Hip & Pelvis

Bundling care in arthroplasty

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In those parts of the world with a very large state-funded healthcare system, the concept of bundled payments is nothing new – where remuneration is given for the ‘episode of care’ rather than for the individual components of this episode. Care bundles offer subtly different approaches, with some including all components of treatment but covering costs of complications, and others failing to cover, or even (as in some procedures in the UK) reducing payments for failure to reach quality metrics or withholding payment if there is a readmission or complication. Bundled payments are increasingly being implemented in total joint arthroplasty across the world, and this study from Philadelphia, Pennsylvania (USA) specifically examines the ‘fairness’ of such a system in total hip arthroplasty.³ In the US the use of bundled payment models, such as the Comprehensive Care for Joint Replacement Model, set out a price for performing a certain procedure, but do not take patient characteristics into account. This study highlights the following demographic factors as being more costly: advanced age, increasing BMI, cases performed for fractures, elevated ASA grade, and major complications. In the future, bundled payment programmes should take these demographic factors into consideration and pay a higher amount for specific patients.

Bariatric surgery helpful prior to hip arthroplasty

There is controversy over the risks, benefits and funding for arthroplasty in the elderly. One of the unanswered questions, however, is about the optimisation of patients, and in the case of this study from Rochester, Minnesota (USA), whether weight loss surgery reduces the risks enough to warrant the increased costs.⁴ There is now good evidence to suggest that a high BMI is associated with an increased risk of wound complications, peri-prosthetic joint infection (PJI), hip dislocation, re-operation and revision following total hip arthoplasty (THA). Bariatric surgery is capable of reducing BMI, and there are established benefits with improvements in diabetes mellitus, hyperlipidaemia, hypertension and sleep apnoea. Despite these benefits, the evidence currently suggests that patients undergoing total knee arthroplasty (TKA) after bariatric surgery actually do worse, but there is little to no evidence to support its use or otherwise in THA. The authors report a total of 137 obese patients, 47 of whom underwent a THA having had previous bariatric surgery, and 90 patients who underwent 94 THAs who had not had bariatric surgery. The mean age of the patients was 57 years in both groups. The mean time between bariatric surgery and THA was five years (4 months to 12 years), during which time the mean BMI improved from 49.7 kg/m² to 35.3 kg/m². The BMI in the comparison group (who did not have prior bariatric surgery) was 50.2 kg/m². Patients who did not have bariatric surgery before THA were statistically more likely to require further surgery and revision than those who did have pre-operative bariatric surgery. The most common reason for revision in both groups was PJI. A number of other studies have shown little evidence to support the authors’ conclusion that bariatric surgery should be considered prior to THA in morbidly obese patients. However, the reason these patients are at high risk of complication is not just their weight but also their additional co-morbidities including nutritional and protein deficiencies. These deficiencies may not be addressed with bariatric surgery and in fact may be exacerbated, which may explain why some studies have shown poor outcomes of THA and TKA following bariatric surgery. Patients who lose a lot of weight following bariatric surgery have poorly organised collagen structure, and together with elastic degradation this can lead to increased incidence of arthrofibrosis and instability after a TKA, for example, making soft-tissue balancing a challenge. This is an interesting study, with some weaknesses, that highlights the difficulty in managing patients who are morbidly obese with degenerative joints. This study also highlights the fact that the high incidence of further surgery and revision following THA in morbidly obese patients is multifactorial and that patients’ nutritional status and the effects of weight loss on the soft-tissues also need to be considered.