[Mid-term complications of the monopolar, modular radial head prosthesis]. / Complicaciones a mediano plazo de la prótesis monopolar modular de cabeza radial.

INTRODUCTION: The objective of this study is to assess the type, frequency and severity of complications after the implantation of the modular monopolar radial head prosthesis. MATERIAL AND METHODS: Forty-seven patients with 48 radial head prostheses implanted between 2009 and 2017 were reviewed retrospectively. Patients were evaluated clinical and radiographically for a mean follow-up of 43.55 months (range: 12-89). RESULTS: The same type of prosthesis was implanted in every patient (Ascension Modular Radial Head). The average score in the Mayo Elbow Performance Score was 88.29 ± 9.9 points. During the follow-up, three patients (6.25%) suffered from continuous pain. Twelve cases (25.5%) showed radiological oversizing, though only five were symptomatic. Heterotopic ossification was detected in twenty-seven cases (57.4%). Eleven patients (23.4%) developed postoperative stiffness. Nineteen cases (40.42%) showed periprosthetic osteolysis, from which seven were symptomatic. Thirteen patients (27%) developed surgery-related complications: three cases of infection, four cases of symptomatic loosening, two neurapraxies, one instability and three cases of oversizing with associated stiffness. Nine patients (18.75%) required reintervention. DISCUSSION: Our study obtains a 27% of overall complications, mostly related to oversizing and prosthetic loosening, and 19% of reinterventions. These results are similar to those presented in previous studies, with variations depending on the time of follow-up. Further research is also required to evaluate long-term results and the potential progression of the radiographic findings. CONCLUSION: Taken together, these data stress the need for improvement in both the surgical technique and the design of the implants.

INTRODUCCIÓN: El objetivo de este estudio es evaluar el tipo, la frecuencia y la gravedad de las complicaciones después de la implantación de la prótesis monopolar modular de cabeza radial. MATERIAL Y MÉTODOS: Se revisaron retrospectivamente 47 pacientes con 48 prótesis de cabeza radial implantadas entre 2009 y 2017 durante una media de 43.55 meses (rango: 12-89). RESULTADOS: Se implantó el mismo tipo de prótesis en cada paciente (Ascension Modular Radial Head). La puntuación media obtenida en la clasificación Mayo Elbow Performance Score fue de 88.29 ± 9.9 puntos. Durante el seguimiento tres pacientes (6.25%) sufrieron dolor continuo. Doce casos (25.5%) mostraron sobredimensión radiológica, aunque sólo cinco fueron sintomáticos. Se detectó osificación heterotópica en 27 casos (57.4%), 11 pacientes (23.4%) desarrollaron rigidez postoperatoria, 19 casos (40.42%) mostraron osteólisis periprotésica, de los cuales siete fueron sintomáticos, 13 pacientes (27%) presentaron complicaciones: tres casos de infección, cuatro casos de aflojamiento sintomático, dos neuroapraxias, una inestabilidad y tres casos de sobredimensionamiento con rigidez asociada. Nueve pacientes (18.75%) fueron reintervenidos. DISCUSIÓN: Presentamos 27% de complicaciones globales, principalmente relacionadas con la sobredimensión y el aflojamiento protésico y 19% de reintervenciones. Estos resultados son similares a los descritos en estudios previos con variaciones en función del tiempo de seguimiento. Asimismo, se requieren nuevos estudios para evaluar los resultados a largo plazo y la posible progresión de los hallazgos radiográficos. CONCLUSIÓN: En conjunto, estos datos ponen de manifiesto la necesidad de mejoría tanto de la técnica quirúrgica como del diseño de los implantes.

[Medium term results of unipolar modular radial head arthroplasty]. / Resultados a medio plazo de la artroplastia monopolar modular de cabeza radial.

