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Category Anatomy

Year of publishing 2022

Perry AK, Dandu N, Knapik DM, Inoue N, Gursoy S, Bush-Joseph CA, Yanke AB, Chahla J. Lateral Harvest of an Osseous-Based Quadriceps Tendon Autograft Results in Thinner Remaining Patellar Bone. Orthop J Sports Med. 2022;10(5):23259671221093685.

Abstract Background: Patellar fracture after quadriceps tendon (QT) autograft harvest for anterior cruciate ligament reconstruction (ACLR) has been reported in up to 8.8% of patients. Purpose: To determine the thickness of the remaining patellar bone across the QT graft harvest location while providing clinical guidance for safely harvesting a patellar bone block when using a QT graft in ACLR. Study design: Descriptive laboratory study. Methods: Medial and lateral QT graft boundaries were marked using a bone saw on 13 cadaveric patellae, and 3-dimensional computed tomography models were created. After the harvest of a virtual bone block with a maximum depth of 10 mm, the thickness of the remaining bone was measured across the graft harvest location in 9 zones. The thickness of the remaining bone was analyzed according to zone, graft harvest location, and patellar facet length. Risk zones were defined as <50% total patellar depth remaining. Results: We observed substantial variability in QT bone block harvest location, in which the distance between the lateral boundary of the harvest location and the lateral patellar cortex was from 21.2% to 49.2% of the axial patellar width. There was significantly less bone remaining in the lateral columns (mean ± SD, 7.56 ± 2.19 mm) compared with the medial columns (9.83 ± 2.10 mm) of the graft harvest location (P = .028). The number of risk zones was significantly associated with distance to the lateral cortical edge, with an increase in 0.59 zones with every 1-mm decrease in distance to the lateral cortex edge (b = -0.585; R 2 = 0.620; P = .001). With every 1-mm increase in the distance of the lateral cortex to the lateral graft boundary, the thickness of bone remaining in the lateral column increased by 0.412 mm (P < .001). No risk zones were encountered when the lateral boundary of the harvest location was created 18.9 mm from the lateral edge of the patella or 43% of the total patellar width from the lateral edge. Conclusion: Harvest of a more laterally based QT autograft bone block resulted in thinner remaining patellar thickness, increasing the potential of encountering a risk zone for fracture. Clinical relevance: Care should be taken to avoid harvesting the patellar bone block too laterally during ACLR.
Keywords: ACL reconstruction; patella; patellar fracture; quadriceps tendon.

Year of publishing 2022

Strauss MJ, Miles JW, Kennedy ML, Dornan GJ, Moatshe G, Lind M, Engebretsen L, LaPrade RF. Full thickness quadriceps tendon grafts with bone had similar material properties to bone-patellar tendon-bone and a four-strand semitendinosus grafts: a biomechanical study. Knee Surg Sports Traumatol Arthrosc. 2022;30(5):1786-1794.

Abstract Purpose: Despite increasing interest in utilizing quadriceps tendon (QT) grafts in anterior cruciate ligament reconstruction (ACLR), data on the optimal quadriceps graft thickness are limited. The purpose of this study was to characterize the mechanical properties for the quadriceps tendon, comparing full-thickness (FT) QT grafts with and without bone to a partial-thickness (PT) QT graft, and comparing the three QT grafts to four-stranded semitendinosus (4-SST) and bone-patellar tendon-bone (BTB) grafts and one experimental graft, the two-stranded rectus femoris (RF). Methods: Forty-eight (n = 48) young cadaveric grafts (mean age 32 ± 6 years) were utilized for testing with N = 8 specimens in each of the following groups; (1) FT QT with bone, (2) FT QT without bone, (3) PT QT without bone, (4) BTB, (5) RF, and (6) 4-SST. Each specimen was harvested and rigidly fixed in custom clamps to a dynamic tensile testing machine for biomechanical evaluation. Graft ultimate load and stiffness were recorded. Independent groups one-factor ANOVAs and Tukey's pairwise comparisons were performed for statistical analyses. Results: FT QT with bone and 4-SST grafts demonstrated similar ultimate loads to BTB grafts (both n.s), whereas PT QT demonstrate statistically significantly lower ultimate loads to BTB grafts (n.s) and 4-SST grafts (n.s). Furthermore, no statistically significant differences were observed between the ultimate loads of FT QT vs. PT QT grafts without bone (n.s) or between FT QT with vs. without bone (n.s). FT QT grafts with bone did not demonstrate statistically significantly greater ultimate loads than PT QT grafts without bone (n.s). The RF graft demonstrated statistically significantly lower ultimate loads to BTB grafts (p < 0.005) and 4-SST grafts (p < 0.014). Conclusions: Full thickness QT grafts with bone had similar material properties to BTB and a 4-SST grafts, while Partial thickness QT graft without bone had significantly lower material properties than BTB and 4-SST, in a biomechanical setting.
Keywords: ACL; ACL reconstruction; Biomechanics; Bone-patellar tendon-bone; Hamstring tendon; Knee ligament; Quadriceps tendon.

