ASSESSMENT OF THE FUNCTIONAL CAPACITY OF INDIVIDUALS SUBMITTED TO SURGICAL TREATMENT AFTER TIBIAL PLATEAU FRACTURE

O joelho é a articulação intermediária do membro inferior, situado entre os dois braços de alavanca mais longos do corpo humano (fêmur e tíbia)(1,2). Apesar do seu complicado mecanismo e estruturas, desempenha importante papel nas atividades de vida diária. Sob o ponto de vista funcional é indispensável para a locomoção, manutenção da posição bípede e realização de movimentos básicos como: marcha, corrida, posição sentada e de cócoras. Por ser tão solicitada, essa articulação sofre com muita freqüência alteração de função e estabilidade(1,2). As lesões traumáticas e suas consequências representam 80% das patologias que acometem a articulação do joelho(3). A fratura do planalto tibial envolve a superfície articular proximal da tíbia que suporta o côndilo femoral do mesmo lado. Podem estar envolvidos os planaltos lateral e/ou medial. A maioria das lesões afeta o platô lateral isoladamente (55-70%). Lesões apenas do planalto medial ocorrem entre 10-23% dos casos, enquanto os envolvimentos de ambos os planaltos (lesões bicondilares) são encontrados entre 10-30%(4). Os mecanismos de trauma mais freqüentes estão divididos entre quedas, acidentes no trânsito e lesões no esporte. Estudos realizados observaram que acidentes automobilísticos representaram 40% a 60% das fraturas do planalto tibial(5-8). Recentemente, a analise de 1.426 fraturas de planalto tibial mostrou que 45% ocorrem por acidentes com pedestres, 13% são automobilísticos, 17% por quedas de locais elevados, 12% decorrentes de escorregões e torções, atividades atléticas representaram 3% e acidentes de motocicleta, bicicleta e outros foram de 10%(9). Forças em valgo ou varo combinadas com carga axial são responsáveis pela maioria das fraturas tibiais proximais(9,10). Estudo, analisando joelhos de cadáveres submetidos a estresse em valgo ou varo, tanto isolado como combinado com compressão axial, obteve alguns dos tipos de fratura do planalto tibial comumente encontrados(11). A distribuição em relação à idade e ao sexo dos pacientes com esta lesão parece mostrar um padrão bimodal. O pico de incidência em homens ocorre na quarta década, causada por um trauma de alta energia, enquanto que nas mulheres ocorre na sétima década de vida e são fraturas tipicamente de baixa energia em ossos com grau avançado de osteoporose(4,12). Os traumas de baixa energia, geralmente causam fraturas unilaterais com depressão do planalto e os traumas de alta energia, fraturas cominutivas com maior lesão de partes moles e neurovasculares(13). ARTIGO ORIGINAL


