P. D. Hinduja National Hospital and Research Center, Orthopaedics, Mumbai, Maharashtra, India
Correspondence to: D. K. Jain. E-mail: drdjain{at}hotmail.com
We thank Dr Desai and associates for the interest shown in our paper and the queries raised.
Our conclusion is that alendronate improves function, reduces pain and retards the progression of AVN, not that it halts it, as interpreted by Dr Desai.
We agree that the natural course of AVN is unpredictable but most of the literature until now has emphasized that the collapse occurs within 23 yr (references 2 and 3 in our article). We also mentioned in the article that the site and size of the lesion are more important than the MRI grade. MRI results were not analysed as not all the patients had an MRI at final follow-up. This fact was stated in our response to the queries raised by the reviewers. Ficat and Arlet staging is still the most accepted and used system the world over.
If the stage 1 and 2 lesions can halt without treatment, why is core decompression being recommended and done for early AVN?
When the remodelling spaces are large, collapse occurs early and at a faster rate. By contracting the remodelling spaces, the architecture of the bone is preserved for a longer time; bone is more solidified with more mineral and gets stabilized in that state. The collapse never reverses but further progression of collapse is reduced. Tables 3 and 4 give the details about the radiological progression.
The cases shown in Figs 6 and 7 are both at the 3-yr follow-up, not 2 yr. We again emphasize that most of the literature mentions collapse occurring within 3 yr, and if the head does not collapse within 3 yr it is unlikely to do so in future.
Figure 6d shows the involvement of the whole sector of the head (4050%), and this cannot be considered a small lesion. Similarly, the case shown in Fig. 7 had involvement of the weight-bearing part also, as revealed by MRI; it is the cystic lesion that is located more medially.
The authors have declared no conflicts of interest.
Accepted 24 May 2005
|