Long-Term Functional Outcomes and Quality of Life at Minimum 10-Year Follow-Up After Fixed-Bearing Unicompartmental Knee Arthroplasty and Total Knee Arthroplasty for Isolated Medial Compartment Osteoarthritis

Health-related quality of life after total knee arthroplasty and unicompartmental knee arthroplasty for unicompartmental osteoarthritis: A systematic review and meta-analysis

BACKGROUND

While previous research has demonstrated potential advantages of unicompartmental knee arthroplasty (UKA) over total knee arthroplasty (TKA), particularly in terms of clinical outcomes such as function and pain relief, the specific impact on health-related quality of life (HRQOL) remains unclear. This systematic review and meta-analysis aim to address this gap by comparing HRQOL outcomes between UKA and TKA, providing valuable insights for clinical decision-making.

METHODS

We conducted a literature search in the PubMed, Embase, Cochrane Controlled Register of Trials (CENTRAL), and Web of Science databases up to July 15, 2023. Eligible studies assessed HRQOL using EQ-5D, SF-36, or SF-12 and were assessed for methodological quality using the Newcastle-Ottawa Scale (NOS).

RESULTS

Seven eligible studies were included, comprising a total of 64,585 patients with 35,809 undergoing TKA and 28,776 undergoing UKA. Patient age ranged from 52.0 to 67.7 years with an average BMI ranging from 27.2 to 31.0 kg/m2. Follow-up periods ranged from 6 months to 10 years. Five studies (63,829 patients) that evaluated HRQOL using EQ-5D showed significantly better outcomes for UKA compared to TKA (MD -0.04, 95% CI -0.05 to -0.02). Two studies (756 patients) that evaluated HRQOL using SF-36 showed no significant difference between TKA and UKA. Five studies (63,286 patients) that evaluated functional outcomes using Oxford Knee Score (OKS) showed significantly better functional scores for UKA compared to TKA (MD -1.29, 95% CI -1.86 to -0.72). Four studies (24,570 patients) that reported patient satisfaction showed no statistically significant difference between TKA and UKA (MD 0.97, 95% CI 0.90 to 1.05). Further subgroup analysis did not affect the conclusions.

CONCLUSIONS

Our meta-analysis suggests that UKA is associated with better HRQOL and knee function, as well as similar patient satisfaction, compared to TKA for patients with unicompartmental osteoarthritis.

Lateral versus medial approach for total knee arthroplasty for valgus knee deformity shows comparable functional outcomes, hip-knee-ankle angle values, and complication rates: a meta-analysis of comparative studies

INTRODUCTION

The aim of this meta-analysis of comparative studies was to update the current evidence on functional and radiographic outcomes and complications between medial and lateral approaches for total knee arthroplasty (TKA) for valgus knee deformity.

MATERIALS AND METHODS

The PubMed, MEDLINE, Scopus, and the Cochrane Central databases were used to search keywords and a total of ten studies were included. The methodological quality of the included studies was assessed. Data extracted for quantitative analysis included the Knee Society score (KSS), range of motion (ROM), surgical time, hip-knee-ankle angle (HKA), and number and types of complications. Random- and fixed-effect models were used for the meta-analysis of pooled mean differences (MDs) and odds ratios (ORs). The Mantel-Haenszel method was adopted.

RESULTS

A total of 1008 patients were identified, of whom 689 and 319 underwent TKA for valgus knee deformity with lateral and medial approach, respectively. The mean age was 70 ± 9.5 and 67.3 ± 9.6 years for the lateral and medial approaches, respectively. The mean follow-up was 37.8 ± 21.9 and 45.9 ± 26.7 months for the lateral and medial approach groups, respectively. Significantly higher functional outcomes were found for the medial approach, as measured by the postoperative KSS (MD = 1.8, 95% CI [0.48, 3.12], P = 0.007) and flexion ROM (MD = 3.12, 95% CI [0.45, 5.79], P = 0.02). However, both of these differences were lower than the minimal clinically important difference. Comparable surgical time and postoperative HKA angle values (MD = 0.22, 95% CI [- 0.30, 0.75], P = 0.40) between the two surgical approaches were found. The incidence of periprosthetic joint infections, fractures, transient peroneal nerve injuries, and deep vein thrombosis was comparable.

CONCLUSION

This meta-analysis of comparative studies showed that when lateral and medial approaches are used for total knee arthroplasty for valgus knee deformity, comparable functional outcomes in terms of the KSS and ROM, surgical time, and postoperative hip-knee-ankle angle values can be expected. Similar rates of periprosthetic joint infection, fracture, and peroneal nerve injury were also found.

