Perthes Disease: 100 Years Later

Kishore Mulpuri MBBS, MS (Ortho), MHSc (Epi)
Assistant Professor
Department of Orthopaedics
University of British Columbia
Vancouver, BC

Harish Hosalkar M.D.
Consultant Orthopaedic Surgeon
Paediatric, Adolescent and Young Adult Hip and Trauma Specialist
AO-North America Faculty for Paediatric Orthopaedic Traumatology
Rady Children's Hospital
San Diego, CA

Legg-Calve-Perthes (LCP) disease remains a challenging hip condition to treat. A century after identification, its etiology remains unclear and treatment continues to be controversial. The goal is to minimize the risk of premature hip arthritis. The immediate goals of treatment include maintaining hip motion and articulating surface sphericity by containing the femoral head within the acetabulum during its biologically plastic phase and thereby providing the best chance for joint remodeling. However, the best ways to achieve these goals remain elusive. While there appears to be increasing interest in timing of the surgical treatment and outcomes, there is a need for a deformity index that can be measured on a linear scale as opposed to categorical outcomes (such as those of Mose1 and Stulberg et al.2) and a need for functional outcome measures that will reflect long-term durability. There are no disease-specific or paediatric hip scores available. These will help in well-powered comparative studies to compare outcomes from different treatments. Several biologic treatments are being explored.

 

We have made tremendous strides in cartilage imaging recently. GAG as well as isotropic MR imaging are being routinely performed at advanced centres. Intra-articular and intravenous contrast enhancement with dGEMRIC, T2* mapping, 3D T1 mapping, and non-contrast based T1rho imaging are emerging sequences3. Individual shape characterization of the proximal femur from advanced imaging information is also possible (Figure 7). Moreover, better imaging modalities like perfusion and diffusion MR are now widely available and can help better understand the process of ischemia and revascularization. It is likely that the patterns of ischemia and revascularization are different in each case of LCPD and that someday, we may individualize treatment modalities depending on the specific biological phase of the disease and its revascularization pattern. Dr. Harry Kim of the Texas Scottish Rite Hospital for Children has put together the International Perthes Study Group (IPSG) to launch a prospective, multicentre, comparative study in LCPD patients (Figure 1).

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Figure 1: The International Perthes Study Group

 

Interestingly, the pendulum is swinging back towards more and earlier surgical intervention (Figures 2 and 3). Surgical intervention in early phases of the disease (prior to late fragmentation) to obtain spherical congruity of the articulating surfaces in a biologically plastic femoral head seems to be the most reasonable approach, irrespective of the surgeon preference for surgical option (femoral/ pelvic/ both) ( Figures 4 and 5)4,5.

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Figure 2: Preoperative Radiograph of seven-year-old male with Perthes on left side

 

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Figure 3: Preoperative Radiograph of seven-year-old male frog-legged AP

 

 

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Figure 4: 19-month follow-up Radiograph following Varus Derotational Osteotomy

 

 

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Figure 5: 19-month follow-up frog-legged AP following Varus Derotational Osteotomy

Typically, in past decades, 'teenage and young-adults' with sequelae of LCPD were an age spectrum that went unnoticed from an intervention perspective but are now receiving more attention. With better understanding of the vascularity patterns of the hip in general6,7 and more so in LCPD8, we are able to offer multiple interventions for hip preservation primarily aimed at attempted restoration of morphology (including femoral head-neck offset restoration, relative neck lengthening, trochanteric distalization, correction of acetabular dysplasia, labral re-fixation). The pinnacle of hip-preservation in the form of 'head-reduction' surgery is also possible today (to be performed with extreme caution in highly trained hands) (Figure 6 and 7). Time will be the best judge as to 'what works and what does not'; thus showing the importance of the prospective studies conducted by the International Perthes Study Group.

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Figure 6: Severe coxa magna with central head necrosis and saddle-shaped head with additional acetabular dysplasia. Surgically managed with femoral head-reduction surgery, femoral head-neck osteochondroplasty, relative neck lengthening, trochanteric distalization, labral repair and acetabuloplasty. Courtesy Dr. Harish. Hosalkar.
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Figure 7: Shape characterization of the proximal femur using data points from the computed tomography and computerized software. Courtsey Professor Robert Sah and Elaine Chan, UCSD.

References

  1. Mose K. Methods of measuring in Legg-Calve´-Perthes disease with special regard to prognosis. Clin Orthop Relat Res. 1980;150:103-109.
  2. Stulberg S.D., Cooperman D.R., Wallensten R. The natural history of Legg-Calve´-Perthes disease. J Bone Joint Surg Am. 1981;63:1095-1108.
  3. Bittersohl B., Hosalkar H.S., Apprich S., Werlen S.A., Siebenrock K.A., Mamisch T.C. Comparison of pre-operative dGEMRIC imaging with intra-operative findings in femoroacetabular impingement: preliminary findings. Skeletal Radiology. 2011:40:553-561
  4. Saran N., Varghese R., Mulpuri K. Do Femoral of Salter Innominate Osteotomies Improve Femoral Head Sphericity in Legg-Calve´-Perthes Disease? A Meta-analysis. Clin Orthop Relat Res. 2012:470:2383-2393
  5. Benjamin J., Nair N.S., Rao N.K., Mulpuri K., Varghese G. Optimal Timing for Containment Surgery for Perthes Disease. J Pediatric Orthopaedics. 2003:23:601-606
  6. Ganz R., Gill T.J., Gautier E., Ganz K., Krügel N., Berlemann U. Surgical dislocation of the adult hip: A technique with full access to the femoral head and acetabulum without the risk of avascular necrosis. J Bone Joint Surg Br. 2001:83B:1119-1124
  7. Gautier E., Ganz K., Kr¨ugel N., Gill T., Ganz R.Anatomy of the medial femoral circumflex artery and its surgical implications. J Bone Joint Surg Br.2000;82B:679-683
  8. Shore B.J., Millis M.B., Young-Jo K. Vascular Safe Zones for Surgical Dislocation in Children with Healed Legg-Calve-Perthes Disease. J Bone Joint Surg Am. 2012:94:721-727

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