[Translated article] Comparative clinical and biomechanical study of different types of osteosynthesis in the treatment of distal femur fractures.

INTRODUCTION AND OBJECTIVES: Distal femoral fractures represent a problem due to their high number of complications. The aim was to compare the results, complications and stability achieved with retrograde intramedullary nailing and the angular stable plate in the treatment of distal femoral diaphyseal fractures. MATERIAL AND METHOD: A clinical and experimental biomechanical study was carried out using finite elements. The results of the simulations allowed us to obtain the main results related to the stability of osteosynthesis. For clinical follow-up data, frequencies were used for qualitative variables, and Fisher's exact test and χ2 test were used to evaluate the significance of the different factors, with the condition of P<.05. RESULTS: In the biomechanical study, the retrograde intramedullar nails demonstrated superiority, obtaining lower values in terms of global displacement, maximum tension, torsion resistance, and bending resistance. In the clinical study, the rate of consolidation of the plates was lower than nails (77% vs. 96%, P=.02). The factor that most influenced the healing of fractures treated with plate were the central cortical thickness (P=.019). The factor that most influenced the healing of nail-treated fractures was the difference between the diameter of the medullary canal and the nail. CONCLUSIONS: Our biomechanical study shows that both osteosynthesis provide sufficient stability, but biomechanically behaves differently. Nails provide greater overall stability being preferable the use of long nails adjusted to the diameter of the canal. Plates form less rigid osteosynthesis, with little resistance to bending.

Comparative clinical and biomechanical study of different types of osteosynthesis in the treatment of distal femur fractures. / Estudio comparativo clínico y biomecánico de distintos tipos de osteosíntesis en el tratamiento de fracturas distales de fémur.

INTRODUCTION AND OBJECTIVES: Distal femoral fractures represent a problem due to their high number of complications. The aim was to compare the results, complications and stability achieved with retrograde intramedullary nailing and the angular stable plate in the treatment of distal femoral diaphyseal fractures. MATERIAL AND METHOD: A clinical and experimental biomechanical study was carried out using finite elements. The results of the simulations allowed us to obtain the main results related to the stability of osteosynthesis. For clinical follow-up data, frequencies were used for qualitative variables, and Fisher's exact test and χ2 test were used to evaluate the significance of the different factors, with the condition of P<.05. RESULTS: In the biomechanical study, the retrograde intramedullar nails demonstrated superiority, obtaining lower values in terms of global displacement, maximum tension, torsion resistance, and bending resistance. In the clinical study, the rate of consolidation of the plates was lower than nails (77% vs. 96%, P=.02). The factor that most influenced the healing of fractures treated with plate were the central cortical thickness (P=.019). The factor that most influenced the healing of nail-treated fractures was the difference between the diameter of the medullary canal and the nail. CONCLUSIONS: Our biomechanical study shows that both osteosynthesis provide sufficient stability, but biomechanically behaves differently. Nails provide greater overall stability being preferable the use of long nails adjusted to the diameter of the canal. Plates form less rigid osteosynthesis, with little resistance to bending.

Influence of plate size and screw distribution on the biomechanical behaviour of osteosynthesis by means of lateral plates in femoral fractures.

Distal femoral fractures are fractures associated with high rates of morbidity and mortality, affecting to three different groups of individuals: younger people suffering high-energy trauma, elderly people with fragile bones and people with periprosthetic fractures around previous total knee arthroplasty. They have been classically treated with conventional plates and intramedullary nails and more recently with locked plates that have increased their indications to more types of fractures. The main objective of the present work is the biomechanical study, by means of finite element simulation, of the stability achieved in the osteosynthesis of femoral fractures in zones 4 and 5 of Wiss, by using locked plates with different plate lengths and different screw configurations, and analysing the effect of screw proximity to the fracture site. A three dimensional (3D) finite element model of the femur from 55-year-old male donor was developed, and then a stability analysis was performed for the fixation provided by Osteosynthesis System LOQTEC® Lateral Distal Femur Plate in two different fracture zones corresponding to the zones 4 and 5 according to the Wiss fracture classification. The study was focused on the immediately post-operative stage, without any biological healing process. The obtained results show that more stable osteosyntheses were obtained by using shorter plates. In the cases of longer plates, it results more convenient disposing screws in a way that the upper ones are closer to fracture site. The obtained results can support surgeons to understand the biomechanics of fracture stability, and then to guide them towards the more appropriate osteosynthesis depending on the fracture type and location.

