Anterior Cruciate Ligament Patellar Tendon Autograft Fixation at 0° Versus 30° Results in Improved Activity Scores and a Greater Proportion of Patients Achieving the Minimal Clinical Important Difference For Knee Injury and Osteoarthritis Outcome Score Pain: A Randomized Controlled Trial

Published:December 21, 2021DOI:


      The aim of the current study was to determine the effect of the knee flexion angle (KFA) during tibial anterior cruciate ligament (ACL) graft fixation on patient-reported outcomes, graft stability, extension loss, and reoperation after anatomic single-bundle ACL reconstruction.


      All 169 included patients (mean age 28.5 years, 65% male) were treated with anatomic single-bundle ACL reconstruction using patellar tendon autograft and were randomized to tibial fixation of the ACL graft at either 0° (n = 85) or 30° (n = 84). The primary outcome was the Knee Injury and Osteoarthritis Outcome Score (KOOS) 2 years after surgery. Secondary outcomes were the Marx Activity Scale (MAS), the rate of reoperation, and physical examination findings at 1 year, including KT-1000 and side-to-side differences in knee extension.


      The follow-up rate was 82% (n = 139) for the primary outcome. Graft failure rate at 2 years was 1% (n = 2, 1 per group). ACL tibial graft fixation at 0° or 30° did not have a significant effect on KOOS scores at 2 years after ACLR. Patients whose graft was fixed at a knee flexion angle of 0° had greater scores on the MAS (mean 9.6 95% confidence interval [CI] 8.5 to 10.6, versus 8.0, 95% CI 6.9 to 9.1; P = .04), and a greater proportion achieved the minimal clinical important difference (MCID) for the KOOS pain subdomain (94% versus 81%; P = .04). There was no significant difference in knee extension loss, KT-1000 measurements, or reoperation between the 2 groups.


      In the setting of anatomic single-bundle ACLR using patellar tendon autograft and anteromedial portal femoral drilling, there was no difference in KOOS scores between patients fixed at 0° and 30°. Patient fixed in full extension did demonstrate higher activity scores at 2 years after surgery and a greater likelihood of achieving the MCID for KOOS pain.

      Level of Evidence

      II, prospective randomized trial
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        • Iriuchishima T.
        • Shirakura K.
        • Fu F.H.
        Graft impingement in anterior cruciate ligament reconstruction.
        Knee Surg Sports Traumatol Arthrosc. 2013; 21: 664-670
        • Lubowitz J.H.
        Anatomic ACL reconstruction produces greater graft length change during knee range-of-motion than transtibial technique.
        Knee Surg Sports Traumatol Arthrosc. 2014; 22: 1190-1195
        • Brophy R.H.
        • Voos J.E.
        • Shannon F.J.
        • et al.
        Changes in the length of virtual anterior cruciate ligament fibers during stability testing: A comparison of conventional single-bundle reconstruction and native anterior cruciate ligament.
        Am J Sports Med. 2008; 36: 2196-2203
        • Lee J.S.
        • Kim T.H.
        • Kang S.Y.
        • et al.
        How isometric are the anatomic femoral tunnel and the anterior tibial tunnel for anterior cruciate ligament reconstruction?.
        Arthroscopy. 2012; 28: 1504-1512
        • Kim Y.K.
        • Yoo J.D.
        • Kim S.W.
        • Park S.H.
        • Cho J.H.
        • Lim H.M.
        Intraoperative graft isometry in anatomic single-bundle anterior cruciate ligament reconstruction.
        Knee Surg Relat Res. 2018; 30: 115-120
        • Riboh J.C.
        • Hasselblad V.
        • Godin J.A.
        • Mather 3rd, R.C.
        Transtibial versus independent drilling techniques for anterior cruciate ligament reconstruction: A systematic review, meta-analysis, and meta-regression.
        Am J Sports Med. 2013; 41: 2693-2702
        • Austin J.C.
        • Phornphutkul C.
        • Wojtys E.M.
        Loss of knee extension after anterior cruciate ligament reconstruction: Effects of knee position and graft tensioning.
        J Bone Joint Surg Am. 2007; 89: 1565-1574
        • Gertel T.H.
        • Lew W.D.
        • Lewis J.L.
        • Stewart N.J.
        • Hunter R.E.
        Effect of anterior cruciate ligament graft tensioning direction, magnitude, and flexion angle on knee biomechanics.
        Am J Sports Med. 1993; 21: 572-581
        • Mae T.
        • Shino K.
        • Nakata K.
        • Toritsuka Y.
        • Otsubo H.
        • Fujie H.
        Optimization of graft fixation at the time of anterior cruciate ligament reconstruction. Part II: Effect of knee flexion angle.
        Am J Sports Med. 2008; 36: 1094-1100
        • Yoo Y.S.
        • Jeong W.S.
        • Shetty N.S.
        • Ingham S.J.
        • Smolinski P.
        • Fu F.
        Changes in ACL length at different knee flexion angles: An in vivo biomechanical study.
        Knee Surg Sports Traumatol Arthrosc. 2010; 18: 292-297
        • McEwen P.J.C.
        • McArthur M.
        • Brereton S.G.
        • O’Callaghan W.B.
        • Wilkinson M.P.R.
        Flexion deformity and laxity as a function of knee position at the time of tensioning of rigid anatomic hamstring ACL grafts.
        Asia Pac J Sports Med Arthrosc Rehabil Technol. 2020; 22: 67-73
      1. Adouni M, Faisal T, Dhaher Y. Effect of surgical design variations on the knee contact behavior during anterior cruciate ligament reconstruction. J Knee Surg. Online ahead of print.

