Re: Association of hip pain with radiographic evidence of hip osteoarthritis: diagnostic test study
Hip pain and radiographic signs of osteoarthritis: Sickle cell & other haemoglobinopathy differential diagnosis
Dr M J Nieuwenhuijse and Professor Rob G Nelissen’s Editorial  linked to Kim and colleagues' paper (doi:10.1136/bmj.h5983) is probably more suited for developing countries where MRI is often unavailable for investigating hip pain and “osteoarthritis” than for the UK, yet the authors appear to have only a Caucasian audience in mind for their message. We know that haemoglobinopathy is the commonest cause of hip pathology in Africa as I pointed out in The Lancet in “Hip disease in Africans” 
1 IN 3 WEST AFRICANS HAS SICKLE CELL OR HAEMOGLOBIN C GENE
With every third West African at home and abroad possessing a beta-globin gene variant as Sickle Cell Trait (‘AS’) or Haemoglobin C Trait (‘AC’) we proved conclusively in Ghana that 3 out of every 100 births will have Sickle Cell Anaemia (‘SS’) or Sickle cell Haemoglobin C Disease (‘SC’) [3-9], thereby confirming veracity of the Hardy Weinberg gene frequency Equation p + q + r =1 producing phenotypes p2 + q2 + r2 +2pq + 2pr + 2qr =1 (the square of the gene frequencies) which was exactly what we observed on investigating 1,000 and 13,000 consecutive babies born at Korle Bu Hospital in Accra.[4 5]. Many of these babies grew to develop hip problems that often confused some radiologists , and which needed differentiating from Perthes’ disease 
TERMINOLOGY INADEQUATE TO HIGLIGHT PAITENT’S REAL NEEDS
Dr Nieuwenhuijse and Professor Nelissen are right to use phraseology like “clinical symptoms suggestive of degenerative hip joint disease” and “asymptomatic degenerative changes”  – terms that describe many patients with haemoglobinopathy [7 8]. The authors’ advice “Treat patients, not radiographs” also needs to be heeded because too often we clinicians refer patients for investigation without examining them, using the term “osteoarthritis” when osteo-arthropathy was better. Few Resident Doctors these days on both sides of The Atlantic practice the five cardinal “Introductory Course” drill before sending patients for investigations. These 5 are: 1. History 2. Inspection 3. Palpation 4. Percussion 5. Auscultation. Therefore, in answer to the authors’ question “How should we respond to patients presenting with hip pain?”  my first answer would be history: “Do you have hereditary rheumatism?”, using tribal names for sickle cell disease (chwechweechwe, ahututuo, nwiiwii, lakuragbee, etc) [6 7 8]. For many patients HISTORY alone gave me the diagnosis of hip pain. INSPECTION - Before he/she sat down I had observed the limp, and then I looked for jaundice and estimated straight leg raising, leg shortening, and elicited pain on hip rotation. PALPATION - I noted Corrigan’s pulse in my sickle cell anaemia patients and looked for abdominal signs, before pressure for groin tenderness. PERCUSSION: Liver enlarged? Spleen? AUSCULTATION – Precordial systolic bruit made me advise radiologists to comment on heart size, “cod fish vertebra”, and splenic calcification.
GENETIC CAUSES OF HIP PAIN
There is phenotype variation in incidence : Sickle Cell Disease, ‘SC’ phenotype, has more frequent hip pain than Sickle Cell Anaemia (‘SS’) for the reasons explained elsewhere after personally surveying over 1,200 consecutive patients of all ages . Seventeen of 600 consecutive Hb ‘SS’ ie 2.8% and 40 of 603 consecutive Hb ‘SC’ patients ie 6.6% with hip pain and limp had femoral head problem (p<00.1) [6 7 8 11 12]. Arthritic hip incidence in Sickle Cell Trait (‘AS’) is not different from that in the rest of the population with no ‘S’ gene, unless one’s definition of Sickle Cell Trait was the seriously flawed definition common in American publications where sickle cell disease ‘SC’ was often called Sickle Cell Trait merely because the mother of the patient with symptoms had Negative Sickling Test. Brilliant haematologists have been known not to proceed to haemoglobin electrophoresis when sickling test was negative, thereby missing Hb ‘C’ which, combined with Hb ‘S’ is sickle cell disease, ‘SC’ phenotype. In my 36 consecutive Haemoglobin ‘CC ’patients just the 35th presented with hip pain .
COHORT STUDIES OVER RATED IN CLINICAL VALUE
Results from cohort studies with varying degrees of expertise cannot be better than careful observation of consecutive patients over many years by the same clinician as in Ghana  and West Indies . Both this Editorial  and Kim and colleagues’ paper it is linked to (doi:10.1136/bmj.h5983) mention cohort studies which fail to take into account the numerous non-Caucasians as well as white Mediterranean people with sickle cell disease whose hip pain has not alerted doctors to haemoglobinopathy. An exception was Professor Malcolm Milne who once asked me on a postgraduate ward round to examine a Greek patient.
