Arthritus in amputees

An increased risk of arthritis is often an area of dispute between claimants and defendants in amputation claims. There are studies that support the view that amputees will have an increased risk of arthritis in their hip or intact knee (Pieter A. Struyf et al & Jasvinder A. Singh et al) whereas other studies do not support such a view (Welke et al). An increased risk of arthritis will of course result in an increase in future treatment costs as well as associated care needs. It is therefore an important issue for claimants and defendants to address with their orthopaedic and rehab experts.

A new study by Ziyun Ding et al in the Journal of Orthopaedic Research now sheds further light on the issue.  The study involved a gait analysis of 11 below-knee amputees, comparing them to the same number of able bodied subjects. The study provides that “All eleven had previously completed the rehabilitation program at the Defence Medical Rehabilitation Centre Headley Court; were capable of walking continuously for at least twelve minutes without a cane or other assistive device; and had worn their definitive, energy storage and return (ESAR) prosthetic feet for at least six months."  The cohort had average ages of 28 years and an average of two years since amputation.

The study found that the forces on both medial and lateral knee compartments of the intact knee were higher than for the control group.  This essentially derived from the amputees placing increased pressure on their intact limb while walking and also using the intact limb more often while standing.  The authors believe this may explain a higher risk of arthritis in transtibial amputees. 

It is however worth noting that the authors of the study themselves highlight several limitations with this study.  “First, the articular joint geometry (such as the knee alignment and contact locations) and muscle attachments were not personalized between individuals. These parameters were found to affect the results of knee contact forces and muscle forces significantly... second, the body segment parameters of the amputated and intact limbs were identical in this study. A measure of the prosthetic components and the stump in the future study will allow a better investigation of the effect from the socket type, socket/stump interface and prosthetic foot. Third, the amputated limb was modelled consistently as a series of rigid body segments, following the common approach used in inverse-dynamics. However, the prosthetic components differ remarkably among TTAs (Table 1) and some elastic components in the prosthetic feet (for example, the composite spring in Echelon VT and Re-Flex Shock) mean that the effect of this assumption needs to be assessed; others have incorporated this effect”.  It also must be borne in mind that this was a very small study.

This content was written by BLM prior to its merger with Clyde & Co.