Hip fracture in centenarians, what can we expect? / Fractura de cadera en pacientes centenarios, ¿qué podemos esperar?

INTRODUCTION: Hip fractures in centenarians are rising due to the increase in life expectancy. The objective of this study is to compare the characteristics of centenarians' hip fracture with a younger control group, and to analyze whether there are differences in terms of in-hospital mortality, complications, and short-medium-term survival between them. MATERIAL AND METHODS: Retrospective case-control study, with a series of 24 centenarians and 48 octogenarians with a hip fracture. Comorbidities and Charlson index, surgical delay, complications and mortality during admission, and hospital stay were analyzed. At discharge, early mortality, survival after one year, and return to previous functionality were assessed. RESULTS: No significant differences were found in baseline parameters or comorbidities (P>.05), and the type of was a woman with an extracapsular fracture. Hospital stay was longer in the control group (P=.038), and the most frequent complication was anemia requiring transfusion (23/24 in centenarians, P<.0001). In-hospital mortality and accumulated at one year in the centenarians was 33 and 67%, respectively, compared to 10 and 25% in the octogenarians (P=.017, OR=4.3 [1,224-15,101] and P=.110). Only 2 centenarian patients were able to walk again after the intervention, while in the control group 53.84% returned to the previous functional situation (P=.003). CONCLUSIONS: Compared to a control group of younger patients, in-hospital mortality and in the first year after a hip fracture is significantly higher in centenarians, and very few recover activity prior to the fracture.

Primary total hip arthroplasty for acetabular fractures in elderly patients. / Artroplastia total de cadera primaria en fractura de acetábulo en el paciente anciano.

INTRODUCTION: Life expectancy has risen, leading to an increase in acetabular fractures in fragile patients. Total hip arthroplasty with a reinforcement cage is a technically complex option, but allows fracture control and early mobilization. Our aim is to assess whether the use of Burch-Schneider cage in fragile patients with acetabular fractures allows immediate load stabilization without threatening the early survival of the arthroplasty. MATERIAL AND METHODS: Descriptive study of a series of 14 patients with acetabular fractures treated by a reinforcement cage associated with autologous bonegraft plus a cemented acetabular cup, and mobilization and bearing. Judet Letournel fracture types, surgical delay, and complications during admission were analyzed. Following hospital discharge we recorded the incorporation of grafts according to Gie's classification, presence of calcifications according to Brooker, consolidation of the fracture, loosening of implants and functional aspects according to the HHS and Merlé D'Aubigné Postel score. RESULTS: The most common fracture was both columns (6/14), with a surgical delay being of 11 days mean and 21,5 days of length of stay. One patient died after surgery. The mean follow-up was 34.4 months. All fractures healed and the bonegraft was incorporated in all cases. The mean HHS was 82 points and the Merle Score was 15/18. There were no complications related to arthroplasty. CONCLUSIONS: Total hip arthroplasty with Burch-Schneider cage on bonegraft and no added osteosynthesis is a good option of treatment of all types of displaced acetabular fractures in a fragile patient.

A new approach for initial callus growth during fracture healing in long bones.

The incidence of bone fracture has become a major clinical problem on a worldwide scale. In the past two decades there has been an increase in the use of computational tools to analyse the bone fracture problem. In several works, various study cases have been analysed to compare human and animal bone fracture healing. Unfortunately, there are not many publications about computational advances in this field and the existing approaches to the problem are usually similar. In this context, the objective of this work is the application of a diffusion problem in the model of the bone fragments resulting from fracture, working together with a mesh-growing algorithm that allows free growth of the callus depending on the established conditions, without a pre-meshed domain. The diffusion problem concerns the different biological magnitudes controlling the callus growth, among which Mesenchymal Stem Cells and chondrocytes concentrations were chosen, together with Tumour Necrosis Factor α and Bone Morphogenetic Protein as the factors influencing the velocity in the callus formation. A Finite Element approach was used to solve the corresponding diffusion problems, obtaining the concentration values along the entire domain and allowing detecting the zones in which biological magnitudes reach the necessary thresholds for callus growth. The callus growth is guided by a geometrical algorithm which performs an additional mesh generation process (self-added mesh) at each step of the iterative procedure until complete callus formation. The proposed approach was applied to different types of diaphyseal femoral fractures treated by means of intramedullary nailing. Axisymmetric models based on triangular quadratic elements were used, obtaining results in good agreement with clinical evidence of these kinds of fractures. The algorithm proposed has the advantage of a natural callus growth, without the existence of a previous mesh that may affect the conditions and direction of growth. The approach is intended for the initial phase of callus growth. Future work will address the implementation of the corresponding formulations for tissue transformation and bone remodelling in order to achieve complete fracture healing.

