Review Question - QID 219455

This patient presents with bilateral shallow acetabulum with uncovering of the femoral heads, consistent with adult hip dysplasia. Given symptom persistence recalcitrant to conservative measures, she is indicated to undergo a Bernese (i.e. Ganz) periacetabular osteotomy. This procedure is performed through the anterior hip approach (Answer 2).

Hip dysplasia can present with various morphologies, but ultimately results in early cartilaginous wear and a propensity towards early hip replacement. Classically these patients will have anterior acetabular insufficiency with poor coverage of the femoral head, relative lateralization of the hip center of rotation, and a relatively small contact area between the femoral head and dysplastic acetabulum (i.e. edge loading). These dysplastic acetabula are often accompanied by proximal femur abnormalities including smaller aspherical femoral heads and an increased neck-shaft angle (coxa valga). In skeletally mature patients, a reorienting periacetabular osteotomy (PAO; specifically the Bernese/Ganz procedure) can correct the deformity and negate the long-term risk of undergoing hip arthroplasty. This procedure is performed via an anterior hip approach (i.e. Smith-Peterson approach) to perform the appropriate osteotomies, acetabular reorientation, and corrected positional fixation.

Schmitz and colleagues provided a comprehensive review regarding the diagnosis and treatment of developmental dysplasia of the hip in adolescents and young adults. The authors reviewed the Ganz/Bernese PAO technique for patients with closed triradiate cartilage, which preserves the integrity of the posterior column while allowing for large multidirectional corrections. They cite a 7% major complication rate requiring revision surgery to include symptomatic heterotopic ossification, intra-articular screw migration, posterior column fracture with nonunion, acetabular implant migration after trauma, and deep infection. They conclude that with proper training and modern-day techniques, long-term survivability and improvements in patient-reported outcomes have been demonstrated.

Hussell and colleagues reported their technical complications after performing over 500 cases of the Ganz/Bernese PAO. They discuss complications based on chronologic steps to the procedure such as injury to the lateral femoral cutaneous nerve (LFCN) during the anterior approach, iatrogenic posterior column fracture during iliac osteotomy, or impingement secondary to over-correction. The authors concluded that given that 85% of their major complications occurred within their first 50 cases, this procedure is safe and effective after an initial learning curve.

Figure A shows an AP pelvis radiograph showing this patient’s bilateral adult hip dysplasia appreciated briefly by shallow acetabula and femoral head under-coverage. Illustration A shows immediate post-operative imaging after undergoing a Ganz/Bernese PAO with continuity of the posterior column. Illustration B demonstrates this patient’s AP radiographic imaging 3 months post-operatively with progressive union at each osteotomy site. Illustration C demonstrates post-operative imaging after she underwent contralateral PAO with more aggressive correction regarding anterior and lateral coverage.

Incorrect Answers:
Answer 1: The medial hip approach is mainly only employed for open reduction of congenital hip dislocations, psoas releases, and obturator neurectomies.
Answer 3 &4: The anterolateral hip and direct lateral hip approaches are often employed in the setting of total hip arthroplasty (THA). They have been described in case reports of PAO procedures; however, the majority of cases are performed via the direct anterior approach.
Answer 5: The posterior hip approach and similar variations (i.e. Kocher-Langenbach) are workhorse operative approaches to address intra-articular hip and posterior acetabular pathology. However, this approach does not allow for adequate anterior/medial visualization of the inner tables of the ileum or anterior pelvic ring needed to perform the osteotomies of the PAO.