approach with overall good results, 4 of whom had their resected femoral head-neck junction transferred as an osteochondral graft to the central portion of the head with excellent results.FIGURE 5. Autograft osteochondral autograft. View from superior demonstrating a large osteochondral section removed from the anterior aspect of the femoral head and placed into the central aspect of the weight-bearing zone.The central head resection procedure is technically demanding adding additional steps to the SHD approach. Careful dissection of the soft tissues to preserve the femoral head perfusion is critical to the success of the procedure. Following the standard SHD approach, the retinacular vessels are mobilized after the proximal aspect of the stable trochanter is removed to allow for improved access to the entry of the retinacular vessels on the lateral aspect of the femoral neck and head. Subperiosteal dissection is carried out posteriorly to continue this dissection of retinacular vessels leaving the attachment to the proximal epiphysis. The blood flow to the femoral head can be monitored using an intracranial pressure monitor that works very well to develop a waveform which can be easily visualized during surgery. The author’s preferred method is to watch this waveform during the entire procedure without specific regard to the pressure magnitude. The waveform of the pressure monitor is visualized and should mirror the pattern seen from the systemic monitor of arterial pressure. Any decline of the wave pattern should alert the surgeon to impending vascular occlusion and the need to temporarily stop the dissection until the waveform returns. Often arterial spasm occurs during the development of the retinacular flap and a short pause during this step will result in return of the waveform. If return is not seen, central head resection should be abandoned and the outside-in technique of osteochondroplasty should be performed.The author generally utilizes a periosteal elevator to develop the posterior soft-tissue flap on the posterior neck while visualizing the insertion of this soft-tissue flap into the epiphysis. This is developed medially just past the level of the planned medial vertical osteotomy of the neck. The medial aspect of the femoral head is monitored without monitoring of the lateral femoral head as monitoring is fairly difficult and expensive because 2 monitor devices would be necessary.Following the soft-tissue dissection posteriorly, a thin-blade saw is used to create the lateral cut in the head and neck at the edge of the planned resection (Fig. 6A). The osteotomy is made perpendicular to the anterior cortex of the neck and should just penetrate the posterior cortex of the neck, whereas Homan retractors are protecting the posterior soft-tissue sleeve. A transverse osteotomy is made at the base of the neck allow for the lateral column to be retracted laterally (Fig. 6B). The more medial osteotomy is then created parallel with the first cut and is similarly made to end just at the posterior edge of the neck. The soft-tissue attachment to the epiphysis is sharply removed from the planned central head-neck region.FIGURE 6. Intracapital osteotomy with removal of the central femoral head. A, The saw is used to create the longitudinal cut just lateral to the aspect of the head requiring removal. B, The saw is used to create a transverse cut at the base of the lateral cut. C, The central portion of the femoral head is removed with a Kocher clamp while the pressure monitor is in the medial column of the femoral head. D, The lateral column has been approximated with the medial column and secured with 2 cannulated screws. E, The preoperative anteroposterior radiograph of the right hip of a 16-year-old girl. F, The 2-year radiographs following the intracapital femoral osteotomy demonstrating a more round femoral head with good healing of the lateral column to the medial column. The range of motion of her hip was vastly improved.Once the central portion of the femoral head has been removed (Fig. 6C), the lateral column is reduced to the medial column and the articular cartilage should be approximated in a way to prevent any formal step-off at the weight-bearing zone (Fig. 6D). Because of variations in the sagittal diameter of the lateral and medial columns, there may be some residual step-off which is probably ideal to be in the anterior aspect of the head and can be removed using a modified osteochondroplasty procedure. The lateral column is provisionally secured with Kirschner wires to assess reduction and then overdrilled and filled with cannulated screws, usually 3.5 mm in diameter. The hip is put through a range of