Hip Dysplasia:

Uncovering the Past and Reorienting Future Treatments

By: Ian M. Al’Khafaji, M.D, FAANA Member, AANA Communications and Technology Committee

 

Developmental dysplasia of the hip (DDH) in adolescents and young adults is best understood as a spectrum of structural undercoverage and instability that accelerates chondrolabral wear and, if untreated, progresses to early osteoarthritis. A brief historical perspective is helpful. Hippocrates distinguished congenital from traumatic dislocations and advocated traction-based reduction maneuvers, establishing the first organized approach to treating hip pathology more than two millennia ago1. In the 19th century, Dupuytren systematically described congenital hip dislocation, and modern radiography ushered in Wiberg’s center-edge angle (CEA) in 1939, giving surgeons a reproducible way to quantify acetabular coverage and recognize residual dysplasia in skeletally mature patients2,3,4. Through the mid-to-late 20th century, several pelvic osteotomies (e.g., Salter, triple innominate/Steel, spherical, Chiari) attempted to restore coverage, but they disrupted the posterior column, distorted pelvic geometry (complicating future vaginal delivery), altered leg length and complicated eventual arthroplasty.

 

Ganz and colleagues designed the Bernese periacetabular osteotomy (PAO) in 1988 specifically to correct those shortcomings. The osteotomy preserves the posterior column and pelvic ring, permits powerful multiplanar reorientation of the true acetabular articular surface, minimizes muscular detachment and maintains pelvic geometry and leg length5. Clinically, that translates into earlier mobilization, more physiologic joint loading, better gait restoration and easier future total hip arthroplasty (THA) because native pelvic landmarks are retained – advantages not reliably achieved by earlier techniques6,7.

 

History and examination remain the cornerstone of diagnosis; however, clinically diagnosing DDH can be difficult, as there are no specific symptoms or exam findings unique to the condition. Typically, patients present with groin pain worsened by prolonged activity and standing, raising suspicion. Provocative testing (FADIR/FABER for chondrolabral irritation; anterior apprehension; log roll/axial distraction for capsuloligamentous laxity), gait assessment, and generalized laxity scoring (e.g., Beighton) inform risk and may uncover connective tissue disorders that increase failure rates after soft tissue–only strategies6,8,9. A response to an intra-articular anesthetic injection in the hip can help determine whether symptoms are driven by intra-articular hip pathology versus extra-articular sources of pain.

 

Standardized radiographs (standing AP pelvis, false profile, Dunn lateral) frame decision-making. Typical thresholds include lateral CEA < 20° for frank dysplasia and 20-25° for borderline/“mild” dysplasia, with Tönnis angle > 10-12° indicating instability-biased inclination; crossover and ischial spine signs suggest acetabular retroversion that may require tailored reorientation6,8,10. MRI characterizes labral pathology, compensatory labral hypertrophy, torn ligamentum teres, cartilage status and can evaluate femoral torsion. 3-D CT/MRI reconstructions are valuable for complex morphology and preoperative planning11.

 

Where does hip arthroscopy fit? In frank DDH, isolated arthroscopy is associated with poor outcomes and higher failure/revision rates (including iatrogenic hip dislocations) because structural undercoverage remains uncorrected – even when labral/capsule repair is meticulous12,13,14. In mild DDH, outcomes can be acceptable in carefully selected patients – particularly when capsular plication is rigorously performed and instability radiographic markers are absent, but failure risks remain higher with malselected morphology, labral debridement or pre-existing OA15,16,17. Recent meta-analyses and five-year series continue to refine selection criteria, but the message is consistent: arthroscopy treats the consequences; PAO treats the cause16,18.

 

PAO remains the gold standard joint-preserving operation for symptomatic DDH with preserved joint space. Indications include radiographic diagnosis of frank DDH, a congruent joint space and age < 40-45 years, though chronological age is not an absolute cutoff6,8,19. Contemporary series demonstrate > 80% 10-15-year survivorship with durable improvements in pain and function10. While initially PAOs were hesitantly offered to highly active patients, athletes can reliably return to moderate/high-impact sport, particularly with early intervention and structured rehabilitation20. Importantly, there are current multicenter randomized trials investigating whether augmenting PAOs with hip arthroscopy to treat concomitant intra-articular pathology will improve long-term outcomes and survivorship of the native symptomatic dysplastic hip21. Natural history data further support timely correction: surgical osteotomy to treat DDH may be one of the few disease-modifying procedures in orthopaedics10.

