Timing of Readmissions After Elective Total Hip and Knee Arthroplasty: Does a 30-Day All-Cause Rate Capture Surgically Relevant Readmissions?

BACKGROUND: The 30-day all-cause readmission rate is a widely used metric of hospital performance. However, there is lack of clarity as to whether 30 days is an appropriate time frame following surgical procedures. Our aim is to determine whether a 90-day time window is superior to a 30-day time window in capturing surgically relevant readmissions after total hip arthroplasty (THA) and total knee arthroplasty (TKA). METHODS: We analyzed readmissions following all primary THAs and TKAs recorded in the English National Health Service Hospital Episode Statistics database from 2008 to 2018. We compared temporal patterns of 30- and 90-day readmission rates for the following types of readmission: all-cause, surgical, return to theater, and those related to specific surgical complications. RESULTS: A total of 1.47 million procedures were recorded. After THA and TKA, over three-quarters of 90-day surgical readmissions took place within the first 30 days (78.5% and 75.7%, respectively). All-cause and surgical readmissions both peaked at day 4 and followed a similar temporal course thereafter. The ratio of surgical to medical readmissions was greater for THA than for TKA, with THA dislocation both being one of the most common surgical complications and clustering early after discharge, with 73.5% of 90-day dislocations occurring within the first 30 days. CONCLUSION: The 30-day all-cause readmission rate is a good reflection of surgically relevant readmissions that take place in the first 90 days after THA and TKA.

Predictors of 30-Day Readmission After Total Knee Arthroplasty: Analysis of 566,323 Procedures in the United Kingdom.

BACKGROUND: All-cause 30-day readmission after total knee arthroplasty (TKA) is currently used as a measure of hospital performance in the United States and elsewhere. Readmissions from surgical causes may more accurately reflect preventability and costs. However, little is known about whether predictors of each type of readmission differ. METHODS: All primary TKAs recorded in England's National Health Service administrative database from 2006 to 2015 were included. Multilevel logistic regression analysis was used to describe the effects of patient-related factors on 30-day readmission risk using 3 different readmission metrics: all-cause, surgical (defined using International Classification of Disease-10 primary admission diagnoses), and those resulting in return to theater (RTT). RESULTS: In total, 566,323 procedures were recorded. The comorbidity with the highest odds ratio (OR) for all types of readmission was psychoses (RTT OR 2.52, P < .001). Obesity was a strong independent predictor of RTT (OR 1.36, P < .001) and had the highest population attributable fraction of any comorbidity (4.7%). Unicompartmental arthroplasty was associated with a significantly lower risk of all types of readmission when compared with TKA, with the effect being most pronounced for surgical readmission (OR 0.66, P < .001). RTT in the index episode increased the risk of RTT readmission (OR 2.80, P < .001), as did any emergency admission to hospital in the preceding 12 months (for >2 emergency admissions, all-cause OR 2.38, P < .001). Length of stay either more than or less than 2 days was associated with an increased risk of all-cause and surgical readmission but not RTT readmission. CONCLUSION: Patient-related predictors of surgical and RTT readmission following TKA differ from those for all-cause readmission, but only the latter metric is in widespread use.

Comparison of 3 Types of Readmission Rates for Measuring Hospital and Surgeon Performance After Primary Total Hip and Knee Arthroplasty.

BACKGROUND: All-cause 30-day hospital readmission is in widespread use for monitoring and incentivizing hospital performance for patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA). However, little is known on the extent to which all-cause readmission is influenced by hospital or surgeon performance and whether alternative measures may be more valid. METHODS: This is an observational study using multilevel modeling on English administrative data to determine the interhospital and intersurgeon variation for 3 readmission metrics: all-cause, surgical, and return-to-theater. Power calculations estimated the likelihood of identifying whether the readmission rate for a surgeon or hospital differed from the national average by a factor of 1.25, 1.5, 2, or 3 times, for both average and high-volume providers. RESULTS: 259,980 THAs and 311,033 TKAs were analyzed. Variations by both surgeons and hospitals were smaller for the all-cause measure than for the surgical or return-to-theater metrics, although statistical power to detect differences was higher. Statistical power to detect surgeon-level rates of 1.25 or 1.5 times the average was consistently low. However, at the hospital level, the surgical readmission measure showed more variation by hospital while maintaining excellent power to detect differences in rates between hospitals performing the average number of THA or TKA cases per year in England. In practice, more outliers than expected from purely random variation were found for all-cause and surgical readmissions, especially at hospital level. CONCLUSION: The 30-day surgical readmission rate should be considered as an adjunctive measure to 30-day all-cause readmission rate when assessing hospital performance.

