Thank you for the review of our article.

The PROMs used in the study correlated well with the clinical findings, both the Knee Society score and the Harris hip score, and while parts of those assessment tools are subjective there is a significant objective component, which allows some comfort that the two scoring mechanisms, subjective and objective, are measuring results accurately. This is the basis of the argument that the specific PROM test can be used on its own to assess outcomes.

The important issue that Dr Purnell discusses is that the PROM score on its own should not be used as an indication of the need for surgery, nor is it an indicator of patient satisfaction postoperatively. These points are correct. Decision for surgery is a clinical activity; a PROM at that stage is only an adjunct.

The concept of the minimal clinically important difference in PROMs scores is put forth as a way to see that the PROMs improvement actually indicates a significant improvement for the patient.[1 [12]]

The demonstration that the PROMs value before and after surgery reaches or exceeds the minimal clinically important difference would be de facto evidence of the success and appropriateness of the surgery. If this methodology was adopted in BC it would change the way surgical care is provided in the province to a more evidence-based approach. This type of accountability would be a dramatic departure from the status quo.

Dr Purnell points out that there are a multitude of factors that influence treatment outcomes and PROMs. Mention is made of posttraumatic conditions and back surgery. This article proposes using PROMs in elective nonemergency surgery, and it is acknowledged that assessing spinal surgery is more complex. This is not to say that standardized, formal postoperative evaluation should not be done.

Finally, the use of PROMs cannot be the only means of assessing outcomes; the surgeon’s assessment of the patient must be part of the evaluation. It is noted that different populations may need different tools and, in fact, the Oxford group has now provided a North American electronic version of their scoring system. 
—Michael Stanger, MCCM, FRCSC
Victoria

References

1.    Judge A, Arden NK, Kiran A, et al. Interpretation of patient-reported outcomes for hip and knee replacement surgery: Identification of thresholds associated with satisfaction with surgery. J Bone Joint Surg Br 2012;94:412-418.