Outcomes of basicervical femoral neck fracture treated with percutaneous compression plate (PCCP).

INTRODUCTION: Basicervical femoral neck fracture is associated with high rates of failure due instability patterns, mainly collapse and rotational instability. The purpose of this study was to evaluate the clinical-radiological results of a group of patients with a bascervical proximal femoral fractures treated with Percutaneous Compression Plate (PCCP). MATERIAL AND METHODS: Among 5817 patients with a hip fracture who were admitted in our hospital from January 2005 to December 2017, 234 factures (4%) were diagnosed of basicervical femoral fracture. 30 of them were treated with a PCCP, 22 women and 8 men, mean age was 81.2 years (63-94). Demographic and perioperative variables were collected. The patients were followed up at 1, 3 and 6 months clinically and radiologically. RESULTS: There were no intra-operative complications and no conversions to open surgery. There was no early implant failure. No surgical wound infection was diagnosed. Crude mortality was 13% the first year and 87% were able to walk at the 6 months. The last follow-up x-rays revealed 97% fracture healing and the collapse at fracture site occurred in 4 hips. No instances of cut-out were observed. In one case, a fatigue failure of the lag screws of a PCCP plate was observed at 3 months from osteosynthesis. CONCLUSION: PCCP is an appropriated implant for basicervical femoral neck fractures.

Are the unreamed nails indicated in diaphyseal fractures of the lower extremity? A biomechanical study.

INTRODUCTION: Intramedullary nailing is generally accepted as the first choice for the treatment of diaphyseal fractures of femur and tibia, with a gradual incease in the use of unreamed nails. Different studies during last years show controversial outcomes. Some authors strongly favor unreamed nailing, but most of the authors conclude that reamed nailing have proved to be more successful. MATERIAL AND METHODS: This study simulates unreamed intramedullary nailing of four femoral and three tibial fracture types by means of Finite Element (FE) models, at early postoperative stages with a fraction of physiological loads, in order to determine whether sufficient stability is achieved, and if the extent of movements and strains at the fracture site may preclude proper consolidation. RESULTS: The behavior observed in the different fracture models is very diverse. In the new biomechanical situation, loads are only transmitted through the intramedullary nail. Mean relative displacement values of fractures in the femoral bone range from 0.30 mm to 0.82 mm, depending on the fracture type. Mean relative displacement values of the tibial fractures lie between 0.18 and 0.62 mm, depending on the type of fracture. Concerning mean strains, for femoral fractures the maximum strains ranged between 12.7% and 42.3%. For tibial fractures the maximum strains ranged between 10.9% and 40.8%. CONCLUSIONS: The results showed that unreamed nailing provides a very limited mechanical stability, taking into account that analyzed fracture patterns correspond to simple fracture without comminution. Therefore, unreamed nailing is not a correct indication in femoral fractures and should be an exceptional indication in open tibial fractures produced by high-energy mechanism.

Biomechanical behavior of retrograde intramedullary nails in distal femoral fractures.

