Review Question - QID 217864

Subtrochanteric shortening osteotomies are often required in the treatment of Crowe IV dysplastic hips to relax the soft tissue envelope after obtaining an anatomic hip center.

Dysplastic hips are classified using the Crowe classification, which is based on the amount of superior displacement of the femoral head compared to the native acetabulum (Illustration A). Crowe IV hips have 100% proximal displacement of the femoral head. When these patients undergo total hip arthroplasty (THA) it's important to select an anatomic hip center to maintain normal hip biomechanics. With this, there is significant limb lengthening and stretch placed on the soft tissues which can lead to neurovascular injury. To circumvent this, a subtrochanteric osteotomy can be performed. Additional hardware is not typically required if a prosthesis is selected that obtains proximal fit (ie. sleeve) as well as distal fit with a diaphyseal engaging stem as seen in this case.

Sanchez-Sotelo et al review the non-arthroplasty surgical treatment of developmental dysplasia of the hip in adults. They report that many patients with hip dysplasia become symptomatic before the development of severe degenerative changes because of abnormal hip biomechanics, mild hip instability, impingement, or associated labral pathology. They conclude that because the deformity is mostly acetabular, a reconstructive osteotomy that restores more normal pelvic anatomy (ie. Bernese pelvic osteotomy) is the preferred treatment.

Ogawa et al review subtrochanteric transverse shortening osteotomy in cementless total hip arthroplasty. They report osteotomy fixation with a modular-type stem, S-ROM, that can be fixed to both the proximal and distal parts of the femur individually with a stepped proximal sleeve and polished distal flutes with fins, respectively. They conclude that this technique facilitates union of the osteotomy by maintaining rigid rotational stability and generating compression pressure between bone parts of the femur with the transverse subtrochanteric osteotomy.

Sofu et al review transverse subtrochanteric shortening osteotomies during total hip arthroplasty in Crowe III and IV hips. They report a mean leg length discrepancy improvement from 56.5 mm to 10.7 mm and a mean time to union of 5.2 months. They did also report a non-union rate of 5% (n=4). They conclude that transverse subtrochanteric shortening osteotomies are an effective and reliable method for the restoration of a more normal limb.

Figure A is the preoperative and postoperative radiographs of a patient with a Crowe IV dysplastic hip that underwent left total hip arthroplasty and subtrochanteric shortening osteotomy. An S-ROM stem was utilized to obtain both proximal and distal fixation without the use of additional hardware. Illustration A demonstrates the Crowe classification for adult hip dysplasia.

Incorrect Answers:
Answer 1 and 2: Direct hamstring or quadriceps lengthening would not treat the stretch of the neurovascular structures with this amount of limb lengthening.
Answer 4: Trochanteric osteotomies with progressive femoral shortening can be performed, however, this procedure has a higher rate of non-union and requires additional hardware.
Answer 5: While distal femoral shortening osteotomy has been described using customizable implants a healed subtrochanteric osteotomy and appropriate components are shown in Figure A.