Medial Unicondylar Knee Arthroplasty Research Articles

Study on accuracy of prosthesis size selection for Naton robot-assisted medial unicondylar knee arthroplasty

To analyze the accuracy of prosthesis size selection in Naton robot-assisted medial unicondyle knee arthroplasty by comparing the actual prosthesis size used during operation and the preoperative planning. The clinical data of 100 patients (110 knees) who underwent Naton robot-assisted medial unicondylar knee arthroplasty between June 2023 and July 2024 was retrospectively analyzed, including 47 knees on left side and 63 knees on right side. There were 37 males (40 knees) and 63 females (70 knees) with a mean age of 65.4 years (range, 59-71 years). Body mass index was 22.2-28.6 kg/m 2 (mean, 25.4 kg/m 2). The disease duration ranged from 1 to 8 years (mean, 3.4 years). Preoperative planning was performed by Naton robotic surgical system based on lower limb CT data. The final prosthesis size after osteotomy was recorded and compared with the preoperative plan to analyse whether it was consistent with the preoperative plan, as well as the situation of knee flexion and extension gaps (<0.5 mm, >2.0 mm) corresponding to the different models of prostheses. During operation, 5 patients (5 knees) were treated with traditional UKA due to mechanical arm failure, software obstacles, significant bone amputation bias, or loose reference frame, and were excluded from the final analysis. The remaining 95 patients (105 knees) successfully received Naton robot-assisted surgery, and no related complications occurred. The prosthesis size was consistent with the preoperative plan in 101 knees (96.2%) on the femur side, 100 knees (95.2%) on the tibia side, and 97 knees (92.4%) on both femur and tibia sides. The prosthesis size was inconsistent in 3 cases (2.86%) on the femur side alone, 4 cases (3.81%) on the tibial side alone, and 1 case (0.95%) on both femur and tibial sides. Among the prostheses with different models, the flexion and extension gaps were less than 0.5 mm in 3 knees, the flexion gap was less than 0.5 mm and the extension gap was more than 2.0 mm in 3 knees, and the flexion gap was more than 2.0 mm and the extension gap was less than 0.5 mm in 2 knees. The accuracy of prosthesis size selection for Naton robot-assisted medial unicondylar knee arthroplasty is relatively high.

Knee

The December 2023 Knee Roundup360 looks at: Obesity is associated with greater improvement in patient-reported outcomes following primary total knee arthroplasty; Does mild flexion of the femoral prosthesis in total knee arthroplasty result in better early postoperative outcomes?; Robotic or manual total knee arthroplasty: a randomized controlled trial; Patient-relevant outcomes following first revision total knee arthroplasty, by diagnosis: an analysis of implant survivorship, mortality, serious medical complications, and patient-reported outcome measures using the National Joint Registry data set; Sagittal alignment in total knee arthroplasty: are there any discrepancies between robotic-assisted and manual axis orientation?; Tourniquet use does not impact recovery trajectory in total knee arthroplasty; Impact of proximal tibial varus anatomy on survivorship after medial unicondylar knee arthroplasty; Bone cement directly to the implant in primary total knee arthroplasty?; Maintaining joint line obliquity optimizes outcomes in patients with constitutionally varus knees.

Long-term results of per-operative knee arthroscopy in confirming suitability for unicompartmental arthroplasty

BackgroundPatient selection is key to the success of medial unicondylar knee arthroplasty (UKA). Progression of arthritis is the most common indication for revision surgery. Per-operative arthroscopy is a means of directly assessing the integrity of the lateral compartment. The aim of the study is to assess the long-term survivorship of UKA performed when per-operative arthroscopy is used as a final means of deciding whether to proceed with UKA. MethodsWe used per-operative arthroscopy as a means to confirm suitability for UKA in a consecutive series of 279 Oxford medial UKA. Our series of UKA with per-operative arthroscopy (Group 1) was compared to all Oxford UKA (Group 2) and all UKA in the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) (Group 3). ResultsThe 14-year cumulative percentage revision (CPR) was 18.5% (95% CI 12.7, 26.4) for group 1, 19.7% (95% CI 18.8, 20.6) for group 2, and 19.2% (95% CI 18.5, 19.8) for group 3. There was no statistically significant difference in the (CPR) for the entire period when group 1 was compared to groups 2 or 3. Progression of arthritis was least in Group 1 compared to groups 2 and 3; 3.6 versus 4.4 and 4.1% respectively. Following per-operative arthroscopy 21.6% (77/356) of knees underwent a change of surgical plan from UKA to TKA. ConclusionIn our practice, which includes per-operative arthroscopy, we have identified a reduced risk of revision due to progression of arthritis but no difference in overall long-term implant survivorship.