Fractures of the distal femur affect three different groups of individuals: younger people suffering high-energy trauma, elderly people with fragile bones and people with periprosthetic fractures around previous total knee arthroplasty. Main indications of intramedullary nailing are for supracondylar fractures type A or type C of the AO classification. The main objective of the present work is to analyze, by means of FE simulation, the influence of retrograde nail length, considering different blocking configurations and fracture gaps, on the biomechanical behavior of supracondylar fractures of A type. A three dimensional (3D) finite element model of the femur from 55-year-old male donor was developed, and then a stability analysis was performed for the fixation provided by the retrograde nail at a distal fracture with different fracture gaps: 0.5 mm, 3 mm y 20 mm, respectively. Besides, for each gap, three nail lengths were studied with a general extent (320 mm, 280 mm and 240 mm), considering two transversal screws (M/L) at the distal part and different screw combinations above the fracture. The study was focused on the immediately post-operative stage, without any biological healing process. In view of the obtained results, it has been demonstrated new possibilities of blocking configuration in addition to the usual ones, which allows establishing recommendations for nail design and clinical practice, avoiding excessive stress concentrations both in screws, with the problem of rupture and loss of blocking, and in the contact of nail tip with cortical bone, with the problem of a new stress fracture.

Salvage of cephalomedullary nail cutout with the variable angle proximal femoral plate.

INTRODUCTION: Excellent results have been published in the treatment of the trochanteric fractures in the elderly with cephalomedullary nails or compression hip screws but not free of complications. The perforation of the lag screw through the superior cortex of femoral neck or head followed by rotation and varus collapse of the head-neck fragment, also known as cut-out, is one of them. Probably total hip arthroplasty is the most common solution, but there is no systematic technique for treatment. The objective of this study is to evaluate the results obtained in the treatment of this complication using a variable angle femoral plate. MATERIAL AND METHODS: This retrospective study concerns patients over 65 years with peritrochanteric fractures treated with cephalomedullary nail with cut-out failure solved by re-osteosyntesis with variable angle femoral plate between 1st January 2000 and 31 st December 2017. The series includes 29 patients, 26 women and 3 men with average age 87,3. Patients were followed up clinically and radiologically at regular intervals until fracture consolidation at least 9 months. RESULTS: No patients died at the first 9 months after surgery. Fracture mean consolidation has occurred in all patients in 14th weeks (6-20). Operative time was 93,2 minutes (62-129) including removal of nail. No intraoperative complications were observed. Five patients experienced medical complications and two had a superficial wound infection. The mean tip-apex distance (TAD) was 5mm (2-7mm). The neck-shaft angle was 127 degrees. The mean valgization achieved was 32 degrees (15-40). Only one patient needed a second revision surgery due to aseptic hip joint subluxation after 8 weeks of the surgery solved with total hip arthroplasty. CONCLUSIONS: The use of variable angle femoral plate in the cut-out treatment is an attractive option which allows the valgization of the fracture to virtually physiological limits and the placement of the cephalic screw in the most sutiable position with good outcomes and few complications.

Is the mortality higher in patients who have suffered a hip fracture? / ¿Es mayor la mortalidad en los pacientes que han sufrido una fractura de cadera?

BACKGROUND AND OBJECTIVE: The aim of this study is to value whether patients who have suffered a hip fracture have a higher mortality than expected. MATERIAL AND METHODS: A prospective, observational study was carried out where patients with hip fracture were collected as a sample over a year. The study included 284 patients and a minimum follow-up was 2 years. The mean age of these patients was 84.26 years, with 21.48% (61/284) males and 78.5% (223/284) females. Survival and previous diseases that affect mortality, as risk factors, were collected and analyzed using the Kaplan-Meier method and the Cox regression model. Actual mortality was compared with that expected according to the Charlson Comorbidity Index, adjusted for age. RESULTS: Previous pathology was the main mortality factor, with heart disease being the most significant (OR 1.817, CI95%: 1.048; 3.149). The real mortality at one year of the sample was 22.5%, while the estimated annual mortality according to the Charlson Comorbidity Index was 29.68% (CI95%:44,36-15). CONCLUSIONS: Hip fracture does not cause an increase in mortality according to the Charlson Comorbidity Index estimate.

Risk factors of periprosthetic femoral fracture after total knee arthroplasty. / Factores de riesgo en fractura periprotésica femoral tras artroplastia sustitutiva primaria de rodilla.

