Rheumatology Advance Access originally published online on June 21, 2005
Rheumatology 2005 44(10):1331-1332; doi:10.1093/rheumatology/kei003
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LETTER TO THE EDITOR |
Efficacy of alendronate in the treatment of avascular necrosis of the hip
Orthopaedics, Seth GS Medical College and KEM Hospital, Mumbai, India
Correspondence to: M. M. Desai. E-mail: md1964{at}satyam.net.in
SIR, We read with interest the article titled ‘Efficacy of alendronate, a bisphosphonate, in the treatment of AVN of the hip. A prospective open-label study’ [1]. We commend the authors for exploring this relatively unexplored area of medical management of avascular necrosis (AVN) of the hip.
However, we differ with the conclusion drawn in this article that ‘alendronate halts the progression of AVN of the hip’ for the following reasons. First, 66% of cases shown in this article are grade 1 and grade 2 (Ficat and Arlet classification). Hips with less than 2 mm collapse and necrotic lesions occupying less than the medial two-thirds of the weight-bearing area have a high chance of cessation of collapse and improvement of symptoms [2]. The course of the disease has been extremely unpredictable [3–5]. The size (large or small), the location (in the weight-bearing or non-weight bearing zone) and the type of lesion (cystic or sclerotic) are more important as regards progression of the condition. Hence, quantitative staging, such as the MRI classification by Steinberg et al. [6], is preferable to the radiological classification of Ficat and Arlet, both before initiation of therapy and when comparing the end result. This is especially true since the authors used MRI as a diagnostic modality and follow-up indicator.
Secondly, 34% of cases were in advanced stages (grade 3 and grade 4), in which the femoral head was already deformed and collapsed. We fail to understand how ‘contracted remodeling’, as proposed by the authors, would prevent or reverse these changes, since it is a mechanically irreversible phenomenon. Though the authors state that 54% of the cases had deteriorated radiologically at a follow-up of more than 2 yr, they do not categorize this group separately into pre- and post-collapse cases.
Thirdly, there are two illustrations (shown in Figs 6 and 7) that have been quoted as successful cases. However, these do not come as a surprise since the lesions in these cases were either too medial (the case in Fig. 7) or too small (the case in Fig. 6) to be collapsed. Two years is too short a period to study the natural course of lesions such as these. Similarly, it would not be appropriate to conclude that alendronate altered the progression of these cases.
The authors have declared no conflicts of interest.
References
- Agarwala S, Jain D, Joshi VR, Sule A. Efficacy of alendronate, a bisphosphonate, in the treatment of AVN of the hip. A prospective open-label study. Rheumatology 2005;44:352–9.
[Abstract/Free Full Text] - Nishii T, Sugano N, Ohzono K et al. Progression and cessation of collapse in osteonecrosis of the femoral head. Clin Orthop Rel Res 2002;400:149–57.
- Bradway JK, Morrey BF. The natural history of the silent hip in bilateral atraumatic osteonecrosis. J Arthroplasty 1993;8:383.[Medline]
- Guyton GP, Brand RA. Apparent spontaneous joint restoration in hip osteoarthritis. Clin Orthop Rel Res 2002;404:302–7.
- Koo KH, Ahn IO, Kim R et al. Bone marrow edema and associated pain in early stage osteonecrosis of the femoral head: prospective study with serial MR Images. Radiology 1999;213:715–22.
[Abstract/Free Full Text] - Steinberg ME, Hayken GD, Steinberg DR. A quantitative system for staging avascular necrosis. J Bone Joint Surg Br 1995;77:34–41.
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