Clinical , laboratory and densitometric comparison of patients with coxarthrosis and femoral neck fractures

1 Federal University of Rio Grande do Sul (UFRGS), Post-Graduation Programme in Medicine: Surgical Sciences Porto Alegre Rio Grande do Sul Brasil. 2 Irmandade da Santa Casa de Misericórdia de Porto Alegre, Department of Orthopedics Porto Alegre Rio Grande do Sul Brasil. 3 University of Passo Fundo, Laboratory of Bioengineering, Biomechanics and Biomaterials Passo Fundo Rio Grande do SulBrasil. 4 Hospital de Clinicas de Porto Alegre (HCPA), Research Group in Hip, Biomaterials and Tissue Bank Porto Alegre Rio Grande do Sul Brasil. 5 Hospital de Clinicas de Porto Alegre (HCPA), Tissue Bank Porto Alegre Rio Grande do Sul Brasil. 6 Federal University of Santa Maria (UFSM), Department of Surgery Santa Maria Rio Grande do Sul Brasil. 7 Federal University of Rio Grande do Sul (UFRGS), Department of Surgery Porto Alegre Rio Grande do Sul Brasil. Spinelli Clinical, laboratory and densitometric comparison of patients with coxarthrosis and femoral neck fractures. 2 Rev Col Bras Cir 45(5):e1985 METHODS The research project was submitted to, and approved by, the Scientific Committee and the Ethics in Research Committee of our institution (CAAE 05745712.0.0000.5327). We clarified all subjects invited to participate about the research and its objectives prior to performing the surgical procedure and collecting material for blood analysis. The consenting subjects signed an Informed Consent Term. We collected the information between March 2014 and October 2016. The research consists in a cross-sectional study of patients affected by femoral neck fractures and by osteoarthrosis of the hip that underwent hip arthroplasty. We included 53 patients, 22 with fracture and 31 with osteoarthrosis. We selected patients sequentially as they underwent total hip arthroplasty, at the same time as we checked the inclusion and exclusion criteria. As inclusion criterion, we considered patients older than 60 years submitted to hip arthroplasty, having fracture of the femoral neck or hip osteoarthrosis as cause. As exclusion criteria, we considered those patients who did not wish to participate in the study and who did not sign the Informed Consent Term, those with femoral fractures other than of the femoral neck, with dysplasias and deformities of the femur or acetabulum, previously operated on the hip for other reasons, patients with osteoarthrosis associated with osteonecrosis, metabolic disorders (Morquio syndrome, etc.), patients with rheumatic diseases (Rheumatoid Arthritis, Ankylosing Spondylitis, Systemic Lupus Erythematosus), those using bisphosphonates, hormone replacement therapy, glucocorticoid use in the month prior to surgery, and supplementation of calcium, vitamin B12, folate or vitamin D. We questioned and examined the patients the day before the surgical procedure. We collected information directly with the patient, such as demographic data and the cause of arthroplasty (fracture of the femoral neck or arthrosis), and measured the strength of the patients' palmar grip through a dynamometer regulated and measured by INMETRO. We collected blood samples for measuring serum total calcium, ionic calcium, sodium, potassium, phosphorus, complete blood count, thyrotropin (TSH), free thyroxine (T4L), 25-OH-vitamin D, aldosterone, androstenedione, estradiol, folliclestimulating hormone (FSH), luteinizing hormone (LH), parathyroid hormone (PTH), progesterone, total testosterone, alkaline phosphatase, creatinine, urea, TP and TTPA. We performed densitometries in the immediate postoperative period. We performed data analysis using the Statistical Package for The Social Sciences (SPSS 18.0) software. We determined the means and dispersion of the quantitative variables and the proportions of the qualitative ones. We assessed homogeneity with the Kolmogorov-Smirnov test. For analysis of possible differences, we used the Student’s t, the chi-square or the ANOVA tests. We used the Mann-Whitney test to identify differences in non-parametric variables. We considered p<0.05 as statistically significant.


