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Clinical Policy Bulletin:
Knee Ligament Arthrometer Testing
Number: 0397


Aetna considers knee ligament arthrometer testing experimental and investigational for evaluating ligament laxity in the knee or for other indications because the peer-reviewed medical literature does not support the clinical value of this testing.


There are a number of commercially available knee arthrometers.  These devices provide computerized measurements of knee laxity.  Knee ligament arthrometer testing can not replace the need for a physical examination and/or magnetic resonance imaging (MRI).

According to the manufacturer of one of the commercially available arthrometers, the KT1000™ (MEDmetric® Corporation, San Diego, CA) was developed to provide objective measurement of the sagittal plane motions of the tibia relative to the femur.  This motion, sometimes referred to as drawer motion, occurs when an examiner applies force to the lower limb or when the muscles of the quadriceps are contracted.  Although the KT1000 (or KT2000) and other knee ligament arthrometers have been employed for research purposes for quantifying outcomes of anterior cruciate ligament reconstruction, the peer-reviewed medical literature does not support its reliability, reproducibility, and clinical utility in the general clinical setting.

Spindler et al (2004) performed a evidence-based systematic review of randomized controlled trials assessing patellar tendon versus hamstring tendon autografts.  Objective and subjective outcome measures included surgical technique, rehabilitation, instrumented laxity, isokinetic strength, patello-femoral pain, return to pre-injury activity, as well as Tegner, Lysholm, Cincinnati, and International Knee Documentation Committee-1991 scores.  Slight increased laxity on arthrometer testing was observed in the hamstring population in 3 of 7 studies.  Pain with kneeling was greater for the patellar tendon population in 4 of 4 studies.  Only 1 of 9 studies reported increased anterior knee pain in the patellar tendon group.  Frequency of additional surgery seemed to be related to the fixation method and not graft type.  No study showed a significant difference in graft failure between patellar tendon and hamstring tendon autografts.  Objective differences (e.g., range of motion, isokinetic strength, arthrometer testing) were not detected between groups in the majority of studies, suggesting that their sensitivity to detect clinical outcomes may be limited.

Papannagari et al (2006) stated that recent follow-up studies have reported a high incidence of joint degeneration in patients with anterior cruciate ligament (ACL) reconstruction.  Abnormal kinematics after ACL reconstruction have been thought to contribute to the degeneration.  These investigators hypothesized that ACL reconstruction, which was designed to restore anterior knee laxity under anterior tibial loads, does not reproduce knee kinematics under in-vivo physiological loading conditions.  In a controlled laboratory study, these researchers examined both knees of 7 patients with complete unilateral rupture of the ACL with magnetic resonance image, and constructed 3D models from these images.  The ACL of the injured knee was arthroscopically reconstructed using a bone-patellar tendon-bone autograft.  Three months after surgery, the kinematics of the intact contralateral and reconstructed knees were measured using a dual-orthogonal fluoroscopic system while the subjects performed a single-legged weight-bearing lunge.  The anterior laxity of both knees was measured using a KT-1000 arthrometer.  The anterior laxity of the reconstructed knee as measured with the arthrometer was similar to that of the intact contralateral knee.  However, under weight-bearing conditions, there was a statistically significant increase in anterior translation of the reconstructed knee compared with the intact knee at full extension (approximately 2.9 mm) and 15 degrees (approximately 2.2 mm) of flexion.  Furthermore, there was a mean increase in external tibial rotation of the ACL-reconstructed knee beyond 30 degrees of flexion (approximately 2 degrees at 30 degrees of flexion), although no statistical significance was detected.  The authors concluded that the data showed that although anterior laxity was restored during KT-1000 arthrometer testing, ACL reconstruction did not restore normal knee kinematics under weight-bearing loading conditions.

