No abstract

Isolated polyethylene liner exchange (IPLE) is infrequently selected as a treatment approach for patients with primary total knee arthroplasty (TKA) prosthetic joint instability. Potential advantages of less immediate surgical morbidity, faster recovery, and lower procedural cost need to be measured against reoperation and re-revision risk. Few published studies have directly compared IPLE with combined tibial and femoral component revision to treat patients with primary TKA instability. After obtaining institutional review board (IRB) approval, we performed a retrospective comparison of 20 patients treated with IPLE and 126 patients treated with tibial and femoral component revisions at a single institution between 2011 and 2018. Patient demographic characteristics, medical comorbidities, time to initial revision TKA, and reoperation (90 days, <2 years, and >2 years) were assessed using paired Student's t-test or Fisher's exact test with a p-value <0.01 used to determine significance. Patients undergoing IPLE were more likely to undergo reoperation (60.0 vs. 17.5%, p = 0.001), component revision surgery (45.0 vs. 8.7%, p = 0.002), and component revision within 2 years (30.0 vs. 1.6%, p < 0.0001). Differences in 90-day reoperation (p = 0.14) and revision >2 years (p = 0.19) were not significant. Reoperation for instability (30.0 vs. 4.0%, p < 0.001) and infection (20.0 vs. 1.6%, p < 0.01) were both higher in the IPLE group. IPLE does not provide consistent benefits for patients undergoing TKA revision for instability. Considerations for lower immediate postoperative morbidity and cost need to be carefully measured against long-term consequences of reoperation, delayed component revision, and increased long-term costs of multiple surgical procedures. This is a level III, case–control study.

Instability is a common indication for early revision total knee arthroplasty (rTKA). The comparative performance of instability rTKA performed after primary TKA and instability rerevision TKA (rrTKA) performed after a previous rTKA performed for any aseptic indication have not been defined. This study was performed to determine the rate of adverse outcomes for patients undergoing aseptic instability TKA revision following a primary TKA or a previous aseptic any-cause rTKA. After obtaining Institutional Review Board approval, we retrospectively identified 126 rTKA and 28 rrTKA component revision procedures performed for an exclusive instability diagnosis between January 1, 2011 and April 30, 2018. We excluded patients undergoing isolated liner exchange, single component revision for mid-flexion instability, and patients treated with a constrained hinge. Patient demographic characteristics, medical comorbidities, time to initial revision TKA, and adverse postrevision outcomes (reoperation, component revision, infection, amputation) were assessed using paired Student's t-test or Fisher's exact test with a p-value < 0.05 used to determine significance. Patients in the rrTKA cohort were more commonly female (57.1 vs. 27.8%, p < 0.01), with no other demographic differences. The rrTKA cohort had higher reoperation (39.3 vs. 18.4%, p = 0.02) and component revision rates (25.0 vs. 8.7%, p = 0.03), with a trend towards early reoperation < 2 years after surgery (25.0 vs. 11.1%, p = 0.07). The rrTKA cohort also had higher adverse outcomes related to infection (14.3 vs. 1.6%, p = 0.01), extensor mechanism failure (14.3 vs. 3.2%, p = 0.04) and above-knee amputation (14.3 vs. 2.4%, p = 0.02). Component revision is beneficial for patients with TKA instability; however, higher adverse outcome rates occur after instability rrTKA performed after a previous aseptic any-cause rTKA. Infection prevention and extensor mechanism protection are important to minimize the most common adverse outcomes identified among patients undergoing aseptic rrTKA for instability.

Intraoperative imaging may improve total hip arthroplasty (THA) component placement, but the time and cost associated with this approach have not been well described. We assessed component placement accuracy, operative time, and operating room (OR) charges for 270 patients undergoing posterolateral THA (PL-THA) with or without intraoperative imaging. This study retrospectively compared 135 PL-THA performed with intraoperative digital radiography (group PLxr) and a contemporary cohort of 135 PL-THA performed without imaging (group PL). Postoperative radiographs were evaluated to determine outlier rates for acetabular inclination of 55 degrees or higher, anteversion less than 15 or more than 40 degrees, and leg length or offset differences more than 10 mm. Surgical procedure time was extracted from hospital OR records, and procedural costs were estimated from facility charges associated with 30-minute OR time blocks and intraoperative imaging. Group PLxr had significantly fewer outliers for acetabular inclination more than 50 degrees (5.2 vs. 21.5%, p < 0.001), acetabular inclination of 55 degrees or higher (0.7 vs. 8.1%, p = 0.01), acetabular anteversion less than 15 or more than 40 degrees (14.8 vs. 28.9%, p < 0.01), leg length difference more than 10 mm (2.2 vs. 10.4%, p = 0.01), and femoral offset difference more than 10 mm (1.5 vs. 9.6%, p < 0.01). The difference in component inclination less than 30 degrees was not significant (0.0 vs. 2.2%, p = 0.24). Intraoperative component adjustment occurred in 26 cases (21.5%), was associated with a 19-minute mean increase in operative time (p < 0.001) and $1,504 mean increase in facility charges compared with nonimaged cases. Imaged cases without component adjustment increased mean operative time by 9.4 minutes (p < 0.001) and mean operative charges by $766. Intraoperative imaging improves component placement accuracy during PL-THA and significantly reduces component placement outliers, particularly with respect to acetabular component inclination, femoral length, and femoral offset. Level of Evidence Level III, case-control study.