LONG-TERM RESULTS OF PER-OPERATIVE KNEE ARTHROSCOPY IN CONFIRMING SUITABILITY FOR UNICOMPARTMENTAL KNEE ARTHROPASTY

AbstractIntroductionPatient selection is key to the success of medial unicondylar knee arthroplasty (UKA). Progression of arthritis is the most common indication for revision. Various methods of assessing the lateral compartment have been used including stress radiography, radioisotope bone scanning, MRI, and visualisation at the time of surgery. Arthroscopy is another means of assessing the integrity of the lateral compartment.MethodsWe used per-operative arthroscopy as a means to confirm suitability for UKA in a consecutive series of 279 Oxford medial UKA. This study reports the long-term results of a previously published cohort of knees. Our series of UKA with per-operative arthroscopy (Group 1) was compared to all Oxford UKA (Group 2) and all UKA in the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) (Group 3).ResultsThe 14-year cumulative percentage revision (CPR) was 18.5% (95% CI 12.7, 26.4) for group 1, 19.7% (95% CI 18.8, 20.6) for group 2, and 19.2% (95% CI 18.5, 19.8) for group 3. There was no statistically significant difference in the (CPR) for the entire period when group 1 was compared to groups 2 or 3. Progression of arthritis was the indication for revision in similar proportions for the three groups (Group 1: 32.3%, Group 2: 35.7% and Group 3: 33.5%). Following per-operative arthroscopy 21.6% (77/356) of knees underwent a change of surgical plan from UKA to TKA.ConclusionPer-operative arthroscopy may improve medium-term medial unicompartmental knee survivorship but does not improve long-term survivorship nor reduce revision due to progression of arthritis.

The clinical outcome of total knee arthroplasty is compromised by a previously implanted medial unicondylar knee arthroplasty

ObjectiveTo investigate the clinical outcome of patients that underwent conversion of a medial unicondylar knee arthroplasty (UKA) to a total knee arthroplasty (TKA) and to compare that outcome to patients that underwent primary TKA. It was hypothesized that those groups would significantly differ in terms of knee score outcome and implant survival.MethodsA retrospective-comparative study was conducted utilizing data from the Federal state’s arthroplasty registry. Included were patients from our department that undergone a conversion of a medial UKA to a TKA (UKA-TKA group). The Western Ontario and MacMaster Universities Osteoarthritis Index (WOMAC) from preoperative and 1-year postoperative was used. Moreover, the implant survival was analyzed.ResultsIn the UKA-TKA group, there were 51 cases (age 67 ± 10, 74% women), and in the TKA group, there were 2247 cases (age 69 ± 9, 66% women). The one-year postoperative WOMAC total score was 33 in the UKA-TKA group und 21 in the TKA group (p < 0.001). Similarly, the WOMAC pain, WOMAC stiffness, and WOMAC function scores were significantly worse in the UKA-TKA. After 5 years, the survival rates were 82% and 95% (p = 0.001). The 10-years prosthesis survival was 74% and 91% in the UKA-TKA and TKA groups, respectively (p < 0.001).ConclusionsBased on our findings it is concluded that patients who received a TKA after UKA have inferior results than those that directly receive a TKA. This is true for both patient-reported knee outcome and prosthesis survival. Converting UKA to TKA should not be seen as an easy operation, but should rather be done by surgeons with considerable experience in both primary and revision knee arthroplasty.

