Clinical Outcomes and Risks of Single-stage Bilateral Unicompartmental Knee Arthroplasty via Oxford Phase III

Incidence of Postoperative Infection Following Simultaneous Bilateral Knee Arthroplasty: A Systematic Review and Meta-Analysis

Total knee arthroplasty is one of the most common orthopedic procedures. Simultaneous bilateral knee arthroplasty involves performing total knee arthroplasty on both knees in a single anesthetic session. This systematic review and meta-analysis followed the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020. A primary search was performed using PubMed, EBSCO, Scopus, Web of Science, Clarivate, and Google Scholar databases. Quantitative data synthesis was performed using MedCalc® Statistical Software version 20.115 to determine the pooled prevalence of the infection among patients who underwent simultaneous bilateral knee arthroplasty. The Newcastle-Ottawa Scale was used to assess study quality. We included 30 studies in our quantitative data synthesis, with a total population of 118,502 patients (237,004 knees). The pooled prevalence of superficial infection, deep infection, and unspecified surgical site infection was estimated to be 0.86% (95% confidence interval: 0.62-1.13%), 0.84% (95% confidence interval: 0.64-1.05%), and 1.18% (95% confidence interval: 0.45-2.27%), respectively. There was significant heterogeneity (I2 >50%) in all analyses, and inspection of funnel plots revealed a symmetrical distribution of plotted data. We found that the infection rates following simultaneous bilateral knee arthroplasty were relatively low but heterogeneous, as the data showed marked variability. Superficial infections were more common than deep infections; however, there was a small difference in their prevalence. Furthermore, the reliability of our findings was limited owing to significant heterogeneity.

Advantages of Simultaneous Cementless Bilateral Unicondylar Knee Arthroplasty Compared to Staged Surgery

Background

Unicondylar knee arthroplasty (UKA) is an effective procedure, which reduces pain, increases range of motion, and improves function. UKA could be performed simultaneously or in staged sessions. This study aimed to compare bilateral cementless UKA performed simultaneously and in staged sessions in terms of complications, hemoglobin levels, transfusions, and functional outcomes.

Methods

Patients undergoing bilateral UKA for symptomatic medial compartment osteoarthritis were retrospectively analyzed. Of the 73 patients who met the inclusion criteria, 40 underwent surgery simultaneously and 33 underwent surgery in separate sessions. Operative time, length of hospital stay, change in hemoglobin, need for blood transfusion, complications, and functional outcomes were assessed.

Results

There was no statistically significant difference between the two groups in demographic data. Simultaneously operated patients had a significantly shorter hospital stay and shorter operative time. Statistically significant improvements in clinical scores were noted in both groups. The degree of improvement in functional scores did not differ between the groups. There was no difference between the two groups in terms of complication rates, but the number of periprosthetic tibial fractures was higher in the simultaneous group.

Conclusions

Simultaneous bilateral cementless UKA was more advantageous in terms of cumulative hospital stay and total operation time with similar clinical results when compared to a staged procedure. While the overall complication rate was similar, the rate of periprosthetic fractures was 5% in the simultaneous group.

STAGED VERSUS SIMULTANEOUS APPROACH IN COMPLEX BILATERAL TOTAL KNEE REPLACEMENT: EXPERIENCE FROM TERTIARY INSTITUTION IN NIGERIA

Background

Bilateral end-stage knee osteoarthritis is a common presentation. The decision facing both patient and surgeon is whether to undertake the replacement of both knees in one sitting i.e. simultaneous bilateral total knee replacement (SMTKR) or to undertake this as a staged bilateral total knee replacement (STTKR). The decision is made harder by the presence of severe coronal and sagittal plane deformities and associated bone loss. We present our results of treating such patients with a focus on a trilogy of cost, complication and functional outcome following SMTKR.

Methodology

A retrospective review of 31 patients who presented with bilateral knee arthritis. 19 underwent SMTKR and 12 underwent STTKR. Data on the trilogy of complication, cost and functional outcome were collected and analysed.

Results

Our cohort of patients was overwhelmingly female in both groups at overall F/M = 30/1. Patients in the SMTKR group were slightly younger at a mean of 65 years compared to 69 years in the STTKR group. Mean Oxford Knee Score (OKS) improved significantly in all groups, mean of 54 in SMTKR and 56 in the STTKR groups. There was one fatality in the STTKR from upper GI bleeding and 1 revision for bone graft failure. The overall cost is less with SMTKR.