Year of publishing 2022

Gagliardi AG, Howell DR, Stein JM, Monson MA, Pearce SS, Albright JC. Prediction of quadriceps tendon-patellar bone autograft diameter in adolescents with 2-dimensional magnetic resonance imaging and anthropometric measures. Skeletal Radiol. 2022;51(3):619-623


Objectives: This study evaluates the correlation between the bone end and soft tissue end of the quadriceps tendon-patellar bone autograft (QPA) size and pre-operative MRI measurements of the quadriceps tendon along sections to be included in the graft harvest in adolescents. We also assessed association between graft diameter and anthropometric measures (height, weight, and BMI), age, and sex. Methods: Patients (10-18 years) who underwent QPA ACL reconstruction and had a pre-operative MRI were considered for inclusion. Age, height, and weight, tibial and femoral side graft diameter, and patellar bone block dimensions were collected. Using a pre-operative 2D sagittal plane MRI, we measured the quadriceps at 10-mm increments above the patella, up to 40 mm. We assessed correlation between the bone-end graft diameter and the AP measure at 10 mm above the patella, and correlation between the soft-tissue end graft diameter and the most proximal AP measure. Results: A total of 103 patients were included. A significant correlation between the soft-tissue side graft diameter and most proximal AP measurement was observed (rs = 0.51; p < 0.001). However, measurements significantly underestimated the soft-tissue end graft diameter (9.6 ± 0.8 vs. 7.4 ± 1.1; p < 0.001). There was no correlation between the bone-end graft diameter and AP measurement 10 mm above the patella. Anthropometric measures were not associated with graft size. Skeletal maturity was associated with smaller graft size (p = 0.08). Conclusion: Soft-tissue end graft diameter is associated with the AP measure of the quadriceps at 20-40 mm above the superior pole of the patella.
Keywords: ACL reconstruction; Anthropomorphic measures; Magnetic resonance imaging; Pediatrics; Quadriceps tendon.

Year of publishing 2022

Sadoghi P, Röggla V, Beiglböck H, et al. Prediction of individual graft for anterior cruciate ligament reconstruction using anthropometric. Arch Orthop Trauma Surg. 2022;10.1007/s00402-022-04682-0.

Abstract Introduction: Multiple options for individual anterior cruciate ligament (ACL) reconstruction exist; still, there are no guidelines for the preoperative preparation. The aim of this study was to assess the correlation between patients' anthropometric data (height, weight, and age) and measurements of potential tendons (quadriceps-, patella, hamstrings tendon) for an anterior cruciate ligament reconstruction. Material and methods: MR images of 102 patients have been analyzed. Measurements of the ACL were performed with respect to its length and angle. The diameter and length as well as width of the quadriceps and patella tendon, the cross-sectional area (CSA) and diameter of the hamstring tendons have been assessed. Patients' height, weight, BMI, sex and age have been recorded. The correlations of these measurements with the patients' anthropometric data have been calculated. Inter-rater and intra-rater reliability based on intra-class correlation (ICC) was evaluated. Results: The mean lengths of the ACL were 29.8 ± 3.5 mm, tibial insertion sites 15.8 ± 2.5 mm and femoral insertion sites 15.2 ± 3.0 mm. Thickness of the quadriceps tendons was 4.7 ± 1.1 mm and patella tendon 3.2 ± 0.7 mm. The patients' height showed significant positive correlations with the CSA of the hamstring tendon measurements, the length of the ACL, and the insertion sites of the ACL. Patients' weight showed significant positive correlations with patella tendon thickness, the CSA of the hamstring tendons, the length of the ACL, and the tibial and femoral insertion sites. Patients' age showed a significant positive correlation with patella tendon thickness. The ICCs for intra- and inter-rater reliability were 0.98 (95% CI 0.95-0.99, p < 0.001) and 0.94 (95% CI 0.88-0.99, p < 0.001). Conclusion: Anthropometric data with respect to height, weight, and sex can help to predict the dimension of tendons for ACL reconstruction and do correlate with ACL tendon. Patients at risk for small graft dimensions and failure are younger than 20 years and physically active. MRIs of patients at risk for small graft dimensions should be analyzed on tendon length and cross section areas preoperatively to determine the appropriate tendon harvest and fixation technique.
Keywords: ACL; Anthropometry; Individual; MRI; Reconstruction.