INSPECTION: - Slight icterus. Nails pale. Right shoulder muscle wasting giving angular contour. Straight leg raising – only 450 from the bed on the left side, with pain on hip rotation. PALPATION: Murphy’s sign positive. Corrigan’s sign positive. AUSCULTATION: Precordial systolic bruit. I then announced: “This patient has Sickle Cell beta-Thalassaemia, with gall stones and articular bone necrosis of the right humeral head and left femoral head”. Professor Milne gave me full marks and showed us the detailed blood results from Professor J G Humble confirming the phenotype. But why did I not say Sickle Cell Anaemia (‘SS’), which was also very common in Greece? ANSWER: Because the patient's nails and conjunctivae were not as pale as I had known them to be in Sickle Cell anaemia. I then announced to the impressed gathering that I knew much about sickle cell disease before I went to Medical School. My parents were among the 1 in 3 very healthy Ghanaians with Hb ‘S’ or ‘C’ Trait, and they produced 11 of us of whom 3 had sickle cell disease. Growing up in the Manya Krobo Tribe I was surrounded by close and distant relatives born with chwechweechwe-hemkom, and who walked with a limp . No cohort studies were needed for my education.
Conflict of Interest: None declared.
email@example.com and Twitter@profkonoteyahul
Felix I D Konotey-Ahulu FGA MD(Lond) FRCP(Lond) FGCP, DTMH(L’pool)
1 Nieuwenhhuisje MJ, Nelissen RG. Hip pain and radiographic signs of osteoarthritis. BMJ 2015; 351:h6262 (03 December 2015)
2 Konotey-Ahulu FID. Hip disease in Africans. Lancet 1970; 1: 999
3 Ringelhann B, Konotey-Ahulu FID. Hemoglobinopathies and Thalassaemia in Mediterranean areas and in West Africa: historical and other perspectives 1910-1997 – A Century Review. Atti del’Accademia della Science di Ferrara 1998; 74: 267-307.
4 Gbedemah KA, Acquaye CTA, Konotey-Ahulu FID, Reindorf CA. Haemoglobin phenotype patterns in more than 1,000 consecutive new-born babies in Ghana. Ghana Med Journal 1976; 15: 253-256.
5 Bonney GE, Walker M, Gbedemah K, Konotey-Ahulu FID. Multiple births and visible birth defects in 13,000 consecutive deliveries in one Ghanaian hospital. In Proceedings of the Second International Congress on Twin Studies Part C. Ed Walter Nance. Progress in Clinical and Biological Research 1978; 24B: 105-108.
6 Konotey-Ahulu FID. The Sickle Cell Diseases: Clinical manifestations including the Sickle Crisis. Archives of Internal Medicine 1974; 133: 611-619.
7 Konotey-Ahulu FID. The Sickle Cell Disease Patient: Natural History from a Clinico-epidemiological study of the first 1550 patients of Korle Bu Hospital Sickle Cell Clinic. The Macmillan Press Ltd, London 1991 & 1992 and T-A’D Co Watford 1996.
8 Konotey-Ahulu FID. Pattern of Sickle Cell Disease in Accra (A STUDY OF 1,550 PATIENTS): A THESIS PRESENTED FOR THE DEGREE OF DOCTOR OF MEDICINE (MD) IN THE UNIVERSITY OF LONDON. 1971
9 Ringelhann B, Dodu SRA, Konotey-Ahulu FID, Lehmann H. A survey of haemoglobin variants, thalassaemia, and Glucoose-6 Phosphate Dehydrogenase Deficiency in Northern Ghana. Ghana Medical Journal 1968; 7: 120-124.
10 Konotey-Ahulu FID. Perthes’ Disease versus Sickle Cell Disease hip. October 24 2014 BMJ Rapid Response www.bmj.com/content/349/bmj.g5584/rr/778350 or http://bit.ly/1tGmuYm
11 Konotey-Ahulu FID. The spectrum of phenotypic expression of clinical haemoglobinopathy in West Africa. New Istanbul Contribution to Clinical Science 1978; 12: 246-247.
12 Konotey-Ahulu FID. Effect of environment on Sickle Cell Disease in West Africa: epidemiologic and clinical considerations – In SICKLE CELL DISEASE: Diagnosis, Management, Education and Research, Editors Harold Abramson, John F Bertles, Doris L Wethers. Saint Louis 1973 The C V MOSBY Company, pages 20-38.
Serjeant GR. Sickle Cell Disease. Oxford, Oxford University Press, 1992.
14. Konotey-Ahulu FID. Sickle Cell Disease in Successive Ghanaian Generations For Three Centuries (Manya Krobo Tribe) 1670 to 1970 – The Human Genome Diversity Project: Cogitations of an African Native. In Human Genome Diversity Project. POLITICS and The LIFE SCIENCES 1999; 18: 317-322.
Competing interests: No competing interests