Resident Participation is Not Associated With Worse Outcomes After TKA

Approximately one-half of all US surgical procedures, and one-third of orthopaedic procedures, are performed at teaching hospitals. However, the effect of resident participation and their level of training on patient care for TKA postoperative physical function, operative time, length of stay, and facility discharge are unclear.

(1) Are resident participation, postgraduate year (PGY) training level, and number of residents associated with absolute postoperative Patient-Reported Outcomes Measurement Information System (PROMIS®-10) global physical function score (PCS), and achieving minimum clinically important difference (MCID) PCS improvement, after TKA? (2) Are resident participation, PGY, and number of residents associated with increased TKA operative time? (3) Are resident participation, PGY, and number of residents associated with increased length of stay after TKA? (4) Are resident participation, PGY, and number of residents associated with higher odds of patients being discharged to another inpatient facility, rather than to their home (facility discharge)?

We performed a retrospective study using a longitudinally maintained institutional registry of TKAs that included 1626 patients at a single tertiary academic institution from April 2011 through July 2016. All patients who underwent primary, elective unilateral TKA were included with no exclusions. All patients were included in the operative time, length of stay, and facility discharge models. The PCS model required postoperative PCS score (n = 1417; 87%; mean, 46.4; SD, 8.5) and the MCID PCS model required pre- and postoperative PCS (n = 1333; 82%; 55% achieved MCID). Resident participation was defined as named residents being present in the operating room and documented in the operative notes, and resident PGY level was determined by the date of TKA and its duration since the resident entered the program and using the standard resident academic calendar (July - June). Multivariable regression was used to assess PCS scores, operative time, length of stay, and facility discharge in patients whose surgery was performed with and without intraoperative resident participation, accounting for PGY training level and number of residents. We defined the MCID PCS score improvement as 5 points on a 100-point scale. Adjusting variables included surgeon, academic year, age, sex, race-ethnicity, Charlson Comorbidity Index, preoperative PCS, and patient-reported mental function, BMI, tobacco use, alcohol use, and postoperative PCS time for the PCS models. We had postoperative PCS for 1417 (87%) surgeries.

Compared with attending-only TKAs (5% of procedures), no postgraduate year or number of residents was associated with either postoperative PCS or MCID PCS improvement (PCS: PGY-1 = -0.98, 95% CI, -6.14 to 4.17, p = 0.708; PGY-2 = -0.26, 95% CI, -2.01to 1.49, p = 0.768; PGY-3 = -0.32, 95% CI, -2.16 to 1.51, p = 0.730; PGY-4 = -0.28, 95% CI, -1.99 to 1.43, p = 0.746; PGY-5 = -0.47, 95% CI, -2.13 to 1.18, p = 0.575; two residents = 0.28, 95% CI, -1.05 to 1.62, p = 0.677) (MCID PCS: PGY-1 = odds ratio [OR], 0.30, 95% CI, 0.07-1.30, p = 0.108; PGY-2 = OR, 0.86, 95% CI, 0.46-1.62, p = 0.641; PGY-3 = OR, 0.97, 95% CI, 0.49-1.89, p = 0.921; PGY-4 = OR, 0.73, 95% CI, 0.39-1.36, p = 0.325; PGY-5 = OR, 0.71, 95% CI, 0.39-1.29, p = 0.259; two residents = OR, 1.23, 95% CI, 0.80-1.89, p = 0.337). Longer operative times were associated with all PGY levels except for PGY-5 (attending surgeon only [reference] = 85.60 minutes, SD, 14.5 minutes; PGY-1 = 100. 13 minutes, SD, 21.22 minutes, +8.44 minutes, p = 0.015; PGY-2 = 103.40 minutes, SD, 23.01 minutes, +11.63 minutes, p < 0.001; PGY-3 = 97.82 minutes, SD, 18.24 minutes, +9.68 minutes, p < 0.001; PGY-4 = 96.39 minutes, SD, 18.94 minutes, +4.19 minutes, p = 0.011; PGY-5 = 88.91 minutes, SD, 19.81 minutes, -0.29 minutes, p = 0.853) or the presence of multiple residents (+4.39 minutes, p = 0.024). There were no associations with length of stay (PGY-1 = +0.04 days, 95% CI, -0.63 to 0.71 days, p = 0.912; PGY-2 = -0.08 days, 95% CI, -0.48 to 0.33 days, p = 0.711; PGY-3 = -0.29 days, 95% CI, -0.66 to 0.09 days, p = 0.131; PGY-4 = -0.30 days, 95% CI, -0.69 to 0.08 days, p = 0.120; PGY-5 = -0.28 days, 95% CI, -0.66 to 0.10 days, p = 0.145; two residents = -0.12 days, 95% CI, -0.29 to 0.06 days, p = 0.196) or facility discharge (PGY-1 = OR, 1.03, 95% CI, 0.26-4.08, p = 0.970; PGY-2 = OR, 0.61, 95% CI, 0.31-1.20, p = 0.154; PGY-3 = OR, 0.98, 95% CI, 0.48-2.02, p = 0.964; PGY-4 = OR, 0.83, 95% CI, 0.43-1.57, p = 0.599; PGY-5 = OR, 0.7, 95% CI, 0.41-1.40, p = 0.372; two residents = OR, 0.93, 95% CI, 0.56-1.54, p = 0.766) for any PGY or number of residents.

Our findings should help assure patients, residents, physicians, insurers, and hospital administrators that resident participation, after adjusting for numerous patient and clinical factors, does not have any association with key medical and financial metrics, including postoperative PCS, MCID PCS, length of stay, and facility discharge. Future research in this field should focus on whether residents affect knee-specific patient-reported outcomes such as the Knee Injury and Osteoarthritis Score and additional orthopaedic procedures, and determine how resident medical education can be further enhanced without compromising patient care and safety.Level of Evidence Level III, therapeutic study.