Sirs,
We read with enthusiasm the article entitled “Proximal femur prosthetic interposition arthroplasty for painful dislocated hips in children with cerebral palsy” by Silverio et al.1 We appreciate the authors for providing alternative hip salvage options for improving the quality of life of cerebral palsy (CP) children. We wish to provide another perspective in regards to that topic.
There is insufficient consensus on the optimal treatment modality and its exact indications for hip dislocation in CP children.2-4 The chief surgical strategies employed to address hip dislocation are hip reconstruction,4 and hip salvage.2,3,5 Reports of both strategies have documented satisfactory long-term outcomes.4-7 Pain relief and improved hip motion are considered universal treatment goals.2-7 Reconstruction and arthroplasty have an advantage over other salvage that they can achieve stability. Additionally, the authors aimed at achieving hip stability in painful spastic dislocated CP hips. We believe that the attempt to achieve hip stability through prosthetic interposition arthroplasty may yield an unfavourable risk-benefit ratio especially on the long-term. We assume that the notion of restoring hip stability in a non-ambulatory CP patient with extremely low functional demands is less appealing if compared to ambulatory patients with higher functional hip demands. Cartilage wear and peri-prosthetic osteolysis are justified concerns after hemiarthroplasty.3,5 These phenomena may constitute a precursor of hip pain taking into consideration the potentially unhealthy state of articular cartilage and skeletally immature patient population. In the article, the patient profiles comprised painful spastic dislocated and mostly virgin hips. We believe that such patients were more suited to other salvage procedures such as proximal femoral osteotomies with or without femoral head resection. We also propose that proximal femoral interposition arthroplasty may be one of the more suited options for CP children in whom primary hip reconstruction or salvage procedure has failed. While the authors are praised for employing a quality of life assessment instrument and a structured quantitative pain score, their validity remains to be ascertained.
The retrospective and non-randomised nature of the study design may eventually serve to intensify the already heated controversies over optimal treatment modality rather than creating a unifying approach. Interestingly, the overwhelming majority of studies addressing hip reconstruction and salvage in CP hip instability are retrospective.2-7 Although there is room for retrospective observational studies to inform clinical practice and decision making, they should be interpreted with extreme caution. Retrospective studies are likely associated with selection and performance bias that may undermine validity of extracted data and generalisability of conclusions.2-5 It is acknowledged that randomised control studies may be unrealistic in CP clinical research due to technical complexity, high economic demands, and ethical considerations.
In consequence, we encourage the design of prospective randomised control studies where various adequately randomised and homogenous patient groups can be subjected to different surgical interventions namely reconstruction versus salvage. Such study designs demonstrate a significant potential for controlling bias originating from confounding variables. They are also more ethically appealing if compared to randomised case-control studies where the control group does not receive any surgical intervention. Equally important are the implementation of validated and reliable outcome scores that allow for reasonable generalisation of conclusions. Patients and parents are mostly interested in the subjective patient-reported quality of life outcome measures, whereas surgeons may find objective physician-reported radioclinical measurments more gripping. We perceive subjective and objective outcome measures to be in a congruent relationship.
Yours Sincerely
The Authors
Compliance with Ethical Standards
Ethical Statement
The authors declare no conflict of interest.
References
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