INTRODUCTION AND OBJECTIVES: Periprosthetic fractures after primary knee arthroplasty has great importance in our environment due to the increase in their incidence and to the challenge they pose to the surgeon. Multiple factors have been associated with its production. The objective of the study was to identify the risk factors that could influence the appearance of these fractures, which of them are all modifiable and generate a probability prediction model based on these factors. MATERIAL AND METHODS: Analytical, observational, retrospective, unpaired study of 38 cases of periprosthetic femoral knee fractures and 80 controls with knee prostheses. In total, 118 patients, 83 women and 35 men with a mean age of 72.49 years were included in the study. Sociodemographic data, medical history and drug consumption were collected, as well as those related to surgery. A univariate and bivariate analysis of the fracture determining factors was performed, using a logistic regression model to avoid confusion bias. RESULTS: Of all the factors studied according to the logistic regression model, it was obtained that female sex (OR = 7.6), dementia (OR = 5), motor/parkinson's alteration (OR = 19.3) and femoral overcut Previous (OR = 8.6) were factors associated with the increased risk of this type of fractures. CONCLUSIONS: This work allows us to conclude that there are risk factors such as female sex, dementia and parkinson's that increase the probability of periprosthetic fracture that are inherent to the patient and are not modifiable. However, there is any other totally modifiable that can be avoided by being demanding and thorough in the surgical technique, such as the anterior femoral overcut.

Biomechanical analysis of the stability of anterograde reamed intramedullary nails in femoral spiral fractures.

Femoral shaft fractures present high morbidity and important complications and consequences, being spiral fractures the most complicated from a biomechanical point of view, being unstable and without possibility of getting a good contact between nail and femoral endosteum. Femoral diaphyseal fractures are treated, usually, by means of intramedullary nailing. So, it is necessary to know the osteosynthesis stability and which locking screws combination is optimal. This work studies the use of reamed locked intramedullary nails in spiral femoral fractures located along zones 2 and 4 of wiss, depending on the spire length, corresponding to 32-A spiral type in AO/OTA classification, which represent a percentage of 23% within the total of diaphyseal fractures. A three-dimensional finite element model of the femur was developed, modeling a spiral fracture with different spiral lengths and gaps. A femoral nail was used, considering two transversal screws both at the proximal and the distal parts. The study was focused on the immediately post-operative stage, verifying the appropriate stability of the osteosynthesis. Reamed intramedullary blocked nails provide appropriate stability of femoral spiral fractures, considering global mobility of femoral head with respect to femoral condyles, relative displacements between fragments at fracture site, stresses at nail and locking screws, and stresses at cortical bone. The obtained results show that the use of blocked reamed nails in spiral femoral fractures can be considered as an appropriate surgical technique, providing sufficient stability in order to obtain an adequate fracture healing.

Comparative analysis of the biomechanical behavior of anterograde/retrograde nailing in supracondylar femoral fractures.

Supracondylar femoral fractures account for a noticeable percentage of the femoral shaft fractures, affecting two etiological groups: high energy trauma in young men, with good bone quality, and older women with osteoporotic femur. Surgical treatment of those kind of fractures remains controversial, with different surgical options such as plate and sliding barrel locking condylar plate, less invasive stabilization system (LISS) or intramedullary nailing, which has emerged as a new fixation choice in the treatment of that type of fractures. The present work performs a comparative study about the biomechanical behavior of anterograde and retrograde nailing in supracondylar femoral fractures type A, in order to determine the best choice of nailing and locking configuration. A three-dimensional finite element model of the femur was developed, modeling femoral supracondylar fracture and different nailing configurations, both for anterograde and retrograde nails. The study was focused on the immediately post-operative stage, verifying the appropriate stability of the osteosynthesis. The obtained results show a better biomechanical behavior for anterograde nails, providing a better stability from the point of view of global movements, lower stresses in screws, and less stress concentration in cortical bone. So, for the analyzed fractures and osteosyntheses types, anterograde nailing has demonstrated to be a better surgical option, being an excellent indication in supracondylar fractures of femur, with clear benefits compared to retrograde nailing, providing a better stabilization which enables for a more satisfactory fracture healing.

Causes of unplanned admission after orthopedic procedures in ambulatory surgery. / Causas de ingresos no deseados tras la realización de procedimientos quirúrgicos de cirugía ortopédica y traumatología en cirugía mayor ambulatoria.

