1. Stress-radiography of the knee Anterior and posterior translation at 20° of flexion in 563 normal knees and 487 ACL deficient knees JL. LERAT, JL. BESSE, F. CHOTEL, F. CLADIERE, B. MOYEN Department of Orthopaedic Surgery and Sports Medicine Lyon – France

2. Aims of the study The measurements of anterior and posterior laxityThe measurements of anterior and posterior laxity –in normal knees –and in ACL deficient knees Diagnosis valueDiagnosis value Grading the knee play in order to choose adaptated surgeryGrading the knee play in order to choose adaptated surgery

3. Flexion : 90° Nyga : 1970 Kennedy, Fowler : 1971 Lerat : 1971 Jacobsen : 1976 Anterior stress-radiography

4. TORG introduced the "LACHMAN test" in 1976 Test practised since 1963 by TRILLAT in Lyon-France Anterior stress-radiography

5. 20° of flexion Lerat (manually) : 1979 Lerat (apparatus) : 1982 Stäubli, Jakob : 1982 Hooper : 1986 Iversen : 1988 apparatus l Manualy

6. Anterior and posterior stress-radiography The same apparatus is used for both anterior and posterior tests 20° of flexion20° of flexion Fixed load (9 kg)Fixed load (9 kg) Free translationFree translation Free rotationFree rotation Comfortable for the patientsComfortable for the patients

7. Anterior translation of the tibia Posterior tibial cortexPosterior tibial cortex as reference line as reference line Parallels tangent to the posterior aspect of the condylesParallels tangent to the posterior aspect of the condyles Distance between these tangent lines and theDistance between these tangent lines and the tibial compartments tibial compartments ATMC: Anterior Translation of Medial Compartment ATMC: Anterior Translation of Medial Compartment ATLC : Anterior Translation of Lateral Compartment ATLC : Anterior Translation of Lateral Compartment

8. Landmarks Lateral condyle : anterior notch and posterior angle

9. ATMC

10. ATLC

11. ATMC and ATLC ATMC and ATLC Anterior radiological drawer

12. PTMC = Posterior Translation of Medial Compartment PTMC = Posterior Translation of Medial Compartment PTLC = Posterior Translation of Lateral Compartment PTLC = Posterior Translation of Lateral Compartment Posterior translation of the tibia

13. 1050 knees measured 487 ACL insufficient knees 487 contra-lateral normal knees 76 normal subjects age : 27.5 ± 9 years ( 16-50 ) 70.5 % males, 29.5 % females no previous surgery no meniscus bucket-handle Materiel

14. 2100 X-ray films 4200 measurements One observer (JL L) methods

15. Interobserver intraclass correlation 3 observers 50 patients measured (ruptured ACL - normal knee) Intraobserver intraclass correlation 1 observer measured 50 patients twice Methods

16. Normal Deficient ACL ATMC0.91 (0.85 - 0.95) 0.95 (0.90 - 0.98) 0.97 (0.95 - 0.98) 0.98 (0.94 - 0.98) ATLC0.92 (0.85 - 0.95) 0.92 (0.85 - 0.95) 0.93 (0.89 - 0.96) 0.95 (0.92 - 0.97) Intra and interobserver intraclass correlation for ATMC and ATLC All values include 95 % confidence intervals

17. Right-left difference 38 normal subjects A nt T ransl M edial C omp : 0.5 ± 0.4 mm A nt T ransl L ateral C omp : 1.2 ± 0.4 mm P ost T ransl M edial C omp : 1.1 ± 0.7 mm P ost T ransl L ateral C omp : 1.5 ± 1.2 mm RESULTS

18. ATMC = 10.4 ± 4.3 ATLC = 18.5 ± 5.1 PTMC = 2.7 ± 2.9 PTLC = 1.1 ± 4.1 ATMC = 2.1 ± 2.6 ATLC = 10.5 ± 3.5 PTMC = 2.1 ± 2.9 PTLC = 1.7 ± 4.1 563 normal knees478 ACL deficient knees No difference between males and females RESULTS

19. No difference for posterior translation (ACL ruptured or not ) Posterior position is different from the radiological "zero position" It is the "starting position" for clinical tests and for arthrometric measurements RESULTS PTMC = 2.1 ± 2.9 PTLC = 1.7 ± 4.1

