Postarthroscopic Meniscus Repair Analgesia with Intraarticular Ketorolac or Morphine

To the Editor: We read Drs. Reuben and Connelly's paper on the use of intraarticular ketorolac, morphine, and bupivacaine with interest [1]. We wish to raise several points. First, the use of combinations of drugs at novel sites should ideally follow definitive evidence that the single drugs involved have the desired effect. This is established by placebo-controlled studies with single drugs. While many institutions use local anesthetics at the termination of arthroscopic surgery for analgesia, there are several placebo-controlled studies in which no benefit of this technique was shown [2,3] and others in which the benefit was short lived [5].1 The intraarticular use of morphine has also not always been found to be effective [6-8]. Combinations of local anesthesia and morphine are not universally found to be effective [8-10]. (1) White AP, Laurent S, Wilkinson DJ. Ann R Coll Surg Engl 1990;72:350-2. In the case of ketorolac, we are aware of two previous studies in which intraarticular ketorolac was used [11,12]. Both showed efficacy similar to that of intraarticular bupivacaine. The latter study [12] suggested that combining the drugs improved analgesia. In one study, pain scores were recorded only for the first two hours (the approximate duration of bupivacaine action). In the other, they were recorded daily for five days. Neither study contained a placebo group. Neither, therefore, clearly demonstrated that intraarticular ketorolac is an effective analgesic in this setting. Second, the dose of ketorolac used is six times the parenteral dose currently recommended in the United Kingdom. This dose was revised downward after the occurrence of cases of gastrointestinal hamorrhage and renal failure when larger doses were used [13]. The use of intraarticular nonsteroidal antiinflammatory drugs (NSAIDs) exposes the synovium and cartilage to high concentrations of the drugs. There is concern in the rheumatological and orthopaedic literature about the effects on cartilage of these drugs even when given parenterally [14]. Damage results from the disruption of chondrocyte metabolism and inhibition of proteoglycan synthesis. These effects may be more pronounced in patients with osteoarthritis [14]. Different NSAIDs have different effects on cartilage metabolism, with some having marked catabolic effects [15]. It would be prudent to select those NSAIDs least likely to damage cartilage in studies of intraarticular use. We have recently completed a study on the use of intraarticular tenoxicam for postarthroscopy analgesia in patients receiving general anesthesia. Tenoxicam has no solubilizing or preservative agents and has a long half-life, and in vitro studies suggest that it should not have deleterious effects on cartilage [16,17]. Our study was placebo-controlled and compared placebo, bupivacaine 0.5%, and tenoxicam 20 mg. We found a small reduction in analgesic requirements in the first 24 hours after knee arthroscopy in those patients receiving intraarticular tenoxicam. There was no reduction in patients' perception of their postoperative pain. We considered tenoxicam to be of negligible benefit for the patient. We would caution against the widespread use of intraarticular NSAIDs until their safety and efficacy can be established. In addition, the use of combination therapy for intraarticular analgesia should wait until the efficacy of single drugs is clearly substantiated. T. M. Cook, FRCA J. P. Nolan, FRCA J. P. Tuckey, FRCA Department of Anaesthesia; Royal United Hospital; Combe Park; Bath BA1 3NG, United Kingdom