John Yates and colleagues' article ('Blade runners', pages 20-21, 27 April) is an unjustified attack on orthopaedic surgeons.

The thesis is that the number of consultants has risen in 10 years more than the volume of recorded work (similarly, junior orthopaedic staff ), and that therefore orthopaedic surgeons must be slacking, moonlighting in the private sector and letting down their patients.

Nowhere is there a reference to quality, let alone to outcomes.All surgical procedures can be weighted according to complexity. No 10-year comparison can reach conclusions about productivity on an unweighted study. The rising volume of work on shoulders and knees, the increasing age of patients who are now successfully operated on for a hip replacement, and the ever tighter quality standards are ignored.

The article makes great play of comparisons based on averages. The average of 3.2 theatre sessions per consultant is used as a stick to beat everyone below that level. Professor Yates should use the median, the inter-quartile range or 'trimmed means', but he is probably aware that they won't produce the results he wishes.

There is a total misunderstanding of the consequences of the current training regulations. In the 10 years since Calman training was introduced, there have been quite specific rules about the amount of one-to-one training and the amount of time trainees must spend away from their historic role as a workhorse of the NHS.

The article shows an 84 per cent increase in the number of trainees at specialist registrar level over 10 years - the effect of this large increase on consultant surgeons is unquestionably to reduce the consultants' overall productivity.

Because the staffing numbers are known, as are the theatre details, it should be possible to calculate precisely the negative effect on patient output of the training commitment.

The article makes a virtue of excluding all private patients on lists.

This is unjustified because many trusts have their own private beds and encourage consultants to take private patients on their ordinary NHS lists.

Lip-service is paid to the existence of the Dobson lists and the extra weekend and night-time working for the NHS, but it is not clear whether the whole of this workload has been included in the analysis.

The article recognises the existence of the consultant daytime commitment to trauma lists.Where is the reference to the NCEPOD reports about the urgent necessity for consultants to be available for trauma lists in the daytime?

Where is the reference to the evidence that patients have more positive outcomes when the trauma work is undertaken by consultants?

Where is the recognition that in trying to respond to these initiatives, orthopaedic surgeons have been trying to improve the quality of patient services and outcomes, but inevitably have a small negative effect on their cold workload?

Why have orthopaedic surgeons been picked on when the traditional pattern of operating lists among surgical specialties means that there is substantial similarity across the specialties, and there are unquestionably specialties with a smaller proportion of theatre time than orthopaedics?

The article advocates three-list days but evidence suggests patients do less well from a three-list day.

The list is rarely 10.5 hours of operating time, and the reality is that people need short breaks if they are to work for that length of time.

A major omission is the impact of day surgery on the productivity of all consultants. Same-day admission does reduce the net surgical theatre time.Anaesthetists need the extra 15 minutes Professor Yates complains about because they have to see patients first. But the benefits of day surgery to patients and the hospital budget have been tremendous.Where is the recognition that day surgery has made 10-year comparisons of this sort usable only with great care?

The biggest audacity is the suggestion that instead of trying to bring the number of orthopaedic surgeons to European levels we should first increase their productivity.

Has Professor Yates never looked at comparative consultant productivity in Europe? The Scandinavian data would surely leave him embarrassed.

The article will only serve to worsen the relationship between consultant medical staff and those trying to organise and manage a professional patient service. Everyone is aware that the government is holding back on the expansion of consultant posts in the NHS and that the rate of expansion has fallen sharply since May 1997.Why should orthopaedic surgeons co-operate with government initiatives if they see such a blatant piece of intellectually bankrupt blackmail?

The increased quality of training, surgery and outcome now required cannot be delivered against a background of greater productivity demands (let alone the 33 per cent required by Professor Yates) and the NHS will not find positive solutions to the challenges that face it unless that point is recognised.

Professor Roger Dyson Director Clinical management unit Keele University