Importance of the gender and preoperative knee sagittal alignment to avoid unnecessary tibial resection in TKR.

BACKGROUND: Standard resections according to the TKR manufacturers can lead to unnecessary bone resections in some patients. The objective of this study was to determine in which patients is recommended to perform a minimal tibial resection (MTR) that could restore the joint line height (JLH). METHODS: Navigation records of 108 consecutive posterior cruciate-substituting TKR performed by one surgeon were analyzed. Optimal tibial resection depth to restore the JLH (0 mm) was calculated by an algorithm. Postoperatively, the knees were distributed in two groups: those in which a MTR (depth ≤ 8 mm) would have been enough to restore the JLH and those in which a standard resection depth would have been necessary. ROC curves and Youden index were used to determine the cutoff point of the coronal and sagittal mechanical axis that predicted a MTR restoring the JLH. Multivariate analysis was used to identify independent factors associated with requiring an MTR. RESULTS: A MTR could be required in 20 (18.5%) knees. In the ROC curve analyses, the cutoff points that best discriminated between minimal and standard tibial resection was ≤ 3° of varus and < 2° of flexion preoperative deformity. Multivariate analysis showed that female gender and preoperative flexion < 2° were significant predictors of requiring a MTR to restore JLH. CONCLUSION: A MTR with the JLH restoration could be possible in female patients with a preoperative sagittal deformity less than 2° of flexion. Preoperative coronal alignment had no influence to discriminate when a MTR is required.

Complications of computer-assisted navigation in total knee replacement: retrospective cohort of eight hundred and seventy eight consecutive knees.

PURPOSE: The main objective was to analyze the computer-assisted navigation (CAN)-specific complications that forced to switch to conventional procedure in primary total knee replacement (TKR). The secondary objective was to determine the influence of those complications on TKR short-term survival. METHODS: Retrospective study of 878 primary TKR in 753 patients. Two consecutive versions of the OrthoPilot navigation system (Braun Aesculap, Germany) were used during the study time. Specific complications of CAN were defined as those due to the instrumentation (hardware or software failures), which were classified in one of two categories according to whether they occurred during the registration or tracking process. RESULTS: There were 20 (2.3%) complications related to the navigation system use that forced to switch to conventional surgery: in 11 (1.2%) knees due to loosening of the tracking pins, and in the other nine (1.0%) there were information system failures. There was a trend for a higher conversion rate to conventional surgery with the use of the first version of the software. There were no fractures, infections, or nerve injuries at the pin site. We found no differences in the distribution of baseline variables among those with or without conversion to conventional surgery. There was no significant difference (p = 0.488) in the two year survival between patients with or without conversion. CONCLUSION: CAN for primary TKR is a safe method with few specific complications that forced to switch from the navigated to the conventional procedure. Conversion to conventional surgery did not affect the short-term survival of TKR.

Offset femoral en los resultados clínicos y funcionales de los pacientes / Femoral offset in the clinical and functional results of patients; Le déport fémoral dans les résultats cliniques et fonctionnels des patients

Introducción: La restauración de las fuerzas biomecánicas a través del ajuste del offset y la longitud de miembros se ha convertido en un objetivo importante cuando el cirujano busca un buen resultado funcional postoperatorio. Sin embargo, las ventajas clínicas de la restauración del offset femoral y las complicaciones del fallo en la restauración no han sido claramente establecidas. Objetivo: Evaluar el efecto del offset o voladizo femoral en los resultados clínicos y funcionales de los pacientes. Adquisición de la evidencia: Se realizó una exploración en la base de datos Pubmed, con las palabras clave: artroplastia de cadera, prótesis de cadera, resultado clínico y resultado funcional.Se buscaron artículos publicados entre 2008 y 2018, basados en humanos y escritos en inglés, español o francés. Se seleccionaron seis artículos que incluían la presencia de una medición radiológica del offset femoral claramente explicada, escalas validadas y análisis comparativo. Resultados: La literatura consultada reflejó resultados heterogéneos. En el grupo de pacientes con offset disminuido, un artículo mostró menos función. En otro estudio se observó mejor puntuación en el grupo de enfermos con offset aumentado. A su vez, en una investigación se comprobó menos dolor en el grupo de offset disminuido. Conclusiones: Debido a la inconsistencia en los resultados y en las metodologías empleadas, no ha sido posible reconocer el beneficio clínico y funcional de la restauración del offset. Algunos autores incluidos en esta revisión, después de no encontrar diferencias estadísticamente significativas, afirmaron que la restauración o el aumento del offset femoral aportó buenos resultados, sin efectos negativos(AU)

Introduction: The restoration of biomechanical forces through offset adjustment and limb length has become an important objective when the surgeon seeks a good postoperative functional result. However, the clinical advantages of femoral offset restoration and complications of restoration failure have not been clearly established. Objective: To evaluate the effect of offset or femoral cantilever on the clinical and functional results of the patients. Acquisition of evidence: An exploration was carried out in the Pubmed database, with the keywords: hip arthroplasty, hip prosthesis, clinical result and functional result. We searched for articles published from 2008 to 2018, based on humans and written in English, Spanish or French. Six articles were selected because they clearly explained the presence of a radiological measurement of the femoral offset, including validated scales and comparative analysis. Results: The literature consulted reflected heterogeneous results. In the group of patients with decreased offset, one article showed less function. In another study, a better score was observed in the group of patients with increased offset. In turn, one investigation reported less pain was found in the reduced offset group. Conclusions: Due to the inconsistency in the results and the methodologies used, it has not been possible to recognize the clinical and functional benefit of offset restoration. Some authors included in this review, after not finding statistically significant differences, stated that the restoration or increase of the femoral offset provided good results, without negative effects(AU)

Usefulness of a risk scale based on procalcitonin for early discrimination between necrotising fasciitis and cellulitis of the extremities. / Utilidad de una escala de riesgo basada en la procalcitonina sérica para la discriminación temprana entre fascitis necrosante y celulitis de las extremidades.

BACKGROUND AND OBJECTIVE: To assess the usefulness of a risk scale based on serum procalcitonin (PCT) compared to the Laboratory Risk Indicator for Necrotising Fasciitis (LRINEC) scale in the early discrimination between necrotising fasciitis (NF) and cellulitis of the extremities. MATERIALS AND METHODS: Retrospective study of consecutive patients with confirmed diagnosis of NF in one limb (n=11). This study group was compared with 23 consecutive patients with a diagnosis of severe limbs cellulitis during the same period. The clinical data and laboratory parameters were analysed, the main variable was the serum level of PCT upon admission. The capacity for NF diagnosis of the two methods, PCT level and LRINEC scale score, were evaluated by ROC curve and determined by the calculation of the area under the curve (AUC). RESULTS: The AUC was significantly higher with PCT measurement, both as a continuous variable and when the risk was categorised. The cut-off point for the PCT level with the highest AUC under the curve was from 0.87ng/ml (sensitivity 90.9%, specificity 82.6%), whereas it was a score of 5 on the LRINEC scale (sensitivity 72.7%, specificity 82.6%). CONCLUSION: PCT measurement was a more effective method than the LRINEC score for early discrimination between NF and cellulitis of the extremities. A low level of PCT, associated with the patient's clinical status and physical examination is especially useful to rule out an early diagnosis of NF.