LEVEL OF EVIDENCE

I.

PROSPERO REGISTRATION NUMBER ID

CRD42023392807.

Finite Element Analysis of the Effect of Femoral Prosthesis Varus and Valgus Angle Installation on the Lateral Compartment in Unicompartmental Knee Arthroplasty

BACKGROUND

This study used finite element analysis (FEA) to investigate the effect of varus and valgus angle on the lateral compartment in unicompartmental knee arthroplasty (UKA).

METHODS

One patient who underwent UKA was enrolled as the subject. Thirteen working conditions of the femoral prosthesis were simulated at varus and valgus angles of 0°, 2°, 4°, 6°, 8°, 10°, and 12°. A load of 1,000 N was applied downward along the mechanical axis of the femur, and the highest stress values on the surface of the polyethylene liner, cancellous bone under the tibial prosthesis, cartilage of femur lateral condyle, lateral meniscus, and tibial lateral plateau cartilage in each model were recorded. The six highest points were used to calculate the mean value.

RESULTS

The highest stress values on the surface of the polyethylene liner, cancellous bone under the tibial prosthesis, cartilage of femur lateral condyle, lateral meniscus, and tibial lateral plateau cartilage increased with an increase in the femoral prosthesis varus/valgus angle. As compared with the standard position of the femoral prosthesis, there was no significant difference in the surface stress values of the polyethylene liner, cancellous bone under the tibial prosthesis, cartilage of femur lateral condyle, lateral meniscus and tibial lateral plateau cartilage when the femoral prosthesis varus/valgus angle was less than 4° (p > 0.05). In addition, the stress magnitude on the polyethylene liner, cancellous bone under the tibial prosthesis, cartilage of femur lateral condyle, lateral meniscus, and tibial lateral plateau cartilage significantly increased when the femoral prosthesis varus/valgus angle was greater than 4° (p < 0.001).

CONCLUSIONS

The optimal femoral prosthesis varus/valgus angle in UKA was less than 4°.

Malposition is main cause of failure of Oxford mobile-bearing medial unicompartmental knee arthroplasty

Aims

Unicompartmental knee arthroplasty (UKA) is the preferred treatment for anterior medial knee osteoarthritis (OA) owing to the rapid postoperative recovery. However, the risk factors for UKA failure remain controversial.

Methods

The clinical data of Oxford mobile-bearing UKAs performed between 2011 and 2017 with a minimum follow-up of five years were retrospectively analyzed. Demographic, surgical, and follow-up data were collected. The Cox proportional hazards model was used to identify the risk factors that contribute to UKA failure. Kaplan-Meier survival was used to compare the effect of the prosthesis position on UKA survival.

Results

A total of 407 patients who underwent UKA were included in the study. The mean age of patients was 61.8 years, and the mean follow-up period of the patients was 91.7 months. The mean Knee Society Score (KSS) preoperatively and at the last follow-up were 64.2 and 89.7, respectively (p = 0.001). Overall, 28 patients (6.9%) with UKA underwent revision due to prosthesis loosening (16 patients), dislocation (eight patients), and persistent pain (four patients). Cox proportional hazards model analysis identified malposition of the prostheses as a high-risk factor for UKA failure (p = 0.007). Kaplan-Meier analysis revealed that the five-year survival rate of the group with malposition was 85.1%, which was significantly lower than that of the group with normal position (96.2%; p < 0.001).

Conclusion

UKA constitutes an effective method for treating anteromedial knee OA, with an excellent five-year survival rate. Aseptic loosening caused by prosthesis malposition was identified as the main cause of UKA failure. Surgeons should pay close attention to prevent the potential occurrence of this problem.

Are patients with preoperative synovitis suitable for unicompartmental knee arthroplasty? Magnetic resonance imaging evidence from a retrospective cohort study

BACKGROUND

The use of unicompartmental knee arthroplasty (UKA) in patients with preoperative synovitis is controversial. This study aimed to investigate the association between synovitis detected by magnetic resonance imaging (MRI) and prognosis after UKA.

METHODS

Synovitis was graded using the MRI Osteoarthritis Knee Score criteria based on preoperative MRI findings of 132 UKAs performed between June 2020 and August 2021. The Knee Society Knee Score (KS-KS) and the Knee Society Function Score were collected preoperatively and 1 year postoperatively. The relationship between synovitis and the changes in the Knee Society score was analyzed using logistic regression.

