Outcomes Of Unicompartmental Knee Arthroplasty Research Articles

Gender does not influence outcomes and complications in medial unicompartmental knee arthroplasty.

The impact of gender on the outcomes of unicompartmental knee arthroplasty (UKA) remains a topic of active discussion with limited exploration thus far. The study aims to elucidate the gender effect on clinical outcomes, complications, pre- and postoperative radiological outcomes following the implantation of a medial UKA at mid-term follow-up in a large sectionof patients. This was a single-centre, retrospective cohort study encompassing patients undergoing medial UKA between 2011 and2019. The International Knee Society (IKS) Knee and Function score, patient satisfaction, complications, revisions, pre- and postoperative radiological outcomes (coronal plane alignment, femoral and tibial component positioning, posterior tibial slope) were evaluated. Survival rate at the time of the last follow-up was also recorded. Of the 366 knees that met the inclusion criteria, 10 were lost to follow-up, accounting for a 2.7% loss. Mean follow-up was 5.2 ± 2 years [2.1-11.3]. Out of the total population, 205 patients were females (57.6%, 205/356) and 151 were males (42.4%, 151/356). Men exhibited superior pre- and postoperative IKS function scores (p = 0.017). However, no significant differences were observed between women and men regarding improvements of IKS Knee and Function scores, radiographic outcomes and implant survivorship. At a mean follow-up of 5 years, this study revealed no significant impact of gender on clinical outcomes and complications in patients undergoing medial UKA. Furthermore, no significant differences were evident in radiographic outcomes, implant positioning and knee phenotype. Level III.

Impact of postoperative femorotibial axis on functional outcomes in unicompartmental knee arthroplasty.

This study aimed to compare the functional outcomes of patients undergoing fixed-bearing medial unicompartmental knee arthroplasty (UKA) classified as either varus or neutral based on their postoperative femorotibial angle (FTA), with the goal of evaluating the impact of FTA on functional results. A total of 38 knees of 35 patients (27 females, 8 males; mean age: 63.6±7.1 years; range, 52 to 75 years) were included in this retrospective study. The data was collected between December 15, 2020, and January 15, 2021. Patients were categorized into two groups based on their postoperative FTA. The neutral group consisted of patients with an FTA range of 5.1° to 7.4°, while the varus group included patients with an FTA range of 0.1° to 4.8°. Knee Outcome Osteoarthritis Score (KOOS), Visual Analog Scale (VAS) scores, sit to stand test results, and six minute walk test data were analyzed. The mean follow-up was 42.0±19.3 months. The postoperative VAS score for the varus group was 0.95±0.99, whereas the neutral group had a VAS score of 2.19±1.83 (p=0.021). The mean KOOS for the varus group was 88.01±7.88, whereas the neutral group had a mean KOOS score of 78.46±13.69 (p=0.006). In patients undergoing UKA, mild varus alignment could yield superior early and midterm functional outcomes compared to a neutral femorotibial angle.

The Impact of Different Anterior Cruciate Ligament Status on Unicompartmental Knee Arthroplasty: Short Term Clinical and Functional Results

Purpose: Purpose of this study is to compare the short-term results of unicompartmental knee arthroplasty applied stable knees regardless of the condition of the ACL and the application of unicompartmental knee arthroplasty and ACL reconstruction combined surgery applied to ACL deficient cases with anterior instability and to identify the condition and function of the ACL for success in this surgery. Patients and Methods: 80 out of the 105 patients who were operated in 2013-2015 and came for follow-up were included in the study and the patients were divided into four groups. The VAS pain score, KSS Score, WOMAC score, OKS questionnaires and joint range of motion measurements were conducted pre-operatively and post-operatively. One leg standing test, joint position sense measurement, and isokinetic muscle strength test were performed in post-operative controls. Results: There was no statistically significant difference between the demographic data and follow-up of the groups (p˃0.05). While there was a statistically significant difference in knee flexion between Group 2-Group 4 and Group 3-Group 4 in the pre-operative period, no difference was found in the post-operative period (p˃0.05). While there was no difference among the groups, knee joint range of motion in direction of extension declined in a statistically significant way in all four groups (p˂0.05). Pain felt postoperatively was the most in Group 1 and the least in Group 3. A statistically significant difference was found between Group 1 and Group 3 in the test performed with the eyes closed (p˂0.05). Conclusion: The presence of a functional anterior cruciate ligament is expected to make a positive contribution to surgical results especially in young patients with high activity expectation. Whether the patient’s ACL rupture is primary or secondary and his/her activity expectation should be effective in the choice of a surgical method.

