Total hip and knee joint replacement : perioperative clinical aspects

Objective: To understand the profile of patients undergoing hip and knee replacement during two years, and to compare the data obtained with the literature. Methods: A total of 323 medical records were reviewed to analyze the perioperative data of patients submitted to hip and knee replacement. results: Osteoarthritis was the main indication for both procedures and male patients were heavier than females (p < 0.05). Hypertension was the prevalent disease among patients. Blood loss was more frequent in knee surgery than in the hip. conclusions: The profile of patients undergoing total arthroplasty improved substantially over the past decade due to shorter hospital stay, lower risk of thromboembolic events and no infection as compared to previous reports.


intrODUctiOn
The use of hip and knee joint replacement has been steadily increasing during the last decade because these are effective procedures that improve the patients' quality of life, their functional capacity and diminish the pain (1)(2)(3)(4)(5)(6)(7) .
Although joint replacement is a cost-effective treatment both from the clinical and joint perspective, there is a considerable variation on the clinical aspects surrounding the procedure from the perioperative period until the moment of discharge, including variations according to region, sex, race or socioeconomic status, aspects related to the surgical technique itself and the duration of prophylaxis against infections and venous thromboembolism, among others.In addition, with the increase in the prevalence of arthritis, obesity, and old age, a further increase in total knee and joint replacement procedures can been anticipated (5,8,9) .
The analysis of the evolution of hip and knee arthroplasties can enlighten information on future developments of the surgery as well as to the population characteristics.The present paper reports the findings observed on the cases submitted to arthroplasties at a specialized institution for the care of bone and joint diseases.

OBJectiVe
To understand the profile of patients undergoing hip and knee replacement during two years at a specialized institution for the care of musculoeskeletal diseases, and to compare the data obtained from the literature.

MetHODS
A retrospective analysis was performed in medical records of all knee and hip replacements done at the Hospital Abreu Sodré da Associação de Assistência à Criança Deficiente (AACD), during the period of 2008-2009, with approval from the Researcher Ethics Committee -CEP 90/2010.Baseline demographic data including age, sex, diagnosis, associated diseases and etiologic diagnosis were recorded.The clinical data collected after the procedure comprised days of hospitalization, blood loss, infection and thromboembolism, comparison between total knee arthroplasty (TKA) and total hip arthroplasty (THA).Descriptive analyses were performed.Data collection could not be performed in 23 charts during this period.

reSUltS
A total of 323 medical records were reviewed, 225 (69.7%) for knee replacement and the remainder for hip procedures.Table 1 summarizes the demographic data per type of procedure.Sex was significantly different in both types of replacement and women were older than man.When comparing weight of patients in both surgeries, men were heavier than women, and the difference was statistically significant (p < 0.05).Table 2 presents the indications for total joint replacement and the type of surgery performed.Osteoarthritis was the main indication for both procedures, followed by a small number of other causes, including inflammatory arthritis.Length of stay (days) (SD) 5.3 (2.9) 5.5 (4) Figure 1.Joint diseases before joint replacement Total number of patients is greater than the total sample of the study, since some cases presented more than one associated disease.*Osteonecrosis, inflammatory arthritis, hip fracture, failed osteosynthesis.
Table 3 shows the variables related to the procedure itself and comorbidities that could affect the perioperative and immediate postoperative outcomes.Arterial hypertension was the most prevalent medical condition found in patients operated at the institution for both knee and hip surgeries.Blood loss was more prevalent in knee surgery when compared to the procedure of hip replacement.No major differences were observed in other social and morbidity factors, including diabetes, smoking, anemia and complicating factors due to infection.The average length of stay was similar for both procedures.All patients received low-dose low-molecular-weight heparin and no immediate thrombotic events were recorded.Figure 1 shows a preliminary evaluation of this population according to the number of joint replacements.