Summary

SMTKR is a safe and effective undertaking in properly selected patients with bilateral end-stage knee arthritis with severe deformities. Significant experience is however needed to successfully tackle complex deformities and such procedures should be undertaken by experienced arthroplasty surgeons.

Can single-stage bilateral unicompartmental knee arthroplasty be safely performed in patients over 70?

Background

For patients with bilateral, symptomatic unicompartmental knee arthritis, single-stage bilateral unicompartmental knee arthroplasty (ssBUKA) presents an attractive option. However, most studies have examined younger patient cohorts and the safety of ssBUKA remains controversial for older individuals. Therefore, the purpose of this study was to compare complication rates following ssBUKA for patients ≤70 and > 70 years old.

Methods

A retrospective chart review of 238 patients having undergone ssBUKA was performed, including 134 patients ≤70 and 104 patients >70. Post-operative complications were recorded at the six-week post-operative visit, along with emergency room visits and hospital readmissions within 90 days.

Results

Compared to patients ≤70, patients >70 were more frequently female (43.3% and 55.8%, respectively) (p = 0.037) and had significantly lower body mass index (30.41 ± 4.64 and 27.30 ± 3.68, respectively) (p < 0.001). Patients >70 were discharged home (50%) less commonly than patients ≤70 (73.1%) (p < 0.001). Two patients ≤70 (1.5%) and two patients >70 (1.9%) sought emergency room treatment (p = 0.589), with respiratory complications most common. There were no differences regarding any postoperative complications between patients ≤70 and > 70 years old.

Conclusion

These results suggest that patients >70 can safely undergo ssBUKA, as it does not appear to increase the incidence of early post-operative complications compared to patients ≤70. However, 50% of patients >70 were not able to discharge directly home following surgery.

True "outpatient discharge" following single-stage bilateral unicompartmental knee arthroplasty may be unrealistic for most

BACKGROUND

Single-stage bilateral unicompartmental knee arthroplasty (BUKA) has shown post-operative function and cost benefits over staged bilateral procedures, without increased complications. A rapid discharge protocol at the current study site has reported outpatient discharge for the unilateral procedure exceeding 97%. However, the feasibility of outpatient discharge following BUKA remains unclear. Therefore, the purpose of this study was to determine the success of achieving outpatient (< 24 h) discharge following BUKA, and identify patient variables associated with failure.

METHODS

A retrospective chart review was completed for 104 BUKA patients. All patients with bilateral, symptomatic unicompartmental knee arthritis were offered the single-stage procedure. Data collection included patient demographics, discharge status, and disposition location. Independent t tests (continuous) and Chi-squared tests (categorical) determined differences between discharge (outpatient/inpatient) and disposition (home/other) groups. Variables associated with discharge status and location were assessed with multivariable regression.

RESULTS

While 96 (92.3%) patients discharged within 24 h, only 63.5% were able to discharge directly home. Patients requiring a longer hospital stay (> 24 h) were more likely to require a pre-operative assistive device (62.5% and 25.0%, p = 0.037) and live alone (37.5 vs 8.3%, p = 0.033). For those discharged within 24 h, living alone significantly increased the risk (odds ratio: 5.800, p = 0.038) of requiring an acute inpatient facility prior to transition home.

CONCLUSION

Achieving "true" outpatient discharge is only modestly successful for most BUKA patients, as many required an acute inpatient or short-term rehabilitation facility prior to returning home. BUKA should be differentiated from the unilateral procedure regarding outpatient discharge expectations.

LEVEL OF EVIDENCE

III, Case-control study; Retrospective comparative study.

Safety and Efficacy of Unicondylar Knee Prosthesis Treatment for Unicompartmental Osteoarthritis of the Knee Joint

Background

Knee osteoarthritis (KOA) is a chronic disease that seriously endangers the health of the elderly. Choosing appropriate surgery for knee osteoarthritis patients is especially important.

Objective

To investigate the safety and efficacy of unicondylar knee prosthesis treatment for unicompartmental osteoarthritis of the knee.

