The Shake Test:A New Clinical Test For The Diagnosis Of Partial Anterior Cruciate Ligament Injury

Section Ⅰ Reliability of physical examinations for diagnosing different degrees of Anterior cruciate ligament injuryObjective To analysis the reliability of three special physical tests for the different grades of anterior cruciate ligament(ACL)injury.Methods The severity of the ACL injury was graded using a 4-point system from MRI images proposed by Hong et al.In 2003,namely,intact,low-grade injury,intermediate-grade injury,and high-grade injury.Prospective review was performed in 120 cases,which complained with anterior knee pain from September 2015 to April 2017.All cases were followed by physical examinations(Anterior Drawer test(ADT),Lachman test(LT),Pivot Shift test(PST))and MRI examination,and to analysis the reliability of three special physical tests for the different degrees of ACL injury based on MRI findings.Results For the normal ACL or the other knee structures injury,the Se,Sp,PPV,NPV,positive likelihood ratio(PLR)and negative likelihood ratio(NLR)of the three tests were 0.03,0.04 and 0.01,respectively;0.69,0.43 and 0.66,respectively;0.07,0.05 and 0.02,respectively;0.48,0.37 and 0.47,respectively;0.40,0.26 and 0.38,respectively;0.10,0.07 and 0.03,respectively;and 1.41,2.23 and 1.50 respectively.For the low grade ACL injury,the Se,Sp,PPV,NPV,PLR,NLR of the three tests were 0.05,0.20 and 0.10,respectively;0.78,0.63 and 0.78,respectively;0.05,0.10 and 0.09,respectively;0.80,0.79 and 0.81,respectively;0.65,0.55 and 0.67,respectively;0.23,0.54 and 0,45,respectively;and 1.22,1.27 and 1.15 respectively.For the intermediate grade ACL injury,the Se,Sp,PPV,NPV,PLR,NLR of the three tests were 0.26,0.53 and 0.35,respectively;0.82,0.69 and 0.83,respectively;0.20,0.23 and 0.27,respectively;0.87,0.89 and 0.88,respectively;0.74,0.67 and 0.76,respectively;1.44,1.71 and 2.06,respectively;and 0.90,0.68 and 0.78 respectively.For the high-grade ACL injury,the Se,Sp,PPV,NPV,PLR,NLR of the three tests were 0.53,0.86 and 0.49,respectively;0.92,0.83 and 0.90,respectively;0.68,0.62 and 0.62,respectively;0.85,0.95 and 0,84,respectively;0.82,0.83 and 0.80,respectively;6.63,5.06 and 4.90,respectively;and 0.51,0.17 and 0.57 respectively.For the low and intermediate grade injury,the performance of three special physical tests is poor;there have a good reliability for the high-grade ACL injury,the sensitivity of the Anterior Drawer test,Lachman test and Pivot Shift test were 0.57,0.83 and 0.50,respectively;and the specificity of the three tests were 0.92,0.70 and 0.84,respectively.Conclusion For the diagnosis of low and intermediate grade injury,physical examination revealed a poor value;but it is of high value in diagnosis of high-grade injury.Section Ⅱ The Shake Test:A new clinical test for the diagnosis of partial anterior cruciate ligament injuryObjective To propose a new test for the diagnosis of partial ACL injury,which we termed as the "Shake test" to evaluate its sensitivity for ACL injury.It should be performed:The patient is placed supine being fully extended on hard surface,such as the examining table.The examiner stands at the side of the patient and hold the heel of the injured knee,the other hand is placed at the distal of femur,the effected limb is lifted up slightly,starts at 0°,maintaining the angle invariant for every 15° interval,the knee is shaken at lateral direction repeatedly 4～5 times,about 3 times/sec,until the flexion at 90°.During the process of inspection,the examiner should ask the patient whether the knee was feeling unwell.If the patient feels aching pain in the affected knee,it represents positive performance of the Shake test.If not,it represents the negative result.During the whole process,the hip should be placed at 45° flexion,and calf in a neutral position.Methods Based on time elapsed from injury and MRI findings,the cases were divided into four groups:Group A(acute phase with positive MRI for complete ACL injury),Group B(chronic phase with positive MRI for complete ACL injury),Group C(acute phase with positive MRI for partial ACL injury),and Group D(chronic phase with positive MRI for partial ACL injury).Prospectively 200 cases of ACL injury were collected,50 cases in each group.All the patients accepted clinical assessment and MRI.Based on MRI findings,each test’s sensitivity was evaluated for ACL injury.Clinical assessment was performed with the Anterior Drawer test,the Lachman test,the Pivot Shift test,and the Shake test.Results All the available tests were sensitive for patients with complete ACL injury,especially for chronic complete injury,the sensitivity was nearly 100%,but not with partial ACL injury.Instead,for patients with acute or chronic partial ACL injury,the sensitivity was much higher with the Shake test,the sensitivity was 92%,86%,respectively.However,the same result was not obtained in the case of complete ACL injury.Discussion In general,complete ACL injury was most successfully diagnosed but partial ACL injury was least successfully diagnosed.With the advent of the Shake test,the diagnostic efficiency of partial ACL injury would be greatly improved.