INTRODUCTION
O steoarthrosis (OA) is a chronic and degenerative disease that affects synovial joints, including the hip 1 .It is basically characterized by the wear of the cartilage that covers the surfaces of the joint formed by the femoral head and the acetabulum.It is considered as having a multifactorial etiology, therefore being influenced by several factors 2 .
Fractures of the femoral neck occur more frequently in elderly patients, being uncommon in patients under 60 years of age.Most of these fractures occur in female patients, the incidence increasing exponentially with age.The risk of a hip fracture is high, ranging from 40% to 50% in women over 60 years and 13% to 22% in men 3 .Biochemical markers may reflect the status of bone metabolism and provide information on bone remodeling (turnover) 4 , which is often altered in skeletal disorders.Few studies have investigated the potential differences in the characteristics of bone markers.Resmini et al. observed changes in serum calcium and PTH levels in the fracture group when compared with the control group (or with osteoarthrosis).
All patients were vitamin D3-deficient, with no difference between groups 5 .
The objective of this study is to compare clinical, laboratory and densitometric data of patients who underwent hip arthroplasty for neck fractures and for hip osteoarthrosis.
Original Article

Comparação clínica, laboratorial e densitométrica de pacientes com coxartrose e com fraturas do colo femoral.
A B S T R A C T

METHODS
The research project was submitted to, and approved by, the Scientific Committee and the Ethics in Research Committee of our institution (CAAE 05745712.0.0000.5327).We clarified all subjects invited to participate about the research and its objectives prior to performing the surgical procedure and collecting material for blood analysis.The consenting subjects signed an Informed Consent Term.We collected the information between March 2014 and October 2016.
The research consists in a cross-sectional study of patients affected by femoral neck fractures and by osteoarthrosis of the hip that underwent hip arthroplasty.We included 53 patients, 22 with fracture and 31 with osteoarthrosis.We selected patients sequentially as they underwent total hip arthroplasty, at the same time as we checked the inclusion and exclusion criteria.
As inclusion criterion, we considered patients older than 60 years submitted to hip arthroplasty, having fracture of the femoral neck or hip osteoarthrosis as cause.As exclusion criteria, we considered those patients who did not wish to participate in the study and who did not sign the Informed Consent Term, those with femoral fractures other than of the femoral neck, with dysplasias and deformities of the femur or acetabulum, previously operated on the hip for other reasons, patients with osteoarthrosis associated with osteonecrosis, metabolic disorders (Morquio syndrome, etc.), patients with rheumatic diseases (Rheumatoid Arthritis, Ankylosing Spondylitis, Systemic Lupus Erythematosus), those using bisphosphonates, hormone replacement therapy, glucocorticoid use in the month prior to surgery, and supplementation of calcium, vitamin B12, folate or vitamin D.
We questioned and examined the patients the day before the surgical procedure.We collected information directly with the patient, such as demographic data and the cause of arthroplasty (fracture of the femoral neck or arthrosis), and measured the strength of the patients' palmar grip through a dynamometer regulated and measured by INMETRO.We collected blood samples for measuring serum total calcium, ionic calcium, sodium, potassium, phosphorus, complete blood count, thyrotropin (TSH), free thyroxine (T4L), 25-OH-vitamin D, aldosterone, androstenedione, estradiol, folliclestimulating hormone (FSH), luteinizing hormone (LH), parathyroid hormone (PTH), progesterone, total testosterone, alkaline phosphatase, creatinine, urea, TP and TTPA.We performed densitometries in the immediate postoperative period.
We performed data analysis using the Statistical Package for The Social Sciences (SPSS 18.0) software.We determined the means and dispersion of the quantitative variables and the proportions of the qualitative ones.We assessed homogeneity with the Kolmogorov-Smirnov test.
For analysis of possible differences, we used the Student's t, the chi-square or the ANOVA tests.We used the Mann-Whitney test to identify differences in non-parametric variables.We considered p<0.05 as statistically significant.

RESULTS
We evaluated 22 patients with fracture and 31 with hip osteoarthrosis.Tables 1 and 2 show the relations of the surgical intervention with gender, age and categorized age.In the fractures group, we observed that the majority of the patients were female (68.2%) and the mean age was higher than in the arthrosis group.There was no statistically significant difference between genders (p>0.05),but there was for age between groups (p=0.005).
Table 3 shows patients' clinical data, with a higher age range in patients with fracture, as well as lower weight, lower body mass index (BMI) and lower palmar grip strength (PGS) in the right and left hands compared with patients with osteoarthrosis, all with statistical significance.The only parameter that did not differ significantly between groups was height.
Table 4 shows the comorbidities: neurological disease (Parkinson's, Alzheimer's and dementia) was significant, as well as previous surgeries.The use of tobacco (p=0.377) and alcohol (p=0.280) did not present significant differences.
With respect to the ASA score, the number of ASA I, II, III and IV patients was 1, 8, 12 and 1, respectively, among patients with fractures, and 0, 25, 6 and 0 among patients with osteoarthritis, with statistical significance (p=0.002).
Among the various laboratory parameters evaluated, we found a statistically significant difference for total and ionic serum calcium, 25-OHvitamin D, erythrocytes, hemoglobin, hematocrit, total leukocytes, lymphocytes, basophils, creatinine and free thyroxine.Other biochemical parameters showed tendencies between the two groups, such as alkaline phosphatase and testosterone, but were not statistically significant (Table 5).

