Isolated Medial Patellofemoral Ligament Reconstruction in Patellar Instability: Does the Distance Between Tibial Tuberosity-Trochlear Groove Make a Difference?

Introduction: Medial patellofemoral ligament reconstruction (MPFLR) is used in most patellar instability surgeries, there is controversy on adding a tibial tuberosity osteotomy (TTO). Objective: To describe the results of isolated MPFLR in patellar instability according to the Tibial Tuberosity-Trochlear Groove distance (TT-TG). Methods: Retrospective study of patients with patellar instability with a mature skeleton in one center between 2016 and 2021, using isolated MPFLR. Patients with incomplete clinical and/or radiological records and less than one year follow-up were excluded. Pre-surgical demographic and radiological data (TT-TG, Caton-Deschamps (CD) index, patellar tilt, trochlear dysplasia) were recorded. Patients were divided into three groups according to TT-TG distance (Group 1: < 17 mm, Group 2: 17-19, Group 3: ≥ 20 mm). A pre and post-surgical Kujala score was performed. Local complications, satisfaction, recurrence and/or reintervention were recorded. Pre-surgical variables between groups, intra and inter-group Kujala differences were compared using Bartlett's test. Consent from the patients and approval from the local ethics committee were obtained. Results: 67 patients met the selection criteria, mean age of 23 years, 70% were women. There were no pre surgical, radiological nor follow-up differences between the groups (average 27 months). Pre and post-surgical Kujala score, respectively: Group 1: 37-78, Group 2: 37-78, Group 3: 39-79. All groups had a significant improvement (p < 0.05), there were no significant differences in improvement between groups (p > 0.05). There were three patients with a redislocation episode, all in group 1. One patient had a mobilization under anesthesia due to an arthrofibrosis (Group 2). 97% of all cases reported being satisfied. Conclusion: Isolated MPFLR in patellar instability presents a functional improvement, with a low rate of complications and failure, regardless of the pre surgical TT-TG. Supplementary Information: The online version contains supplementary material available at 10.1007/s43465-023-00906-6.

Tratamiento de la inestabilidad femoropatelar objetiva. Resultados a cinco años de seguimiento / Treatment of objective patellar instability. Results after five years of follow-up

Resumen: Objetivo: Presentar los diferentes procedimientos quirúrgicos en el tratamiento de las inestabilidades femoropatelares objetivas, incluyendo la osteotomía de la tuberosidad tibial anterior y la trocleoplastía femoral. Material y métodos: Con un diseño prospectivo con seguimiento a cinco años que incluyó a 21 pacientes (21 rodillas) tratados por luxación rotuliana recidivante entre Marzo de 2010 y Agosto de 2014, tratándose de forma quirúrgica mediante dos técnicas diferentes según el tipo de inestabilidad estructural de base. Para determinarlo, se analizó el índice radiográfico de Caton-Deschamps (para la evaluación de la altura rotuliana) y parámetros tomográficos para valorar el configuración troclear y distancia desde la tuberosidad tibial anterior hasta la tróclea femoral (TT-TG) en la superposición de imágenes en el plano axial. Resultados: Hemos tenido resultados satisfactorios tanto con la transferencia de la tuberosidad tibial anterior como con la trocleoplastía. En ambos procedimientos se realizó una reconstrucción del ligamento patelofemoral medial (LPFM). Conclusiones: La recurrencia de inestabilidad es muy rara después de estos procedimientos y es más probable que ésta resulte de anomalías asociadas no diagnosticadas o subestimadas. Se requiere una planificación precisa preoperatoria para determinar la altura rotuliana, la ubicación de la tuberosidad tibial anterior y la configuración troclear para obtener resultados satisfactorios.

Abstract: Objective: To present the different surgical procedures in the treatment of objective femoropateral instability, including osteotomy of anterior tibial tuberosity and femoral trocleoplasty. Material and methods: With a prospective 5-year follow-up design that included 21 patients (21 knees) treated for relapsing patellar dislocation between March 2010 and August 2014, treated surgically using 2 different techniques depending on the type of basic structural instability. To determine this, the Caton-Deschamps X-Ray Index (for the evaluation of the patellar height) and tomographic parameters were analyzed to assess the troclear configuration and distance from the anterior tibial tuberosity to the femoral trochlea (TT-TG) in the overlapping of images in the axial plane. Results: We have had satisfactory results both with the transfer of the anterior tibial tuberosity and with the trocleoplasty. In both procedures, a reconstruction of the medial patelo-femoral ligament (LPFM) was performed. Conclusion: Recurrence of instability is very rare after these procedures and is more likely to result from undiagnosed or underestimated associated abnormalities. Precise preoperative planning is required to determine the patellar height, location of the anterior tibial tuberosity, and troclear configuration for satisfactory results.

[Treatment of objective patellar instability. Results after five years of follow-up]. / Tratamiento de la inestabilidad femoropatelar objetiva. Resultados a cinco años de seguimiento.

OBJECTIVE: To present the different surgical procedures in the treatment of objective femoropateral instability, including osteotomy of anterior tibial tuberosity and femoral trocleoplasty. MATERIAL AND METHODS: With a prospective 5-year follow-up design that included 21 patients (21 knees) treated for relapsing patellar dislocation between March 2010 and August 2014, treated surgically using 2 different techniques depending on the type of basic structural instability. To determine this, the Caton-Deschamps X-Ray Index (for the evaluation of the patellar height) and tomographic parameters were analyzed to assess the troclear configuration and distance from the anterior tibial tuberosity to the femoral trochlea (TT-TG) in the overlapping of images in the axial plane. RESULTS: We have had satisfactory results both with the transfer of the anterior tibial tuberosity and with the trocleoplasty. In both procedures, a reconstruction of the medial patelo-femoral ligament (LPFM) was performed. CONCLUSION: Recurrence of instability is very rare after these procedures and is more likely to result from undiagnosed or underestimated associated abnormalities. Precise preoperative planning is required to determine the patellar height, location of the anterior tibial tuberosity, and troclear configuration for satisfactory results.

OBJETIVO: Presentar los diferentes procedimientos quirúrgicos en el tratamiento de las inestabilidades femoropatelares objetivas, incluyendo la osteotomía de la tuberosidad tibial anterior y la trocleoplastía femoral. MATERIAL Y MÉTODOS: Con un diseño prospectivo con seguimiento a cinco años que incluyó a 21 pacientes (21 rodillas) tratados por luxación rotuliana recidivante entre Marzo de 2010 y Agosto de 2014, tratándose de forma quirúrgica mediante dos técnicas diferentes según el tipo de inestabilidad estructural de base. Para determinarlo, se analizó el índice radiográfico de Caton-Deschamps (para la evaluación de la altura rotuliana) y parámetros tomográficos para valorar el configuración troclear y distancia desde la tuberosidad tibial anterior hasta la tróclea femoral (TT-TG) en la superposición de imágenes en el plano axial. RESULTADOS: Hemos tenido resultados satisfactorios tanto con la transferencia de la tuberosidad tibial anterior como con la trocleoplastía. En ambos procedimientos se realizó una reconstrucción del ligamento patelofemoral medial (LPFM). CONCLUSIONES: La recurrencia de inestabilidad es muy rara después de estos procedimientos y es más probable que ésta resulte de anomalías asociadas no diagnosticadas o subestimadas. Se requiere una planificación precisa preoperatoria para determinar la altura rotuliana, la ubicación de la tuberosidad tibial anterior y la configuración troclear para obtener resultados satisfactorios.