Profile of the distal femur anterior cortex – a computer-assisted cadaveric study

Abstract Purpose In navigated TKA, the risk of notching is high if femoral component sagittal positioning is planned perpendicular to the sagittal mechanical axis of femur (SMX). We intended to determine if, by opting to place the femoral component perpendicular to distal femur anterior cortex axis (DCX), notching can be reduced in navigated TKA. Methods We studied 171 patients who underwent simultaneous bilateral computer-assisted TKA. Femoral component sagittal positioning was planned perpendicular to SMX in one knee (Femur Anterior Bowing Registration Disabled, i.e. FBRD group) and perpendicular to DCX in the opposite knee (Femur Anterior Bowing Registration Enabled, i.e. FBRE group). Incidence and depth of notching were recorded in both groups. For FBRE knees, distal anterior cortex angle (DCA), which is the angle between SMX and DCX, was calculated by the computer. Results Incidence and mean depth of notching was less (p = 0.0007 and 0.009) in FBRE versus FBRD group, i.e. 7% versus 19.9% and 0.98 mm versus 1.53 mm, respectively. Notching was very high (61.8%) in FBRD limbs when the anterior bowing was severe (DCA > 3°) in the contralateral (FBRE) limbs. Conclusion Notching was less when femoral component sagittal positioning was planned perpendicular to DCX, in navigated TKA. Level of evidence Therapeutic level II.

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A cadaveric study of the location and morphology of the central patellar ridge for bone-patellar tendon-bone graft

Journal of Orthopaedic Surgery and Research ◽

10.1186/s13018-021-02244-5 ◽

2021 ◽

Vol 16 (1) ◽

Author(s):

Thanathep Tanpowpong ◽

Thun Itthipanichpong ◽

Thanasil Huanmanop ◽

Nonn Jaruthien ◽

Nattapat Tangchitcharoen

Keyword(s):

Patellar Tendon ◽

Cancellous Bone ◽

Average Distance ◽

Cadaveric Study ◽

Anterior Cortex ◽

Length Width ◽

Central Ridge ◽

The Mean ◽

Bone Patellar Tendon ◽

And Cartilage

Abstract Introduction The central ridge of the patella is the thickest area of patella and varies among patients. This cadaveric study identified the location and thickness of the bone at the central patella ridge for bone-patellar tendon-bone (BPTB) harvesting. Materials and methods Fifty cadaveric knees were assessed. First, the morphology, length, width, and location of the central patellar ridge were recorded. Then, we transversely cut the patella 25 mm from the lower pole and measured the thickness of the anterior cortex, cancellous bone, and cartilage from both the mid-patella and the central ridge location. Finally, the depth of the remaining cancellous bone at the mid-patella was compared to the bone at the central ridge. Results The location of the central-patellar ridge deviated medially from the mid-patella in 46 samples with an average distance of 4.36 ± 1 mm. Only 4 samples deviated laterally. The mean patella length was 41.19 ± 4.73 mm, and the width was 42.8 ± 5.25 mm. After a transverse cut, the remaining cancellous bone was significantly thicker at the central ridge compared to the bone at the mid-patella. Conclusions Most of the central patellar ridge deviated medially, approximately 4 mm from the mid-patella. Harvesting the graft from the central ridge would have more remaining bone compared to the mid-patella.

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