Joints emit a variety of noises, including popping, snapping, catching, clicking, grinding, grating and clunking. The technical term for these noises is "crepitus", from the Latin "to rattle".
MCL injuries often happen during contact sports. Direct contact to the outside of the knee during a collision can push the knee sideways. This puts a lot of pressure on the MCL, which can tear. Contracting the muscle while running and turning can also put enough stress on the ligament to sprain or tear it.
One of the benefits of the direct anterior approach over the traditional posterior approach to total hip arthroplasty (THA) is the lower risk of early dislocation, making standard hip precautions in the weeks after surgery unnecessary.