Total hip replacement for developmental dysplasia of the hip with more than 30% lateral uncoverage of uncemented acetabular components

Abstract

In developmental dysplasia of the hip (DDH), a bone defect is often observed superior to the acetabulum after the reconstruction at the level of the true acetabulum during total hip replacement (THR). However, the essential amount of uncemented acetabular component coverage required for a satisfactory outcome remains controversial. The purpose of this study was to assess the stability and function of acetabular components with a lack of coverage > 30% (31% to 50%). A total of 760 DDH patients underwent THR with acetabular reconstruction at the level of the true floor. Lack of coverage above the acetabular component of > 30% occurred in 56 patients. Intra-operatively, autogenous morcellised bone grafts were used to fill the uncovered portion. Other than two screws inserted through the acetabular shell, no additional structural supports were used in these hips. In all, four patients were lost to follow-up. Therefore, 52 patients (52 hips, 41 women and 11 men) with a mean age of 60.1 years (42 to 78) were available for this study at a mean of 4.8 years (3 to 7). There were no instances of prosthesis revision or marked loosening during the follow-up. The Harris hip score improved from a mean of 40.7 points (sd 12.2) pre-operatively to 91.1 (sd 5.0) at the last follow-up. Radiological analysis with medical imaging software allowed us to calculate the extent of the uncoverage in terms of the uncovered arc of the implant as viewed on the anteroposterior pelvic radiograph. From this we propose that up to 17 mm of lateral undercoverage in the presence of a stable initial implantation in the presence of bone autografting, with an inclination angle of the acetabular component between 40° and 55°, is acceptable. This represents undercoverage of ≤ 50%.

Controlled Fracture of Medial Wall Versus Structural Autograft With Bulk Femoral Head to Increase Cup Coverage by Host Bone for Total Hip Arthroplasty in Osteoarthritis Secondary to Developmental Dysplasia of Hip: a Retrospective Cohort Study

“…And placement of the acetabular implant can be located in true acetabulum or high hip centre. High hip centre is de ned as the perpendicular distance from the femoral head center to the inter-teardrop line more than 35 mm [21]. Some scholars [8,10,14,16,31] agreed on the inserting the cup into true acetabulum due to superior biomechanics, better…”

“…1). The height of hip center is de ned as the perpendicular distance from the femoral head center to the inter-teardrop line [21]. Inclination of cup is de ned as the angle between a horizontal line joining the ischial spines and a line parallel to the opening plane of the cup [22].…”

Total Hip Replacement in Developmental Dysplasia of the Hip: Pitfalls and Challenges

“…There were no prosthesis revision and loosening during the mean 4.8 years follow-up [48]. Tikhilov et al recommend acetabular component fixation without screws with moderate uncoverage within 25% but they offer two-screw fixation with significant uncoverage to 35% [49].…”

Biomechanical rationale for acetubalar component selection for total hip replacement in patients with dysplastic coxarthrosis

“…При эндопротезировании ТБС рассмотрены фазы послеоперационного процесса, различающиеся по уровню восстановления костной ткани: первичной стабильности (послеоперационная), регенерации костного дефекта и полного восстановления (вторичной стабильности) [12] в случаях различных СД ВВ.…”