Year of publishing 2022

Bourgeault-Gagnon Y, Leang AK, Bédard S, Lebel K, Balg F, Vézina F. A Partial-Thickness Quadriceps Autograft Reliably Augments the Size of the Hamstring Graft During Anterior Cruciate Ligament Reconstruction. Arthrosc Sports Med Rehabil. 2022;4(6):2005-2009.

Abstract Purpose: To measure the increase in diameter resulting from the augmentation of a hamstring autograft with a partial width rectus femoris tendon band in anterior cruciate ligament reconstruction. Methods: Thirty-three cadaveric knees were dissected to harvest semitendinosus and gracilis tendons (4S) along with a 6-mm wide tendon band from the rectus femoris. Harvesting was done according to the usual surgical techniques of both harvests. Measures of length and diameter in 4S and 4S augmented with the rectus femoris band (4S +Q) configurations were performed separately by 3 evaluators. Results: The quadriceps augmentation led to an average increase of 1.49 mm (95% confidence interval 1.03-1.95 mm) in diameter of the 4-strand hamstring grafts. The previously demonstrated threshold diameter of 8.5 mm was attained in only 30% of 4S grafts within this population in comparison with 88% when augmented with a quadriceps band. Conclusions: In conclusion, supplementing doubled hamstring graft (4S) with quadricipital tendon in anterior cruciate ligament reconstruction (ACLR) increases the graft diameter by an average of 1.49 mm. It has the physical potential to reliably augment hamstring grafts that measure 7.5 mm in diameter or more in order to obtain an 8.5 mm when necessitated. Clinical relevance: Increased graft diameter is associated with a decreased risk of graft failure after ACLR. Because of this, it is important to identify methods to increase the size of grafts. This study investigates the use of a partial-width rectus femoris tendon band as an option to reliably augment graft sizes during ACLR.

Year of publishing 2023

Kinoshita T, Hashimoto Y, Iida K, Nakamura H. ACL Graft Matching: Cadaveric Comparison of Microscopic Anatomy of Quadriceps and Patellar Tendon Grafts and the Femoral ACL Insertion Site. Am J Sports Med. 2022;50(11):2953-2960.

Abstract Background: The optimal graft choice between the bone-patellar tendon-bone (BPTB) and the quadriceps tendon remains controversial. Studies evaluating the microscopic anatomy of the quadriceps tendon-patellar bone (QTB) and BPTB grafts for anterior cruciate ligament (ACL) reconstruction are currently lacking. Hypothesis: The relationship between post-ACL reconstruction graft bending angle (GBA) and the angle corresponding to the GBA (cGBA) would indicate that the BPTB can bend more than the QTB at the femoral tunnel aperture. Study design: Controlled laboratory study. Methods: Twenty paired human cadaveric knees fixed at <10° of knee joint flexion (mean age, 82.5 years) underwent histological sectioning and staining with Masson trichrome and toluidine blue. The femoral ACL insertion, QTB graft, and BPTB graft were microscopically analyzed. The width of the direct insertion, thickness of the uncalcified fibrocartilage and calcified fibrocartilage, ligament attachment angle, and cGBA for each group were measured. Eighteen patients who underwent ACL reconstruction with QTB or BPTB autograft were included for the evaluation of GBA using computed tomography images at 1 week postoperatively. Results: The mean insertion widths of the femoral ACL, QTB, and BPTB were 7.81, 9.07, and 6.54 mm, respectively. The QTB was 16% wider than the ACL, while the BPTB was 16% narrower than the ACL. The mean insertion thicknesses of the femoral ACL, QTB, and BPTB were 0.53, 0.94, and 0.38 mm, respectively. The QTB was 77% thicker than the ACL (P < .001), while the BPTB was 28% thinner than the ACL (P = .017). The mean ligament attachment angles of the femoral ACL, QTB, and BPTB were 20.3°, 30.2°, and 33.3°, respectively, and the QTB and the BPTB were 49% and 64% larger, respectively, than the ACL. The mean cGBAs of the femoral ACL, QTB, and BPTB were 33.9°, 35.1°, and 12.3°, respectively. The BPTB was 64% smaller than the ACL, while there was no significant difference between the QTB and the ACL. The mean GBA was 57.7°. Conclusion: The insertion width and thickness were significantly greater and smaller in the QTB and BPTB grafts, respectively, than in the ACL. The relationship between GBA after ACL reconstruction and cGBA in knee extension indicates that at the femoral tunnel aperture, the BPTB can bend more than the QTB. Clinical relevance: QTB graft may allow more anatomic ACL reconstruction to be performed.
Keywords: anterior cruciate ligament; bone–patellar tendon–bone; enthesis; human cadaver; quadriceps tendon bone.

