The cup-on-cup technique for managing massive acetabular defects in revision total hip arthroplasty: a systematic review
摘要
Severe acetabular bone loss, particularly Paprosky types IIIA and IIIB, remains a major challenge in revision total hip arthroplasty (rTHA). The “cup-on-cup” or “double-cup” construct has been introduced as a salvage technique to improve fixation and restore hip biomechanics. The aim of this systematic review is to synthesise the available evidence regarding the indications, clinical outcomes, and complication rates of this technique.
MethodsA comprehensive literature search was conducted in PubMed, Embase, Scopus, and the Cochrane Library up to April 2025, following PRISMA guidelines. Studies reporting clinical outcomes of cup-on-cup constructs for acetabular revision were included. Six studies met the inclusion criteria. The methodological quality was assessed using OCEBM criteria.
ResultsThe study population comprised 111 patients (52 men, 59 women). Primary indications were aseptic loosening with massive bone loss: defects were classified as Paprosky type IIIA (n = 51, 46%) and type IIIB (n = 58, 52%), with only two cases of type IIC. At a mean follow-up of 2.4–4.6 years, the weighted mean Harris Hip Score (HHS) improved significantly from 33.6 points to 86.7 points. Radiographic assessment showed stable fixation, with only one study reporting a 6.3% rate of aseptic loosening. However, complications were relatively frequent, with dislocation rates varying widely (0% to 30%) and deep infection occurring in up to 20% of cases in specific cohorts.
ConclusionThe cup-on-cup technique represents a promising solution for managing severe acetabular bone loss without pelvic discontinuity, combining the biological benefits of porous metal with the mechanical stability of a modular construct. Despite satisfactory functional outcomes, the procedure is associated with a non-negligible risk of instability. Current evidence is limited to low-quality studies; therefore, this technique should be used judiciously in carefully selected patients.
Level of evidenceLevel IV, Systematic Review of Level III and IV studies.