High Risk of Failure With Bimodular Femoral Components in THA

Abstract

Background The bimodular femoral neck implant (modularity in the neck section and prosthetic head) offers several implant advantages to the surgeon performing THAs, however, there have been reports of failure of bimodular femoral implants involving neck fractures or adverse tissue reaction to metal debris. We aimed to assess the results of the bimodular implants used in the THAs we performed. Questions/purposes We asked: (1) What is the survivorship of the PROFEMUR 1 bimodular femoral neck stems? (2) What are the modes of failure of this bimodular femoral neck implant? (3) What are the major risk factors for the major modes of failure of this device?Methods Between 2003 and 2009, we used one family of bimodular femoral neck stems for all primary THAs (PRO-FEMUR 1 Z and PROFEMUR 1 E). During this period, 277 THAs (in 242 patients) were performed with these implants. One hundred seventy were done with the bimodular PROFE-MUR 1 E (all are accounted for here), and when that implant was suspected of having a high risk of failure, the bimodular PROFEMUR 1 Z was used instead. One hundred seven THAs were performed using this implant (all are accounted for in this study). All bearing combinations, including metal-on-metal, metal-on-polyethylene, and ceramic-on-ceramic, are included here. Data for the cohort included patient demographics, BMI, implant dimensions, type of articular surface, length of followup, and C-reactive protein serum level. We assessed survivorship of the two stems using Kaplan-Meier curves and determined the frequency of the different modes of stem failure. For each of the major modes of failure, we performed binary logistic regression to identify associated risk factors. Results Survivorship of the stems, using aseptic revision as the endpoint, was 85% for the patients with the PROFE-MUR 1 E stems with a mean followup of 50 months (range, 1-125 months) and 85% for the PROFEMUR 1 Z with a mean followup of 50 months (range, 1-125 months)(95% CI, 74-87 months). The most common modes of failure were loosening (9% for the PROFEMUR 1 E), neck fracture (6% for the PROFEMUR 1 Z and 0.6% for the PROFEMUR 1 E), metallosis (1%), and periprosthetic fracture (1%). Only the bimodular PROFEMUR 1 E was associated with femoral stem loosening (odds ratio [OR] =1.1; 95% CI, 1.04-1.140; p = 0.032). Larger head (OR = 3.2; 95% CI, 0.7-14; p = 0.096), BMI (OR = 1.19; 95% CI, 1-1.4; p = 0.038) and total offset (OR = 1.83; 95% CI, 1.13-2.9; p = 0.039) were associated with neck fracture.

How to Proceed with Asymptomatic Modular Dual Taper Hip Stems in the Case of Acetabular Revision

“…A major disadvantage of dual taper modular hip stems is the additional interface at the neck-stem junction, increasing the risk for fatigue fracture, fretting, crevice corrosion and metal particle and ion release [6,[16][17][18][19][20][21][22]. For Ti alloy hip stem designs with Ti alloy neck adapters, the main implant-related clinical failure mode is fatigue fracture of the neck taper in the highly stressed neck-stem junction due to fretting corrosion, local stress concentration and crack initiation by multi-directional bending and torsion [16,[23][24][25][26][27].…”

Inovacijska past: izmenljivi vrat totalne kolčne endoproteze

“…Skupno smo našli 9 člankov, ki opisujejo zlom izmenljivega vratu (6,7,(11)(12)(13)(14)(15)(16)(17). Prvih osem člankov opisuje zlome pri 13 bolnikih (11 bolnikov pri modelu Profemur Z in 2 bolnika pri modelu GSP), ki jih zbirno prikazujemo v Tabeli 1.…”

“…so opisali zlom 7 vratov v skupini 242 bolnikov, ki so jim v obdobju od 2003 do 2009 vstavili skupno 277 endoprotez z izmenljivim vratom modela Profemur E (170 endoprotez) in modela Profemur Z (107 endoprotez) (17). V povprečno 50 mesecev dolgi opazovalni dobi je bilo potrebno zaradi omajanja debla zamenjati 15 (9 %) endoprotez modela Profemur E, zaradi zloma izmenljivega vratu pa 6 (6 %) endoprotez modela Profemur Z. Zanimivo je, da je bil vzrok za revizijo pri modelu Profemur E le v 1 primeru (0,6 %) zlom izmenljivega vratu.…”

“…V povprečno 50 mesecev dolgi opazovalni dobi je bilo potrebno zaradi omajanja debla zamenjati 15 (9 %) endoprotez modela Profemur E, zaradi zloma izmenljivega vratu pa 6 (6 %) endoprotez modela Profemur Z. Zanimivo je, da je bil vzrok za revizijo pri modelu Profemur E le v 1 primeru (0,6 %) zlom izmenljivega vratu. Vsi zlomljeni vratovi so bili dolgi (17).…”

Corrosion and adverse local tissue reaction after total hip arthroplasty with a modular titanium alloy femoral neck

“…Unfortunately, early failures have been documented in cases of some bi-modular neck designs secondary to mechanically assisted crevice corrosion (MACC) at the neck-stem junction [2] , [3] , [4] , [5] , [6] . MACC resulted in recalls of Rejuvenate, ABG II (both Stryker Orthopedics, Mahwah, NJ), and some Profemur (MicroPort Orthopedics, Memphis, TN) implants [2] , [3] , [7] , [8] .…”