A catheter system can include a first catheter including a first proximal end portion and a lumen. The first proximal end portion has a first key joint component that extends along a partial length of the first proximal end portion. The catheter system can also include a second catheter including a second key joint component that corresponds with the first key joint component. The first key joint component and the second key joint component are configured to be coupled together when the second catheter is slidably disposed within the lumen of the first catheter such that a rotational orientation of the second catheter is fixed relative to a rotational orientation of the first catheter. The first proximal end portion can be a fitting, and the first key joint component can include an opening defined by the fitting.