Year of publishing 2022

Latiff S, Olateju OI. Quantification and comparison of tenocyte distribution and collagen content in the commonly used autografts for anterior cruciate ligament reconstruction. Anat Cell Biol. 2022;55(3):304-310.

Abstract Anterior cruciate ligament is a commonly damaged ligament of the knee. Reconstruction of this ligament usually entails the use of graft harvested from the same subject (i.e., autografts). Several tendons, for example quadriceps, patellar or semitendinosus tendon can be used as an autograft. The composition of the tendons is similar to the anterior cruciate ligament but there is no data that directly compares the compositions of the quadriceps, patellar and semitendinosus tendons. This study quantified and compared the tenocyte distribution and collagen content of these tendons from cadavers of South Africans of European Ancestry. The tenocyte distribution and collagen content were assessed using the ImageJ software. The results showed similarities in the collagen content across the tendons in both sexes (P>0.05). The tenocyte distribution was significantly higher in the quadriceps (P=0.019) or semitendinosus (P=0.016) tendon than in the patellar tendon in the female but no difference was seen in the male (P=0.872). This shows that a large harvestable area may not be directly associated with a more abundant collagen content or tenocyte distribution in the tendon. However, sex-specific tenocyte distribution is an important observation that underpins the possible influence of underlying biological factors on the composition of each tendon and this requires further investigations. In all, this study will contribute to knowledge and assist orthopaedic surgeons in making an informed decision on the choice of graft.
Keywords: Anterior cruciate ligament; Autografts; Collagen; Tendons; Tenocytes.

Year of publishing 2022

Yuksel Y, Kose O, Torun E, Ergun T, Yardibi F, Sarikcioglu L. Estimating the adequacy of the free quadriceps tendon autograft length using anthropometric measures in anterior cruciate ligament reconstruction. Arch Orthop Trauma Surg. 2022;142(8):2001-2010.

Objective: This prospective study aimed to predict the adequacy of free quadriceps tendon (QT) autograft length using simple anthropometric measures. Materials and methods: One hundred and eighty-four consecutive patients who underwent knee high-resolution MRI were enrolled in this study. The QT and native anterior cruciate ligament (ACL) length were measured using the oblique sagittal section. The adequate free QT length was calculated using the native ACL length and 30 mm for femoral and tibial tunnels in each patient. A QT shorter than the calculated length was considered inadequate. Age, sex, height, weight, body mass index, thigh circumference, and activity score were used to predict the adequacy of QT length with regression analysis. Results: There were 92 men and 92 women with a mean age of 34.1 ± 8.0 years (range 18-45). The mean QT and ACL lengths were 69.0 ± 8.8 mm (range 48.1-90.3 mm) and 35.6 ± 2.5 mm (range 29.2-42.6 mm), respectively. The QT and the ACL lengths were longer in men (p < 0.001 for both). Twenty-three men and 39 women (total: 62, 33.7%) had inadequate QT length for a free QT autograft, and 6 patients (3 males, 3 females, 3.3%) had inadequate QT length with the bone block technique. There was a weak positive correlation between QT length and height (p < 0.001), weight (p < 0.001), and activity score (p = 0.007). Height was the only independent variable that predicted the QT length adequacy (r2 = 0.051, p = 0.009) but ROC analysis showed that height did not have an ability to detect a subject with an inadequate QT length (AUC: 0.384, 95% CI 0.300-0.468). Conclusions: Free QT autografts may be inadequate in one-third of the patients, while a QT autograft with a bone block is almost always sufficient. Inadequate free QT autograft is more common in women. Although QT length correlated with height, it cannot be used as an accurate diagnostic tool to identify patients with an inadequate QT autograft. Preoperative measurement of the ACL and QT lengths by MRI might be beneficial to decide whether QT is usable, especially when harvesting without a bone block. Level of evidence: Level II, diagnostic, prospective cohort study.
Keywords: Anterior cruciate ligament; Anthropometrics; Autograft; Graft; Quadriceps tendon; Reconstruction.

Year of publishing 2023

Yiannakopoulos CK, Theotokatos G, Vlastos I, Sachinis NP, Gianzina E, Kalinterakis G, Papakonstantinou O. Morphometric MRI Evaluation of Three Autografts Used in Anterior Cruciate Ligament Reconstruction in Athletes. J Funct Morphol Kinesiol. 2023;8(1):14.