Factors Associated With 30-Day Readmission After Primary Total Hip Arthroplasty: Analysis of 514 455 Procedures in the UK National Health Service.

IMPORTANCE: Thirty-day readmission to hospital after total hip arthroplasty (THA) has significant direct costs and is used as a marker of hospital performance. All-cause readmission is the only metric in current use, and risk factors for surgical readmission and those resulting in return to theater (RTT) are poorly understood. OBJECTIVE: To determine whether patient-related predictors of all-cause, surgical, and RTT readmission after THA differ and which predictors are most significant. DESIGN, SETTING, AND PARTICIPANTS: Analysis of all primary THAs recorded in the National Health Service (NHS) Hospital Episode Statistics database from 2006 to 2015. The effect of patient-related factors on 30-day readmission risk was evaluated by multilevel logistic regression analysis. The analysis comprised all acute NHS hospitals in England and all patients receiving primary THA. MAIN OUTCOMES AND MEASURES: Thirty-day readmission rate for all-cause, surgical (defined using International Statistical Classification of Diseases and Related Health Problems, Tenth Revision primary admission diagnoses), and readmissions resulting in RTT. RESULTS: Across all hospitals, 514 455 procedures were recorded. Seventy-nine percent of patients were older than 60 years, 40.3% were men, and 59.7% were women. There were 30 489 all-cause readmissions (5.9%), 16 499 surgical readmissions (3.2%), and 4286 RTT readmissions (0.8%); 54.1% of readmissions were for surgical causes. Comorbidities with the highest odds ratios (ORs) of RTT included those likely to affect patient behavior: drug abuse (OR, 2.22; 95% CI, 1.34-3.67; P = .002), psychoses (OR, 1.83; 95% CI, 1.16-2.87; P = .009), dementia (OR, 1.57; 95% CI, 1.11-2.22; P = .01), and depression (OR, 1.52; 95% CI, 1.31-1.76; P < .001). Obesity had a strong independent association with RTT (OR, 1.46; 95% CI, 4.45-6.43; P < .001), with one of the highest population attributable fractions of the comorbidities (3.4%). Return to theater in the index episode was associated with a significantly increased risk of RTT readmission (OR, 5.35; 95% CI, 4.45-6.43; P < .001). Emergency readmission to the hospital in the preceding 12 months increased the risk of readmission significantly, with the association being most pronounced for all-cause readmission (for >2 emergency readmissions, OR, 2.33; 95% CI, 2.11-2.57; P < .001). Hip resurfacing was associated with a lower risk of RTT when compared with cemented implants (OR, 0.69; 95% CI, 0.54-0.88; P = .002) but for other types of readmission, implant type had no significant association with readmission risk. Increasing age and length of stay were strongly associated with all-cause readmission. CONCLUSIONS AND RELEVANCE: Many patient-related risk factors for surgical and RTT readmission differ from those for all-cause readmission despite the latter being the only measure in widespread use. Clinicians and policy makers should consider these alternative readmission metrics in strategies for risk reduction and cost savings.

Pre-operative digital templating in cemented hip hemiarthroplasty for neck of femur fractures.

Pre-operative digital templating allows the surgeon to foresee any anatomical anomalies which may lead to intra-operative problems, and anticipate appropriate instruments and implants required during surgery. Although its role is well-established in successful elective total hip arthroplasty, little work has been done on its use in hip hemiarthroplasty in neck of femur fractures. We describe our initial experience of digital templating in 40 consecutive patients who have undergone cemented hip hemiarthroplasty, assessing templating accuracy between templated implant sizes to actual implant sizes. 81% of implanted heads were templated to within two head sizes, and 89% of implanted stems were templated to within two sizes. Although there was a moderately strong correlation of 0.52 between templated and actual head sizes, this correlation was not demonstrated in femoral stem sizes. Mean leg length discrepancy was -2.5mm (S.D. 8.5), and the mean difference in femoral offset between the operated and non-operated hip was -1mm (S.D. 4.4). Digital templating is a useful adjunct to the surgeon in pre-operative planning of hip hemiarthroplasty in the restoration of leg length and femoral offset. However, its accuracy is inferior to that of elective total hip arthroplasty.