The adverse effect of elevated body mass index on outcome after autologous chondrocyte implantation

P. K. Jaiswal, G. Bentley, R. W. J. Carrington, J. A. Skinner, T. W. R. Briggs

Abstract

We analysed whether a high body mass index (BMI) had a deleterious effect on outcome following autologous chondrocyte implantation (ACI) or matrix-carried autologous chondrocyte implantation (MACI) for the treatment of full-thickness chondral defects of the knee from a subset of patients enrolled in the ACI vs MACI trial at The Royal National Orthopaedic Hospital.

The mean Modified Cincinnati scores (MCS) were significantly higher (p < 0.001) post-operatively in patients who had an ideal body weight (n = 53; 20 to 24.9 kg/m2) than in overweight (n = 63; 25 to 30 kg/m2) and obese patients (n = 22; > 30 kg/m2). At a follow-up of two years, obese patients demonstrated no sustained improvement in the MCS. Patients with an ideal weight experienced significant improvements as early as six months after surgery (p = 0.007). In total, 82% of patients (31 of 38) in the ideal group had a good or excellent result, compared with 49% (22 of 45) of the overweight and 5.5% (one of 18) in the obese group (p < 0.001). There was a significant negative relationship between BMI and the MCS 24 months after surgery (r = -0.4, p = 0.001).

This study demonstrates that obese patients have worse knee function before surgery and experience no sustained benefit from ACI or MACI at two years after surgery. There was a correlation between increasing BMI and a lower MCS according to a linear regression analysis. On the basis of our findings patient selection can be more appropriately targeted.

Footnotes

  • No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.

  • Received February 20, 2012.
  • Accepted June 6, 2012.
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