Radiographic Changes in Nonoperative Contralateral Knee After Unilateral Total Knee Arthroplasty

Mental Robustness May Be Associated With Improved Physical Function in Bilateral Total Knee Arthroplasty Patients

BACKGROUND

In accordance with the high incidence of bilateral knee osteoarthritis, many patients have undergone bilateral total knee arthroplasty (BTKA). Whether patients undergo bilateral procedures in a staged or simultaneous fashion, the physical and mental burden of undergoing 2 major orthopedic procedures is considerable. The aims of this study were to (1) investigate differences between minimal clinically important difference (MCID) achievement between staged versus simultaneous BTKA, and (2) identify the patient variables, specifically mental scores, that were associated with MCID achievement in patients undergoing BTKA.

METHODS

Simultaneous and staged BTKA patients within a single health care network from 2016 to 2021 were retrospectively reviewed. Patient demographics, surgery details, and Patient-Reported Outcome Measurement Information System Physical Function Short Forms 10a (PROMIS PF10a), PROMIS Mental scores, and Knee Disability Osteoarthritis Outcome Scores (KOOS) were reviewed. Preoperative and postoperative patient-reported outcome measures were collected before the first total knee arthroplasty (TKA) and after the second TKA, respectively, in staged BTKA patients. The final cohort consisted of 249 patients, with an average age of 66 years (range, 21 to 87), 63% women, and an average body mass index of 32 (range, 20 to 52), at a mean follow-up of 1.1 years (range, 0.5 to 2.4). Multivariate regressions were performed on MCID PF10a and KOOS achievement, as well as whether the BTKA was performed simultaneously versus staged.

RESULTS

A preoperative PROMIS Mental score in the upper 2 quartiles was associated with MCID PF10a achievement in BTKA. Men and surgeries performed at an Academic Medical Center were negatively associated with the achievement of MCID KOOS. Interestingly, those who underwent simultaneous BTKA were less likely to achieve MCID KOOS than those who underwent a staged BTKA.

CONCLUSIONS

Preoperative mental robustness may be positively associated with improved physical function outcome in BTKA patients.

Implication of Changes in the Imaging Measurements after Mechanically Aligned Total Knee Arthroplasty

OBJECTIVE

Imaging measurements allow assessment of the mechanical alignment before and after total knee arthroplasty (TKA). The changes in radiographic parameters in each period of time within 1 year after TKA has been poorly understood. The purpose of this study was to examine the timing and causes of imaging changes in lower extremity force lines after total knee arthroplasty with mechanical alignment.

METHODS

A total of 93 mechanically-aligned TKA were radiographically examined before, 3 days, 3 months, and 1 year after surgery. Radiographic parameters included hip-knee angle (HKA), lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), knee joint line orientation (KJLO), ankle joint line orientation (AJLO), the knee joint line relative to ankle joint line angle (KJLTA) and midpoints of the ankle distance (MAD). Paired t-test were used to analyze the changes of these imaging parameters, By establishing a simple tibial model, the time points of changes in the imaging parameters after TKA was determined, with an attempt to understand the post-TKA changes in these imaging parameters.

RESULTS

Statistically significant differences were found between the preoperative data and the data measured 3 days after surgery in HKA, LDFA, MPTA, MAD, KJLTA, AJLO (P < 0.05) while KJLO exhibited no significant difference (P = 0.089). There existed significant differences between the data measured 3 days and the measurements taken 3 months after operation in HKA, MPTA, KJLTA, KJLO, AJLO (P < 0.05), whereas LDFA and MAD showed no significant difference (P > 0.05). Significant differences were revealed between the data measured 3 months and those collected 1 year after surgery in LDFA, MPTA, AJLO, KJLTA (P < 0.05) but HKA, KJLO, AJLO showed no significant differences (P > 0.05). The tibial model was made to look into the changes in postoperative imaging parameters. ΔMAD and postoperative AJLO were calculated to verify the model and hypothesis.

CONCLUSIONS

Postoperative changes in radiographic parameters and tibial models showed that the lower extremities were in an unnatural state within 1 year after TKA. The changes in the lower extremities force line were the results of the gradual adaptation of the lower extremities to TKA and the lateral swing of the extremities (3°) after surgery. Imaging data 1 year after surgery should be taken into account in the explanation of post-TKA changes in lower limb force lines.

Staged Versus Simultaneous Bilateral Knee Arthroplasty: Does Minimal Cost Difference Justify Risks?

BACKGROUND

Simultaneous bilateral total knee arthroplasty (BTKA) is associated with a higher risk but can be perceived to afford faster improvement and mitigated costs versus staged BTKA. We aimed to explore (1) health care utilization, (2) surgical supply costs of simultaneous BTKA; and (3) 1-year improvement in patient-reported pain, function, and quality of life (QOL) versus staged BTKA.