Wiertsema et al (2008) examined the reliability of the KT1000 arthrometer and the Lachman test in patients with an ACL rupture.  A total of 20 patients with a complete tear of the ACL were examined in a single session each.  During the assessment, 2 physical therapists measured the anterior-posterior translation of the knee using both the KT1000 arthrometer and the Lachman test.  One examiner performed a repeated measurement of each test for determination of intra-rater reliability.  The examiners were blinded to the findings of their colleague.  The intraclass correlation coefficient (ICC) was used to describe the degree of reliability of the measurements.  High ICCs were found for the intra-rater reliability and the inter-rater reliability of the Lachman test (ICC = 1.0 and 0.77).  For the KT1000 arthrometer both ICCs were clearly lower (ICC = 0.47 and 0.14).  The KT1000 arthrometer showed inadequate reliabilities, even when measurements are repeated within a single measurement session.  Contrastingly, the Lachman test is a reliable measurement to determine the anterior-posterior laxity of the ACL deficit knee.  The results of the present study suggested good within-session intra-rater reliability as well as inter-rater reliability for the Lachman test.

An UpToDate review on “Anterior cruciate ligament injury” (Friedberg, 2013) states that “The KT-1000 knee ligament arthrometer is a device that provides an objective measurement of anterior-posterior translation and is often used in studies evaluating ACL tears.  This machine is seldom used in clinical practice because physical examination is generally reliable.  Due to the high sensitivity of the Lachman and the high specificity of the pivot shift, we suggest performing both tests to confirm an ACL rupture. The combination of a positive Lachman and a negative pivot shift can mean the ACL is partially torn”.

CPT Codes / HCPCS Codes / ICD-9 Codes
There are no specific codes for knee ligament arthrometer testing:
CPT codes not covered for indications listed in the CPB:
Other CPT codes related to the CPB:
ICD-9 codes related to the CPB:
717.81 Old disruption of lateral collateral ligament
717.82 Old disruption of medial collateral ligament
717.83 Old disruption of anterior cruciate ligament
717.84 Old disruption of posterior cruciate ligament
717.85 Old disruption of other ligaments of knee
717.89 Other internal derangement of knee
728.4 Laxity of ligament
844.0 Sprain and strain of lateral collateral ligament of knee
844.1 Sprain and strain of medial collateral ligament of knee
844.2 Sprain and strain of cruciate ligament of knee
844.3 Sprain and strain of tibiofibular (joint) (ligament), superior