OBJECTIVE: Orthopaedic procedures performed in Day Surgery Units provide important advantages which disappear when patients require admission when postoperative recovery is not as expected. The aim of this study was to analyse the reasons for unplanned hospital admissions after orthopaedic procedures in a Day Surgery Unit and their relationship between variables such as patient age, anaesthetic risk and technique, procedure or duration. METHODS: Ambispective cohort study of 5,085 patients who underwent surgical orthopaedic procedures between 1995 and 2017. Thirty-nine variables provided by the Unit's database were analysed. The database was opened on the day of admission and closed the 30th postoperative day. RESULTS: Of the patients, 98.2% were discharged from the Unit. Seventy-four (1.5%) required overnight admission. This percentage showed significant differences in relation to the type of procedure, type of anaesthesia and duration, which conditioned overnight admission due to inadequate postoperative pain management, nausea or wound complications. Seventeen patients (0.3%) required readmission after discharge due to complications that arose at home, such as wound infection, which was the most common. CONCLUSIONS: Unplanned admissions are more frequently related to general anaesthesia, lengthy surgeries and procedures such as arthroscopy, hallux valgus corrections or removal of osteosynthesis material. The major reasons for unplanned admissions were inadequate postoperative pain management for overnight admissions and wound infection for admissions after discharge.

Burch-Schneider ring associated with morselized bone allografts, survival and clinical outcomes after acetabular revision surgery. / Anillo de Burch-Schneider asociado a injerto óseo triturado, supervivencia y resultados clínicos en revisión acetabular.

INTRODUCTION AND OBJECTIVES: Acetabular revision surgery is a challenge due to the appearance of bone defects that make primary fixation of implants difficult when extracting loosened components. Reinforcement rings, such as Burch-Schneider (BS), have been shown to be allies in moderate or severe bone defects. The objective of the study is to evaluate the results and survival of these types of implants in acetabular revision surgery in the medium follow-up. MATERIAL AND METHODS: Retrospective study on a cohort of 64 patients (67 replacements) with BS rings associated with morselized bone allografts in a 2 years minimum follow-up. Data were collected regarding clinical outcomes, graft incorporation, implant mobilization, survival and complications. RESULTS: The mean follow-up was 5.06 years (R=2.2-12). The Merle scale improved from 8 points to 15 points at the end of follow-up (P<.0001) with 76.11% of good or excellent results. Reproduction of the anatomical centre of rotation was associated with a better result (P<.05). There was total or subtotal incorporation of the bone allograft in 97% of the patients, although this did not prevent a significant migration of the ring according to Gill criteria in 6 cases. We observed an overall survival of the implant for any cause of 93.4% at 5 years, and 84.6% at 10 years. CONCLUSIONS: The BS reinforcement ring shows good results in the medium and long term enabling anatomical reconstruction in revision surgery as well as replacement of the bone stock. These results are also comparable and are a vast improvement on other rings.

Navigated versus conventional total knee arthroplasty: A prospective study at three years follow-up. / Artroplastia total de rodilla navegada versus convencional; estudio prospectivo a 3 años de seguimiento.

OBJECTIVE: Computer-assisted surgery application in total knee arthroplasty (TKA) has shown more accurate implant alignment compared with conventional instrumentation and is associated with more homogeneous alignment results. Although longer implant survival and superior clinical outcomes should be expected from navigated TKA, currently available evidence does not support this hypothesis. The aim of this study was to compare navigated TKA with conventional TKA regarding clinical and radiological outcomes after a 3-year follow-up under the hypothesis that navigated TKA would provide better outcomes than conventional TKA. MATERIAL AND METHOD: In a prospective multicentre study, 119 patients underwent navigated TKA and 80 patients received conventional instrumentation. Patients were evaluated at the baseline and at postoperative months 3, 12, 24, and 36. Analysis included the American Knee Society Score (KSS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Short Form-12 (SF12) Health Survey, and radiographic assessment. RESULTS: All clinical scores improved significantly for all patients during the follow-up but were significantly better in the navigation group. The percentage of patients showing a mechanical axis between 3° of varus and 3° of valgus was significantly higher in the ATR group (93%) than in the conventional TKA group (71%) (P<.01). CONCLUSIONS: The use of computer-assisted surgery in TKA provides more accurate mechanical alignment and superior short-term functional outcomes compared to conventional TKA.