Outcomes of Unicompartmental Knee Arthroplasty in Patients Receiving Long-Term Anticoagulation Therapy: A Propensity-Matched Cohort Study

BackgroundAlthough total knee arthroplasty has been considered the gold-standard treatment for severe osteoarthritis of the knee, unicompartmental knee arthroplasty (UKA) has become an increasingly favorable alternative for single-compartment osteoarthritis of the knee. Few studies have examined potential high-risk populations undergoing this procedure. The purpose of this study was to investigate the outcomes of UKA in patients receiving long-term anticoagulation therapy. MethodsIn this study, a large administrative database was queried to identify patients undergoing UKA between 2009 and 2019, who were then divided into a cohort receiving long-term anticoagulation and a control cohort. Propensity scores were utilized to match these patients. Multivariable logistic regression was utilized to compare 90-day and 2-year complication rates between cohorts. ResultsPatients who were on long-term anticoagulation had significantly increased odds of extended length of stay, surgical site infection, wound complication, transfusion, deep vein thrombosis, pulmonary embolism, and readmission at 90-day follow-up. The long-term anticoagulation cohort also experienced significantly higher odds of periprosthetic joint infection and mechanical complications at 2-year follow-up; however, odds of conversion to total knee arthroplasty were not increased. ConclusionsThis study demonstrated that long-term anticoagulation use was associated with poorer medical and surgical outcomes at both 90 days and 2 years postoperatively in patients undergoing UKA, even after rigorous adjustment for confounders.

Artificial intelligence-based detection of posterior tibial slope on X-ray images of unicompartmental knee arthroplasty patients

ObjectiveThis paper aims to improve the assessment of the outcomes of unicompartmental knee arthroplasty (UKA) from the angle of posterior tibial slope (PTS) on X-Ray images, using the artificial intelligence (AI) tool of RetinaNet. MethodsFirstly, RetinaNet was trained and tested on patients who underwent unilateral knee replacement surgery in our hospital due to osteoarthritis in the medial compartment of either their left or right knee between July 2018 and July 2022. The trained network was applied to detect the region of interest (ROI) on the pre- and postoperative X-ray images of each subject. Next, the subjects were divided into three groups according to the PTS changes measured by the trained RetinaNet. Furthermore, the surgical effect of UKA was evaluated from multiple angles, including pre- and postoperative PTSs, knee joint mobility (KJM) values, the Hospital for Special Surgery (HSS) scores, as well as the Joint Replacement Forgetting Index (JRFI). ResultsAfter training, the RetinaNet achieved an astounding accuracy level, with the Cronbach's alpha value 0.864 (95%CI 0.762–0.915). There significant differences were found between Group II and Group I (P = 0.017) and Group III and Group I (P = 0.032); in terms of JRFI, Group II had a significantly better than Group I (P = 0.011) and Group III (P = 0.037). ConclusionsThe trained RetinaNet is suitable for assisting with PTS measurements in X-ray images; the PTS variation through UKA should be controlled within 2° to ensure the best possible surgical effect.

Clinical Outcomes of Unicompartmental Knee Arthroplasty in Patients with Full-versus Partial-Thickness Cartilage Loss: A Systematic Review and Meta-Analysis.

