Outcomes of shoulder replacement surgery in routine care
Keywords: shoulder replacement
revision risk
adverse events
registry
shared decision making
PROMs

Better evidence is needed on the expected outcomes of shoulder replacement surgery to help patients to decide whether it is the right treatment for them. This thesis systematically evaluates the potential benefits and risks of shoulder replacement surgery observed in routine UK practice, and explores the patient factors associated with good and poor outcomes.
A Cochrane review of randomised controlled trials (RCTs) was performed. The available studies were of low quality and produced few reliable findings to inform practice. RCTs provided very little useful data on the rates of revision surgery and adverse events.
Despite the lack of high-quality evidence, temporal trend analysis revealed that the standardised incidence of primary shoulder replacement surgery recorded by NHS England increased from 3.9/10000 in 1999 to 13.6/10000 in 2017. These trends were marked by an increase in the number of conventional and reverse polarity total shoulder replacements performed in patients aged 65 years and older, and an increase in recorded patient comorbidities.
Hospital Episode Statistics data were used to calculate the risks of long-term revision and early serious adverse events. The lifetime risk of implant revision surgery following an elective shoulder replacement was less than 1 in 20 for patients aged 85 years or older, but as high as 1 in 4 for some patients aged less than 60 years. These rates were approximately 1.5 times higher if other types of reoperation were included. Serious adverse events were recorded after 1 in 30 elective procedures within the first 30 days. Patients aged over 85 years were far more likely to experience a serious adverse event (1 in 5 men and 1 in 10 women). Following procedures performed for acute trauma, the risk of needing revision surgery was considerably lower, but the likelihood of experiencing a serious adverse event was three times higher.
National Joint Registry data for England, Wales, Northern Ireland and the Isle of Man were used to predict postoperative patient reported outcomes with modest accuracy. Most patients experienced considerable improvement in pain and function within the first year following an elective shoulder replacement, but 1 in 10 patients experienced no benefit at all. Patients aged 70 to 80 years with a diagnosis of primary osteoarthritis or rotator cuff-tear arthropathy had the best predicted outcomes. Younger age and a history of previous trauma and/or surgery were the most important predictors of no improvement. Patient reported outcomes were better following total shoulder replacement compared with hemiarthroplasty in patients without a tear of the rotator cuff. This agreed with the low-quality evidence from RCTs. In patients with an attenuated rotator cuff, there was no clear difference between conventional and reverse polarity total shoulder replacements.
This thesis estimated lifetime risks of revision surgery following a primary shoulder replacement for the first time. This new information, together with the predicted patient reported outcomes and adverse event data, represents the best available evidence from routine practice for surgeons and patients considering shoulder replacement surgery. Further research needs to identify treatment strategies that optimise long-term outcomes for younger patients and the safety of surgery for older patients with comorbidities. The choice of procedure type for patients with incomplete rotator cuff tears is an ongoing uncertainty and may be best addressed with a future well-designed trial.