Where a pre-existing degenerative condition would certainly have required surgical intervention within a reasonably well-defined timeframe, the appropriate method of assessing damages is to compare the plaintiff's actual position with the position absent the accident, rather than applying a percentage discount to full damages. The percentage discount approach (treating the defendant as wholly responsible then discounting) is more appropriate where the potential for materialisation of the underlying condition is less certain. Costs of surgery that would inevitably have been incurred are not recoverable unless the plaintiff establishes that the compensable nature of the injury placed her in a different financial position.
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