Femoral Head Size is Correlated With Head Position in Very Elderly Patients.
In cases of femoral neck fracture, it is often not possible to accurately determine the original position of the head center to assess appropriate restoration of leg length. The aim of this study was to determine the accuracy of predicting the position of the femoral head center based on new and established correlations between the femoral head diameter (FHD) and the distance between the lesser trochanter and the femoral head center (LT-FHC) in the very elderly (aged ≥80 years) as the mainly affected but yet underinvestigated group.



The FHD and the LT-FHC distance were determined in 148 subjects (104 males, 44 females); 90 aged ≥80 years and 58 aged <80 years. For each age and gender subgroup one specific (LT-FHC)/FHD ratio was determined. The accuracy of the new determined ratios and the established ratios by others were compared by recalculating the LT-FHC distance of each individual subject.



The FHD and the LT-FHC were significantly correlated, most strongly in elderly females (R = 0.554, P < .001). Using the new age- and gender-specific ratios, the LT-FHC distance could be predicted within 10 mm of the true value in 95% of the cases and in only 77% using previously reported formulas.



Age- and gender-specific formulas yield higher accuracy than generic formulas. The formulas presented in this study can offer a practical, easy to use instrument for orthopedic surgeons performing hip arthroplasty in very elderly patients in addition to classic techniques to prevent significant leg-length discrepancy.
Department of Orthopaedic Surgery and Traumatology, AHORSE Research Foundation, Zuyderland Medical Center Heerlen, Heerlen, The Netherlands.
Tim A E J
TAEJ
Boymans
Department of Orthopaedic Surgery and Traumatology, AHORSE Research Foundation, Zuyderland Medical Center Heerlen, Heerlen, The Netherlands.
Hidde D
HD
Veldman
Department of Orthopaedic Surgery and Traumatology, AHORSE Research Foundation, Zuyderland Medical Center Heerlen, Heerlen, The Netherlands.
Bernd P
BP
Grimm
Department of Orthopaedic Surgery, Institute of Orthopedic Research & Education, Baylor College of Medicine, Houston, Texas.
Philip C
PC
Noble
Department of Orthopaedic Surgery and Traumatology, AHORSE Research Foundation, Zuyderland Medical Center Heerlen, Heerlen, The Netherlands.
Ide C
IC
Heyligers
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D059925:Anatomic Landmarks; D019643:Arthroplasty, Replacement; D019644:Arthroplasty, Replacement, Hip; D005260:Female; D005265:Femoral Neck Fractures; D005269:Femur; D005270:Femur Head / Q000033:anatomy & histology*; D006621:Hip Joint / Q000033:anatomy & histology*; D006801:Humans; D007870:Leg Length Inequality; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical
femoral head position; femoral head size; femoral neck fracture; hip arthroplasty; lesser trochanter; very elderly