An ultrasonic surgical instrument comprises a reusable housing including an internal transducer and an internal end effector rotation assembly. An exemplary rotation assembly is a ratchet and pawl assembly, which allows the transducer to rotate in a first direction but not in a second, opposite direction. The end effector, including an integral torque wrench, is attached to the transducer to form a single unit that is rotatable relative to the housing. The transducer attaches to a stationary cable via slip rings. The cable communicates with a generator, which provides electrical power to the transducer. The transducer converts the electrical power into ultrasonic vibrational energy, which is transmitted to the end effector.