The Association Between Anterior Cruciate Ligament Length and Femoral Epicondylar Width Measured on Preoperative Magnetic Resonance Imaging or Radiograph

Abstract

Purpose: To determine whether femoral epicondylar width (FECW) obtained from either magnetic resonance imaging (MRI) or plain radiographs could be used to predict anterior cruciate ligament (ACL) length. A secondary purpose was to develop a formula to use maximum FECW on either MRI or plain radiographs to estimate ACL length preoperatively. Methods: The MRIs and radiographs of 40 patients (mean age 41.0 years), with no apparent knee pathology, surgery, or trauma were included. The ACL length was measured on MRI followed by FECW on both MRI and radiograph of the same patient. This allowed the development of equations able to predict ACL length according to the FECW measured on either an MRI or radiograph. Results: The mean ACL length was 40.6 AE 3.6 mm. FECW measured on both MRIs and radiographs was sufficient to predict ACL length. Pearson's correlations revealed a high positive relationship between ACL length and FECW on MRI (r ¼ 0.89, P < .0001) and ACL length and FECW on radiograph (r ¼ 0.83, P < .0001). The coefficient of determination (R 2) was calculated to be MRI: R 2 ¼ 0.78 and radiograph: R 2 ¼ 0.68 and confirmed that FECW measured on both MRI and radiograph were sufficient to predict ACL length. Based on these models, ACL length can be predicted by FECW using the following formulas: MRI: ACL length ¼ 0.47 (FECW) þ 1.93 and radiograph: ACL length ¼ 0.31 (FECW) þ 11.33. Conclusions: This study demonstrated that FECW measured on either MRI or anteroposterior radiograph could reliably estimate ACL length on a sagittal MRI. There was a high positive relationship between ACL length and FECW on both MRI and radiographs, although MRIs do predict ACL length more reliably. Clinical Relevance: Preoperative ACL length assessment, using FECW on MRI or radiograph, is useful in graft selection and in preventing inadequate graft harvesting for ACL reconstruction, especially if an individualized anatomical approach is pursued.

Tibial Tubercle Trochlear Groove Distance Does Not Correlate With Patellar Tendon Length in Patients Who Underwent Anterior Cruciate Ligament Reconstruction

“…Additionally, many consider the intra-articular distance of the ACL, not the patellar tendon length, as the most integral parameter to when attempting to mitigate graft-tunnel mismatch. However, the ACL is an obliquely oriented structure that cannot be easily measured with a single sagittal image 31 or requires complex formulas for accurate measurement 32 ; therefore, identifying more easily measured structures such as patellar tendon length and TT-TG would be a more reproducible source of information if a correlation did exist. In addition, accurate preoperative knowledge of patellar tendon length affords the surgeon with valuable information that may indicate the need for longer tibial tunnels, rotation of the graft, or other strategies necessary to circumvent graft-tunnel mismatch.…”

Exploring Anatomo-Morphometric Characteristics of Infrapatellar, Suprapatellar Fat Pad, and Knee Ligaments in Osteoarthritis Compared to Post-Traumatic Lesions

“…Fayad et al studied gender differences in ACL and PCL volumes and showed that gender differences in ACL volume are present, but may be accounted for height differences between males and females [ 42 ]. The mean ACL length reported by Van Zyl et al was 40.6 mm in subjects with no apparent knee pathology, surgery, or trauma [ 44 ]. In our study, we observed a mean ACL length of 35.2 mm for patients with meniscal tears and 33.9 for end-stage OA patients).…”

Patients with a quadriceps tendon shorter than 60 mm require a patellar bone plug autograft in anterior cruciate ligament reconstruction

“…Sagittal proton density‐weighted scans taken from the tibial tubercle to 10 cm proximal to the proximal patellar pole using 3‐mm slices were obtained, and the length of the QT was measured from the superior pole of the patella to the musculotendinous junction of the rectus femoris on the slice in which the longest tendon was seen. The ACL was imaged using multi‐slice planes to visualize both the femoral and tibial insertions, and the distance between the mid‐portion of the insertion sites was measured as the ACL length [3, 39]. The thickness of the QT and PT was measured at a site 3 cm from the patellar attachment [40] (Fig.…”