SLR - August 2016 - Ryan David Moss
The Influence of Patient Age and Bone Mineral Density on Osteotomy Fixation Stability After Hallux Valgus Surgery: A Biomechanical Study
Reference: Hofstaetter, Stefan G., et al. "The Influence of Patient Age and Bone Mineral Density on
Osteotomy Fixation Stability After Hallux Valgus Surgery: A
Biomechanical Study." Clinical Biomechanics 32 (2016): 255–260.
Scientific Literature Review
Reviewed By: Ryan David Moss, DPM
Residency Program: North Colorado Medical Center Podiatric Medicine and Surgery Residency
Podiatric Relevance: Oblique osteotomies of the first metatarsal are common surgical treatments for moderate to severe hallux valgus deformity. Fixation integrity is important to minimize motion across the osteotomy and maintain correction during healing. Observations have been made, which suggest that patient age and bone quality affect fixation stability and ultimately the clinical outcome. In this article, the authors hypothesize that these patient factors have a negative effect on the osteotomy fixation stability. Patient age and bone quality were correlated with key mechanical measures of osteotomy angulation resistance in a cadaver hallux valgus correction model.
Methods: Standard Ludloff osteotomies were created in 31 fresh-frozen first metatarsals and fixed with two cannulated, dual-pitch headless screws. Each specimen underwent 1,000 plantar-to-dorsal bending loads while monitoring bending stiffness and distal fragment dorsal angulation. Donor age and bone mineral density were then correlated with each mechanical measure at selected cycling increments. There was a significant positive correlation between bone mineral density and osteotomy fixation stiffness for all evaluated load cycles. Moderate negative correlation between bone density and angulation was identified, significant for load cycle 500. Little correlation was demonstrable between age and angulation.
Results: A significant positive correlation was found between bone mineral density and osteotomy fixation stiffness for all evaluated load cycles. Moderate negative correlation between bone density and angulation was identified, significant for load cycle 500. There was a weak, nonsignificant negative correlation between donor age and osteotomy bending stiffness, with r ranging from −0.134 to −0.243 between the first and 1,000th loads. Little correlation was demonstrable between age and angulation.
Conclusions: The results of this study suggest that there is potential for the treatment of hallux valgus patients to be optimized based on their bone mineral density. Specifically, those with particularly low bone mineral density would likely benefit from a longer period of protected postoperative weightbearing and greater efforts to assure compliance with weightbearing recommendations. Further, they may benefit from fixation augmentation during the corrective surgery. Findings from this study were not significant in correlating fixation instability or bending stiffness with patient age. Conversely, patients with especially high bone mineral density who receive Ludloff osteotomy hallux valgus correction may be candidates for earlier weightbearing and active physical therapy. Although the findings are isolated to a Ludloff osteotomy, logical inferences indicate similar findings would result from other osteotomy types, which would warrant further investigation with other osteotomy types for hallux valgus correction.