 

The difficulty of incorporating PAOs in practice is daunting, given the technical demands of completing each bone cut, mitigating intraoperative blood loss, avoiding neurovascular injury and reproducing adequate osteotomy correction. Best-practice reviews endorse standardized positioning, calibration and awareness of how pelvic tilt/rotation can alter radiographic metrics and affect intraoperative interpretation of correction4,11,10. Three-dimensional planning and 3D-printed patient-specific guides can improve osteotomy accuracy, fragment control and reduce fluoroscopy22. Looking ahead, robotic assistance and navigation for PAO, along with AI-enabled preoperative modeling and version/coverage simulations, promise precise execution and reproducibility, potentially flattening the learning curve and reducing malcorrection – potentially converting complex pelvic osteotomies from a demanding specialist procedure to one that can be more widely incorporated into general orthopaedic practice23. In addition, these technologies may provide insight into when to perform femoral osteotomies to correct rotational/coronal deformities, improving intra-articular biomechanics and maintaining adequate joint stability.

 

In practice, further development of a dysplasia clinical algorithm will help: (1) identify symptoms and exam findings associated with a patient’s bony morphology; (2) quantify bony deformities of the hip with appropriate imaging; (3) characterize concomitant intra-articular pathology; (4) correct the structural deformity with an osteotomy, such as a PAO, when indicated to improve native hip biomechanics; and (5) selectively address intra-articular disease (arthroscopically or open) when it will meaningfully augment outcomes.

 

References

  1. On Joints. (Classical translation; historical reference to congenital hip dislocation).
  2. Dupuytren G. Leçons Orales de Clinique Chirurgicale. Paris: Baillière; 1832.
  3. Lorenz, A. The Bloodless Method of Treatment of Congenital Dislocation of the Hip. Medical Record. 1894;45:737-739.
  4. Wiberg, G. Studies on Dysplastic Acetabula and Congenital Subluxation of the Hip Joint. Acta Chirurgica Scandinavica. 1939;83(Suppl 58):7-135.
  5. Ganz, R., Klaue, K., Vinh, T.S., Mast, J.W. A New Periacetabular Osteotomy for the Treatment of Hip Dysplasias. Clinical Orthopaedics and Related Research. 1988;(232):26-36.
  6. Gala, L., Clohisy, J.C., Beaulé, P.E. Hip Dysplasia in the Young Adult. Journal of Bone and Joint Surgery – American Volume. 2016;98(1):63-73. doi:10.2106/JBJS.O.00109.
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  8. Schmitz, M.R., Murtha, A.S., Clohisy, J.C.; ANCHOR Study Group. Developmental Dysplasia of the Hip in Adolescents and Young Adults. Journal of the American Academy of Orthopaedic Surgeons. 2020;28(3):91-101. doi:10.5435/JAAOS-D-18-00533.
  9. Kerrigan, A., Ayeni, O.R., Kishta, W. Developmental Dysplasia of the Hip in Patients with Connective-Tissue Disorders. JBJS Reviews. 2019;7(4):e5. doi:10.2106/JBJS.RVW.18.00092.
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  15. Tang, H.C., Dienst, M. Surgical Outcomes in Concomitant Mild Dysplasia and FAI. 2020;36(4):1176-1184. doi:10.1016/j.arthro.2019.11.122.
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  17. Lee, M.S., Owens, J.S., Fong, S., Kim, D.N., Gillinov, S.M., Mahatme, R.J., Simington, J., Monahan, P.F., Islam, W., Moran, J., Grimm, N.L., Jimenez, A.E. Mid-/Long-Term Outcomes in Borderline Dysplasia After Primary Arthroscopy. 2023;39(4):1060-1073. doi:10.1016/j.arthro.2022.12.030.
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  19. Perry, K.I., Trousdale, R.T., Sierra, R.J. Hip Dysplasia in the Young Adult: An Osteotomy Solution. Bone and Joint Journal. 2013;95-B(11 Suppl A):21-25.
  20. Curley, A.J., Padmanabhan, S., Chishti, Z., O’Brien, J.J., Kraeutler, M.J., Mei-Dan, O. PAO in Athletes: RTS >70% for Competitive Sport. 2023;39(3):868-880. doi:10.1016/j.arthro.2022.12.004.
  21. Beaulé, P.E., Verhaegen, J.C.F., Clohisy, J.C., Millis, M.B., Novais, E.N., Sink, E.L., Sierra, R.J. Does Hip Arthroscopy at the Time of PAO Improve Outcomes? Multicenter RCT. Journal of Arthroplasty. 2024;39(9S1):S9-S16. doi:10.1016/j.arth.2024.05.035.
  22. Ma, S., Xiao, L., Guo, D., Shi, Q., Shen, R., Li, X. Application of 3D-Printed Osteotomy Guides in PAO: Short-Term Clinical Study. International Journal of Artificial Organs. 2022;45(11):945-951. doi:10.1177/03913988221120026.
  23. Kraeutler, M.J., Samuelsson, K., Mei-Dan, O. The Principles of Hip Joint Preservation. Journal of the American Academy of Orthopaedic Surgeons.2024;32(22):1017-1024. doi:10.5435/JAAOS-D-24-00340.
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