Sir,
We read the article Head size and dislocation rate in primary total hip arthroplasty,1 with keen interest. We appreciate the authors work; however, we would like to point out certain issues.
The authors have made two groups based on head size; however, it was not clear from the study if any criteria or randomization was used to allocate a patient into either of these groups
The authors have discussed that there was no difference between the groups so far as age, sex, and indications for primary total hip arthroplasty were concerned. However, the demographic profile of the two groups was not sex-matched; female-to-male ratio between groups A and B was 0.37 and 0.68, respectively. According to the literature, female gender is associated with a higher dislocation rate;2,3,4 so was this a contributing factor in causing increased dislocation rate in group B (28 mm group)
According to the authors, the etiology of dislocation (one in group A and three in group B) was component malposition. While component malposition itself is an independent risk factor for dislocation,4,5 is it justifiable to consider head size as the only factor when other confounding factors are also present
REFERENCES
- 1.Singh SP, Bhalodiya HP. Head size and dislocation rate in primary total hip arthroplasty. Indian J Orthop. 2013;47:443–8. doi: 10.4103/0019-5413.118198. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Kim YH, Choi Y, Kim JS. Influence of patient-, design-, and surgery-related factors on rate of dislocation after primary cementless total hip arthroplasty. J Arthroplasty. 2009;24:1258–63. doi: 10.1016/j.arth.2009.03.017. [DOI] [PubMed] [Google Scholar]
- 3.Leichtle UG, Leichtle CI, Taslaci F, Reize P, Wünschel M. Dislocation after total hip arthroplasty: Risk factors and treatment options. Acta Orthop Traumatol Turc. 2013;47:96–103. doi: 10.3944/aott.2013.2978. [DOI] [PubMed] [Google Scholar]
- 4.Turner RS. Postoperative total hip prosthetic femoral head dislocations. Incidence, etiologic factors, and management. Clin Orthop Relat Res. 1994;301:196–204. [PubMed] [Google Scholar]
- 5.Biedermann R, Tonin A, Krismer M, Rachbauer F, Eibl G, Stöckl B. Reducing the risk of dislocation after total hip arthroplasty, the effect of orientation of acetabular component. J Bone Joint Surg Br. 2005;87:762–9. doi: 10.1302/0301-620X.87B6.14745. [DOI] [PubMed] [Google Scholar]