SLR - March 2012 - Jacob Jones
Reference: Obesity Reviews. 2011 Dec;12(12):1071-82. doi: 10.1111/j.1467-789X.2011.00916.x. Epub 2011 Aug 3.
Scientific Literature Review
Reviewed by: Jacob Jones, DPM
Residency Program: Southern Arizona VA Healthcare System
Podiatric Relevance:
Foot and ankle practitioners frequently encounter obese patients, commonly in treatment of diabetic foot ulcers. Additionally, obesity increases the load on weight bearing joints in the lower extremity and has been thought to contribute to osteoarthritis. This article is a systematic review of changes to lower extremity biomechanics in obese patients compared to that of the non-obese.
Methods:
A literature search was performed on Pubmed and Embase databases regarding lower extremity joints, biomechanical items, everyday movements and patient population of interest. The search had inclusion criteria including: (1) Ten or more subjects, (2) Subjects 19 years or older, (3) Absence of degenerative rheumatic or neurological disease, (4) Description of weight bearing joint angles during gait, rising from a sitting position, or climbing stairs, (5) Comparison of obese vs. normal-weight subjects, and (6) Original research.
Results:
Twelve studies were found that met the inclusion criteria. Results of gait analyses were compared among studies and broken down into two categories: (1) patial and temporal kinematics, and (2) biomechanics. Within these two categories, results were compared with patients walking at a self-selected speed and walking at a standardized speed. Obese patients were found to have decreased walking speed, stride length and single support time, while having increased step width, stance time, and double support time. Biomechanically, the ankle joints of obese patients had increased inversion on heel strike, greater toe-out during stance phase, and increased eversion at midstance.
Conclusions:
This systematic review of studies of biomechanical differences in the lower extremity in otherwise healthy obese versus normal-weight individuals concludes that obese individuals walked slower, with shorter, wider steps and longer stance duration. Additionally, obese individuals had greater heel inversion on heel strike and heel eversion at midstance. This alteration of lower extremity biomechanics among the obese patient population could lead to initiation of osteoarthritis not only by increasing the amount of time each articular surface is loaded, but also changing the load-bearing regions of the articular cartilage of weight bearing joints.