Preoperative pulse and thermal radiofrequency facilitates prehabilitation and subsequent rehabilitation of a patient scheduled for total knee arthroplasty

To the Editor,

The presence of pain and frailty1 (in part defined as poor strength and flexibility and limited capacity to complete physiological tasks) has been shown to be a consistent predictor of poor recovery from knee surgery.2

This letter describes the use of pulsed and thermal radiofrequency (PRF and TRF) denervation, followed by a six-week preoperative prehabilitation program3 to strengthen the physical function of a 79-yr-old elderly Caucasian female (non-smoker, body mass index 24 kg·m⁻²) with severe osteoarthritis of the knee requiring total knee arthroplasty. She was suffering from significant knee pain unrelieved by opioid medication (codeine 30 mg/paracetamol 325 mg six times a day and pregabalin 50 mg twice a day) and had severely impaired functional activity, poor nutritional status, and moderate depression. In view of her relatively large opioid consumption, she agreed to radiofrequency (RF) denervation of the affected knee.

Using a RF technique based on the recent and novel description of innervation of the anterior knee,4 the right saphenous nerve was approached at the adductor canal using ultrasound guidance. Saline (0.9%) 2 mL was injected beside the saphenous nerve in the adductor canal prior to PRF treatment using the RF device, OWL sterile single-use (disposable) RF cannulae, and an OWL URF-3AP (ML) RF generator (Diros Company, Markham, ON, Canada) for four minutes at 42°C. Ropivacaine (0.5%) 10 mL was then injected near the saphenous nerve. Next, the genicular terminal branches of the sciatic and femoral nerves were also treated with continuous RF for two minutes at 80°C using a 10-mm 18G active tip RF curved needle (OWL sterile single-use (disposable) RF cannulae), and then ropivacaine (0.5%) 2 mL and methylprednisolone 10 mg added to the local anesthetic were administered to each nerve. Finally, two pulses of PRF treatment were applied for four minutes at 42°C inside the knee joint on each recess beside the patella.

After the block, the patient experienced complete pain relief (numerical pain rating scale =1 at rest and 3 on movement: 0 = no pain and 10 = worst pain experienced for the patient) until surgery with no need of any analgesics. Following the RF treatment, the patient started her six-week multimodal prehabilitation program which included aerobic and resistance exercises three times a week, nutritional optimization by providing (20 g·day⁻¹) a whey protein supplement (taken within one hour following exercise in order to maximize muscle protein synthesis), and daily relaxation strategies (imagery, visualization, deep breathing exercises). The program resumed at home on week two after surgery and included the specific physiotherapy exercises from week two to eight and the pool exercises from week four to eight.

The knee arthroplasty was performed under spinal anesthesia, and for postoperative analgesia, the patient received a continuous femoral blockade catheter with ropivacaine (0.2%) 5 mL·hr⁻¹ for two days and subsequently acetaminophen 1 g four times a day, Celebrex 200 mg twice a day, and tramadol 50 mg iv three times a day. Ambulation started with the help of a physiotherapist on the first postoperative day, and the physiotherapy continued until discharge on the fourth postoperative day. The Table reports the changes in various domains during the prehabilitation period and up to eight weeks following surgery. The excellent preoperative analgesia allowed significant improvement in all the objective and self-reported outcome measures recorded during the six weeks before surgery and the eight postoperative weeks. The high quality of analgesia achieved with the RF had a major impact by facilitating the implementation of prehabilitation and rehabilitation. In addition, the physical training likely played an important role in enhancing the patient’s physical strength.

Table List of outcome measures

This case illustrates that analgesia achieved by PRF may facilitate the implementation of prehabilitation programs in patients experiencing severe pain that can lead to decreased functional capacity and physical strength while waiting for total knee arthroplasty. In addition, prehabilitation might enhance the physical and emotional reserve to overcome the stress of surgery and accelerate the rehabilitation process. An appropriately designed and adequately powered clinical trial is needed to confirm these findings.