Materials and Methods

One hundred patients with unicondylar osteoarthritis of the knee treated in our hospital from June 2019 to June 2021 were selected as retrospective study subjects and were divided into 50 cases each in the comparison group and the observation group according to the different surgical methods. Among them, the comparison group was treated with unicondylar knee arthroplasty (UKA), and the observation group was treated with unicondylar knee prosthesis replacement, and the differences in AKS score, knee flexion angle, tibial angle orthosis, joint mobility, and postoperative recovery were compared between the two groups.

Results

The AKS score and knee flexion angle score of the observation group were higher than those of the comparison group after surgery. However, the tibial angle orthopedic score of the observation group was significantly lower than that of the comparison group after surgery for comparison, and the VAS score of the observation group was lower than that of the comparison group. However, the Lysholm score of the observation group was higher than that of the control group after surgery (P < 0.05). The complication rate of patients in the observation group was significantly lower than that of the comparison group, and the HSS score, VAS score, and knee mobility (ROM) of the two groups were statistically significant (P < 0.05) when compared at 7 d after surgery and 6 months after surgery.

Conclusion

The clinical efficacy of unicondylar knee prosthesis replacement for osteoarthritis of the knee is better than that of unicondylar knee arthroplasty (UKA) treatment.

A Case-Control Comparison of Single-Stage Bilateral vs Unilateral Medial Unicompartmental Knee Arthroplasty

BACKGROUND

We aimed to compare postoperative pain, functional recovery, and patient satisfaction among patients receiving one-stage medial bilateral or medial unilateral UKA (unicompartmental knee arthroplasty). Our main hypothesis was that during the first 72 postoperative hours, patients who underwent medial bilateral UKA did not consume more analgesics than those who underwent medial unilateral UKA.

METHODS

A prospective case-control study was undertaken involving 148 patients (74 one-stage medial bilateral vs 74 medial unilateral Oxford UKA). The primary outcome was evaluation of the postoperative total consumption of analgesics from 0 to 72 hours. Next, the postoperative evolution of pain scores and functional recovery were assessed. Oxford Knee Scores were assessed preoperatively at 6 and 12 months with the occurrence of clinical or radiological complications. Finally, patient satisfaction was evaluated at the final follow-up.

RESULTS

The cumulative sums of analgesic consumption (0-72 hours) calculated in the morphine equivalent dose were 21.61 ± 3.70 and 19.11 ± 3.12 mg in the patient and control groups, respectively (P = .30). Moreover, there were no significant differences in terms of pain scores (P = .45), functional recovery (P = .59, .34), length of stay (P = .18), Oxford Knee Scores (P = .68, .60), complications (P = .50), patient satisfaction (P = .66), or recommendations for intervention (P = .64).

CONCLUSION

Patients who undergo one-stage medial bilateral UKA do not experience more pain and do not consume more analgesics than those who undergo medial unilateral UKA. A bilateral procedure is not associated with a lower recovery or a higher rate of complications, as functional outcomes at 6 and 12 months are similar to those of unilateral management.

Staged vs simultaneous bilateral unicompartmental knee arthroplasty for clinical outcomes: A protocol of systematic review and meta-analysis

BACKGROUND

Bilateral unicompartmental knee arthroplasty (UKA) can be divided into one or two stages clinically. Compared with staged bilateral UKA, whether simultaneous bilateral UKA has better clinical efficacy remains to be verified.

METHODS

PubMed, EBSCO, and Web of Science were searched by us for meta-analysis. Studies were considered eligible for inclusion if they included simultaneous and staged UKA. We excluded studies unrelated to the research question, studies in non-selected languages, and studies where the full-text was not available. The data were extracted by two independent investigators, and disagreements were resolved through discussions with a third party. If important data or information about the content of the paper were not available, authors were contacted. Publication bias in studies has been assessed. Meta-analysis was done using Review Manager 5.3.

