Acetabular Cage Survival and Analysis of Factors Related to Failure

Abstract

The reported results of acetabular cage reconstruction for pelvic deficiency are widely variable. Our primary question was: what is the survivorship of cage reconstruction with a primary end point of cage revision and secondary end points of radiographic loosening and any reoperation? Secondary questions were: which factors predict cage failure, and what is the functional outcome (SF-36, WOMAC, Harris hip score) of this reconstructive method? We reviewed 72 cage reconstructions in 68 patients. Minimum followup was 1.2 years (mean, 5.1 years; range, 1.2-10.7 years). Five-year cage revisionfree survivorship was 87.8%. Five-year loosening-free and acetabular reoperation-free survivorships were 80.7% and 81.3%, respectively. No single preoperative factor (age, gender, severity of pelvic defect, degree of heterotopic ossification, difference in limb lengths and centers of rotation) or intraoperative factor (type of bone graft, type of cage, changes in limb length and center of rotation) predicted cage failure. Functional outcomes were 28.9 (SF-36 Physical Component), 52.4 (SF-36 Mental Component), 33.7 (WOMAC), and 44.2 (Harris). We judged these outcomes acceptable for this sometimes challenging problem.

Trabecular Metal™ Cups for Acetabular Defects With 50% or Less Host Bone Contact

“…We still do not have long term followup of the use of TM cups, and the selection criteria and outcome assessment vary considerably among studies (Table 3). Nevertheless, cages had no advantage over TM cups regarding mechanical failure rates at a mean followup of 4 to 5 years, despite their potential better initial stability [1,9,20]. Other studies that evaluated the performance of TM cups for more heterogeneous groups of acetabular defects had failure rates comparable to that of our series [5,13,21,22].…”

“…Acetabular component revision in the face of large contained bone defects with no more than 50% host bone contact has been traditionally treated with roof reinforcement rings or antiprotrusio cages, associated with substantial complication and failure rates [9,20]. Trabecular Metal TM cups may offer a reasonable treatment alternative.…”

“…migration [10]. A failure rate as high as 24% at 5 years has been reported (Table 3) [1,9,20]. Cages also have a high rate of complications, such as sciatic nerve injuries, flange fractures, and dislocations [9].…”

Clinical evaluation and surgical options in acetabular reconstruction: A literature review

“…The cage is constructed from titanium alloy and thought to transfer load off the acetabular socket and onto the peri-acetabular bone through adjustable illeal and ischial flanges that provide intimate contact with native bone when secured to the pelvis using cancellous screws. 10,17 Cages protect underlying bone graft from lysis and permit remodeling with native bone. True survivorship of cages is unclear but has ranged from less than 70% to 100% according to Sembrano et al who report that the end-points of each study varied depending on time of cage removal, evidence of radiographic loosening, and reason for revision.…”

“…True survivorship of cages is unclear but has ranged from less than 70% to 100% according to Sembrano et al who report that the end-points of each study varied depending on time of cage removal, evidence of radiographic loosening, and reason for revision. [17][18][19][20][21][22][23][24][25][26][27] Regis et al reported an 87% (49/56) survival rate at a mean follow-up of 11.7 years in type IIIA (32%) and IIIB (68%) hips using cages and structural allografts using radiographic evidence of bone ingrowth and remodeling as the primary endpoint. 28 The major disadvantage of cages includes high complication rates previously reported by multiple authors.…”