OBJECTIVE: Analyze the results of unipolar modular radial head arthroplasty in the treatment of complex fractures associated with elbow joint instability. MATERIAL AND METHOD: Retrospective design study of 44 patients, 17 men and 27 women with a mean age of 51 years (17-78) who suffered radial head fractures (Mason III) in the context of an unstable elbow injury. Mean follow-up was 21.2 months (12-60). Radial head replacement was performed with a unipolar modular prosthesis with a fixed stem (Ascension(®) Modular Radial Head [MRH]), associating repair of concomitant lesions. The Mayo scale Elbow Performance Score (MEPS) was used to perform the functional assessment. A radiological evaluation was performed at the last follow-up and the complications were recorded. RESULTS: Final arc of flexion-extension was 108° with an average of 135° of prono-Supination. At final follow-up, 82% of results were satisfactory according to the MEPS. The 40% of patients (17) had radiographic signs of lucencies around the stem, although most of them were asymptomatic. Two of them needed a second surgical procedure because of painful prosthetic loosening and further surgery was required for a prosthesis dislocation. DISCUSSION: Radial head implants are an adequate treatment option for restoring stability in complex radial head fractures. Modularity allows a wide range of size combination and helps to avoid overstuffing. Periprosthetic osteolysis could be associated with the presence of pain, so it is necessary to perform long-term studies to test the potential complications of this finding.

Resultados a medio plazo de la artroplastia monopolar modular de cabeza radial / Medium term results of unipolar modular radial head arthroplasty

Objetivo. Analizar los resultados de la artroplastia monopolar modular de la cabeza radial como tratamiento de fracturas complejas del codo asociadas a inestabilidad articular. Material y método. Estudio retrospectivo de 44 pacientes, 17 varones y 27 mujeres con una edad media de 51 años (17-78), que fueron intervenidos de fracturas de la cabeza radial tipo iii de Mason en el contexto de lesiones inestables del codo. El seguimiento medio fue de 21,2 meses (12-60). La sustitución de la cabeza radial se realizó con una prótesis monopolar modular de vástago fijo, denominada Ascension® Modular Radial Head (MRH), asociando la reparación de las lesiones concomitantes en el mismo acto quirúrgico. Para la evaluación funcional se utilizó la escala Mayo Elbow Performance Score (MEPS). También se registraron los hallazgos radiográficos y complicaciones durante el seguimiento. Resultados. El arco final de flexo-extension fue de 108° con una prono-supinación media de 135°. Al final del seguimiento, el 82% de los resultados fueron satisfactorios de acuerdo con la MEPS. El 40% de los pacientes (17) presentaron signos radiográficos de radiolucencia alrededor del vástago que resultaron asintomáticos. Dos de estos 17 pacientes precisaron reintervención por aflojamiento protésico doloroso y una nueva cirugía fue necesaria por luxación de la prótesis. Discusión. Los implantes monopolares son una opción válida de tratamiento para restaurar la estabilidad en las fracturas complejas de la cabeza radial. Su modularidad permite ampliar la selección de tamaños y evitar el pinzamiento radio-capitelar. La osteólisis periprotésica no es siempre sinónimo de ausencia de sintomatología, siendo necesarios estudios con seguimiento más prolongado para valorar la asociación de este hallazgo con el desarrollo de complicaciones potenciales (AU)

Objective. Analyze the results of unipolar modular radial head arthroplasty in the treatment of complex fractures associated with elbow joint instability. Material and method. Retrospective design study of 44 patients, 17 men and 27 women with a mean age of 51 years (17-78) who suffered radial head fractures (Mason III) in the context of an unstable elbow injury. Mean follow-up was 21.2 months (12-60). Radial head replacement was performed with a unipolar modular prosthesis with a fixed stem (Ascension® Modular Radial Head [MRH]), associating repair of concomitant lesions. The Mayo scale Elbow Performance Score (MEPS) was used to perform the functional assessment. A radiological evaluation was performed at the last follow-up and the complications were recorded. Results. Final arc of flexion-extension was 108° with an average of 135° of prono-Supination. At final follow-up, 82% of results were satisfactory according to the MEPS. The 40% of patients (17) had radiographic signs of lucencies around the stem, although most of them were asymptomatic. Two of them needed a second surgical procedure because of painful prosthetic loosening and further surgery was required for a prosthesis dislocation. Discussion. Radial head implants are an adequate treatment option for restoring stability in complex radial head fractures. Modularity allows a wide range of size combination and helps to avoid overstuffing. Periprosthetic osteolysis could be associated with the presence of pain, so it is necessary to perform long-term studies to test the potential complications of this finding (AU)