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Knee: R. Ramesh, O. Von Arx, T. Azzopardi, and P. J. Schranz The risk of anterior cruciate ligament rupture with generalised joint laxity J Bone Joint Surg Br 2005; 87-B: 800-803 [Abstract] [Full text] [PDF]

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Response to the letter by Messrs Gul and Sambandam from the authors

Rangaraju Ramesh, Peter J Schranz   (1 August 2005)

Is knee hyperextension the best way of measuring joint laxity?

Arif Gul, S.Sambandam   (12 July 2005)

Response to the letter by Messrs Gul and Sambandam from the authors 1 August 2005
Rangaraju Ramesh, Consultant Torbay Hospital, Peter J Schranz Send letter to journal: Re: Response to the letter by Messrs Gul and Sambandam from the authors rramesh{at}rramesh.plus.com Rangaraju Ramesh, et al.	Sir, We would like to respond to the issues raised by Messrs Gul and Sambandam. Firstly, the aim of the article was to see if joint laxity and hyperextension of the knee predispose to rupture of the anterior cruciate ligament by using a simple screening method. While anteroposterior laxity is objectively assessed using a KT 1000 arthrometer, it may not be available in all clinics. On the other hand, assessing joint laxity and hypertextension of the knee can be done in any setting. We took a reading for all of our patients using a KT 1000 arthrometer. The comment regarding the soft surface is a valid one. In the original version of the article we included two further figures which showed how we derived our technique of hyperextension of the knee. These were later edited. We must again stress that this is a screening method only. To assess hyperextension, the thigh and popliteal fossa should be in contact with the couch, and the leg hyperextended. The heel clearance is assessed using the number of digits that can be placed under the heel with the foot in a neutral position. We took any angle greater than 10° to show hyperextension. We know from logarithmic tables the value of tan 10 and by using this we found that on most occasions, if one could place more than two digits under the heel there was evidence of hyperextension of the knee. This is then confirmed with a goniometer. R. RAMESH, FRCS(Tr & Orth) P. J. SCHRANZ, FRCS(Orth) Princess Elizabeth Hospital, Exeter, UK.
Is knee hyperextension the best way of measuring joint laxity? 12 July 2005
Arif Gul Princess of Wales Hospital, S.Sambandam Send letter to journal: Re: Is knee hyperextension the best way of measuring joint laxity? arif_pgi{at}yahoo.co.in Arif Gul, et al.	Sir, We read this article with great interest. The authors suggested that knee hyperextension is the major determinant of knee laxity and the predisposing factor for anterior cruciate ligament (ACL) rupture. The majority of recent studies1,2 use the anteroposterior laxity of the knee joint as measured by KT 1000 arthrometer, Lachman’s test etc. to study its relation to ACL rupture. We are unsure as to why the authors chose to use knee hyperextension instead. The second point we would like to raise is regarding the technique used for measuring knee hyperextension. Figure 1 shows a couch being used (which looks as if it has a soft surface) and we feel it would be easy to make an error while measuring hyperextension using such a surface for obvious reasons. A. GUL S. SAMBANDAM 1. Sernert N, Kartus JT Jr, Ejerhed L, Karlsson J. Right and left knee laxity measurements: a prospective study of patients with anterior cruciate ligament injuries and normal control subjects. Arthroscopy 2004;20:564-71. 2. Rozzi SL, Lephart SM, Gear WS, Fu FH. Knee joint laxity and neuromuscular characteristics of male and female soccer and basketball players. Am J Sports Med 1999;27:312-19.