        • Asahina S.
        • Muneta T.
        • Ishibashi T.
        • Yamamoto H.
        Effects of knee flexion angle at graft fixation on the outcome of anterior cruciate ligament reconstruction.
        Arthroscopy. 1996; 12: 70-75
        • Pereira V.L.
        • Medeiros J.V.
        • Nunes G.R.S.
        • de Oliveira G.T.
        • Nicolini A.P.
        Tibial-graft fixation methods on anterior cruciate ligament reconstructions: A literature review.
        Knee Surg Relat Res. 2021; 33: 7
        • Debandi A.
        • Maeyama A.
        • Hoshino Y.
        • et al.
        The influence of knee flexion angle for graft fixation on rotational knee stability during anterior cruciate ligament reconstruction: A biomechanical study.
        Arthroscopy. 2016; 32: 2322-2328
        • Ohuchi H.
        Editorial Commentary: Full extension or 30 degrees flexion in graft fixation for anatomic anterior cruciate ligament reconstruction. Is this surgeons’ preference?.
        Arthroscopy. 2016; 32: 2329-2330
        • McRae S.M.
        • Chahal J.
        • Leiter J.R.
        • Marx R.G.
        • Macdonald P.B.
        Survey study of members of the Canadian Orthopaedic Association on the natural history and treatment of anterior cruciate ligament injury.
        Clin J Sport Med. 2011; 21: 249-258
        • Schulz K.F.
        • Altman D.G.
        • Moher D.
        Group C. CONSORT 2010 Statement: Updated guidelines for reporting parallel group randomised trials.
        J Clin Epidemiol. 2010; 63: 834-840
        • Kellgren J.H.
        • Lawrence J.S.
        Radiological assessment of osteo-arthrosis.
        Ann Rheum Dis. 1957; 16: 494-502
        • McCarty L.P.
        • Bach Jr., B.R.
        Rehabilitation after patellar tendon autograft anterior cruciate ligament reconstruction.
        Tech Orthop. 2005; 20: 439-451
        • Roos E.M.
        • Roos H.P.
        • Lohmander L.S.
        • Ekdahl C.
        • Beynnon B.D.
        Knee Injury and Osteoarthritis Outcome Score (KOOS)--development of a self-administered outcome measure.
        J Orthop Sports Phys Ther. 1998; 28: 88-96
        • Roos E.M.
        • Engelhart L.
        • Ranstam J.
        • et al.
        ICRS recommendation document: Patient-reported outcome instruments for use in patients with articular cartilage defecs.
        Cartilage. 2011; 2: 122-136
        • Marx R.G.
        • Stump T.J.
        • Jones E.C.
        • Wickiewicz T.L.
        • Warren R.F.
        Development and evaluation of an activity rating scale for disorders of the knee.
        Am J Sports Med. 2001; 29: 213-218
        • Pugh L.
        • Mascarenhas R.
        • Arneja S.
        • Chin P.Y.
        • Leith J.M.
        Current concepts in instrumented knee-laxity testing.
        Am J Sports Med. 2009; 37: 199-210
        • Schlegel T.F.
        • Boublik M.
        • Hawkins R.J.
        • Steadman J.R.
        Reliability of heel-height measurement for documenting knee extension deficits.
        Am J Sports Med. 2002; 30: 479-482
        • Shelbourne K.D.
        • Freeman H.
        • Gray T.
        Osteoarthritis after anterior cruciate ligament reconstruction: The importance of regaining and maintaining full range of motion.
        Sports Health. 2012; 4: 79-85