RESULTS

The systematic review and meta-analysis identified 3370 trials, of which 8 studies (963 patients) compared simultaneous with staged bilateral UKA. The meta-analysis showed that the clinical outcomes of simultaneous bilateral UKA goes down in operating time (weighted mean difference [WMD] = -19.34, 95% confidence interval [CI] -22.44 to -16.25, P < .00001), postoperative hemoglobin (Std. mean difference [SMD] = -0.46, 95% CI -0.71 to -0.20, P = .0004), length of stay (LOS) (WMD = -4.73, 95% CI -6.39 to -3.06, P < .00001), hospital cost (SMD = -5.42, 95% CI -6.54 to -4.30, P < .00001). There were no significant difference in blood transfusion, venous thrombosis, infection, cardiac complications, pulmonary complications, Oxford Knee Score (OKS) between simultaneous and staged bilateral UKA.

CONCLUSION

Simultaneous bilateral UKA can effectively reduce the operating time, LOS, and hospital cost without increasing postoperative complications compared to stage bilateral UKA.

REGISTRATION NUMBER

CRD42020160056 (www.crd.york.ac.uk/prospero/).

Safety and outcome of simultaneous bilateral unicompartmental knee arthroplasty: A systematic review

Purpose

Simultaneous bilateral unicompartmentsl knee arthroplasty (BUKA) is considered safe and effective. We performed a systematic review to assess the postoperative outcomes.

Methods

The US National Library of Medicine (PubMed/MEDLINE), Google Scholar, and the Cochrane Database of Systematic Reviews were queried for publications.

Results

Ten articles were included with 765 simultaneous BUKA. Overall complication rate was 7.0%, survivorship was 97.6% at mean 17 months follow-up. No differences were reported between simultaneous and staged BUKA.

Conclusion

Simultaneous BUKA is as safe as staged BUKA, it is associated with decreased length of stay and operative time, although it has an increased rate of blood transfusion.

A meta-analysis of clinical and radiological outcomes in simultaneous bilateral unicompartmental knee arthroplasty

BACKGROUND

The most common pattern seen in bilateral knee osteoarthritis involves only the medial compartment in both knees. In such cases, bilateral Unicompartmental Knee Arthroplasty (UKA) would be a suitable surgery, this can be done simultaneously in one surgery or in stages with a period of time between each UKA. Simultaneous bilateral UKA in appropriately selected patients have the potential advantages of a lower cost, a shorter hospital stay, and a shorter overall recovery process. Despite this, there are concerns that operating on both knees in one surgery may increase the risk of complications, revisions and mortality.

METHODS

A PRISMA systematic review and meta-analysis was conducted using three databases (MEDLINE, EMBASE, and Scopus) to identify all studies which investigated either clinical or radiological outcomes in simultaneous bilateral UKA.

RESULTS

All sixteen studies included found that simultaneous bilateral UKA improved clinical and radiological outcomes. Eight studies compared clinical or radiological outcomes between simultaneous and staged bilateral UKA. Simultaneous bilateral UKA was found to have a significantly shorter length of operation, length of hospital stay, and a lower treatment cost (P < 0.001). Our meta-analysis found no statistically significant difference in the all-cause complication rate between simultaneous and staged bilateral UKA (P = 0.36). Only one study compared radiological outcomes between simultaneous and staged bilateral UKA which found no significant difference.

CONCLUSION

Our review suggests that simultaneous bilateral UKA is comparable to staged bilateral UKA in terms of clinical and radiological outcomes and has the potential to be increasingly adopted in clinical practice due to its superior cost-effectiveness.

One stage bilateral unicompartmental knee replacement: Similar early clinical outcome with shorter rehabilitation and better resources utilization compared with two stage

Introduction:

There are a lot of debates on the advantages and safety profile of one stage bilateral knee arthroplasty. Most of the studies focus on total knee replacement, and it may not be applied directly to unicompartmental knee replacement (UKR). We would like to compare the early results of one and two stage bilateral UKR in our center.

Methods:

This is a retrospective review of all the bilateral medial UKR done in our center in 2018–2019. Patients’ demographic data, operative time, postoperative blood, length of stay (LOS) and complications were recorded. The number of admissions, pre-operative assessment sessions (PAS), and weeks of post-operative physiotherapy were analyzed. Clinical outcome was measured by Knee society knee score and range of motion (ROM).