La importancia de la restauración de la línea articular en la revisión de la artroplastía total de rodilla. Índices funcionales, calidad de vida y supervivencia / The importance of the restoration of the joint line in revision total knee arthroplasty. Clinical indexes, quality of life and survival

Resumen: Introducción: La reproducción de la correcta línea articular podría ser un buen índice para la obtención de resultados satisfactorios en la cirugía protésica de rodilla, aunque en la cirugía de revisión no se ha estudiado ampliamente. Es necesaria la búsqueda de un método sencillo y reproducible para evaluar esos resultados. Material y métodos: Se realizó un estudio retrospectivo entre Enero del 2000 y Diciembre del 2013. Se implantaron 97 artroplastías totales de revisión de rodilla. El grupo de estudio lo conformaron 67 pacientes. Para la realización de nuestro trabajo se evaluó la línea articular según el método descrito por Hofmann A. La evaluación de los resultados clínicos incluyó las siguientes variables primarias: flexión, extensión, rango de movimiento, WOMAC, SF-36, KSS (Knee Society Score) y KSS funcional. Se estudió la supervivencia de las artroplastías. Resultados: Las variables de flexión, extensión y rango de movimiento postoperatorio se correlacionaron estadísticamente con esta medición. El KSS se relacionó estadísticamente en su vertiente articular con la restauración de la línea articular. Para el resto de escalas, SF-36 y WOMAC, las puntuaciones fueron más altas pero no se correlacionó con la significación aceptada. Conclusión: Ante estos resultados podemos afirmar que la restauración de la correcta línea articular mejora los resultados clínicos de la cirugía de revisión de rodilla.

Abstract: Introduction: The reproduction of the anatomical joint line could be a good index to obtain good results in knee prosthesis surgery, although in revision surgery has not been enough studied. A search for a simple and reproducible method is needed to review these results. Material and methods: A retrospective study was conducted between January 2000 and December 2013. A total of 97 total revision knee arthroplasties were implanted. Finally, the study group consisted of 67 patients. To perform our study, the joint line was evaluated according to the method described by Hofmann A. The evaluation of the clinical results included the following main variables: Flexion, extension, range of motion, WOMAC, SF-36, KSS (Knee Society Score) and functional KSS. The survival of the arthroplasties was studied. (p = 0.05). Results: The variables of flexion, extension and range of postoperative movement are statistically correlated with this measure. The KSS was statistically related in its joint aspect with the restoration of the joint line. For the other scales, SF-36 and WOMAC, the figures were higher but did not correlate with the accepted p. Conclusion: In view of these results, we can say that the restoration of the anatomical joint line improves the clinical results of revision total knee arthroplasty.

Do we perform surgical programming well? How can we improve it? / ¿Realizamos bien la programación quirúrgica? ¿Cómo podemos mejorarla?

The objective is to establish the duration of our interventions, intermediate times and surgical performance. This will create a virtual waiting list to apply a mathematical programme that performs programming with maximum performance. MATERIAL AND METHODS: Retrospective review of 49 surgical sessions obtaining the delay in start time, intermediate time and surgical performance. Retrospective review of 4,045 interventions performed in the last 3 years to obtain the average duration of each type of surgery. Creation of a virtual waiting list of 700 patients in order to perform virtual programming through the MIQCP-P until achieving optimal performance. RESULTS: Our surgical performance with manual programming was 75.9%, ending 22.4% later than 3pm. The performance in the days without suspensions was 78.4%. The delay at start time was 9.7min. The optimum performance was 77.5% with a confidence of finishing before 15h of 80.6%. The waiting list has been scheduled in 254 sessions. DISCUSSION: Our manual surgical performance without suspensions (78.4%) was superior to the optimal (77.5%), generating days finished later than 3pm and suspensions. The possibilities for improvement are to achieve punctuality at the start time and adjust the schedule to the ideal performance. The virtual programming has allowed us to obtain our ideal performance and to establish the number of operating rooms necessary to solve the waiting list created. CONCLUSIONS: The data obtained in virtual mathematical programming are reliable enough to implement this model with guarantees.