Short lateral posterior condyle is associated with trochlea dysplasia and patellar dislocation.

PURPOSE: Surgeons mainly consider the anterior anatomy of the distal femur in the treatment of patellar instability (PI) with trochlear dysplasia (TD). Through this research, the idea was to analyse the posterior femoral condyle length in TD. The research team posited the presence of morphological differences in the posterior part of the femoral epiphysis in TD compared to a control group. They also postulated that the posterior bicondylar angle (PCA), in the axial plane, was increased in TD. METHODS: This is a single-centre morphological study of 100 patients who had a computed tomography (CT) using the same protocol. 50 patients with PI (25 dysplasias A and 25 B-C-D according to the Dejour classification), and 50 controls were included. All patients presenting a clinical PI were considered for the study. None of these patients had undergone a surgical treatment prior to imaging. Demographic characteristics, BMI, and laterality were comparable in all patients. 20 pilot CT scans were used to establish the methodology. The following measurements were performed: anterior bicondylar angle, PCA, and condylar lengths with respect to the surgical transepicondylar axis. Ratios were calculated in relation to the femoral width. TD was classified according to the Dejour classification in grade A or grades B-C-D. An analysis of variance and a linear model were performed within some groups to investigate which parameters correlated with the classification's grade. RESULTS: This study showed a link between TD and the PCA: control group (1.4 ± 0.2°), type A group (1.6 ± 0.3°), and types B, C, D group (2.6 ± 0.3°) (p = 0.01). The difference between the control group and types B, C, D TD group was significant (p = 0.002). In groups B, C, D, the PCA was more important, which proves that in these groups the posterior part of the lateral condyle was relatively shorter compared to the medial condyle. The greater the dysplasia, the longer the medial condyle was in the anterior posterior (p = 0.02). CONCLUSIONS: This study shows not only an anterior but also a posterior anomaly in PI with TD. There is a correlation between the severity of the anterior deformation and the PCA: in other words, the knee is placed in valgus in flexure which promotes the external dislocation of the patella. This anatomical study could open a field of research on the development of surgical treatments based on the correction of posterior condylar femoral anomalies in PI. LEVEL OF EVIDENCE: III.

Correction to: Short lateral posterior condyle is associated with trochlea dysplasia and patellar dislocation.

Unfortunately, the author name was incorrectly published in the original publication as Sébatien Lustig insted of Sébastien Lustig. The author name is corrected here by this Erratum. The original article has been corrected.

Trend of Perioperative CRP (C-Reactive Protein) Levels in Non-Infected Total Knee Arthroplasty.

The aim of this prospective study was to define the perioperative trend of C-reactive protein (CRP) in non-infected total knee arthroplasty (TKA). CRP was evaluated in 42 patients the day before surgery and 4 and 30 days after surgery. Functional and radiological evaluation was scheduled for 3, 6, and 12 months after surgery. Preoperatively, the median CRP was 3.2 mg/L (IQR,3.2-4.2) (reference range, 0-5 mg/L); 4 and 30 days after surgery, it measured 57.6 mg/L (IQR,36.1-96.4) and 5.3 mg/L (IQR,3.0-11.8), respectively. There were significant differences between the CRP preoperatively and 4 days after surgery (p<0.001) and between CPR levels 4 and 30 days after surgery (p<0.001) but not between CRP values preoperatively and 30 days after surgery (p=0.181). Higher preoperative CRP was associated to heart disease and chronic renal failure (r=0.329, p=0.036, and r=0.437, p=0.004, respectively). Four days after surgery, higher CRP was associated to older patients (r=0.311, p=0.048). In summary, 30 days after primary non-infected TKA, CRP levels were comparable to preoperative values. Older age and comorbidities should be carefully evaluated using postoperative CRP as diagnostic marker for the early detection of infection.