DiScUSSiOn
There are few studies evaluating exclusively the perioperative period of TKA and THA.The findings of the present study indicated some points of interest when compared to other reports from the literature.
Knee and hip replacements were systematically more frequent in women than in men at this hospital.The female/male ratio for both procedures was similar to that reported by Culliford et al. (10) , who analyzed temporal trends in joint replacement in the United Kingdom, from 1991 to 2006.However, in their investigation, the rate of TKA was considerably lower than that of the hip, unlike the present study (10) .These differences may be due to sampling variations.Another hypothesis is that the present patient population comes through health maintenance organizations, while in the UK other regulations apply to patients from the National Health Service referred to joint replacements.
Although men were heavier than women, they had less joint replacements, and the diagnosis of osteoarthritis was more prevalent in females than in the general population.The age of the studied population was similar to previous reports.As mentioned above, the prevalence of THA surpassing TKA was not in accordance with other publications (10,11) .In the present study, knee replacement was twice more frequent than hip procedures in a given period.
Patients undergoing total joint replacement run a high risk of developing venous thromboembolism; however, when prophylaxis is appropriate, like in this study, the risk drops considerably.At Hospital Abreu Sodré -AACD, the frequency of thromboembolic events during the period evaluated was very low (under 1%).In various studies, venous thrombosis was reported in approximately 19% of cases before prophylaxis (12,13) .In the present series, only one patient had venous thromboembolism during hospitalization.There are reports that patients submitted to TKA are more susceptible to venous thromboembolism than those undergoing THA.This difference could not be evaluated in the present investigation, for only one patient presented this complication.White et al. (14) suggested extended prophylaxis after knee surgeries.In the present study, there were no differences in the immediate postoperative period for both joints as to frequency of deep venous thrombosis.The majority of cases occurred after hospital discharge, and this data would not have been collected, although patients were on thrombotic prophylaxis up to six days after surgery and were on low-dose lowmolecular-weight heparin while at hospital under medical supervision.A prospective study is suggested to evaluate thromboembolic events in longer postoperative periods, and to assess other parameters.
Hospital Abreu Sodré -AACD is a reference center for bone and joint diseases in a non-academic setting.A previous comparison between academic and nonacademic institutions failed to show differences in length of hospital stay and in perioperative outcomes for knee and hip arthroplasties (9) .However, the length of stay of this study was almost two days shorter than that reported by Fortin et al. (1) .When comparing the current series with an academic institution, the health status was similar in both procedures, and apparently did not influence on the immediate outcome.In contrast to a previous publication by March et al. (8) , inflammatory and non-inflammatory arthritis could not be evaluated since the number of rheumatoid arthritis patients was significantly small in the present study.The current trend is a considerable drop in the number of joint replacements after the introduction of biologic therapy, and only 2% of cases were due to inflammatory arthritis (15,16) .A preliminary evaluation in the studied population seemed to confirm such observations.Wound disturbances were not found in the patients of both procedures.Naylor et al. reported a high frequency of these events (17) In the present study, patients received prophylaxis with antibiotics, which may explain some of the differences in relation to other reports.Some demographic aspects were similar to those described by Ghandi and Tso (9) .However, the etiology of diseases in this study was quite different.Costs were not analyzed and should be included in further studies; nonetheless, there are reports that nonteaching hospitals, such as the present setting, tend to have reduced cost in resource consumption for joint replacement surgery.The population of the present study, as mentioned above, comprised mainly osteoarthritic patients and recent studies suggested similar costs for procedures related to osteoarthritis and rheumatoid arthritis (8,18,19) .
It was reported that the perioperative knee replacement outcomes were worst when compared to hip replacement (18) .These data could not be confirmed in this series, since postoperative results in both procedures (THA and TKA) were similar.
Although some reports are from the past decade, improvement in hospital care may account for the difference in the present results as compared to the literature (17,(19)(20)(21) .Finally, the results may also depend on other factors that were not clearly described in previous publications such as individual characteristics and success of the operation itself (22,23) .

cOnclUSiOnS
This study showed that, in the perioperative period, the profile of patients undergoing total joint replacement has improved substantially during the last ten years, when compared to previous reports, in terms of shorter hospital stay, lower risk of thromboembolic events and absence of immediate infection.

table 1 .
Demographics and type of joint replacement

table 3 .
Variables related to the procedure and comorbidities during the perioperative and postoperative periods