        • Frobell R.B.
        • Roos E.M.
        • Roos H.P.
        • Ranstam J.
        • Lohmander L.S.
        A randomized trial of treatment for acute anterior cruciate ligament tears.
        N Engl J Med. 2010; 363: 331-342
        • Muller B.
        • Yabroudi M.A.
        • Lynch A.
        • et al.
        Defining thresholds for the patient acceptable symptom state for the IKDC Subjective Knee Form and KOOS for patients who underwent ACL reconstruction.
        Am J Sports Med. 2016; 44: 2820-2826
        • Ingelsrud L.H.
        • Terwee C.B.
        • Terluin B.
        • et al.
        Meaningful change scores in the Knee Injury and Osteoarthritis Outcome Score in patients undergoing anterior cruciate ligament reconstruction.
        Am J Sports Med. 2018; 46: 1120-1128
        • Hoher J.
        • Kanamori A.
        • Zeminski J.
        • Fu F.H.
        • Woo S.L.
        The position of the tibia during graft fixation affects knee kinematics and graft forces for anterior cruciate ligament reconstruction.
        Am J Sports Med. 2001; 29: 771-776
        • Betsch M.
        • Hoit G.
        • Dwyer T.
        • et al.
        Postoperative pain is associated with psychological and physical readiness to return to sports one-year after anterior cruciate ligament reconstruction.
        Arthrosc Sports Med Rehab. 2021; 3: e1737-e1743
        • DeFroda S.F.
        • Karamchedu N.P.
        • Budacki R.
        • et al.
        Evaluation of graft tensioning effects in anterior cruciate ligament reconstruction between hamstring and bone-patellar tendon bone autografts.
        J Knee Surg. 2021; 34: 777-783
        • Yoshiya S.
        • Kurosaka M.
        • Ouchi K.
        • Kuroda R.
        • Mizuno K.
        Graft tension and knee stability after anterior cruciate ligament reconstruction.
        Clin Orthop Relat Res. 2002; : 154-160
        • van Kampen A.
        • Wymenga A.B.
        • van der Heide H.J.
        • Bakens H.J.
        The effect of different graft tensioning in anterior cruciate ligament reconstruction: A prospective randomized study.
        Arthroscopy. 1998; 14: 845-850
        • Nicholas S.J.
        • D’Amato M.J.
        • Mullaney M.J.
        • Tyler T.F.
        • Kolstad K.
        • McHugh M.P.
        A prospectively randomized double-blind study on the effect of initial graft tension on knee stability after anterior cruciate ligament reconstruction.
        Am J Sports Med. 2004; 32: 1881-1886
        • Kirwan G.W.
        • Bourke M.G.
        • Chipchase L.
        • Dalton P.A.
        • Russell T.G.
        Initial graft tension and the effect on postoperative patient functional outcomes in anterior cruciate ligament reconstruction.
        Arthroscopy. 2013; 29: 934-941
        • Ghodadra N.S.
        • Mall N.A.
        • Grumet R.
        • et al.
        Interval arthrometric comparison of anterior cruciate ligament reconstruction using bone-patellar tendon-bone autograft versus allograft: Do grafts attenuate within the first year postoperatively?.
        Am J Sports Med. 2012; 40: 1347-1354
        • Whelan D.B.
        • Dainty K.
        • Chahal J.
        Efficient designs: Factorial randomized trials.
        J Bone Joint Surg Am. 2012; 94: 34-38