The objective of the study was to compare postoperative patient-reported outcomes and reoperation rates following unicompartmental knee arthroplasty (UKA) between patients with full-thickness cartilage loss (FTCL) and partial-thickness cartilage loss (PTCL). Multiple databases, including PubMed, Embase, Cochrane Library, and CNKI, were searched until October 2019 for studies comparing the Oxford Knee Score (OKS), American Knee Society (AKS) score, and reoperation rates between patients with FTCL and PTCL following UKA. Data analysis was performed using Review Manager software. A total of 613 UKA cases from 5 retrospective cohort studies were included. The mean difference in postoperative OKSs was significantly higher by 2.92 in FTCL group than in PTCL group (95% confidence interval [CI] = -5.29 to -0.55; P = 0.02). Improvement in OKS was significantly higher by 2.69 in FTCL group than in PTCL group (95% CI = -4.79 to -0.60; P = 0.01). However, the differences in OKSs were not clinically significant. The mean difference in AKS knee scores was similar between the 2 groups (95% CI = -9.14 to -3.34; P = 0.36), whereas the pooled mean difference in AKS function scores was higher by 5.63 in FTCL group than in PTCL group (95% CI = -9.27 to -1.98; P = 0.002), which was clinically relevant. The reoperation rates were statistically higher in PTCL group than in FTCL group (odds ratio = 2.24; 95% CI = 1.15 to 4.38; P = 0.02). Patients with FTCL achieved superior postoperative patient-reported outcomes and lower reoperation rates following UKA compared with those with PTCL. Thus, we believe this procedure should only be applied to end-stage medial osteoarthritis of the knee joint.

Enhanced recovery after surgery (ERAS) protocol in geriatric patients underwent unicompartmental knee arthroplasty: A retrospective cohort study.

The enhanced recovery after surgery (ERAS) pathway was formulated with the aim to reduce surgical stress response, alleviate pain and guarantee the best-fit experience of patients' perioperative period. However, the application of ERAS in geriatric patients who underwent unicompartmental knee arthroplasty (UKA) was relatively lacking. We hypothesize that UKA patients can benefit from the ERAS protocol. A total of 238 patients were recruited in this retrospective study from August 2018 to December 2021, and Oxford phase III UKA was applied to all patients. ERAS pathway included nutrition support, anesthesia mode, interoperative temperature, and blood pressure control, application of tranexamic acid, early initiation of oral intake and mobilization, and pain management. Demographic data, operation-relative variables, and postoperative complications were analyzed. Forgotten Joint Scores, Oxford Knee Score, Lysholm score, numerical rating scale, and knee range of motion were introduced to estimate the activity function and pain of surgical knee, and these variables were compared between the 2 groups. There were 117 patients in the ERAS group and 121 patients in the traditional group, respectively. The ERAS group had a shorter length of surgical incision and less intraoperative blood loss. Postoperative hemoglobin and albumin of patients in the ERAS group were better than those in the traditional group (P < .05), after 17.0 ± 10.8 months follow-up, the numerical rating scale, Lysholm, Oxford Knee Score, Forgotten Joint Scores, and knee range of motion of patients in the ERAS group were significantly better than the traditional group. The length of hospital stay for patients who underwent ERAS was 11.7 ± 3.8 days and the postoperative complication rate was lower for the ERAS group patients (P = .000 and 0.031). ERAS can reduce the length of hospital stay, and patients can achieve excellent postoperative knee function. The formulation and implementation of the ERAS protocol require good collaboration across multiple disciplines, as well as a deep understanding of the existing clinical evidence and the concept of the ERAS program.

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

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. 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. 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. 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.

Midterm Outcomes of Unicompartmental Knee Arthroplasty for the Treatment of Knee Medial Compartment Osteoarthritis: A Retrospective Study.