20. specificity = 90 %specificity = 90 % sensitivity = 87 %sensitivity = 87 % predict posit. val = 89 %predict posit. val = 89 % predict negat. val = 88 %predict negat. val = 88 % 87%87% 79 %79 % 85 %85 % 82 %82 % ATMC ATLC Cut point : 6 mmCut point : 11.5 mm Diagnosis of ACL rupture The ATMC is the most reliable

21. Medial Compartment PTMC +ATMC 4.2 ± 2.7 mm Physiological ant-post laxity Lateral Compartiment PTLC +ATLC 12.2 ± 4.5 mm

22. Medial Compartment PTMC +ATMC 12.1 ± 4.5 mm Pathological ant-post laxity Lateral Compartiment PTLC +ATLC 19.4 ± 5.5 mm

23. Considering differential laxity Pathological ATMC and ATLC Normal contralateral knee

24. ACL deficient knees : differential ant. translation ATLC 7.5 ± 4.6 mm ATMC 8.1 ± 4.2 mm

25. Translation of the lateral side can be predominent internal tibial rotation Anterior laxities classification Translation of the medial side can be predominent external tibial rotation

26. Anterior laxities classification ATMC Cases number %

27. Anterior laxities : grade 1 5 8 11 Diff. Laxity mm zero position line 15

28. Anterior laxities : grade 1 128 5 8 11 Diff. Laxity zero position line 15 ATMC knees

29. Anterior laxities : grade 1 128 59 5 8 11 Diff. Laxity zero position line 15 ATMC ATLC 1 D 1 C 1 B 1 A

30. Anterior laxities : grade 1 128 36 59 5 8 11 Diff. Laxity zero position line 15 ATMC ATLC 1 D 1 C 1 B 1 A

31. Anterior laxities : grade 1 128 36 22 59 5 8 11 Diff. Laxity zero position line 15 ATMC ATLC 1 D 1 C 1 B 1 A

32. Anterior laxities : grade 1 128 36 22 11 59 5 8 11 Diff. Laxity zero position line 15 ATMC ATLC 1 D 1 C 1 B 1 A

33. 116 25 18 48 5 8 11 Diff. Laxity Zero position line 15 Anterior laxity : grade 2 ATMC ATLC 2 D 2 C 2 B 2 A

34. Anterior laxity : grade 3 Anterior laxity : grade 3 109 19 26 29 35 5 8 11 Diff. Laxity Zero position line 15 3 D 3 C 3 B 3 A ATMC ATLC

35. Anterior laxity : grade 4 91 19 11 5 8 Diff. Laxity zero position line 15 4 D 4 C 4 B 4 A ATLC ATMC

36. Anterior laxity : grade 4 91 19 37 24 11 5 8 Diff. Laxity zero position line 15 4 D 4 C 4 B 4 A ATLC ATMC

37. Anterior laxities classification Anterior laxities classification Grade 4 Grade 3 Grade 2 Grade 1 ATMC (first number) : 4 grades ATLC (A, B, C or D) : 4 grades

38. Grade 4 Grade 3 Grade 2 Grade 1 Number of cases for all categories ( % ) n = 487 Anterior laxities classification ABCDABCD

39. Prospective surgery isolated ACL ACL + extra-articular lateral reconstruction

40. Prospective surgery isolated ACL ACL + medial + lateralACL + medial ACL + extra articular lateral reconstruction 19 % 17 %38 % 26 %

41. Precice and objective measurement of preop and post-op laxity Preoperative ATMC and ATLC Post op 10 years Preoperative ATMC and ATLC Post op 10 years

42. "Mac InJones » procedure Quadricipital tendon is stretched from the condyle to the Gerdy’s tubercule with solid sutures ACL reconstruction with patellar tendon

43. Evolution of radiological laxity after surgery Gain for ATMC : 62 % Gain for ATLC : 77 % Differential left/right laxity ACL reconstruction + lateral plasty : 100 cases

44. In the same way, a prospective study is started to evaluate postero-medial reconstruction

45. Conclusive diagnosis for ACL rupture Better comprehension of laxity physiopathology Laxities classification Judicious surgical treatment adaptated to the lesions Conclusions

46. « Knee instability after injury to the anterior cruciate ligament Quantification of the Lachman test » JL Lerat, B Moyen, F Cladière, JL Besse, H Abidi J. Bone Joint Surgery VOL. 82-B, N°1, January 2000, 42-47.

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