RESULTS

Univariate logistic regression showed that patients with higher preoperative synovitis scores (odds ratio (OR) = 1.925, 95% confidence interval (CI): 1.482-2.500, P < 0.001) had higher KS-KS changes. After adjusting for confounding variables, synovitis was proven to be an independent factor for KS-KS improvement after UKA in multivariate logistic regression (OR = 1.814, 95% CI: 1.354-2.430, P < 0.001). Before UKA, patients with synovitis had lower pain scores (PS) than patients without synovitis (95% CI: -17.159 - -11.160, t = -9.347, P < 0.001). There was no difference in PS between the two groups after UKA (95% CI: -6.559 - 0.345, t = -1.782, P = 0.077).

CONCLUSIONS

Patients with synovitis can achieve good improvement of pain symptoms, and the efficacy is not inferior to that of non-synovitis patients after UKA.

Setting the Tibial Component Rotation Based on Femoral Landmarks Allows Congruent Knee Kinematics in Robotic-Assisted Medial Unicompartmental Knee Replacement

The accurate positioning of the prosthetic components is essential for achieving successful results in medial unicompartmental knee arthroplasty (mUKA). The tibial component rotation in image-based robotic-assisted UKA is usually based on tibial bony landmarks matched to the pre-operative CT model. The study aimed to evaluate whether setting the tibial rotation on femoral CT-based landmarks allows congruent knee kinematics. We retrospectively analyzed data from 210 consecutive image-based robotic-assisted mUKA cases. In every case, we set the tibia rotation landmark parallel to the posterior condylar axis and centered it on the trochlea groove defined on the preoperative CT scan. The implant positioning was primarily set parallel to this rotation landmark and then adjusted based on tibial sizes avoiding component over- or under-hang. During surgery, we recorded the knee kinematics under valgus stress to reduce the arthritic deformity. A femoral-tibial contact point was recorded over the entire range of motion and displayed as a tracking profile on the tibia implant. The femoro-tibial tracking angle (FTTA) was then calculated based on a tangent line to the femoro-tibial tracking-points and the difference to the femur-based rotation landmark. In 48% of the cases, we could position the tibia component exactly to the femoral rotation landmark, whereas in 52% of cases, minimal adjustments were made to avoid component’s under- or over-hang. The mean tibia component rotation (TRA) with reference to our femur-based landmark was +0.24° (SD ± 2.9°). The femur-based tibia rotation landmark showed a high correspondence to the FTTA with 60% of the cases having less than 1° of deviation. Mean FTTA was +0.7° (SD ± 2.2°). The mean difference between the absolute value of the TRA and the FTTA (|TRA| − |FTTA|) was −0.18° (SD ± 2°). Setting the tibial component rotation based on CT scan femoral landmarks and not on tibial anatomical landmarks is a reliable method to obtain congruent knee kinematics during image-based robotic-assisted medial UKA with less the 2° deviations on average.

Image-based robotic unicompartmental knee arthroplasty allowed to match the rotation of the tibial implant with the native kinematic knee alignment

PURPOSE

Image-based robotic tools improve the accuracy of unicompartmental knee arthroplasty (UKA) positioning, but few studies have examined its effect on axial alignment. The aim of this study was to compare the characteristics of tibial and femoral implant positioning, mainly the tibial rotation, during medial or lateral UKA, performed with an image-based robotic assisted system.

METHODS

A total of 71 UKA performed between September 2021 and June 2022 (53 medial and 18 lateral) were analyzed. All data regarding implant positioning (rotation, coronal and sagittal alignment) for tibial and femoral components were obtained using MAKO® software (Stryker®, Mahwah, USA) intra-operatively.

RESULTS

The lateral UKA had a mean internal tibial rotation of 15.4 ± 3°, a mean external femoral rotation of 0.96 ± 2.4°, and a mean tibial slope of 4.7 ± 1.3°. The medial UKA had a mean internal tibial rotation of 0.18 ± 2.7°, a mean internal femoral rotation of 0.35 ± 2.2°, and a mean tibial slope of 5.4 ± 1.3°. The tibial rotations, femoral valgus, tibial varus and tibial size significantly differed between medial and lateral UKA (p < 0.05). There was no significant difference in femoral rotation, flexion, femoral size, slope, and polyethylene thickness between medial and lateral UKA.

CONCLUSION

Medial and lateral UKA had significantly different implantation characteristics related to the biomechanics of the knee compartments. Image-based robotic UKA allowed precise femorotibial positioning per-operatively to match native kinematic alignment.