Many surgeons avoid performing unicompartmental knee arthroplasty (UKA) due to various concerns. Cohort studies showing the satisfactory outcomes of UKA can convince surgeons to use this technique. In this study, we report the mid-term outcomes of UKA in a series of patients with medial compartment knee osteoarthritis. Seventeen patients with unicompartmental degenerative joint disease of the knee that underwent UKA and were available for final evaluation were included. The mean age of the patients was 63 ± 5.1 years. The mean follow-up of the patients was 37.2 ± 18.3 months. The outcome measures were the Oxford Knee Score (OKS), Knee Society Score (KSS) for knee score and knee function, Knee injury and Osteoarthritis Outcome Score (KOOS), knee range of motion (ROM), and satisfaction rate on a 5-point Likert scale. In the last follow-up visit, the mean of OKS and knee score section of the KSS were 44.6 ± 3.2 and 83.8 ± 2.1, respectively. The mean knee function section of the KSS was measured at 98.2 ± 7.2. The mean KOOS score and the mean knee ROM were 84 ± 9.4 and 134.4 ± 7º, respectively. The mean VAS for pain was 8.9 ± 1.1 (range 8-10) before the operation and 1.2 ± 0.8 (range 0-2) at the last follow-up. All the patients were very satisfied (n=14) or satisfied (n=3) with the results. No postoperative complication or reoperation was recorded during the follow-up. Unicompartmental knee arthroplasty provides satisfactory outcomes and a high survival rate, at least in mid-term follow-up. These findings suggest increased use of UKA in future workups.

Unicompartmental knee arthroplasty versus high tibial osteotomy for medial knee osteoarthritis: A systematic review and meta-analysis.

We aimed to systematically compare the clinical and functional outcomes between unicompartmental knee arthroplasty (UKA) and high tibial osteotomy (HTO) for the treatment of medial knee osteoarthritis (KOA). Literatures were searched from PubMed, EMBASE, the Cochrane library, Wanfang DATA, China National Knowledge Infrastructure (CNKI) and SinoMed database until December 2020. Studies comparing postoperative clinical and functional outcomes of UKA versus HTO were included. Totally, 38 studies were included, including 2368 patients with 2393 knees in HTO group and 6536 patients with 6571 knees in UKA group. There was significant difference in postoperative pain, revision rate, complications, and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score between HTO and UKA groups (p < 0.05). No significant difference was found in excellent/good surgical results, Lysholm, Hospital for Special Surgery (HSS) score, Knee Society Knee (KSS) score, knee and function score of Knee Society (KSFS) score and Tegner score between these two groups (p > 0.05). UKA produced less postoperative pain, less complications and superior WOMAC score, whereas HTO offered extended range of motion (ROM) and less revision rate.

Fast-track surgery and telerehabilitation protocol in unicompartmental knee arthroplasty leads to superior outcomes when compared with the standard protocol: a propensity-matched pilot study

BackgroundSeveral strategies have been devised to reduce the length of stay after orthopedic surgery. Telerehabilitation has proved effective in functional outcomes after orthopedic procedures and is appreciated by patients. There is limited information on fast-track surgery and telerehabilitation protocols for unicompartmental knee arthroplasty (UKA). The purpose of this pilot study was to report and compare functional outcomes and satisfaction levels during first 12 months of recovery in patients who underwent UKA according to a fast-track and telerehabilitation protocol (G1) or standard surgery and rehabilitation program (G2).MethodsData were retrospectively collected and reviewed for all elective UKAs from January 2018 to November 2019. A total of seven patients undergoing UKA according to the fast-track and telerehabilitation protocol were propensity score matched (1:3 ratio) to 21 patients undergoing standard surgery and rehabilitation. Patients were matched for age, sex, body mass index (BMI), and laterality. The Western Ontario and McMaster University (WOMAC) osteoarthritis index and range of motion (ROM) were collected pre- and postoperatively in both groups for 12 months. In addition, patient’ satisfaction was collected at 40 days.ResultsThe G1 group demonstrated significantly better outcomes in WOMAC index scores at 2, 15, and 40 days (p < 0.001, p < 0.001, p < 0.020, respectively) and a significantly greater knee ROM after surgery and at 2, 15, 40, and 12 months (p < 0.001, p < 0.001, p = 0.014, p < 0.001, p = 0.003, respectively). No patients in either group had postoperative complications. One patient was not completely satisfied in the G2, while no one in G1 reported not being completely satisfied (p = 1.000).ConclusionsThis fast-track and telerehabilitation protocol after UKA can potentially be applied to patients as it is safe and effective. At 12-months follow-up, both groups reported favorable outcomes after UKA. However, the G1 score was better regarding WOMAC and ROM when compared with the propensity score-matched G2 program. A larger study is warranted to explore the role of fast-track and telerehabilitation in clinical and functional outcomes of UKA.

