Radiographic Location Does Not Ensure a Precise Anatomic Location of the Femoral Fixation Site in Medial Patellofemoral Ligament Reconstruction

Abstract

Background:A frequently used method to determine the anatomic femoral fixation point in the operating room during medial patellofemoral ligament (MPFL) reconstruction is the radiographic method. However, the ability of this radiological method to establish an anatomic femoral attachment point might not be as accurate as expected.Purpose:(1) To evaluate the accuracy of the radiological method to locate the anatomic femoral fixation point in MPFL reconstruction surgery and (2) to determine the factors influencing the predictability of this method to obtain this objective.Study Design:Cohort study (diagnosis); Level of evidence, 2.Methods:A total of 100 consecutive 3-dimensional computed tomography (3D CT) knee examinations were performed at 0° of extension in 87 patients treated for chronic lateral patellar instability. For each knee, 2 virtual 7 mm–diameter femoral tunnels were created: 1 using the adductor tubercle as a landmark (anatomic tunnel) and the other according to the radiological method described by Schöttle et al (radiographic tunnel). We measured the percentage of overlap between both tunnels. Moreover, of the 100 included knees, 10 were randomly selected for a variability study.Results:Considering an overlap area greater than 50% as reasonable, the radiographic method achieved this in only 38 of the 100 knees. Intrarater and interrater reliability were excellent. There was a trend for female patients with severe trochlear dysplasia to have less overlap. This model accounted for 64.2% of the initial variability in the data.Conclusion:An exact anatomic femoral tunnel placement could not be achieved with the radiographic method. Radiography provided only an approximation and should not be the sole basis for the femoral attachment location. Moreover, in female patients with severe trochlear dysplasia, the radiographic method was less accurate in determining the anatomic femoral fixation point, although differences were not statistically significant.

The Medial Patellofemoral Ligament Is a Dynamic and Anisometric Structure: An In Vivo Study on Length Changes and Isometry

“…Several articles have described radiographic landmarks of the MPFL 7,31,48,55,69,76 ; however, others have questioned the accuracy of performing anatomic reconstruction using these radiographic landmarks. 53,80 In this study, the center of the dimple was, on average, 7.2 mm (95% CI, 6.3-8.2 mm) distal and 4.6 mm (95% CI, 4.0-5.2 mm) anterior to the adductor tubercle. We argue that surgeons can use the adductor magnus tendon to routinely locate the adductor tubercle to find the ideal position for MPFL reconstruction.…”

Combined Soft Tissue Reconstruction of the Medial Patellofemoral Ligament and Medial Quadriceps Tendon–Femoral Ligament

“…Moreover, radiographic identification of Schöttle points does not guarantee the precise anatomic location of the femoral fixation site. 13 Besides providing a stronger fixation (bony attachment), placing the femoral fixation more proximally at the adductor magnus tendon will increase the distances between the femoral and patellar attachments points during knee flexion and augment the tension to the patella. 14 Using the adductor tubercle for femoral fixation has been shown to not change the patellofemoral joint contact area and pressure.…”

“…The distance from the femoral insertion of the MPFL to the adductor tubercle is less variable than the distance to the medial femoral epicondyle, 12 which makes the adductor tubercle often used for femoral fixation in MPFL reconstructions. Moreover, radiographic identification of Schöttle points does not guarantee the precise anatomic location of the femoral fixation site 13 . Besides providing a stronger fixation (bony attachment), placing the femoral fixation more proximally at the adductor magnus tendon will increase the distances between the femoral and patellar attachments points during knee flexion and augment the tension to the patella 14 .…”

Reconstrução do ligamento patelofemoral medial com o terço medial do tendão patelar no tratamento da instabilidade recidivante da patela: resultados a médio e longo prazo

“…Não há consenso na literatura sobre qual é o mais confiável, havendo defensores de uma ou outra ou ambas as opções, como citado por Caplan et al (25) . Dentre estas alternativas, há autores que apontaram o método palpatório com maior chance de erros no posicionamento (60,98,148,149) , enquanto outros relataram que pequenas variações tanto na rotação do joelho quanto nos aparelhos de radioscopia ou de raios X resultam num posicionamento intraoperatório inadequado (99,(101)(102)(103) . Na técnica cirúrgica realizada nesta pesquisa, realizou-se o posicionamento do túnel femoral pelo método palpatório das referências anatômicas do TA e do EP devido à execução simples, à experiência do cirurgião com o método e à prevenção de exposição da equipe cirúrgica e do paciente à radiação dos raios X, ratificando-se o relato de Sanchis-Alfonso et al (100) .…”

“…Sanchis-Alfonso et al (103) , em 2017, novamente estudaram a localização anatômica do túnel femoral do LPFM em imagens tridimensionais na TC.…”