Ten-year results of a prospective cohort of large-head metal-on-metal total hip arthroplasty

Abstract

Aims Large-diameter metal-on-metal (MoM) total hip arthroplasty (THA) has demonstrated unexpected high failure rates and pseudotumour formation. The purpose of this prospective cohort study is to report ten-year results in order to establish revision rate, prevalence of pseudotumour formation, and relation with whole blood cobalt levels. Methods All patients were recalled according to the guidelines of the Dutch Orthopaedic Association. They underwent clinical and radiographical assessments (x-ray and CT scan) of the hip prosthesis and whole blood cobalt ion measurements. Overall, 94 patients (95 hips) fulfilled our requirements for a minimum ten-year follow-up. Results Mean follow-up was 10.9 years (10 to 12), with a cumulative survival rate of 82.4%. Reason for revision was predominantly pseudotumour formation (68%), apart from loosening, pain, infection, and osteolysis. The prevalence of pseudotumour formation around the prostheses was 41%, while our previous report of this cohort (with a mean follow-up of 3.6 years) revealed a 39% prevalence. The ten-year revision-free survival with pseudotumour was 66.7% and without pseudotumour 92.4% (p < 0.05). There was poor discriminatory ability for cobalt for pseudotumour formation. Conclusion This prospective study reports a minimum ten-year follow-up of large-head MoM THA. Revision rates are high, with the main reason being the sequelae of pseudotumour formation, which were rarely observed after five years of implantation. Blood ion measurements show limited discriminatory capacity in diagnosing pseudotumour formation. Our results evidence that an early comprehensive follow-up strategy is essential for MoM THA to promptly identify and manage early complications and revise on time. After ten years follow-up, we do not recommend continuing routine CT scanning or whole cobalt blood measurements, but instead enrolling these patients in routine follow-up protocols for THA. Cite this article: Bone Jt Open 2022;3(1):61–67.

Long-term clinical outcomes of the Biomet M2a-38: a retrospective review of 335 total hip arthroplasty cases

“…There is historical and ample evidence on the risks of wear failure with MoM bearing systems [ 16 – 21 ]; however, the current results show a lower rate of these failure mechanisms within this M2a-38 series than registry-reported values for MoM THA [ 2 , 7 , 9 ]. Therefore, we suggest a more thorough assessment of bloodwork and radiographic analysis prior to diagnosis to avoid possible unnecessary revision surgery.…”

Long-Term Clinical Outcomes of the Biomet M2a-38: a Retrospective Review of 335 Total Hip Arthroplasty Cases

“…There is historical and ample evidence on the risks of wear failure with MoM bearing systems [17][18][19][20][21][22]; however, the current results show a lower rate of these failure mechanisms within this M2a-38 series than registry-reported values for MoM THA [8, 10,23]. Therefore, we suggest a more thorough assessment of bloodwork and radiographic analysis prior to diagnosis to avoid possible unnecessary revision surgery.…”

Seudotumor infectado en un paciente con artroplastia de cadera con par de fricción metal-metal

“…evaluaron a 94 pacientes en un seguimiento mínimo de 10 años y comunicaron que la prevalencia de seudotumores en las artroplastias con par de fricción metal-metal era cercana al 41%. 4 La tasa de revisiones a cinco años en pacientes con un seudotumor es del 6,2%, más del doble que con los otros pares de fricción. 3 Muchos organismos reguladores, entre ellos, la British Orthopedic Association, la Food and Drug Administration y el Gobierno de Canadá [12][13][14] alertaron sobre las complicaciones de las ATC con par de fricción metal-metal y sugirieron vigilar a los pacientes con dichos implantes, 15 tengan o no síntomas.…”

“…16 Aunque algunos estudios sugieren la vigilancia obligatoria de los pacientes con una ATC con par de fricción metal-metal mediante ionogramas, 17 esta conducta hoy está en discusión. 4 Se han descrito distintos algoritmos de tratamiento para los seudotumores, entre ellos, el de Lombardi y cols. 15 Según este, se recomienda un seguimiento anual estricto para los pacientes asintomáticos con niveles nulos o bajos de metales en sangre.…”

“…3 Su prevalencia luego de una ATC con un par metal-metal oscila entre el 1% y el 4%, 3 aunque se ha comunicado una tasa hasta del 41%, en su mayoría, seudotumores asintomáticos. 4 En el 32% de los casos, se puede manifestar con dolor inguinal, parestesias, renguera o una masa palpable, y diversas complicaciones por compresión sobre estructuras vasculonerviosas y urinarias. 5 Los estudios complementarios para llegar al diagnóstico incluyen la ecografía, la tomografía computarizada, la resonancia magnética y el ionograma.…”