Is unicompartmental knee arthroplasty truly contraindicated in an obese patient? A meta-analysis

BackgroundObesity has long been considered a relative contraindication to unicompartmental knee arthroplasty (UKA). However, with improved implants and techniques, the criteria for UKAs have been challenged. This paper aims to assess the impact of body mass index (BMI) on revision rates and functional outcomes in UKAs. MethodsDatabases of Pubmed, EMBASE, MEDLINE, CINHL and the Cochrane registries were systematically searched following the PROSPERO protocol. Studies comparing implant survival and functional outcome scores between obese and non-obese patients after a UKA were included. ResultsTwenty-five articles reported revision rates or functional outcomes in 42,434 UKA surgeries. There was a trend to higher revision rates in patients with BMI > 30 kg/m2 (odds ratio [OR] 0.91 [0.79–1.05]), BMI >35 kg/m2 (OR 0.70 [0.48, 1.01]) or BMI >40 kg/m2 (OR 0.66 [0.41, 1.07]), although the difference was not significant. There was a significant larger improvement in Oxford Knee Scores in obese patients after a UKA (OR 2.68 [1.79, 3.57], p < 0.00001), but no difference in Knee Society Scores or Visual Analogue Scale scores. ConclusionWith no significant increase in revision rates after a UKA, a significantly greater improvement in Oxford Knee Scores and no differences Knee Society Scores or Visual Analogue Scales, obesity should no longer be viewed as a relative contraindication when performing unicompartmental knee replacements.

Effects of Surgeon Handedness on the Outcomes of Unicompartmental Knee Arthroplasty: A Single Center's Experience.

Surgeon handedness has been widely discussed in operative surgery, and could cause clinical discrepancy. However, few studies have reported the effect of handedness on unicompartmental knee arthroplasty (UKA). Based on our clinical observation and case analysis, we aimed to find out the effects of surgeon handedness on UKA. We retrospectively studied 94 UKA procedures performed by one right-handed surgeon from January 2017 to December 2018 at a single medical center. The cases were divided into two groups by operation side (49 L-UKAs and 45 R-UKAs). Preoperative demographic data were collected. Imaging parameters (femorotibial and hip-knee-ankle angles and tibial-plateau retroversion) and joint function scores (Knee Society Score [KSS] and Oxford Knee Score [OKS]) were recorded. Patients were followed up regularly and Forgotten Joint Score (FJS) was calculated at the last follow-up. All data were compared between the two groups with independent-samples t-test, and paired t-test was used for intragroup comparisons. The average follow-up was 26.7 ± 3.2 months. The average patient age was 63.5 ± 9.0 years and the average body mass index was 26.89 ± 3.43 kg/m2 . There was no significant group difference in any preoperative characteristic. Both the KSS and OKS improved significantly after surgery (p < 0.05). No significant group difference was found between the KSS or OKS at any follow-up visit. The varus or valgus of tibial component was 3.57 ± 1.42° on the left side and 3.19 ± 1.56° on the right side (p=0.45). The varus or valgus of femoral component was 7.81 ± 2.43° in patients undergoing L-UKA and 7.05 ± 2.90° in those undergoing R-UKA (p=0.04). No statistical differences were found in outliers of component orientation on both sides. The femorotibial and hip-knee-ankle angles improved significantly in both groups, and there was no significant group difference in either lower limb alignment or tibial-plateau retroversion. The complication rate was 8.16% (4/49) in the L-UKA group and 6.67% (3/45) in the R-UKA group. There was no correlation between prosthesis orientation and early joint function score. Surgeon handedness may cause a worse prosthetic orientation on femoral side during surgeon's non-dominant UKA, and surgeons should be cautious of bone resection and prosthesis implantation. However, radiographic difference did not bring variations on short-term clinical outcomes or lower limb alignment.