Results:

Our center performed 97 UKR in 2018–2019, with 50 UKR performed in 25 patients, among which 16 received one stage while 9 received two stage bilateral UKR. Both groups had similar mean age, BMI, sex ratio, ASA grading, pre-operative knee score and ROM. Patient in the one stage group required only 1 PAS/admission/operation to treat both knees with a mean LOS of 7.3 days and 7.8 weeks of physiotherapy, while those in the two stage group required 2 PAS/admissions/operations with a mean cumulative LOS of 9.8 days and 14.1 weeks of physiotherapy. The mean cumulative operative time was similar for both groups but the one stage group only required 1 operative session. There was no difference in blood loss and there was no transfusion or complication. The post-operative knee score and ROM at 3 and 6 months were similar for both groups.

Conclusion:

In suitable patients with bilateral medial OA knee, one stage bilateral UKR offers simliar early clinical outcome with shorter rehabilitation duration but without increasing complications compared with two stage. Resources can therefore be better utilized.

Bilateral unicompartmental knee arthroplasty: one stage or two stages?

BACKGROUND

Bilateral unicompartmental knee arthroplasty (UKA) may be performed as one- or two-stage procedure. Previous reports suggest that UKA provides a more rapid functional recovery than total knee arthroplasty. However, little data exist on whether bilateral UKA can be performed without increasing the perioperative risk compared with unilateral cases.

METHODS

We retrospectively compared 51 patients treated between January 2014 and March 2017 with single-stage UKA (group A) with 51 patients who underwent unilateral procedure (group B) to evaluate perioperative complications. We noted no statistically significant difference between the two groups in terms of gender, age and body mass index.

RESULTS

Patients who underwent single-stage bilateral UKA had longer operating room time with respect to single procedure (93.2 min vs. 50.7 min). However, the bilateral group had a shorter cumulative operating room time (93.2 min) compared to the unilateral group (101.5 min) with a statistically significant difference (p < 0.05). Average hemoglobin loss at discharge was 3.1 points for group A and 2.4 for group B, with a statistically significant difference (p < 0.05).

CONCLUSION

Our results demonstrated that bilateral simultaneous UKA does not increase the risk for perioperative complications. Total blood loss at discharge is statistically higher in bilateral UKA rather than unilateral UKA; however, cumulative hemoglobin loss is statistically lower in bilateral group. Patients can benefit from a single hospital admission and anesthetic time, while the shorter total inpatient stay and lower blood loss can reduce hospital costs in cases of bilateral surgery.

LEVEL OF EVIDENCE IV

Retrospective study.

[Comparison of early effectiveness and safety of simultaneous and staged bilateral unicompartmental knee arthroplasty for bilateral anteromedial compartment osteoarthritis]

Objective

To compare the early effectiveness and safety of simultaneous bilateral and staged bilateral unicompartmental knee arthroplasty (UKA) in treatment of anteromedial compartment osteoarthritis.

Methods

The clinical data of 31 patients with bilateral anteromedial compartment osteoarthritis who underwent bilateral UKAs between January 2015 and January 2017 was retrospectively analyzed. Of them, 17 patients were treated with simultaneous bilateral UKAs (simultaneous group) and 14 patients with staged bilateral UKAs (staged group). There was no significant difference in gender, age, body mass index, osteoarthritis grading, and preoperative hip-knee-ankle angle, knee society score (KSS), visual analogue scale (VAS) score, and range of motion (ROM) of knee between the two groups ( P>0.05). The operation time, blood loss, hospitalization stay, minimum hemoglobin value during 10 days after operation, and hospitalization cost were recorded. The staged group was compared by the sum of two operations. The effectiveness was evaluated by KSS score, VAS score, ROM at 3, 6, 12 months after operation, and patient satisfaction scores were recorded at 12 months after operation.

Results

The operation time, hospitalization stay, and hospitalization cost of the simultaneous group were significantly lower than those of the staged group ( P<0.05). There was no significant difference in blood loss and the minimum hemoglobin value during 10 days after operation between the two groups ( P>0.05). Superficial infection occurred in 1 side of 1 case (7.1%) in staged group. Postoperative delirium occurred in 1 case (5.9%) in simultaneous group. There was no significant difference in incidence of postoperative complications between the two groups ( P=1.000). Patients in both groups were followed up 12-32 months (mean, 24.7 months). There was no significant difference in KSS score between the two groups at 3 months after operation ( t=0.896, P=0.392). KSS scores were significanly higher in simultaneous group than in staged group at 6 and 12 months after operation ( P<0.05). There was no significant difference in ROM and VAS scores between the two groups at 3, 6, and 12 months after operation ( P>0.05). At 12 months after operation, the patient satisfaction scores were significantly higher in simultaneous group than in staged group ( P<0.05). X-ray films showed no loosening of the prosthesis in the two groups.