METHODS

A prospective cohort of 198 simultaneous and 625 staged BTKAs was obtained (2016-2020). Simultaneous BTKA cohort was propensity score-matched (1:2) to a similar group of staged patients (simultaneous = 198 versus staged = 396). Outcomes included length of stay, discharge disposition, 90-day readmission, 1-year reoperation, surgical episode supply cost, Knee Injury and Osteoarthritis Outcome Score (KOOS)-pain, KOOS-Physical Function Short Form, and KOOS-QOL. Rates of attaining minimal clinically important difference and Patient Acceptable Symptomatic State were calculated.

RESULTS

Compared to both staged BTKA surgeries combined, simultaneous BTKA demonstrated shorter median net length of stay (2.00 [2.00, 3.00] days versus 2.00 [2.00, 4.00] days; P < .001) but higher rates of nonhome discharge (n = 56 [28.3%] versus n = 32 [4.04%]; P < .001), 90-day readmission (n = 20 [10.1%] versus n = 48 [6.06%]; P = .047) and similar reoperation rates (P = .44). Simultaneous BTKA afforded slight reduction in net surgical cost compared to that of both staged BTKAs combined ($643; P = .028). There was no significant difference in 1-year improvement and minimal clinically important difference attainment rates with simultaneous versus staged BTKA for KOOS-pain (P = .137 and P = .99), KOOS-QOL (P = .095 and P = .81), or KOOS-Physical Function Short Form (P = .75 and P = .49, respectively) or Patient Acceptable Symptomatic State (P = .12).

CONCLUSION

Staged BTKA is associated with similar 1-year pain, function, and QOL at a better safety profile and minimal surgical supply cost increase compared to simultaneous BTKA.

The incidence and risk factors of contralateral knee arthroplasty after primary unilateral unicompartmental knee arthroplasty

Unicompartmental knee arthroplasty (UKA) is one of the commonly used surgical methods for unicompartmental osteoarthritis in recent years. Although the prognosis of the operated knee has been widely studied, there are relatively little data on the natural history of the contralateral knee after unilateral replacement. The aim of this study was to explore the incidence and risk factors of consequential knee arthroplasty in patients with bilateral knee osteoarthritis (KOA) after receiving primary unilateral UKA, so as to provide a theoretical basis for making a more comprehensive treatment strategy for patients with KOA.We conducted a retrospective study and enrolled patients with bilateral KOA received unilateral UKA from June 2015 to December 2019 in the third department of joint orthopedics, the third hospital of Hebei Medical University. The patients were divided into replacement group and non-replacement group according to whether the contralateral knee joint received knee arthroplasty. Information about treatment of contralateral knee joint was collected from medical records to determine the incidence. Univariate analysis and multivariate logistic regression analysis were performed to identify the independent risk factors.A total of 502 patients were enrolled in this study. The incidence of contralateral knee arthroplasty was 38.64%. In the univariate analysis, vertical angle of mechanical axis, knee joint's internal and external joint space, Kellgren-Lawrence (K-L) classification, femoral tibial angle were the significant risk factors for contralateral knee arthroplasty. In the multivariate model, only vertical angle of mechanical axis ≥3.03° (odds ratio [OR] 4.36, 95% confidence interval [CI], 2.47-9.11), K-L classification grades 3 and 4 (OR 2.46,3.72; 95%CI, 1.31-4.25, 1.98-6.87), and femoral tibial angle ≥187.32° (OR 6.32, 95%, 2.23-18.87) remained associated with the occurrence of knee arthroplasty.About a quarter of patients with bilateral KOA received unilateral UKA will receive contralateral knee arthroplasty. Higher K-L classification, femoral tibial angle, and mechanical axis vertical angle are identified risk factors.

Leg-Length Change After Unilateral Unicompartmental Knee Arthroplasty in Varus Knee and Its Clinical Implications

BACKGROUND

To explore the magnitude of leg-length change after the unilateral index unicompartmental knee arthroplasty (UKA) in varus knee and its influence on clinical outcomes.

METHODS

A total of 114 patients with bilateral knee osteoarthritis who underwent unilateral UKA from June 2015 to June 2017 were included and followed up for at least 2 years. The leg length and hip-knee angle were measured on full-length standing films before and after the surgery. Flexion contracture was evaluated using a goniometer with the patient in the standing position preoperatively and postoperatively. Hospital for Special Surgery scores, perceived leg-length discrepancy (pLLD), the occurrence, and the time interval of subsequent contralateral knee arthroplasty were recorded and analyzed.