DISCUSSION
Aging is a natural and physiological process that occurs in human beings.Due to it, each individual experiences emotional, psychological and environmental experiences that make it unique and individual 6 .Although old age is not synonymous with illness and inactivity, aging may be accompanied by chronic and multiple diseases, depending on the economic context, social and cultural development of the individual.In this sense, the physiological changes, when added to the other diseases, weaken the functional capacity of the elderly, compromising their quality of life.Osteoarthrosis is one of these chronic diseases that affects the elderly, presenting a multifactorial etiology 2 .The genetic component and obesity 7 , age 8 , cellularity at articulation 6 , degree of apoptosis 9 , gender and hormones 10 and morphology 11 have been mentioned.
Epidemiological studies have identified numerous risk factors for femoral neck fractures, such as BMI below 18.5, low exposure to sunlight, low recreational activity, smoking, previous history of osteoporotic fracture, maternal history of hip fracture, and corticosteroid treatment 12 .In addition, 70% of patients with femoral neck fractures have ASA III or IV at the time of fracture 3 .In the present study, we also found a lower BMI in patients with femoral neck fractures, with a higher mean age, being 68.2% of female patients, 59% with ASA III or IV.We did not observe differences for smoking and alcohol use in our sample.The acute use of corticoid was an exclusion factor.
The reduction of bone mass caused by osteoporosis has an unequivocal relationship with hip fracture and is present in more than 84% of patients with fracture of the femoral neck.Only one standard deviation doubles the risk of hip fractures 3 .In this study, we also observed lower mineral density in patients with fractures compared to those with hip osteoarthrosis.
Bone diseases alter the production pattern of biochemical markers.Diseases leading to osteopenia tend to increase the relationship between reabsorption markers and formation markers, as appears to be the case in osteoporosis 13 .Vitamin D deficiency states are characterized by a change in osteoblast differentiation, with a disproportionate increase in levels of alkaline phosphatase 14 .Resmini et al. observed changes in serum calcium and PTH levels in the fracture group when compared with the control group (or with osteoarthrosis).All patients were vitamin D3-deficient, with no difference between groups 5 .In the present study, PTH was not statistically significant, but we observed a significant reduction in vitamin D values, in addition to ionic and total calcium, in the group with femoral neck fracture.In both groups, the measured vitamin D values were below the standard used by the method.Although there was no statistically significant difference, we observed an increase in alkaline phosphatase in response to a decrease in vitamin D. Geriatricians should be trained to discover these comorbidities, to identify and manage patients who are at increased risk for adverse outcomes, particularly patients who will be operated on for hip fractures 15 ; this type of fracture has been described as a "geriatric condition, rather than an orthopedic disease" 16 .The present research aims to contribute in this sense.
The authors recognize the difficulties in comparing patients submitted to osteoarthrosis or fracture of the femoral neck.However, the inclusion and exclusion criteria applied established a scientific rigor in this research.The number of individuals evaluated also reflects the difficulty of including patients in the study due to the rigor of the criteria.
We corroborate several authors that show the multifactorial nature of the risk factors, and the trends found point to the need for a multidisciplinary medical approach.
We conclude that patients with femoral neck fractures present more advanced age, lower weight and lower BMI than patients with osteoarthrosis.The former also displayed a more debilitated clinical picture, with anemia most of the times and reduction of bone mass and of palmar grip strength, in addition to decreased levels of total and ionic calcium, vitamin D and creatinine, with an increase in free thyroxine.

Table 1 .
Demographic data relating the reason for surgery with sex and age.

Table 2 .
Motive of surgery according to age groups.
* Not enough data.
Table 6 shows the values obtained through densitometry.The group with femoral neck fractures presented inferior bone mineral density (BMD), both in the femoral neck and in the lumbar spine region, as well as for the Tscore and Zscore values, all with statistical significance.continuation... 6 Rev Col Bras Cir 45(5):e1985