RESUMEN
BACKGROUND: Both modular and monoblock tapered fluted titanium (TFT) stems are increasingly being used for revision total hip arthroplasty (rTHA). However, the differences between the two designs in clinical outcomes and complications are not yet clear. Here, we intend to compare the efficacy and safety of modular versus monoblock TFT stems in rTHA. METHODS: PubMed, Embase, Web of Science, and Cochrane Library databases were searched to include studies comparing modular and monoblock implants in rTHA. Data on the survivorship of stems, postoperative hip function, and complications were extracted following inclusion criteria. Inverse variance and Mantel-Haenszel methods in Review Manager (version 5.3 from Cochrane Collaboration) were used to evaluate differences between the two groups. RESULTS: Ten studies with a total of 2188 hips (1430 modular and 758 monoblock stems) were finally included. The main reason for the revision was aseptic loosening. Paprosky type III was the most common type in both groups. Both stems showed similar re-revision rates (modular vs monoblock: 10.3% vs 9.5%, P = 0.80) and Harris Hip Scores (WMD = 0.43, P = 0.46) for hip function. The intraoperative fracture rate was 11.6% and 5.0% (P = 0.0004) for modular and monoblock stems, respectively. The rate of subsidence > 10 mm was significantly higher in the monoblock group (4.5% vs 1.0%, P = 0.003). The application of extended trochanteric osteotomy was more popular in monoblock stems (22.7% vs 17.5%, P = 0.003). The incidence of postoperative complications such as periprosthetic femoral fracture and dislocation was similar between both stems. CONCLUSIONS: No significant difference was found between modular and monoblock tapered stems as regards postoperative hip function, re-revision rates, and complications. Severe subsidence was more frequent in monoblock stems while modular ones were at higher risk of intraoperative fracture. LEVEL OF EVIDENCE: Level III, systematic review of randomized control and non-randomized studies. TRIAL REGISTRATION: We registered our study in the international prospective register of systematic reviews (PROSPERO) (CRD42020213642).
Asunto(s)
Artroplastia de Reemplazo de Cadera , Fracturas del Fémur , Fracturas Periprotésicas , Humanos , Reoperación , Bases de Datos Factuales , FémurRESUMEN
BACKGROUND: Diaphyseal fixation remains the mainstay of revision THA. The stability of diaphyseal fixation can be quantified by the extent of contact between the stem and the endosteal cortex. This is highly affected by the morphology of the proximal femur. The purpose of this study was to examine factors affecting diaphyseal contact in the revision THA and to identify preoperative predictors of adequate fixation. METHODS: Three-dimensional femur models were created from CT scans of 33 Dorr B and C femora. The proximal 120 mm of the femur was omitted to mimic proximal bone deficiency. A tapered fluted stem (3 degrees, 150 mm) model was virtually implanted after reaming of the medullary canal. The contact length between stem and endosteal cortex was measured, in addition to other variables. The relationship between variables was evaluated using Spearman's correlation, and logistic regression analysis was used to identify predictors of the contact length (P < .05). RESULTS: The contact length varied widely between specimens (66.5 ± 16.6 mm, range: 21-98 mm). Contact increased with the depth of the isthmus below the lesser trochanter (range: 55-155 mm; r2 = 0.473, P = .005) and the distance between the isthmus and the distal edge of the damage zone (range: -9 to 96 mm; r2 = 0.508, P = .002). Stepwise regression identified the reaming length, distance between fracture and the isthmus, and isthmus diameter as independent predictors of contact length (r = 0.643). CONCLUSIONS: Contact is limited in specimens where the isthmus is more proximally located. In these cases, supplementary fixation using plating and/or longer, curved prosthesis may be considered.
Asunto(s)
Artroplastia de Reemplazo de Cadera , Prótesis de Cadera , Artroplastia de Reemplazo de Cadera/métodos , Fémur/diagnóstico por imagen , Fémur/cirugía , Humanos , Diseño de Prótesis , Reoperación/métodos , Estudios RetrospectivosRESUMEN
PURPOSE: The aim of the study was to systematically evaluate clinical outcomes of tapered fluted stems, either monoblock or modular, in revision total hip arthroplasty. METHODS: PubMed, EMBASE and Web of Science and Cochrane databases were systematically searched by 2 researchers. Clinical studies reporting primarily on survival and re-revision rates, and secondarily on subsidence, dislocation, intraoperative fractures, periprosthetic fractures and infection were included. 2 investigators assessed the quality of the studies. RESULTS: 46 studies were included in this review, reporting on 4601 stem revisions. The pooled re-revision rate was 5.1% and long-term survival ranged from 75% to 98.5%. No differences were observed between monoblock and modular stems regarding re-revision rate, dislocation rate, periprosthetic fracture rate or infection rates. Monoblock stems exhibited more subsidence and modular stems displayed more intraoperative fractures. CONCLUSIONS: Satisfactory results can be obtained with the use of tapered fluted end-bearing stems. Monoblock stems offer the same clinical results as modular stems.
Asunto(s)
Artroplastia de Reemplazo de Cadera , Prótesis de Cadera , Luxaciones Articulares , Fracturas Periprotésicas , Artroplastia de Reemplazo de Cadera/efectos adversos , Fémur/cirugía , Humanos , Luxaciones Articulares/cirugía , Fracturas Periprotésicas/diagnóstico por imagen , Fracturas Periprotésicas/cirugía , Diseño de Prótesis , Reoperación , Estudios Retrospectivos , TitanioRESUMEN
Non-modular tapered fluted, titanium stems are available for use in femoral revision. The combination of taper and flutes on the stem provides axial and rotational stability, respectively. The material and surface properties of the stem promotes bone on-growth. If the surgeon is confident and reasonably experienced in the surgical use of this sort of design and the case is relatively straightforward, a non-modular design is effective. It also potentially reduces implant inventory, and circumvents the potential problems of taper junction corrosion and fatigue fracture. There are reports of excellent survival, good clinical and functional results and evidence of subsequent increase in proximal bone stock.