RESULTS

The average leg length increased after UKA was 9.39 ± 11.24 mm (range -21.00 to 33.79 mm), and 90 (78.9%) patients showed an increase in the leg length. 35 patients had LLD (defined as ≥10 mm), and 25 presented pLLD preoperatively; 25 patients had LLD, and 45 were suspected with pLLD postoperatively. At the last follow-up, 26 patients underwent subsequent contralateral knee arthroplasty. Postoperative LLD and pLLD were not associated with Hospital for Special Surgery scores of UKA but associated with subsequent contralateral knee arthroplasty.

CONCLUSIONS

LLD and pLLD were common in patients both before and after UKA. Most patients showed leg lengthening after UKA. Postoperative LLD and pLLD were not associated with functional scores but associated with a subsequent contralateral knee arthroplasty.

Contralateral knee pain reduces the rate of patient satisfaction but does not clinically impair the change in WOMAC score after total knee arthroplasty

Aims

The primary aim of this study was to assess whether pain in the contralateral knee had a clinically significant influence on the outcome of total knee arthroplasty (TKA) according to the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score. Secondary aims were to: describe the prevalence of contralateral knee pain; identify if it clinically improves after TKA; and assess whether contralateral knee pain independently influences patient satisfaction with their TKA.

Methods

A retrospective cohort of 3,178 primary TKA patients were identified from an arthroplasty database. Patient characteristics, comorbidities, and WOMAC scores were collected preoperatively and one year postoperatively for the index knee. In addition, WOMAC pain scores were also collected for the contralateral knee. Overall patient satisfaction was assessed at one year. Preoperative contralateral knee pain was defined according to the WOMAC score: minimal (> 78 points), mild (59 to 78), moderate (44 to 58), and severe (< 44). Multivariate regression analysis was used to adjust for confounding.

Results

According to severity there were 1,425 patients (44.8%) with minimal, 710 (22.3%) with mild, 518 (16.3%) with moderate, and 525 (16.5%) with severe pain in the contralateral knee. Patients in the severe group had a greater clinically significant improvement in their functional WOMAC score (9.8 points; p < 0.001). Only patients in the moderate (22.9 points) and severe (37.8 points) groups had a clinically significant improvement in their contralateral knee pain (p < 0.001), but they were significantly less likely to be satisfied with their TKA (moderate: odds ratio (OR) 0.64, 95% confidence interval (CI) 0.4 to 0.92, p = 0.022; severe: OR 0.57, 95% CI 0.39 to 0.82, p = 0.002).

Conclusion

Contralateral knee pain did not impair improvement in the WOMAC score after TKA, and patients with the most severe contralateral knee pain had a clinically significantly greater improvement in their functional outcome. More than half the patients presenting for TKA had mild-to-severe contralateral knee pain, most of whom had a clinically meaningful improvement but were significantly less likely to be satisfied with their TKA. Cite this article: Bone Joint J. 2020;102-B(1):125–131

Younger patients with high varus malalignment of the contralateral knee may be candidates for simultaneous bilateral total knee arthroplasty

PURPOSE

Bilateral total knee arthroplasty (TKA) is being performed more frequently. However, a consensus on whether simultaneous or staged procedures should be performed is not available. This study reviewed the clinical course of contralateral knees in patients who underwent unilateral TKA (UTKA) to determine which patients are candidates for simultaneous bilateral TKA (BTKA).

METHODS

One hundred eighty-six patients with osteoarthritis who underwent UTKA at a single hospital between 2006 and 2009 (follow-up mean, 10.1 years) were retrospectively investigated. Age, sex, obesity, contralateral knee pain, Hospital for Special Surgery score, femorotibial angle (FTA), and Kellgren-Lawrence grades at the time of initial surgery were used to evaluate the risk for requiring contralateral TKA. Survival analysis and receiver-operating characteristic (ROC) analysis were performed.

RESULTS

Ninety-one patients (48.9%) underwent contralateral TKA. The FTA of the contralateral knee (CFTA) was an independent related factor (hazard ratio, 1.15; p < 0.001), and the CFTA cut-off value for the next surgery was 183° (area under the curve, 0.85; sensitivity, 80.7%; specificity, 76.2%). The 10-year Kaplan-Meier survival rates for the CFTA < 183° group and the CFTA ≥ 183° group were 79.1% and 27.0%, respectively. In the CFTA ≥ 183° group, age was the predictor of future TKA, and elderly patients tended to not require a second procedure. The age cut-off value for the next surgery was 76 years.

CONCLUSIONS

Varus deformities in the contralateral knee predicted additional contralateral TKA. Patients with CFTA ≥ 183° and aged 75 years or younger are considered reasonable candidates for simultaneous BTKA.

LEVEL OF EVIDENCE

III.