Abstract
Aims
The study was designed to gauge adequacy of pain relief in the first 5 days following TKA, in particular comparing the Painbuster device (B Braun, Sheffield, UK) with more routine modalities.
Methods
In a prospective, multi-disciplinary audit, all post-operative in-patients completed a pain diary. Pain was recorded as none (0), mild (1), moderate (2) or severe (3), three times a day. This information was collated, along with the pre-operative Oxford knee score, type of anaesthetic, and use of post-operative analgesia. This included oral and intravenous medication, local anaesthetic infiltration and the Painbuster, a continuous infusion device which delivers bupivacaine into the knee for 48 hours.
Results
49 patients completed pain diaries between April and August 2009. Forty-two (86%) received a spinal block with sedation. Only 13 patients (27%) required intravenous morphine via a PCA. Ten patients (20%) received a Painbuster device, while another eight (16%) underwent a single local anaesthetic infiltration. Painbuster patients had average pain scores of 1.65 over days 0-4, whereas all other patients had mean scores of 1.49 over the same period. The latter group used more NSAIDs (55% vs 40%) which may partly explain the difference. When patients given a Painbuster were grouped with those receiving local anaesthetic infiltration, there was no superiority to those treated routinely. Of eight pharmacological analgesics offered (paracetamol, PCA etc), more than half of patients received four or more modalities. Median length of stay was 4 days.
Conclusions
Analgesia after TKA is challenging, and most patients experience episodes of severe pain. The Painbuster does not ofer superior analgesia, despite its popularity in other surgical disciplines. This may relate to inadequate delivery of anaesthetic throughout the wound, and to the lingering benefits of a spinal block which may mask the Painbuster's effect. A single answer to early post-operative pain remains elusive, but a flexibile and committed approach can still lead to successful early discharge.