Abstract The purpose of the present study was to quantify the morphometric characteristics of three tendon autografts (hamstring tendons (HT), quadriceps tendon (QT), and patellar tendon (PT)) used in anterior cruciate ligament (ACL) reconstruction. For this purpose, knee magnetic resonance imaging (MRI) was obtained in 100 consecutive patients (50 males and 50 females) with an acute, isolated ACL tear without any other knee pathology were used. The level of the physical activity of the participants was determined using the Tegner scale. Measurements of the tendons' dimensions (PT and QT tendon length, perimeter, cross-sectional area (CSA), and maximum mediolateral and anteroposterior dimensions) were performed perpendicular to their long axes. Higher values were recorded as regards the mean perimeter and CSA of the QT in comparison with the PT and the HT (perimeter QT: 96.52 ± 30.43 mm vs. PT: 63.87 ± 8.45 mm, HT: 28.01 ± 3.73 mm, F = 404.629, p < 0.001; CSA QT: 231.88 ± 92.82 mm2 vs. PT: 108.35 ± 28.98 mm2, HT: 26.42 ± 7.15 mm2, F = 342.415, p < 0.001). The length of the PT was shorter in comparison with the QT (53.1 ± 7.8 vs. 71.7 ± 8.6 mm, respectively, t = -11.243, p < 0.001). The three tendons showed significant differences in relation to sex, tendon type, and position as regards the perimeter, CSA, and the mediolateral dimensions but not for the maximum anteroposterior dimension.
Keywords: anterior cruciate ligament; autograft; magnetic resonance imaging; morphometry.

Year of publishing 2023

Gupton M, Imonugo O, Terreberry RR. Anatomy, Bony Pelvis and Lower Limb, Knee. In: StatPearls. Treasure Island (FL):2022.


The knee is the largest joint in the body. It is a compound synovial joint that consists of the tibiofemoral joint and the patellofemoral joint. It primarily serves as a hinge joint which allows flexion and extension as well as various other movements. It joins the lower leg and thigh bilaterally and is an essential component of efficient bipedal movements such as walking, running, and jumping. The anatomical function and stability of the knee depend on muscles, bones, ligaments, cartilage, synovial tissue, synovial fluid, and other connective tissues. The 4 main stabilizing ligaments of the knee are the anterior cruciate (ACL), posterior cruciate (PCL), medial collateral (MCL), and lateral collateral (LCL). The ACL attaches at the lateral condyle of the femur and the intercondyloid eminence of the tibia and functions to prevent anterior translation of the tibia on the femur. The PCL attaches at the medial condyle of the femur and the posterior intercondylar area of the tibia and functions to prevent forward displacement of the femur on the tibia. The MCL attaches at the medial epicondyle of the femur and the medial condyle of the tibia and functions to prevent valgus stress on the knee. The LCL attaches at the lateral epicondyle of the femur and the head of the fibula and functions to prevent varus stress on the knee. The medial and lateral menisci are 2 separate fibrocartilage structures that are located between the articular surfaces of the tibia and femur. They function as shock absorbers, static stabilizers, and friction reducers during articulation. The knee’s bony structures include the distal end of the femur, proximal end of the tibia, and patella. The patella is the largest sesamoid bone in the body and functions as an attachment point for the quadriceps tendon and patellar ligament. It also protects the anterior articular surface of the femoral portion of the knee. The knee contains multiple bursas, which serve to reduce friction between structures of the knee. Bursas are small sacs made up of synovial membranes and contain synovial fluid. Many of these structures mentioned above are part of the articular capsule, which serves to stabilize the knee further and contain synovial fluid. Synovial fluid is made by synovial membranes and serves to reduce friction between articular surfaces of the knee.

Year of publishing 2022

Takeuchi S, Byrne KJ, Kanto R, Onishi K, Fu FH. Morphological Evaluation of the Quadriceps Tendon Using Preoperative Ultrasound in Anterior Cruciate Ligament Reconstruction. Am J Sports Med. 2022;50(1):111-117.

Background: An evaluation of quadriceps tendon (QT) morphology preoperatively is an important step when selecting an individually appropriate autograft for anterior cruciate ligament (ACL) reconstruction. However, to our knowledge, there are no studies that have assessed the morphology of the entire QT in an ACL-injured knee preoperatively using ultrasound. Abtract Purpose: We aimed to investigate the morphological characteristics of the QT using preoperative ultrasound in ACL-injured knees. Study design: Cross-sectional study; Level of evidence, 3. Methods: A total of 33 patients (mean age, 26.0 ± 11.5 years) with a diagnosed ACL tear undergoing primary ACL reconstruction were prospectively included. Using ultrasound, short-axis images of the QT were acquired in 10-mm increments from 30 to 100 mm proximal to the superior pole of the patella. The length of the QT was determined by 2 contiguous images that did and did not contain the rectus femoris muscle belly. The width of the superficial and narrowest parts of the QT, the thickness of the central and thickest parts of the QT, and the cross-sectional area at the central 10 mm of the superficial QT width were measured at each assessment location. The estimated intraoperative diameter of the QT autograft was calculated using a formula provided in a previous study. Results: There were no significant relationships between QT morphology and any of the demographic data collected. The length of the QT was less than 70 mm in 45.5% of patients (15/33). The width, thickness, cross-sectional area, and estimated intraoperative diameter of the QT autograft were significantly greater at 30 mm than at 70 mm proximal to the superior pole of the patella. Conclusion: Preoperative ultrasound may identify a QT that is too small for an all-soft tissue autograft in ACL reconstruction. Furthermore, harvesting a QT with a fixed width may result in autografts that are smaller proximally than they are distally. Assessing the morphology of the QT preoperatively using ultrasound may help surgeons to adequately reconstruct the native length and diameter of the ACL with a QT autograft.
Keywords: ACL reconstruction; graft size measurement; morphology; preoperative planning; quadriceps tendon; ultrasound.

