The role of cam morphology in the progression of radiographic hip osteoarthritis.

Abstract

To the editor As faithful readers, there is no doubt that we have learned a lot after reading the paper.1 By using the methods mentioned in the article, we can infer that cam morphology was linked with age, higher weight, male gender, and early signs of radiographic damage. These findings are likely to suggest that cam morphology plays a significant role in early osteoarthritis (OA) and may be a precursor or contribute to hip OA in later life. As the author mentions in the article, there were tons of data proving the association between cam morphology and osteoarthritis.1-4 In fact, the results prove that your inference is correct, and we have two points in mind hoping they would be beneficial to your paper. The first point we would like to focus on is the assessment of OA. According to the paper, the assessment of hip OA was used by Prof. Graeme Jones and Dr. Helen Cooley.1 They followed the Osteoarthritis Research Society International grading system and assessed the radiographs. Radiographs were graded on a 4-point scale (range 0 to 3, where 0 represents no disease and 3 represents severe disease). We thought that the judgment on a 4-point scale of OA was vague. The evaluation of a 4-point scale can only be defined by the doctor as artificial. To be argued, the result of the 4-point scale may not be the same due to different patient OA diagnoses. Therefore, we thought that you could try another method that is more automatic and objective in diagnosing patients with OA, such as the Kellgren and Lawrence scale (K-L scale), erythrocyte sedimentation rate, and C-reactive protein.5 These assessments are more objective and are used in many countries. Compared to the 4-point scale in the paper, K-L scale is more specific than the 4-point scale. Therefore, it could be a better choice for you to assess the participants. The second point that we would like to focus on is the method to measure and evaluate participants' hip pain feeling. In the article, the author uses the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index pain score as the measurement of hip pain.1 To a great degree, the feeling of pain is subjective, which largely depends on the participants themselves. For different participants, the same pain level may cause different pain feelings. Therefore, it is tough and complicated to evaluate participants' pain feelings accurately and rigorously.6 Under this premise, we have learned a lot and consider that the pain evaluating method is great and relatively accurate, compared to many other methods. After all, WOMAC is specific to OA. Data from the participants at 3 and 5 years from baseline is also a great decision. During this period, participants' pain feelings are more obvious. If choosing 0–3 years, that pain feeling and impact may not be obvious enough to evaluate. Meanwhile, if choosing more than 5 years, participants may get used to the painful feelings, which could affect the final evaluation of participants' hip pain feelings, and this is probably because the pain evaluation method is self-reported. However, after reading and searching through lots of information, we have an interesting thought about pain feeling evaluation. WOMAC is good and suitable for OA, without a doubt. But why not try using other pain evaluation systems? If using other pain scales, the result might be different. There are various pain evaluation systems, such as the Brief Pain Inventory (BPI), McGill Pain Questionnaire (MPQ), Visual Analog Scale (VAS), Face, Legs, Activity, Cry, and Consolability (FLACC) scale, etc.7, 8 Every system uses different degrees of grading, marks, choosing forms, and so on. In a different system, even the same sign could have a different meaning. As stated above, all of these could give rise to different results when participants do pain feeling evaluation self-reportedly in the different evaluation systems. All authors (KSSM, PEK, SBY, and KHC) provided their ideas and critical contribution. KSSM, PEK, SBY, and KHC contributed to the editing of the manuscript. KSSM and PEK contributed equally as first authors. KSSM, PEK, SBY, and KHC contributed equally as corresponding authors. None declared. The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for profit sectors. The authors declare no conflict of interest. Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research. Not required. Not commissioned; internally peer reviewed.