INTRODUCTION
The knee is an intermediate joint of the lower limb, lying between both the longer lever arms of the human body (femur and tibia) (1,2).Despite of its complex mechanism and structures, it plays an important role for daily life activities.Under a functional point of view, it is essential for ambulation, keeping a bipodal stance, and for performing basic movements such as gait, run, sedestation and squatting.For being so required, this joint usually experiences function and stability changes (1,2) .Trauma injuries and its consequences account for 80% of the pathologies affecting the knee joint (3) .Tibial plateau fractures involve the proximal joint surface of the tibia that supports the femoral condyle on the same side. of the proximal tibial fractures (9,10) .A study assessing cadaver knees submitted to stress in valgus or varus, both alone and combined with axial compression, found some of the kinds of tibial plateau fractures frequently reported (11) .The distribution of the patients with this kind of injury for age and gender seems to show a bimodal pattern.The incidence peak in men occur during the 4 th decade of life, caused by a high-energy trauma, while in women this occurs on the 7 th decade of life, and are typically low-energy trauma on highly osteoporotic bones (4,12) .Low-energy trauma usually cause unilateral fractures with plateau depression, while high-energy traumas cause comminutive fractures with larger soft parts and neurovascular injuries (13) .Left knees are most frequently injured than the right ones (60% versus 40%), which may reflect the feet positioning of a car driver (4,14,15) .Several classifications have been developed for tibial plateau fractures (Hohl, Hohl e Luck, Moore and ASIF-AO), but, today, the most accepted and used classification worldwide is the one recommended by Schatzker (16) .This classification is based on the site and orientation of the fracture lines.Schatzker divided it into six types.Three fracture types involve the tibial lateral condyle: shearing (type I), shearing and depression (type II) and fracture with depression alone (type III).The medial condyle fracture is then subdivided into: type A, which is a high-energy fracture-dislocation, and; type B, with is a compression osteoporotic fracture.Bicondylar fractures are divided into: type V, in which medial and lateral condyles are similarly arranged, and; type VI, in which the metaphysis is separated from the shaft (16) .Joint fractures are regarded as serious.Any fragment displacement determines joint incongruence with resultant localized overload.Often, other surrounding joints are affected due to the poor alignment of the load axis of the involved segment.The result is, then, progressive pain and functional disability.In order to avoid sequels, anatomical reduction and an stable fixation of the joint surface must be pursued, as well as allowing early movements in order to prevent adhesions and capsuloligamentar retractions (10,15,17) Although many factors can influence treatment indication, such as clinical status of the patient, functional demand and kind of fracture, the key factor to be considered is the occurrence or not of fragments displacement or its potential instability.Fractures without displacement or as small as 4 mm are conservatively treated (3) .However, fractures with joint depression larger than 5 mm deserve surgical treatment (3,18,19) .As emphasized by Schatzker, the goal to accomplish when treating tibial plateau fractures is stability, alignment, mobility, relief of joint pain, as well as mitigation of the risks of evolving to osteoarthrosis.The access to fragments is critical for that.There are different treatment approaches: closed reduction with cast or traction; percutaneous fixation, with screws, wires or external fixator, under arthroscopic view or limited arthrotomy and open reduction by broad approach with plates and screws (20,21) .Additionally to the bone injury, soft parts such as blood vessels, nerves, joint capsule, menisci or ligaments are usually injured.A recent study showed that meniscal injuries were present in 70% of the 112 studied cases (22) .Most of the injuries occur on the posterior half and always on the side of the fractured condyle (23) .However, no correlation was found between soft parts injuries and the kind of fracture (22,23) .Preserving the meniscus as much as possible is paramount to achieve a satisfactory outcome when treating tibial plateau fractures, because that structure is responsible for joint congruence, impact absorption, distribution of forces and joint stability (24) .Other studies assessed ligamentar damages associated to fractures, with the medial collateral ligament being more frequently injured.In a retrospective review of the knees, unrepaired collateral ligaments showed worse outcomes for late instability and knee total function when compared to repaired knees.All cruciate ligament ruptures occurred as combined injuries, with its worst result being the late arthrosis (25) .Because of the disability this kind of fracture can cause on knee joint, this study was aimed to analyze, from the answers obtained with the application of the ADLS questionnaire (Activities of Daily Living Scale) (26) , functional capacity during daily life activities of patients experiencing tibial plateau fractures submitted to surgical treatment between 2002 and 2005 at the Hospital das Clínicas, Campinas State University (HC -UNICAMP).

MATERIALS AND METHODS
Patient data was withdrawn from the analysis of medical files stored at the HC -UNICAMP Medical Files Service (SAM).We requested from the operating theater of the hospital the codes corresponding to surgical procedures designed to treat tibial plateau fractures performed between January 2002 and December 2005.
A total of 36 medical files were assessed, studying the cases and assessing data (mechanism of injury, affected lower limb, fracture, surgery and hospital discharge dates, kind of fracture and surgical fixation, associated injuries, as well as personal data of each patient for a potential future contact) where only tibial plateau fractures had been diagnosed.The exclusion criteria selected for the present study were: presence of associated fracture(s), failure to contact the patient, psychotic cases and death.Upon these criteria, 20 patients were subsequently selected and assessed, diagnosed with tibial plateau fracture.For assessing the functional quality of the knee, the ADLS (Activities of Daily Living Scale) 26 questionnaire was applied.This questionnaire is composed of 17 questions, being seven (symptomatic) and ten (concerned to functional disability during daily life activities), each question has multiple alternatives with specific scores (Annex 1).Only one alternative should be checked for each question, and the scores are individually obtained for each subject by summing the scores on each question.The maximum score of the scale -concerned to the functional performance of the knee joint -is 80 and the minimum score is 0. The selection of the tool was based on its sensitivity when compared to other scales specifically designed to knee conditions (Cincinnati, Lysholm and Womac), which contributed to the article and to the new scale for functional evaluation of the knee joint (26,27) .This questionnaire was translated into Portuguese and applied to patients by telephone, without modifications to its overall characteristics.