Year of publishing 2021

Takeuchi S, Rothrauff BB, Taguchi M, Kanto R, Onishi K, Fu FH. In situ cross-sectional area of the quadriceps tendon using preoperative magnetic resonance imaging significantly correlates with the intraoperative diameter of the quadriceps tendon autograft. Knee Surg Sports Traumatol Arthrosc. 2021;29(3):742-749.

Purpose: Preoperative assessment to determine the sizes of potential autografts is necessary for individualized anterior cruciate ligament reconstruction (ACLR). However, no study has investigated the prediction of the intraoperative diameter of the quadriceps tendon (QT) autograft based upon preoperative imaging. This study investigated the correlation between the intraoperative diameter of a QT autograft and in situ thickness or cross-sectional area (CSA) measured using preoperative MRI. Methods: Thirty-one knees of 31 patients (mean age 20.9 ± 5.0 years) who underwent individualized anatomic ACLR using all soft tissue QT autograft were included retrospectively. At 15 mm proximal to the superior pole of the patella, the maximum QT thickness was assessed in the sagittal plane and the CSA was assessed at the central 10 mm of the QT in the axial plane. The angle between the axial plane and a line perpendicular to the QT longitudinal axis was used to calculate an adjusted CSA using a cosine function. Intraoperatively, each QT autograft was harvested with 10 mm width and the diameter was measured using a graft sizing device. Results: Intra- and inter-observer reliabilities of all measurements using preoperative MRI were excellent (intra-class correlation coefficient, 0.833-0.970). Significant correlations were observed between the thickness, CSA, or adjusted CSA, and the intraoperative diameter (R = 0.434, 0.607, and 0.540, respectively; P < 0.05). Conclusions: The CSA correlated most strongly with the QT autograft diameter. For individualized anatomic ACLR, measuring in situ CSA can be useful for preoperative planning of appropriate graft choices prior to surgery. Level of evidence: III.
Keywords: ACL reconstruction; Graft size measurement; MRI; Preoperative planning; Quadriceps tendon autograft.

Year of publishing 2021

Takeuchi S, Rothrauff BB, Taguchi M, Onishi K, Fu FH. Preoperative ultrasound predicts the intraoperative diameter of the quadriceps tendon autograft more accurately than preoperative magnetic resonance imaging for anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc. 2022;30(1):52-60.

Purpose: Sizing of potential autografts is essential to match the native anterior cruciate ligament (ACL) dimensions when performing ACL reconstruction (ACLR). We aimed to investigate the accuracy and reliability of the thickness and cross-sectional area (CSA) assessments for the prediction of the intraoperative diameter of the QT autograft using preoperative ultrasound and MRI. Methods: Thirty patients (mean age ± standard deviation, 19.9 ± 5.0 years), who underwent ACLR using QT autograft, were included. The maximum thickness of the QT was assessed at 15 and 30 mm proximal using ultrasound with a long axis image, and at 15 mm proximal to the superior pole of the patella using MRI with a sagittal image. The CSA was assessed at the central 10 mm of the medial-lateral QT width at 30 mm proximal using ultrasound with a short axis image, and at 15 mm proximal to the superior pole of the patella using MRI with an axial image. Intraoperatively, QT autograft was harvested with a 10 mm width and the diameter was measured using a graft sizing device. Results: Intra- and inter-observer reliabilities of all measurements using ultrasound and MRI were good (Intra-class correlation coefficient, 0.720-0.941). Correlation coefficient with the intraoperative diameter of the QT autograft was higher in ultrasound (R = 0.738-0.791, P < 0.001) than MRI (R = 0.449-0.543, P = 0.002-0.013). Conclusions: Preoperative ultrasound predicted the intraoperative diameter of the QT autograft more accurately than MRI. Ultrasound may be used clinically to assure a sufficiently large QT autograft diameter to match the diameter of the patient's native ACL. Level of evidence: Level III.
Keywords: ACL reconstruction; Graft size measurement; MRI; Preoperative planning; Quadriceps tendon autograft; Ultrasound.

