Correlation of posterior tibial slope with metaphysiodiaphyseal angle in total knee arthroplasty: A radiological study

Abstract

Background:Posterior tibial slope (PTS) is an important factor affecting postoperative range of motion (ROM) following total knee arthroplasty (TKA). Metaphysio-diaphyseal angle (MDA) is a new entity defined as angle between proximal anatomical axis and metaphyseal axis of tibia. This study was undertaken to determine PTS in Indian patients and find its correlation with MDA of tibia. Accuracy of extramedullary jigs and the influence of MDA on the accuracy was also evaluated. This study is a retrospective analysis of prospectively collected data in a tertiary healthcare center.Materials and Methods:Data of 100 consecutive patients undergoing TKA in a single center by a single surgeon was analyzed. Posterior cruciate ligament (PCL) substituting TKA was done with same jig to achieve different PTS in different patients. MDA, preoperative PTS and postoperative PTS were calculated. The data was analyzed using appropriate statistical analysis.Results:Mean preoperative PTS was 11.64° and mean MDA was 23.76° with a strong correlation between them (Pearson's coefficient 0.72). Extramedullary jigs were accurate in 53% cases. In remaining 47%, postoperative PTS was less than planned PTS in 30%, and more in 17%. Mean postoperative PTS was 2.54°. In patients with MDA < 20°, postoperative PTS was significantly less (P = 0.0176) compared with those with MDA > 20°.Conclusions:The study establishes the positive correlation between MDA and PTS in Indians; and that MDA is an independent factor affecting accuracy of extramedullary jigs in TKA.

Measurement of the Posterior Tibial Slope Depends on Ethnicity, Sex, and Lower Limb Alignment: A Computed Tomography Analysis of 378 Healthy Participants

“…The authors 11 evaluated 133 knees using preoperative CT for patients undergoing total knee arthroplasty (TKA) for osteoarthritis and concluded that PTS measurements were deeply influenced by degenerative changes. Mohanty et al 23 evaluated the PTS value in a cohort of 100 Indian patients undergoing TKA. The global PTS was 11.6° (range, 2°-25°).…”

“…Methods of estimating the PTS are controversial and not consistent. The long anatomic axis of the tibia was used in our study, 3,37 as in the studies of Kuwano et al 17 and Mohanty et al 23 However, Weinberg et al 32 took for reference the center of the first third of the tibial shaft, and Han et al 11 published results with 4 different axes: mechanical axis, anatomic axis, anterior cortices, and fibular shaft axis. Yoo et al 35 highlighted the wide difference of the PTS according to the chosen axis: anterior cortices (13.8°), proximal anatomic axis (10.8°), central anatomic axis (12.9°), posterior cortices (7.8°), and fibular shaft (9.5°).…”

Proximal tibial morphology and risk of posterior tibial cortex impingement in patients with AA-sized Oxford unicompartmental knee arthroplasty tibial implants

“…In addition to the offset in the mediolateral direction, an increased anteroposterior offset may further bring the tibial keel in proximity with the posterior cortex. The tibial intramedullary canal is located anterior to the center of the tibial plateau in Asian compared to Caucasian [2,3]. Furthermore, Asians tend to have an increased posterior slope angle as compared to Caucasians, which further increases the risk of posterior cortex impingement [22,23].…”

“…Generally, the size of the tibia in Taiwanese people is relatively smaller than that in Caucasians; hence, smaller sized components are more frequently used. In addition, the Asian population has different tibial intramedullary canal features and proximal tibia morphology compared to Caucasians [2][3][4][5][6]. We, therefore, conducted this study to identify the risk factors for posterior cortex injury associated with AA-sized tibial implants and potential measures for the prevention of complications.…”

Normal anatomical variations of tibial plateau geometry in Indian population: a magnetic resonance image-based study

“…10,11 PTS is steeper in the patients who has osteoarthritis of knee. 12 Tibial plateau slopes, MTS and LTS, independently are important determinants of knee biomechanics. 2,[13][14][15] Steeper medial tibial plateau slope, lateral tibial plateau slope and shallower medial tibial plateau depth has also been recognized as a risk factors for anterior cruciate ligament injury.…”