RESULTS
From the selected patient sample, values for mean, standard deviation, maximum values and minimum value related to the scores of the ADLS questionnaire were obtained (Table 1).Concerning gender, of the total of 20 patients (Table 2), 16 (80%) are males and four (20%) are females (a ratio of 4:1).Concerning the affected side, seven (35%) occurred on the right lower limb, and 13 (65%) on the left lower limb.

Gender Side
Total 20 20

Table 2 -Incidence distribution according to gender (M)-male and (F)female and side: right (R) and left (L) of the affected individuals.
Graph 1 describes the mechanisms of trauma found during the research.There were eight (40%) falls (low-energy trauma) and 12 (60%) traffic accidents (high-energy trauma), being 6 (30%) motorcycle accidents, five (25%) car accidents and one (5) trampling.
Graph 2 shows the distribution of patients for age, grouped according to the age group, in increments of 10 years.Table 3 shows the mean, standard deviation, minimum and maximum values for the hospitalization time of patients submitted to tibial plateau surgery.Graph 3 shows that, among the 20 patients with tibial plateau fracture, four (20%) presented with associated soft parts injuries, two (10%) ligamentar, one (5%) meniscal, and one (5%) meniscal-ligamentar.

DISCUSSION
This study is primarily aimed to assess the functional capacity, after treatment, of individuals with tibial plateau fractures.In addition, several relevant data were analyzed in this research.
A recent study assessed the functional outcome of 35 patients with chronic debilitating knees after multiple ligament reconstruction.There were 27 men and eight women in the study, and the scores achieved on the ADLS questionnaire ranged from 25 to 98, with 72.7 as a mean value.According to the result of the research, 16 individuals were back to sports practice, and almost all of them, except for 3, returned to their professional occupations (28) .
Another study assessed the changes on muscular activation patterns and lower limbs motion in individuals with knee osteoarthritis.After the application of the ADLS questionnaire, the 24 subjects belonging to the group with knee osteoarthritis achieved a score of 70.1 and the remaining 24 subjects included on the control group showed a mean score of 99.8.The mean age in both groups was 62 years (29) .This study assessed 20 individuals (16 men and 4 women).
After the application of the ADLS questionnaire, we found the scores ranging from 11 to 79 (mean: 51.75).We could notice that three individuals scored 0-25%, none of them scored 26-50%, 10 were between 51 and 75%, and seven presented 76-100%, with the individuals presenting the best functional capacity being the ones closer to 100% (80 points) and the worst function closer o zero point.Therefore, most of the sample (17 individuals, 85%) showed a score for functional capacity of 51-100%.We could not qualitatively classify the patients, because the author of the scale did not determine parameters for this.
All the studies mentioned above used the ADLS scale to assess the functional capacity of individuals affected by different conditions compromising the knee joint.Thus, we found a variation on the scores and mean values of the scale that were achieved in each research.We could not make any comparison or discussion due to the different causes interfering on the joint function.
Currently, studies using the Activities of Daily Living Scale (ADLS) have been limited to apply the questionnaire to individuals with ligament and meniscal injuries, femoropatellar pain and osteoarthrosis.
According to the outcomes achieved in this study, left lower limbs were the most frequently affected structures compared to the right ones, with 13 (65%) involving the left side, and seven (35%) involving the right side, a finding that corroborates other studies (15,16) in which left knees were more often affected than the right ones (60% left vs. 40% right).The most common mechanism was the low-energy trauma, accounting for eight (40%) of the cases, with motorcycle and car accidents accounting for six (30%) and five (25%) of the cases, respectively.These data conflict with other studies (5)(6)(7)(8) , in which car accidents are the most prevalent ones.
Regarding the involvement by age group we could notice that for men, the incidence peak was 41-50 years (seven individuals), five of them by high-energy trauma (car or motorcycle accident) and two by low-energy trauma (falls).Therefore, these data are consistent with recent studies (4) .Table 3 -Values corresponding to mean, standard deviation (SD), maximum (max.) and minimum (min.)scores for time of hospitalization (days).
Graph 3 -Sample distribution, in absolute numbers, according to the presence or absence of associated soft parts (ligaments and menisci) injuries.

Graph 1 -Graph 2 -
Incidence of mechanism of trauma, falls and traffic accidents (car and motorcycle accidents, and trampling) affecting the individuals.Patient sample distribution, in absolute numbers, according to the age group (years).

Table 1 -
Values corresponding to mean, standard deviation (SD), maximum (max.) and minimum (min.)scores for knee joint function during daily life activities, obtained by applying the ADLS questionnaire to individuals with tibial plateau fractures.