Year of publishing 2021

Raja BS, Gupta K, V A, Singh S, Maji S. Assessment of thickness of in vivo autograft tendons around the knee and its correlation with anthropometric data, thickness of patella and anterior cruciate ligament tibial foot print diameter. Anat Cell Biol. 2021;54(1):18-24.

Inadequate diameters of the autograft tendons are known to be a major cause of graft failure in ligament reconstruction. The purpose of the study was to measure the in-vivo thickness of the available autograft options around the knee and to seek a correlation between the thickness of the tendons and the anthropometric data, patellar thickness and anterior cruciate ligament (ACL) footprint sagittal diameter. Magnetic resonance imaging of 104 consecutive patients with suspected knee injuries were utilized for measurement of the in vivo thickness of pes anserinus tendon (diameter and cross-sectional area [CSA]), patellar tendon (PT) and quadriceps tendon (QT). Pearson's coefficient was used to find out the relationship between the tendon thickness and anthropometric data, thickness of patella and ACL tibial foot print sagittal diameter. The mean diameters and CSA of the semitendinosus tendon (ST) and gracilis tendon (GT) were 3.77±0.49 mm, 11.62±1.62 mm2 and 2.87±0.27 mm, 6.64±1.18 mm2 respectively. QT and PT thicknesses were 7.36±0.87 mm and 4.50±0.62 mm respectively. Height and the patellar thickness were seen to have moderate correlation with ST and PT thickness. Weak correlation was seen between the other anthropometric variables and tendon thickness. Magnetic resonance imaging (MRI) assessment of tendon sizes is a reliable method with good inter and intra-rater agreement. Assessment of these anatomical structures with help of MRI would be helpful in preoperative planning and can help in identifying those patients at risk of having smaller tendons.
Keywords: Anterior cruciate ligament reconstruction; Arthroscopy; Hamstring tendons; Magnetic resonance imaging; Patellar ligament.

Year of publishing 2020

Ugwuoke A, Syed F, El-Kawy S. Predicting adequacy of free quadriceps tendon autograft, for primary and revision ACL reconstruction, from patients' physical parameters. Knee Surg Sports Traumatol Arthrosc. 2020;28(2):448-453.

Purpose: Free quadriceps tendon autograft (QTA) has gained popularity for both primary and revision ACL reconstruction. The aim of this study is to measure the dimensions of quadriceps tendon and determine its correlation with patient's height, weight and BMI. This is to provide a guide for patients and surgeons in predicting the suitability of QTA for ACL reconstructions. Methods: A cross-sectional study in which the length and thickness of the quadriceps tendon was measured in 51 Caucasian patients who underwent primary total knee arthroplasty. Exclusion criteria include non-Caucasians and previous tendon pathology. Patients were selected from routine elective total knee arthroplasty list. Tendon length is taken from musculotendinous junction to its insertion. Thickness was measured at midpoint and at distal insertion. Patients' height, weight and BMI were recorded. The correlation between patient physical parameters and tendon dimensions were determined. Results: Subjects' median age was 65 years (range 44-87), with 34 females and 17 males. Median length of the tendon was 9 mm (range 70-110), and median insertional thickness was 9 mm (7-10 mm). Median thickness at midpoint was 7 mm (range 4-10 mm). There was moderately positive correlation between subjects' height and tendon length (correlation coefficient 0.50), and also between weight and tendon length (correlation coefficient 0.47). There was no significant correlation between subjects' BMI and the tendon length. There was also no significant correlation between tendon thickness and subject's physical parameters. Conclusion: This study has shown that most patients could provide adequate QTA for ACL reconstruction. It also points to the fact that no investigation is required to predict the adequacy of QTA. Though further studies with larger sample size are required to confirm this, clinician can rely on analysing patients' physical parameter in predicting the adequacy of QTA for ACL reconstruction. Level of evidence: II.
Keywords: ACL reconstruction; Bone–patellar tendon–bone graft; Donor site morbidity; Free quadriceps tendon autograft; Hamstring autograft.