Comparison of the radiological parameters between dynamic-referencing tactile guidance robotic system and Microplasty® instrumentation in unicompartmental knee arthroplasty.

This study aims to compare the radiological outcomes of unicompartmental knee arthroplasty (UKA) performed by a navigation-based robotic system versus Microplasty® instrumentation. Between January 2018 and January 2019, a total of 90 knees of 75 patients (65 males, 10 females; mean age: 62.0±9.4 years; range, 50 to 73 years) were included. Among these, 54 knees underwent Oxford mobile-bearing UKA with an Microplasty® instrumentation set and 36 knees were operated with the aid of a Restoris® MCK with MAKO navigation-based robotic system. Postoperative anteroposterior and lateral X-rays of all patients were evaluated according to nine different parameters. On the femoral side, femoral varus-valgus angle, flexion-extension angle, femoral condyle posterior fit; on tibial side, tibial component varus/valgus, tibial posterior slope, medial, anterior, posterior and lateral fit of tibial component assessed. There was no significant difference between groups in terms of age, sex, and affected side. On the femoral side, no significant difference was observed in the component position between groups. On the tibial side, tibial component medial fit (p=0.032) and anterior fit (p=0.007) were better in navigation-based robotic system group. Microplasty® instrumentation may lead to comparable implant positioning compared to a tactile-based navigated robotic instrumentation.

Prior Anterior Cruciate Ligament Reconstruction Does Not Compromise the Functional Outcomes of Medial Unicompartmental Knee Arthroplasty Although Revision for Progressive Arthritis May Occur Earlier.

Anterior cruciate ligament (ACL) deficiency is commonly considered a contraindication for unicompartmental knee arthroplasty (UKA). The purpose of this study is to compare the outcomes of UKA after prior ACL reconstruction (rACL cohort) to UKA with an intact native ACL (nACL cohort). Forty-five patients from 3 institutions who underwent medial UKA after prior rACL were matched by age, gender, preoperative function scores, and body mass index to 90 patients who underwent UKA with an intact nACL. Primary outcomes were Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, Oxford Knee Scores, Knee Society Functional Scores, and Kellgren-Lawrence scores in the unresurfaced, lateral tibiofemoral compartment. Secondary outcomes were postoperative complications and the need for revision to TKA. At a mean of 3.6 years, all PROMs improved significantly with no differences identified between groups. The incidence of revision TKA was similar between cohorts (P= 1.00); however, the mean time to revision for progressive osteoarthritis was 4.0 years in the nACL group and 2.2 years in the rACL group. Twenty percent of rACL patients had a postoperative complication compared to 8% in the nACL group. Despite presenting with a similar degree of lateral arthritis, a greater percentage of patients developed Kellgren-Lawrence scores of ≥3 in the rACL cohort (9%) than in the nACL cohort (0%). A previously reconstructed ACL does not appear to compromise the short-term functional outcomes of UKA; however, there is a higher rate of minor complications and progression of lateral compartment arthritis, which should be considered with patients in the shared decision process.

