Chapter 15: How to make the diagnosis

INTRODUCTION

This chapter should be read in conjunction with Chapter 14. These chapters are very different from their fourth edition predecessors. In earlier editions of Clinical Sports Medicine, we argued for the importance of accurate pathological diagnosis. At times, this is realistic. A player falls on his or her wrist and sustains an acute scaphoid fracture. You can make a clinical diagnosis and confirm it with imaging. So far, so good. Accurate tissue diagnosis remains a foundation where appropriate.

In this fifth edition, we recognise that we previously overestimated the proportion of settings where accurate, very specific tissue diagnosis is possible. Consider patients who present with low back pain. Is the tissue diagnosis the facet joint, vertebra, fascia, muscle or disc? In these cases, can investigation, such as magnetic resonance imaging (MRI) provide the holy grail of tissue diagnosis? No, MRI cannot.

This chapter reinforces Chapter 14’s key message—the art of diagnosis takes place against a backdrop of patient-based probabilities. Honest teachers will explain that the clinician is narrowing the odds from the ‘pre-test probability’ to a new ‘post-test probability’. (See Likelihood ratios and Fagan’s Nomogram, Chapter 14.)

DOES ‘DIAGNOSIS’ MEAN ‘TISSUE DIAGNOSIS’?

Is there a difference between a diagnosis of: 1. ‘swimmer’s shoulder’; 2. ‘rotator cuff tendinopathy’; and 3. ‘shoulder pain related to training load errors and suboptimal biomechanics’? The first of these (‘swimmer’s shoulder’) represents a 1970s advance in sports medicine. Alongside labels such as tennis elbow, goalie’s elbow, hockey player’s groin and footballer’s ankle, ‘diagnosis’ consisted of the name of a sport paired with a commonly injured body part. This was an advance at the time, as many doctors were not aware of sports medicine conditions and sports physiotherapy had not yet emerged in many countries.

The major limitation of this type of label is lack of precision. Each of those labels (e.g. hockey groin) could apply to a number of pathological entities which may benefit from distinct treatment. Such labels have no place in 21st-century sports medicine.

What about ‘rotator cuff tendinopathy’? Is that a valid diagnosis? The fourth edition of Clinical Sports Medicine asserted that accurate pathological diagnosis was essential for the following reasons.

• It enabled the clinician to explain the problem and the natural history of the condition to the athlete, who will want to know precisely for how long he or she will be affected. A patient may present with an acute knee injury but the diagnosis of anterior cruciate ligament (ACL) tear has markedly different implications to the diagnosis of minor meniscal injury.

• It enabled optimum treatment. Numerous conditions have similar presentations but markedly different treatments. For example, consider the differences in treatment between: lateral ...