The above policy is based on the following references:
  1. Cherney S. Disorders of the knee. In: Principles of Orthopaedic Practice. Vol. II. R Dee, E Mango, LC Hurst, eds. New York, NY: McGraw Hill; 1989: 1286.
  2. Daniel DM, et al. Ligament surgery: The evaluation of results. In: Knee Ligaments: Structure, Function, Injury, and Repair. DM Daniel, WA Akeson, JJ O'Connor, eds. New York, NY: Raven Press; 1990: 521-534.
  3. Noyes FR, Mangine RE, Barber S. Early knee motion and after open and arthroscopic anterior cruciate ligament reconstruction. Am J Sports Med. 1987;15(2):149-160.
  4. Graham GP, Johnson S, Dent CM, Fairclough JA. Comparison of clinical tests and the KT1000 in the diagnosis of anterior cruciate ligament rupture. Br J Sports Med. 1991;25(2):96-97.
  5. Torzilli PA, Panariello RA, Forbes A, et al. Measurement reproducibility of two commercial knee test devices. J Orthop Res. 1991;9(5):730-737.
  6. Rink PC, Scott RA, Lupo RL, Guest SJ. Team physician #7. A comparative study of functional bracing in the anterior cruciate deficient knee. Orthop Rev. 1989;18(6):719-727.
  7. Rijke AM, Perrin DH, Goitz HT, McCue FC 3rd. Instrumented arthrometry for diagnosing partial versus complete anterior cruciate ligament tears. Am J Sports Med. 1994;22(2):294-298.
  8. Liu SH, Osti L, Henry M, Bocchi L. The diagnosis of acute complete tears of the anterior cruciate ligament. J Bone Joint Surg Br. 1995;77(4):586-588.
  9. Adler GG, Hoekman RA, Beach DM. Drop leg Lachman test: A new test of anterior knee laxity. Am J Sports Med. 1995;23(3):320-323.
  10. Fiebert I, Gresley J, Hoffman S, Kunkel K. Comparative measurements of anterior tibial translation using the KT-1000 knee arthrometer with the leg in neutral, internal rotation, and external rotation. J Orthop Sports Phys Ther. 1994;19(6):331-334.
  11. Jonsson H, Karrholm J, Elmqvist LG. Laxity after cruciate ligament injury in 94 knees. Acta Orthop Scand. 1993;64(5):567-570.
  12. Forster IW, Warren-Smith CD, Tew M. Is the KT1000 knee ligament arthrometer reliable? J Bone Joint Surg. 1989;71(5):843-847.
  13. Huber FE, Irrgang JJ, Harner C, Lephart S. Intratester and intertester reliability of KT-1000. Am J Sports Med. 1997;25(4):479-485.
  14. Hewett TE, Noyes FR, Lee MD. Diagnosis of complete and partial posterior cruciate ligament ruptures. Stress radiography compared with KT-1000 arthrometer and posterior drawer testing. Am J Sports Med. 1997;25(5):648-655.
  15. Giannotti BF, Fanelli GC, Barrett TA, Edson C. The predictive value of intraoperative KT-1000 arthrometer measurements in single incision anterior cruciate ligament reconstruction. Arthroscopy. 1996;12(6):660-666.
  16. Barrett GR, Treacy SH. The effect of intraoperative isometric measurement on the outcome of anterior cruciate ligament reconstruction: A clinical analysis. Arthroscopy. 1996;12(6):645-651.
  17. Yunes M, Richmond JC, Engels EA, Pinczewski LA. Patellar versus hamstring tendons in anterior cruciate ligament reconstruction: A meta-analysis. Arthroscopy, 2001;17(3):248-257.
  18. MEDmetric® Corporation. KT1000 [website]. San Diego, CA: MEDmetric; updated May 2001. Available at: Accessed June 21, 2004.
  19. Komdeur P, Pollo FE, Jackson RW. Dynamic knee motion in anterior cruciate impairment: A report and case study. BUMC Proceedings. 2002;15:257-259.
  20. Gross SM, Carcia CR, Gansneder BM, Shultz SJ. Rate of force application during knee arthrometer testing affects stiffness but not displacement measurements. J Orthop Sports Phys Ther. 2004;34(3):132-139.
  21. Spindler KP, Kuhn JE, Freedman KB, et al. Anterior cruciate ligament reconstruction autograft choice: Bone-tendon-bone versus hamstring: Does it really matter? A systematic review. Am J Sports Med. 2004;32(8):1986-1995.
  22. Papannagari R, Gill TJ, Defrate LE, et al. In vivo kinematics of the knee after anterior cruciate ligament reconstruction: A clinical and functional evaluation. Am J Sports Med. 2006;34(12):2006-2012.
  23. Wiertsema SH, van Hooff HJ, Migchelsen LA, Steultjens MP. Reliability of the KT1000 arthrometer and the Lachman test in patients with an ACL rupture. Knee. 2008;15(2):107-110.
  24. Arneja S, Leith J. Review article: Validity of the KT-1000 knee ligament arthrometer. J Orthop Surg (Hong Kong). 2009;17(1):77-79.
  25. Friedberg RP. Anterior cruciate ligament injury. Last reviewed February 2013. UpToDate Inc. Waltham, MA.

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Copyright Aetna Inc. All rights reserved. Clinical Policy Bulletins are developed by Aetna to assist in administering plan benefits and constitute neither offers of coverage nor medical advice. This Clinical Policy Bulletin contains only a partial, general description of plan or program benefits and does not constitute a contract. Aetna does not provide health care services and, therefore, cannot guarantee any results or outcomes. Participating providers are independent contractors in private practice and are neither employees nor agents of Aetna or its affiliates. Treating providers are solely responsible for medical advice and treatment of members. This Clinical Policy Bulletin may be updated and therefore is subject to change.
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