A method of treating a subject having a musculoskeletal disorder includes administering to a subject's articular site in need thereof an effective amount of a hyaluronic acid (HA) composition. In one embodiment, the HA composition includes an HA derivative, wherein carboxyl functionalities of the hyaluronic acid derivative are each independently derivatized to include an N-acylurea or O-acyl isourea, or both N-acylurea and O-acyl isourea. In another embodiment, the HA composition includes a crosslinked HA gel that is prepared by reacting an uncrosslinked HA with a biscarbodiimide in the presence of pH buffer in a range of between about 4 and about 8. The composite can optionally include at least one second bioactive agent other than the HA derivative, such as a steroid.