The walls of the trochlear groove would normally contain the patella as the knee bends and straightens. Sometimes the groove is abnormal - trochlear dysplasia - and this may result in patellar instability.
|The upper part of the trochlear groove is flatter, and the patella is more easily able to ride over the walls of the groove when the knee is in extension (straight).|
The sulcus line of the trochlear groove is more accurate than Whiteside’s Line in determining femoral component rotation. Talbot S, Dimitriou P, Radic R, Zordan R and Bartlett J. Knee Surg Sports Traumatol Arthrosc. 2015; 23(11): 3306–3316.