Patient selection does not improve the success rate of infected TKA one stage exchange.

BACKGROUND: One stage exchange of a chronically infected total knee arthroplasty (TKA) is recommended in selected cases only. However, there is little evidence regarding the usefulness of selection criteria. The goal of this retrospective study was to compare the results of two concomitant cohorts of patients with chronically infected TKA: one treated with a routine one-stage exchange (study group) and one treated with one-stage exchange in selected cases only (control group). The hypoyhesis tested was that the failure rate and repeat surgery rate were higher in the study group than in the control group. METHODS: One hundred and thirty one cases were selected: 54 in the study group and 77 in the control group. There were 63 men and 68 women with a mean age of 70years. All patients were followed up for a minimal period of time of two years or until death or recurrence of infection. RESULTS: Twenty five cases had a recurrence of infection: 9/54 in the study group and 16/77 in the control group (NS). The survival rate for being free of infection after four years was 85% in the study group and 78% in the control group (NS). The repeat surgery rate was significantly higher in the control group. CONCLUSION: The tested hypothesis was rejected. When one stage exchange is considered, patient selection does not improve outcome.

High infection control rate and function after routine one-stage exchange for chronically infected TKA.

BACKGROUND: Many surgeons consider two-stage exchange the gold standard for treating chronic infection after TKA. One-stage exchange is an alternative for infection control and might provide better knee function, but the rates of infection control and levels of function are unclear. QUESTIONS/PURPOSES: We asked whether a one-stage exchange protocol would lead to infection control rates and knee function similar to those after two-stage exchange. METHODS: We followed all 47 patients with chronically infected TKAs treated with one-stage exchange between July 2004 and February 2007. We monitored for recurrence of infection and obtained Knee Society Scores. We followed patients a minimum of 3 years or until death or infection recurrence. RESULTS: Three of the 47 patients (6%) experienced a persistence or recurrence of the index infection with the same pathogen isolated. Three patients (6%) had control of the index infection but between 6 and 17 months experienced an infection with another pathogen. The 3-year survival rates were 87% for being free of any infection and 91% for being healed of the index infection. Twenty-five of the 45 patients (56%) had a Knee Society Score of more than 150 points. CONCLUSIONS: While routine one-stage exchange was not associated with a higher rate of infection recurrence failure, knee function was not improved compared to that of historical patients having two-stage exchange. One stage-exchange may be a reasonable alternative in chronically infected TKA as a more convenient approach for patients without the risks of two operations and hospitalizations and for reducing costs. The ideal one stage-exchange candidate should be identified in future studies.

Small differences between anatomical and mechanical sagittal femur axes: a radiological and navigated study of 50 patients.

BACKGROUND AND PURPOSE: The purposes of the study were to define the orientation of the anatomical and mechanical axes of the femur on the lateral plane on long leg X-rays including the femoral head, and to compare these results to the intra-operative measurement of the mechanical axis by a nonimage-based navigation system. METHODS: Fifty cases of patients operated on for total knee replacement were included. All patients had digital pre- and post-operative long leg lateral X-rays including the femoral head. All prostheses were implanted with a nonimage-based navigation system. Five sagittal femur axes were measured on pre- and post-operative X-rays. The sagittal orientation of the distal femoral resection was measured by the navigation system and on the post-operative X-rays. RESULTS: Significant, but small differences were observed in the orientation of the different axes on the pre- and post-operative X-rays. The correlation and the agreement between all axes were good. There was no significant modification on the post-operative X-rays. There were significant, but small differences between the navigated and radiological orientation of the distal femur resection, but the correlation and the agreement were good. INTERPRETATION: The differences observed are small and have probably little clinical relevance. The distal cortical axis may be the best compromise. The navigation system allows measuring accurately the orientation of the distal femoral resection in the sagittal plane.

Relevance of the anatomical location of the Adamkiewicz artery in spine surgery.

PURPOSE: The aim of this study was to describe the preoperative topography of the Adamkiewicz artery and the blood supply of the lumbosacral spinal cord in patients who underwent spinal surgery. The relevance for anterior approaches of the thoracolumbar spine was then analyzed. METHODS: One hundred consecutive spinal angiographies were reviewed. Surgical indications were: 26 vertebrectomies, 30 anterior fusions in fractures, 13 malunions, 16 anterior releases in scoliosis, 11 pedicle subtraction osteotomies and 4 thoracic disc hernias. The level and the side of the Adamkiewicz artery and the presence of additional radiculomedullary arteries were determined. Modifications of surgical planning owing to the Adamkiewicz artery were analyzed. RESULTS: The Adamkiewicz artery was always located between T8 and L3, at T9 or T10 in 50%, and coming from the left side in 75% of the cases. Additional radiculomedullary arteries were found in 43% of the cases. A concordance between the topography of the Adamkiewicz artery and the planned surgical approach was noted in 15%, which led to ten side changings and three modifications of surgical technique with segmental vessel preservation. An ischemic syndrome of the anterior spinal cord did not occur. CONCLUSIONS: Spinal cord ischemia is rarely reported after segmental vessel ligation. Spinal angiography allows determining the topography of the Adamkiewicz artery safely. If the planned surgical approach is located at the same level, a contralateral approach or selective surgical techniques without vessel ligation could avoid possible damage to the Adamkiewicz artery if the pathology does not dictate the side and the extent of the surgical approach.