Year of publishing 2020

Yamasaki S, Hashimoto Y, Han C, Nishino K, Hidaka N, Nakamura H. Patients with a quadriceps tendon shorter than 60 mm require a patellar bone plug autograft in anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthrosc. 2021;29(6):1927-1935

Purpose: To assess the length and thickness of the quadriceps tendon (QT) and anterior cruciate ligament (ACL) to predict the required QT length for individual ACL reconstruction. Methods: Thirty patients (9 females, 21 males; mean age 24.5 years; mean height 169.3 cm) who underwent ACL reconstruction using the QT with a bone plug autograft were enrolled. The length and thickness of the QT on preoperative magnetic resonance imaging (MRI) were compared with those measured under direct visualization. The ACL length was measured on preoperative MRI and three-dimensional computed tomography after ACL reconstruction. The QT length on MRI was compared with the required graft length, and the factors related to an adequate QT length were assessed. Results: The mean QT length on MRI was 60.8 ± 1.3 mm and was significantly positively correlated with the QT length under direct visualization (P < 0.01). On MRI, the mean ACL length was 30.8 ± 1.2 mm and the mean QT thickness was 6.3 ± 0.2 mm. Although the mean QT was 0.1 mm longer than the mean required graft length, the QT on MRI was shorter than the required graft length in 37% of patients (11/30). Adequate QT length was related to a QT length of more than 60 mm, but not to age, sex, height, or ACL length. Conclusion: Although preoperative MRI predicted the required QT length for ACL reconstruction, 37% of patients lacked an adequate QT length, and a QT shorter than 60 mm required the addition of patellar bone. Level of evidence: III.

Year of publishing 2008

Hadjicostas PT, Soucacos PN, Koleganova N, Krohmer G, Berger I. Comparative and morphological analysis of commonly used autografts for anterior cruciate ligament reconstruction with the native ACL: an electron, microscopic and morphologic study. Knee Surg Sports Traumatol Arthrosc. 2008;16(12):1099-107.

Ligaments and tendons are similar in composition but differ in proportion and arrangement. Tendons are being used as grafts for the ACL reconstruction. Their microscopic structure has not been sufficiently studied and compared to the native ACL. A null hypothesis was declared stating that the anterior cruciate ligament should be histological, morphologically and functionally different from the tendon grafts used for ACL reconstruction. We investigated similarities and differences of the structure of ACL and tendons used as a graft tissue for ACL reconstruction. In this study, standardized samples of quadriceps, hamstrings (semitendinosus and gracilis) and patellar tendons, and the ACL were harvested from 26 autopsies (average age 36.4) and were investigated using light and electron microscopy, immunohistochemistry and morphometry. The thickness of the collagen fibrils, collagen organization and diameter, the fibril/interstitium ratio, density of fibroblasts and blood vessels, and distribution of the collagen type I, III and V fibrils were analyzed. The semitendinosus showed the highest density of fibroblasts and blood vessels, while the gracilis the highest fibril/interstitium ratio. No differences regarding the thickness of collagen fibrils and distribution of fibrils were found. The ACL had the highest concentration of type III and V collagen fibrils as well as elastic fibers. The histological and ultrastructural appearance of the ACL differs from those of the tendons used as graft, for ACL reconstruction. Its ultrastructure is varied and complex, with its collagen fibers bundles lying in many directions.

Year of publishing 2019

Xerogeanes JW. Quadriceps Tendon Graft for Anterior Cruciate Ligament Reconstruction: THE GRAFT OF THE FUTURE! Arthroscopy. 2019;35(3):696-697.

Anterior cruciate ligament (ACL) reconstruction is one of the most common orthopaedic surgeries performed on active people in the world. One of the most important surgical decisions is graft type for use in the reconstruction. Despite extensive research on optimal graft choice for ACL reconstruction, discrepancy exists among practicing surgeons' graft preference. Recently, the quadriceps tendon has gained popularity for use as a graft source for ACL reconstruction. The all soft tissue quadriceps graft offers many advantages over other autograft choices. Histologically it has 20% more collagen fibrils per cross-sectional area than the patellar tendon (PT). Biomechanically, its ultimate load is 70% > than that of a similar width PT graft, while its modulus is more similar to the native ACL than either the PT or hamstring graft. Anatomically the quadriceps tendon has significantly more volume than the PT. Thus, even after harvest of the quadriceps graft, the remaining quadriceps tendon is still 80% stronger than the intact PT! The length and cross-sectional area of the quadriceps tendon graft can be tailored to the needs of the patient. On any patient over 5 feet tall, a graft length of 7 cm can be obtained. Because the thickness of the tendon is almost twice the thickness of the same patient's PT, a graft diameter from 7 to 11 mm can easily be achieved. Thus, this graft can be customized for both primary and revision surgeries. Harvest site morbidity is minimal. An incision less than 2 cm in an area with no significant cutaneous nerves without harvest of any patella bone leads to no significant harvest site pain, numbness, or palpable defect. Clinical outcomes using this graft are excellent. Our prospective data on nearly 1,000 grafts, with a mean patient age of 20 years old, show a 4.2% failure rate. Thus, the all soft tissue quadriceps graft will be the surgical choice for ACL reconstruction for future athletes.