Postoperative clinical outcomes of unicompartmental knee arthroplasty in patients with isolated medial compartmental osteoarthritis following medial meniscus posterior root tear

BackgroundCartilage degradation progresses rapidly following medial meniscus posterior root tear (MMPRT). Unicompartmental knee arthroplasty (UKA) has been performed for medial compartmental osteoarthritis following MMPRT. We evaluated the clinical and radiographic outcomes of UKA for medial compartmental osteoarthritis after an untreated MMPRT. MethodsTwenty-one patients who underwent UKA for isolated medial compartment osteoarthritis following MMPRT were retrospectively investigated. Clinical outcomes were assessed using the Knee Injury and Osteoarthritis Outcome Score and knee range of motion. The posterior tibial slope and tibial component inclination were evaluated using plain radiographs. ResultsThe mean follow-up periods were 25.5 ± 13.8 months. Clinical outcomes improved significantly postoperatively. The mean postoperative knee extension angle was −1.1° ± 2.1°, and the knee flexion angle was 134.3° ± 4.9°. The posterior tibial slope angle decreased from 9.0° ± 2.0° preoperatively to 5.4° ± 1.8° postoperatively, and postoperative tibial component inclination at the final follow-up was 2.9° ± 1.1° varus. No aseptic loosening or deep infections were observed. ConclusionUKA significantly improved clinical outcomes and could be a viable surgical option for treating isolated medial compartmental osteoarthritis accompanied by untreated MMPRT.

Femorotibial alignment measured during robotic assisted knee surgery is reliable: radiologic and gait analysis.

Femorotibial alignment is crucial for the outcome of unicompartmental knee arthroplasty (UKA). Robotic-assisted systems are useful to increase the accuracy of alignment in UKA. However, no study has assessed if the femorotibial alignment measured by the image-free robotic system is reliable. The aim of this study was to determine whether measurement of the mechanical femorotibial axis (mFTA) in the coronal plane with handheld robotic assistance during surgery is equivalent to a static measurement on radiographs and to a dynamic measurement during walking. Twenty patients scheduled for robotic-assisted medial UKA using handheld technology were included in this prospective study. Three measurements of the frontal femorotibial axis were compared: intra-operative acquisition by computer assistance (dynamic, non-weightbearing position), radiographic measurements on long leg X-ray (static, weightbearing position), and by gait analysis during walking (dynamic, weightbearing position). There was no significant difference in the mFTA between computer (174.4 ± 3.4°), radiological (173.9 ± 3.3°), and gait analysis (172.9 ± 5.1°) measurements (p = 0.5). There was a strong positive correlation (r = 0.6577355, p = 0.0016) between robotic-assisted measurements and gait analysis. There was no significant difference in the femorotibial axis measured by the image-free robotic assistance, from the preoperative radiographs or by gait analysis. The reliability of intra-operative measurements of the frontal femorotibial axis by these robotic-assisted systems is acceptable.

Medial Unicompartmental Knee Arthroplasty After Failed Open-Wedge High Tibial Osteotomy

BackgroundControversy exists whether or not a previous high tibial osteotomy (HTO) influences the outcome and survival of a unicompartmental knee arthroplasty (UKA). The aim of this retrospective study was to evaluate clinical, radiological, and functional outcomes of UKA after failed open-wedge HTO compared with UKA with no previous HTO. MethodsBetween 2001 and 2017, 24 post-HTO UKAs (group A) with an average follow-up of 8.1 years (range: 5 to 13) were compared with a control group of 30 patients undergoing simple UKA (group B) with an average follow-up of 9.5 years (range: 2 to 16). All patients were evaluated preoperatively and postoperatively using Knee Society Score, University of California at Los Angeles Activity Score, Western Ontario and McMaster University Osteoarthritis Index, and through objective evaluation. Mechanical coronal alignment and Caton-Deschamps index were measured both preoperatively and postoperatively. ResultsIn both groups, Knee Society Score, University of California at Los Angeles Activity Score, and Western Ontario and McMaster University Osteoarthritis Index scores significantly improved at follow-up (P < .001). In addition, statistically significant greater improvements in clinical and functional scores were reported in group B compared with group A (P < .001). No statistically significant differences concerning postoperative mechanical axis were observed between groups (2.7° and 3.2°, respectively, P = .27) and with regard to Caton-Deschamps index (1.0° and 1.1°, respectively, P = .44). ConclusionThis study demonstrated improvements in clinical and functional outcomes compared with preoperatory status in both groups irrespective of a previous HTO. A prior HTO was a determinant for having reduced postoperative clinical and functional outcomes after UKA.