Conclusion

Simultaneous bilateral UKAs has the same security as staged bilateral UKAs. Meanwhile knee function recovery was better, hospitalization stay and hospitalization cost reduced, and patient satisfaction was higher in simultaneous bilateral UKAs.

Single-stage bilateral medial Oxford Unicompartmental Knee Arthroplasty: A case-control study of perioperative blood loss, complications and functional results

BACKGROUND

The benefits and risks of a single-stage medial UKA remains a subject of debate because of the theoretically higher risk of complications and specifically blood loss. The aim of this study was to evaluate the perioperative blood loss, risks and the functional results of single-stage bilateral medial Oxford Unicompartmental Knee Arthroplasty (OUKA) compared to a standard unilateral medial OUKA procedure (control group).

HYPOTHESIS

The blood loss observed during bilateral single-stage medial Oxford UKA is not different from that of the control group.

METHODS

In this case-control prospective study, fifty patients (100 knees) who underwent single-stage bilateral medial OUKA (study group) were compared to a hundred patients (100 knees) with unilateral medial OUKA (control group), performed by the same surgeon. The real blood loss (in mL of hematocrit at 100%), incidence of blood transfusions, and complication rates were compared. Clinical results were assessed at 6 month and at a two-year minimum follow-up (FU) using IKS, KOOS and OKS scores, in addition to a satisfaction questionnaire.

RESULTS

Groups were deemed comparable. Concerning blood loss, no significant difference was observed compared to the control group (465mL±225 vs. 396±190; p=0.07). No difference was found, either, between groups regarding the complication rates (p=0.36), nor the clinical results (p=0.61) and patient satisfaction (p=0.23) at last FU.

CONCLUSION

Single-stage bilateral procedure does not cause increased blood loss compared with controls. Moreover, clinical results were deemed good and excellent in spite of a slightly greater complication rate than those found in the literature but similar to controls.

LEVEL OF EVIDENCE

Case-control study, level III.

Complications and cost of single-stage vs. two-stage bilateral unicompartmental knee arthroplasty: A case-control study

BACKGROUND

Single-stage bilateral knee arthroplasty, even when unicompartmental, remains controversial, chiefly due to the risk of peri-operative complications. The primary objective of this study was to compare the short-term complication rate and cost of single- vs. two-stage bilateral unicompartmental knee arthroplasty (UCA). The secondary objective was to compare total hospital stay lengths and motion-range recovery.

HYPOTHESIS

Single-stage bilateral UCA is a cost-saving alternative that is not associated with higher complication rates compared to two-stage bilateral UCA.

MATERIAL AND METHOD

This single-centre retrospective comparative study included 70 patients of any age managed between 2010 and 2016. Among them, 44 (88 UKAs) had single-stage surgery (1S group) and 26 (52 UCAs) two-stage surgery (2S group). The two groups were comparable for age, body mass index, gender distribution, compartment replaced, ASA score, and Charlson comorbidity index. The following were evaluated: operative time, haemoglobin level before and after surgery, major and minor complication rates, motion-range recovery, and the radiographic hip-knee-ankle (HKA) angle. Costs were estimated based on the standard codes assigned to the procedures by the national statutory health insurance system (GHM 08C24 for knee arthroplasty to treat knee osteoarthritis and NFKA006 for unicompartmental tibio-femoral or femoro-patellar arthroplasty), modulated according to the concomitant diagnoses.

RESULTS

No differences were found for the haemoglobin level change, time to motion-range recovery, or HKA angle. The complication rates per patient were not significantly different between the groups: major complications, 9.1% (n=4) in the 1S group and 15.4% (n=4) in the 2S group (p=1.00); minor complications, 4.5% (n=2) in the 1S group and 3.8% (n=1) in the 2S group (p=1.00). Cost of the total hospital stay was significantly higher in the 2S group than in the 1S group (11,766.7€) and 5626.4€, respectively; p<0.001). Mean total hospital stay duration per patient was 6.7 days with single-stage surgery and 13.4 days with two-stage surgery.