The mid-term outcomes of mobile bearing unicompartmental knee arthroplasty versus total knee arthroplasty in the same patient

Objective

To compare the mid-term outcomes of unicompartmental knee arthroplasty (UKA) that was performed in one knee and total knee arthroplasty (TKA) performed in the other knee in the same stage.

Methods

This is a retrospective study. A total of 63 patients (126 knees) scheduled for one-stage knee surgery due to osteoarthritis of both knees were selected, and all patients underwent one-stage mobile platform UKA and TKA of the other knee. Differences in general clinical data, functional recovery, complications, and prosthesis revision rates were assessed after UKA and TKA, respectively. The evaluation indicators for knee joint function recovery included the hospital for special surgery knee score (HSS), Joint Forgotten Score (JFS), Knee Injury and Osteoarthritis Outcome Score (KOOS), and Visual analog scale (VAS). Patient preference between UKA and TKA was also recorded.

Results

During a mean follow-up of 76.95 months (range, 65.00 to 87.00 months), there were no significant differences in postoperative complications between the two groups (P = 0.299); however, the prosthesis revision rate was higher in the UKA group than in the TKA group (P = 0.023). The incision length, operation time, blood loss, and postoperative drainage volume in the UKA group were significantly (P < 0.001) lower than those in the TKA group: JFS, ROM, and VAS in the UKA group were higher than those in the TKA group (P < 0.001, P = 0.023, P = 0.032), HSS and KOOS in TKA group were significantly (P < 0.001) higher than those in UKA group. At the last follow-up, 40% and 24% of patients preferred TKA and UKA, respectively.

Conclusions

TKA was found to be superior to UKA in terms of HSS, KOOS, and VAS, while UKA had more significant advantages in terms of less surgical trauma, better ROM, and higher JFS. Complications were not different between groups, but UKA had a higher rate of prosthesis revision. After a follow-up of at least 5 years, more patients preferred TKA.

Cemented Total Knee Arthroplasty Shows Less Blood Loss but a Higher Rate of Aseptic Loosening Compared With Cementless Fixation: An Updated Meta-Analysis of Comparative Studies

BACKGROUND

The aim of this study was to update the current evidence on functional outcomes, complications, and reoperation rates between cemented and cementless total knee arthroplasty (TKA) by evaluating comparative studies published over the past 15 years.

METHODS

The PubMed, MEDLINE, Scopus, and the Cochrane Central databases were used to search keywords and a total of 18 studies were included. Random and fixed effect models were used for the meta-analysis of pooled mean differences (MDs) and odds ratios (ORs).

RESULTS

A total of 5,222 patients were identified with a mean age of 64.4 ± 9.4 and 63 ± 8.6 years for the cemented and cementless TKA groups, respectively. The mean follow-up was 107.9 ± 30 and 104.3 ± 10 months for the cemented and cementless TKA groups, respectively. Cemented TKA showed a significantly greater postoperative Knee Society Score (MD = -0.95, 95% CI [-1.57, 0.33], P = .003) and range of motion (MD = -1.09, 95% CI [-1.88, -0.29], P = .0007), but no differences in other outcome scores were found. The incidence of periprosthetic joint infection, radiolucent lines, instability, and polyethylene wear was also comparable. Cemented TKA showed less perioperative blood loss (SMD = -438.41, 95% CI [-541.69, -35.14], P < .0001) but a higher rate of manipulation under anesthesia (OR = 3.39, 95% CI [1.64, 6.99], P = .001) and aseptic loosening (OR = 1.62, 95% CI [1.09, 2.41], P = .02) than cementless TKA. No differences were found in terms of the reoperation rate.

CONCLUSION

When cemented and cementless fixations are compared in primary TKA, comparable functional outcomes and reoperation rates can be achieved. Cemented TKA showed less blood loss but a higher rate of manipulation under anesthesia and aseptic loosening.

