Jérôme Murgier1, Élodie Chantalat2, Ke Li3, Philippe Chiron1, Norbert Telmon4, Wei Huang3, Emilie Berard4, Etienne Cavaignac5. 1. CHU de Toulouse, hôpital Pierre-Paul Riquet, institut musculo squelettique, 31059 Toulouse, France. 2. Laboratoire d'anatomie, faculté de médecine, 31000 Toulouse, France. 3. Service de chirurgie orthopédique, Premier hôpital affilié de l'université de médecine de Chongqing, Chongqing, China. 4. UMR1027 Inserm, service d'épidémiologie, analyse en santé publique, université de Toulouse III, Centre Hospitalier Universitaire (CHU), Toulouse, France. 5. CHU de Toulouse, hôpital Pierre-Paul Riquet, institut musculo squelettique, 31059 Toulouse, France; Laboratoire AMIS, UMR 5288 CNRS, université Paul-Sabatier, 37, allée Jules-Guesdes, 31000 Toulouse, France. Electronic address: cavaignac.etienne@gmail.com.
Abstract
BACKGROUND: The posterior condylar angle (PCA) is formed by the posterior condylar line (PCL) and the clinical (or anatomic) transepicondylar line (TEL). The primary objective of this study was to compare the distribution of PCA values in Caucasians and Asians free of knee osteoarthritis. The secondary objectives were to assess PCA variability according to age, gender, and side. HYPOTHESIS: PCA values differ between Caucasians and Asians. METHODS: The study included the computed tomography scans of 515 healthy femurs, 259 from Asians in China and 256 from Caucasians in France. PCA values were determined based on four landmarks, namely, the two femoral epicondyles and the most prominent point of each condyle at the posterior aspect of the knee. The Mann-Whitney test was chosen to compare PCA values according to ethnic group, gender, and side and Spearman's correlation coefficient to assess correlations with age. Inter-observer and intra-observer variability of PCA measurements was assessed. RESULTS: Mean PCA was 6.0°±2.5° (range, 0°-14°) overall, 6.4° (range, 0.31°-14.1°) in the Asians, and 5.5° (range, 0°-13.1°) in the Caucasians (p<0.0001). Chinese femurs are significantly more internally rotated. No differences in PCA values were found according to age (p=0.4307), gender (p=0.7113), or side (p=0.4304). Inter-observer and intra-observer variability was limited for each of the landmarks, indicating that PCA measurement was reliable. CONCLUSION: PCA varies not only across individuals as reported previously, but also across ethnic groups. This finding further supports routine PCA measurement on imaging studies before total knee arthroplasty. LEVEL OF EVIDENCE: III, comparative retrospective study.
BACKGROUND: The posterior condylar angle (PCA) is formed by the posterior condylar line (PCL) and the clinical (or anatomic) transepicondylar line (TEL). The primary objective of this study was to compare the distribution of PCA values in Caucasians and Asians free of knee osteoarthritis. The secondary objectives were to assess PCA variability according to age, gender, and side. HYPOTHESIS: PCA values differ between Caucasians and Asians. METHODS: The study included the computed tomography scans of 515 healthy femurs, 259 from Asians in China and 256 from Caucasians in France. PCA values were determined based on four landmarks, namely, the two femoral epicondyles and the most prominent point of each condyle at the posterior aspect of the knee. The Mann-Whitney test was chosen to compare PCA values according to ethnic group, gender, and side and Spearman's correlation coefficient to assess correlations with age. Inter-observer and intra-observer variability of PCA measurements was assessed. RESULTS: Mean PCA was 6.0°±2.5° (range, 0°-14°) overall, 6.4° (range, 0.31°-14.1°) in the Asians, and 5.5° (range, 0°-13.1°) in the Caucasians (p<0.0001). Chinese femurs are significantly more internally rotated. No differences in PCA values were found according to age (p=0.4307), gender (p=0.7113), or side (p=0.4304). Inter-observer and intra-observer variability was limited for each of the landmarks, indicating that PCA measurement was reliable. CONCLUSION: PCA varies not only across individuals as reported previously, but also across ethnic groups. This finding further supports routine PCA measurement on imaging studies before total knee arthroplasty. LEVEL OF EVIDENCE: III, comparative retrospective study.