DISCUSSION

Single-stage bilateral UCA is not associated with a higher rate of peri-operative complications compared to the two-stage alternative and is substantially less costly. Financial incentives from the healthcare authorities are warranted to increase the use of the single-stage procedure.

LEVEL OF EVIDENCE

III, case-control study.

Effects of Lower Limb Alignment and Tibial Component Inclination on the Biomechanics of Lateral Compartment in Unicompartmental Knee Arthroplasty

Background:

Lateral compartmental osteoarthritis (LCOA), a major complication after medial mobile-bearing unicompartmental knee arthroplasty (UKA), is highly associated with the increased stress of the lateral compartment. This study aimed to analyze the effects on the stress and load distribution of the lateral compartment induced by lower limb alignment and coronal inclination of the tibial component in UKA through a finite element analysis.

Methods:

Eight three-dimensional models were constructed based on a validated model for analyzing the biomechanical effects of implantation parameters on the lateral compartment after medial Oxford UKA: postoperative lower limb alignment of 3° valgus, neutral and 3° varus, and the inclination of tibial components placed in 4°, 2° valgus, square, and 2° and 4° varus. The contact stress of femoral and tibial cartilage and load distribution were calculated for all models.

Results:

In the 3° valgus lower limb alignment model, the contact stress of femoral (3.38 MPa) and tibial (3.50 MPa) cartilage as well as load percentage (45.78%) was highest compared to any other model, and was increased by 36.75%, 47.70%, and 27.63%, respectively when compared to 3° varus. In the condition of a neutral position, the outcome was comparable for the different tibial tray inclination models. The inclination did not greatly affect the lateral compartmental stress and load distribution.

Conclusions:

This study suggested that slightly varus (undercorrection) lower limb alignment might be a way to prevent LCOA in medial mobile-bearing UKA. However, the inclination (4° varus to 4° valgus) of the tibial component in the coronal plane would not be a risk factor for LCOA in neutral position.

Bilateral simultaneous unicompartmental knee arthroplasty versus unilateral total knee arthroplasty: A comparison of the amount of blood loss and transfusion, perioperative complications, hospital stay, and functional recovery

BACKGROUND

Unicompartmental knee arthroplasty (UKA) is a good alternative treatment option to total knee arthroplasty (TKA) for single compartment knee osteoarthritis. Several recent reports suggest that UKA results in more rapid functional recovery than TKA, together with fewer complications. Few performed a comparison of bilateral simultaneous UKA and unilateral TKA.

HYPOTHESIS

Bilateral simultaneous UKA would result in fewer perioperative complications, less blood loss, less transfusion and faster recovery of short-term clinical outcomes, compared with unilateral TKA patients.

MATERIAL AND METHODS

In a retrospective trial, the bilateral simultaneous UKA (bUKA) cases were matched one to one with a cohort of unilateral TKA (uTKA) cases according to age, body mass index, gender, Kellgren-Lawrence grade of knee osteoarthritis and American Society of Anesthesiologists score. In bilateral simultaneous UKA group, patients had KL grade 4 of bilateral knee osteoarthritis, and in unilateral TKA group, patients had KL grade 4 of unilateral knee osteoarthritis. The transfusion requirements, estimated blood loss (EBL), duration of hospital stay, incidence of complications, and knee clinical scores of the bUKA and uTKA groups were compared at the 6-month short-term follow-up.

RESULTS

Patients were categorized into the bUKA group (n=52) and uTKA group (n=52). The number of patients requiring transfusion and the amount of EBL was smaller in the bUKA group (P<0.001 for transfusion and P=0.043 for EBL). The duration of hospital stay was shorter and the number of complications was smaller in the bUKA group (P<0.001 for hospital stay and P=0.028 for complications). The clinical outcomes were also superior in the bUKA group (P<0.001).

CONCLUSIONS

Bilateral simultaneous UKA shows fewer perioperative complications, less blood loss, less transfusion, and better functional outcomes at 6 months postoperatively than unilateral TKA. The data suggest that bilateral simultaneous UKA can be performed safely, and results in acceptable clinical outcomes.

LEVEL OF EVIDENCE

III, case-control study.