Robotic-Arm Assisted Technology's Impact on Knee Arthroplasty and Associated Healthcare Costs

Background: The number of total knee arthroplasties (TKA) carried out globally is expected to substantially rise in the coming decades. Consequently, focus has been increasing on improving surgical techniques and minimizing expenses. Robotic arm-assisted knee arthroplasty has garnered interest to reduce surgical errors and improve precision. Objectives: Our primary aim was to compare the episode-of-care cost up to 90 days for unicompartmental knee arthroplasty (UKA) and TKA performed before and after the introduction of robotic arm-assisted technology. The secondary aim was to compare the volume of UKA vs TKA. Methods: This was a retrospective study design at a single healthcare system. For the cost analysis, we excluded patients with bilateral knee arthroplasty, body mass index >40, postoperative infection, or noninstitutional health plan insurance. Costs were obtained through an integrated billing system and affiliated institutional insurance company. Results: Knee arthroplasty volume increased 28% after the introduction of robotic-assisted technology. The TKA volume increased by 17%, while the UKA volume increased 190%. Post introduction, 97% of UKA cases used robotic arm-assisted technology. The cost analysis included 178 patients (manual UKA, n = 6; robotic UKA, n = 19; manual TKA, n = 58, robotic TKA, n = 85). Robotic arm-assisted TKA and UKA were less costly in terms of patient room and operating room costs but had higher imaging, recovery room, anesthesia, and supply costs. Overall, the perioperative costs were higher for robotic UKA and TKA. Postoperative costs were lower for robotic arm-assisted surgeries, and patients used less home health and home rehabilitation. Discussion: Surgeons performed higher volumes of UKA, and UKA comprised a greater percentage of total surgical volume after the introduction of this technology. The selective cost analysis indicated robotic arm-assisted technology is less expensive in several cost categories but overall more expensive by up to $550 due to higher cost categories including supplies and recovery room. Conclusions: Our findings show a change in surgeons' practice to include increased incidence and volume of UKA procedures and highlights several cost-saving categories through the use of robotic arm-assisted technology. Overall, robotic arm-assisted knee arthroplasty cost more than manual techniques at our institution. This analysis will help optimize costs in the future.

[Comparison of unicompartmental knee arthroplasty and total knee arthroplasty in the treatment of severe medial compartment osteoarthritis]

Objective

To compare the effectiveness of unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) in the treatment of severe medial compartment osteoarthritis (OA).

Methods

A clinical data of 69 patients (69 knees), who underwent joint replacement due to severe medial compartment OA between February 2015 and September 2018 and met the selection criteria, was retrospectively analyzed. Among them, 38 cases were treated with UKA (UKA group) and 31 cases with TKA (TKA group). There was no significant difference in gender, age, body mass index, course of disease, lesion side, and preoperative visual analogue scale (VAS) score, Hospital for Special Surgery (HSS) score, Western Ontario and McMaster University Osteoarthritis Index (WOMAC) score, Feller score, range of motion of knee, physiological and psychological scores of short-form 12 health survey scale (SF-12) between the two groups ( P>0.05). The femorotibial angle (FTA) of TKA group was bigger than that of UKA group, and hip-knee-ankle angle (HKA) was smaller, showing significant differences ( P<0.05). The operative time, incision length, blood loss, time for flexion 90°, ambulation time, hospital stay, and incidence of deep venous thrombosis of lower extremity were recorded and compared between the two groups. The VAS score, HSS score, WOMAC score, Feller score, range of motion, and physiological and psychological scores of SF-12 were used to evaluate patients' quality of life. FTA, HKA, and prosthesis looseness were observed by X-ray films. Kaplan-Merier survival analysis was used to evaluate the survival rate of prosthesis.

Results

All operations were successfully completed in both groups. Compared with TKA group, UKA group had shorter incision length, longer operative time, and less blood loss ( P<0.05). There was no significant difference in time for flexion 90°, ambulation time, hospital stay, and the incidence of deep venous thrombosis of lower extremity between the two groups ( P>0.05). The incisions in both groups healed by first intention. During follow-up, 3 patients in the UKA group and 1 patient in the TKA group developed mild anterior knee pain. Patients were followed up (30.7±9.6) months in the UKA group and (34.9±8.7) months in the TKA group, and the difference was not significant ( t=-1.832, P=0.071). At last follow-up, there were significant differences in the HSS score, Feller score, WOMAC score, range of motion, VAS score, and physiological and psychological scores of SF-12 between pre- and post-operation ( P<0.05). The range of motion in the UKA group was bigger than that in the TKA group ( Z=-2.666, P=0.008), and there was no significant difference in the other indexes between the two groups ( P>0.05). X-ray films showed that the alignment of the two groups recovered well, and the FTA and HKA of the two groups were improved at 1 week after operation ( P<0.05). No radiolucency was found around the prosthesis during follow-up, no prosthesis loosening and meniscal bearing dislocation occurred. The survival rates of the prostheses in the two groups were 100%.

Conclusion

For severe medial compartment OA, the early survival rates of the two prostheses are similar, but UKA has less traumatic, can preserve the normal structure of the knee, and the range of motion of the knee after operation is significantly better than TKA.