Current morphological study of quadriceps tendon to assess the adequate and reproducible graft for ACL reconstruction using living knee demonstrated that mean length was 53.1±2.5mm, proximal width was 9.1±0.3mm, thickness was 8.6±0.4mm, and ACL length was 21.3±0.7 mm, 42% of all cases didn’t have enough individual length to ensure sufficient graft length, that means requirement of bone plug.
Quadriceps tendon has attracted attention as an alternative graft for anterior cruciate ligament (ACL) reconstruction because of better mechanical and histological property, and low donor site morbidity. However, there is a few studies about morphological characteristics of quadriceps tendon as a candidate of the ACL reconstruction. Furthermore, previous other studies measured quadriceps tendon size using not living knee but MRI and cadaveric knee.
The purpose of this study was to determine whether the quadriceps tendon had the anatomic characteristics to produce a graft whose length and width were adequate and reproducible for ACL reconstruction using living knee.
Fifty-three patients (44 females, 9 males, mean age 74 years old, mean height 154±2.2 cm) who underwent total knee arthroplasty were recruited in this study. When the capsulotomy was performed via medial parapatellar approach, and quadriceps tendon was exposed, and then length, width and thickness of quadriceps tendon were directly measured with a gauge. Especially, proximal point of the length was set so that 9 mm width was ensured. Width was measured at the proximal and 45 mm and 30 mm proximal from patella and distal attachment of patella. In addition, the length of ACL was directly measured in knee flexion with 90 degrees. Finally, individual quadriceps tendon length enough to ACL reconstruction was assessed by comparing quadriceps tendon length to ACL length combined with total 30 mm intratunnal length (15 mm femoral and 15 mm tibial tunnel), and the ratio that individual quadriceps tendon length is longer than ACL length combined with 30 mm intratunnal length, were calculated.
Mean quadriceps tendon length was 53.1±2.5 mm, from the point where the 9.0 mm width was ensured at the proximal tendon, and mean thickness was 8.6±0.4 mm. Quadriceps tendon width were 9.1±0.3 mm at proximal, 13.6±1.1 mm at 45mm from patella, 22.1±1.9 mm at 30 mm from patella, and 40.5±1.6 mm at the distal attachment of patella. Mean ACL length was 21.3±0.7 mm. Finally, cases in which quadriceps tendon length was longer than ACL length with 30mm as femoral and tibial intartunnal length was 58% of all cases.
This is the first study to assess the morphological characteristics for ACL reconstruction using living knee. In this study, quadriceps tendon and ACL length were shorted than that in previous studies. That is because that both quadriceps tendon of ACL length correlated with patients’ height. Given the short height in current study, current results would be acceptable. And, individual quadriceps tendon length assessment showed 58% cases has quadriceps tendon length enough to reconstruct ACL, however 42% cases need to harvest quadriceps tendon with bone to ensure the ACL and intradunnal length at femoral and tibial side.
Quadriceps tendon could be an alternative graft for ACL reconstruction. However, 42% of all cases need to harvest quadriceps tendon with patella bone to ensure the sufficient length of the graft.