Impact of joint line orientation on clinical outcomes in bilateral Oxford mobile-bearing unicompartmental knee arthroplasty

BackgroundJoint line orientation angle (JLOA) is the angle between the knee joint line and the floor. It has been reported to be related to postoperative outcome after TKA. Regarding unicompartmental knee arthroplasty (UKA), although it can be horizontal after UKA because it is a resurfacing surgery, there are few reports about the JLOA after UKA and its impact on clinical outcomes. PurposeThe purpose of this study was to reveal the relationship between JLOA and clinical outcome after UKA. MethodsThis study included 106 knees in 53 consecutive patients with osteoarthritis who underwent simultaneous bilateral mobile-bearing UKA. Their pre- and postoperative JLOAs were measured by full-leg-length standing coronal radiographs. We also evaluated the tibial component height (TCH) as the factor which we assumed could influence JLOA. We analyzed the patients’ JLOAs, TCHs and clinical outcomes. ResultsPre- and postoperative JLOA were 0.4 ± 2.4° and 2.7 ± 2.6°, respectively. The JLOA significantly tilted medially (P < 0.0001). The JLOA significantly negatively correlated with the improvement of the clinical outcomes (Oxford Knee Score (OKS): r = 0.40, P < 0.0001, Knee Society Knee Score (KSKS): r = 0.25, P < 0.01, Knee Society Function Score (KSFS): r = 0.22, P = 0.02). The TCH showed a positive correlation with postoperative JLOA and with the postoperative JLOA change (r = 0.45, P < 0.001; r = 0.25, P < 0.01, respectively). ConclusionThe JLOA significantly tilted medially after UKA. An excessive medial tilt of the JLOA was associated with poorer postoperative outcomes of UKA. It is therefore recommended to keep the JLOA horizontal and to avoid a lower tibial cut.

Obesity does not adversely impact the outcome of unicompartmental knee arthroplasty for osteoarthritis: a meta-analysis of 80,798 subjects.

Patients with end-stage single compartment osteoarthritis benefit from the less invasive unicompartmental knee arthroplasty (UKA). With increasing financial restraints, some healthcare services have set specific BMI cut-offs when determining patient eligibility for knee arthroplasty due to perceived obesity-related complications. The aim of this systematic review is to determine the effect obesity has on outcomes following UKA, and thus elucidate whether obesity should be a contraindication for UKA. A PRISMA systematic review was conducted using five databases (MEDLINE, EMBASE, Cochrane, PubMed and Web of Science) to identify all clinical studies that examined the effect of obesity on outcomes following UKA. Quantitative meta-analysis was carried out using RevMan 5.3 software. Quality assessment was carried out using the Critical Appraisal Skills Programme (CASP) checklist. Thirty studies, including a total of 80 798 patients were analysed. The mean follow- up duration was 5.42 years. Subgroup meta-analyses showed no statistically significant difference following UKA between patients cohorts with and without obesity in overall complication rates (95% CI, P = 0.52), infection rates (95% CI, P = 0.81), and revision surgeries (95% CI, P = 0.06). When further analysing complications, no differences were identified in minor (95% CI, P = 0.23) and major complications (95% CI, P = 0.68), or venous thromboembolism rates (95% CI, P = 0.06). When further analysing revision surgeries, no differences were identified for revisions specifically for infection (95% CI, P = 0.71) or aseptic loosening (95% CI, P = 0.75). This meta-analysis shows that obesity does not result in poorer post-operative outcomes following UKA and should not be considered a contraindication for UKA. Future studies, including long-term follow-up RCTs and registry-level analyses, should examine factors associated with obesity and consider stratifying obesity to better delineate any potential differences in outcomes.