motion confirming hip stability and to ensure that the impingement is resolved. The hip capsule is reapproximated in a loose manner to avoid creating disruption of the femoral head flow and the trochanter is advanced to the desired level and fixed with 3.5 mm diameter noncannulated screws (Figs. 6E, F).The early results demonstrate promise for this technique, however, caution should be used as the indications are not fully defined. In addition, it is important to have some experience with the surgical dislocation approach and the creation of the retinacular sleeve before moving forward with this technique. Ganz and colleagues reported on his initial experience with the femoral head reduction procedure in 14 patients, 13 of whom had Perthes disease. The surgery was combined with a periacetabular osteotomy in all but 1 patient, either at the time of the femoral procedure or due to subsequently instability presumably created the femoral reduction procedure. There was complete healing in all patients between 6 and 8 weeks without evidence of osteonecrosis and improvement in range of motion was seen in all patients.19 Paley20 reported on 20 patients undergoing the Ganz-described procedure with overall good results, however, an external fixator was necessary in 5 patients to maintain reduction and 1 patient had avascular necrosis. We have performed 6 of these procedures with 4 patients demonstrating significant improvement on their Harris hip scores, whereas 1 patient did not have improvement and 1 was worse. There were no patients who had avascular necrosis.In summary, femoral head surgery in LCPD is an option in the symptomatic skeletally mature patient with FAI. The surgical dislocation approach provides excellent access to the femoral head and the final decision to perform outside-in versus inside-out reshaping of the head can be made. The short-term results of performing an osteochondroplasty with or without using this as an autologous osteochondral graft, although good, are dependent on the surgical technique and the status of the weight-bearing articular cartilage at the time of surgery. The central head intracapital femoral head osteotomy procedure is technically challenging and the indications are in evolution, however, this offers a viable promising option in the treatment of these patients. Further, studies of the long-term results of these procedures are necessary to fully define the indications and the utility of these procedures into the future.REFERENCES1. Stulberg SD, Cooperman DR, Wallensten R.The natural history of Legg-Calve-Perthes disease.J Bone Joint Surg Am.1981;63:1095–1108. [Medline Link] [Context Link]2. 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Eijer H, Podeszwa DA, Ganz R, et al..Evaluation and treatment of young adults with femoro-acetabular impingement secondary to Perthes’ disease.Hip Int.2006;16:273–280. [Context Link]18. Anderson LA, Erickson JA, Severson EP, et al..Sequelae of Perthes disease: treatment with surgical hip dislocation and relative femoral neck lengthening.J Pediatr Orthop.2010;30:758–766. [Context Link]19. Leunig M, Ganz R.Relative neck lengthening and intracapital osteotomy for severe Perthes and Perthes-like deformities.Bull NYU Hosp Jt Dis.2011;69suppl 1S62–S67. [Context Link]20. Paley D.The treatment of femoral head deformity and coxa magna by the Ganz femoral head reduction osteotomy.Orthop Clin North Am.2011;42:389–399. [CrossRef] [Medline Link] [Context Link] Perthes disease; femoral head surgery; treatment; central head resection; surgical hip dislocationovid.com:/bib/ovftdb/01241398-201307001-0001400004623_1981_63_1095_stulberg_natural_|01241398-201307001-00014#xpointer(id(R1-14))|11065405||ovftdb|SL00004623198163109511065405P40[Medline Link]7276045ovid.com:/bib/ovftdb/01241398-201307001-0001400004694_1982_2_39_rab_dimensional_|01241398-201307001-00014#xpointer(id(R6-14))|11065213||ovftdb|SL00004694198223911065213P45[CrossRef]10.1097%2F01241398-198202010-00005ovid.com:/bib/ovftdb/01241398-201307001-0001400004694_1982_2_39_rab_dimensional_|01241398-201307001-00014#xpointer(id(R6-14))|11065405||ovftdb|SL00004694198223911065405P45[Medline Link]7076833ovid.com:/bib/ovftdb/01241398-201307001-0001400006345_2011_42_389_paley_treatment_|01241398-201307001-00014#xpointer(id(R20-14))|11065213||ovftdb|SL0000634520114238911065213P59[CrossRef]10.1016%2Fj.ocl.2011.04.006ovid.com:/bib/ovftdb/01241398-201307001-0001400006345_2011_42_389_paley_treatment_|01241398-201307001-00014#xpointer(id(R20-14))|11065405||ovftdb|SL0000634520114238911065405P59[Medline Link]21742151Role of Femoral Head Surgery in Skeletally Mature Perthes DiseaseSucato, Daniel J. MD, MSHip Disorders Supplement33