Impact of Proximal Tibial Varus Anatomy on Survivorship After Medial Unicondylar Knee Arthroplasty

BackgroundPrecise indications for medial unicondylar knee arthroplasty (UKA) continue to be defined. It is unclear if patients who have proximal tibia vara should be considered candidates for UKA. The purpose of this study was to evaluate the impact of proximal tibial varus alignment on outcomes after UKA. MethodsA retrospective review identified 2,416 patients (3,029 knees) who underwent mobile-bearing medial UKA with 2-year minimum follow-up or revision. Preoperative radiographs were evaluated, and medial proximal tibial angle (mPTA) was measured. Patients were grouped into two groups as follows: mPTA <80 degrees and mPTA ≥80 degrees. Analyses were performed on the impact of mPTA on clinical outcomes, all-cause revisions, and tibial failures. ResultsAt a mean follow-up of 5 years (range, 0.5 years to 12.8 years), there was not a statistically significant difference in clinical outcomes nor increased risk for all-cause revision or tibial failure in patients who had an mPTA <80°. Mean mPTA in patients who had tibial failures was 82.5° and not significantly different than those who did not have a tibial failure (82.9°) (P = .289). Tibial failure rate in knees with an mPTA <80° was 2.2% and not significantly different than knees with an mPTA ≥80° at 1.4% (P = .211). The all-cause revision rate in knees with an mPTA <80° was 5.8% and was not significantly different than knees with an mPTA ≥80° at 4.9% (P = .492). ConclusionPatients who have tibia vara are not at increased risk for tibial related or all-cause failure in medial UKA. This data may allow surgeons to increase their indications for medial UKA.

The risk of tibial eminence avulsion fracture with bi-unicondylar knee arthroplasty

AimsThe aim of this study was to determine the risk of tibial eminence avulsion intraoperatively for bi-unicondylar knee arthroplasty (Bi-UKA), with consideration of the effect of implant positioning, overstuffing, and sex, compared to the risk for isolated medial unicondylar knee arthroplasty (UKA-M) and bicruciate-retaining total knee arthroplasty (BCR-TKA).MethodsTwo experimentally validated finite element models of tibia were implanted with UKA-M, Bi-UKA, and BCR-TKA. Intraoperative loads were applied through the condyles, anterior cruciate ligament (ACL), medial collateral ligament (MCL), and lateral collateral ligament (LCL), and the risk of fracture (ROF) was evaluated in the spine as the ratio of the 95th percentile maximum principal elastic strains over the tensile yield strain of proximal tibial bone.ResultsPeak tensile strains occurred on the anterior portion of the medial sagittal cut in all simulations. Lateral translation of the medial implant in Bi-UKA had the largest increase in ROF of any of the implant positions (43%). Overstuffing the joint by 2 mm had a much larger effect, resulting in a six-fold increase in ROF. Bi-UKA had ~10% increased ROF compared to UKA-M for both the male and female models, although the smaller, less dense female model had a 1.4 times greater ROF compared to the male model. Removal of anterior bone akin to BCR-TKA doubled ROF compared to Bi-UKA.ConclusionTibial eminence avulsion fracture has a similar risk associated with Bi-UKA to UKA-M. The risk is higher for smaller and less dense tibiae. To minimize risk, it is most important to avoid overstuffing the joint, followed by correctly positioning the medial implant, taking care not to narrow the bone island anteriorly.Cite this article: Bone Joint Res 2022;11(8):575–584.

Are the functional outcomes really inferior following unicondylar knee arthroplasty in patients with partial-thickness cartilage loss?

The main indication for medial Unicondylar Knee Arthroplasty (UKA) is Full-Thickness Cartilage Loss (FTCL) in the isolated medial compartment of the knee. However, controversial outcomes were reported in patients with Partial-Thickness Cartilage Loss (PTCL). The aim of this study is to compare PTCL and FTCL based on intraoperative findings in medial UKA in terms of functional outcomes and complication rates requiring reoperation and revision. Two hundred and fifteen knees of 174 patients who underwent mobile-bearing UKA between October 2014 and February 2018 for the diagnosis of symptomatic anteromedial osteoarthritis were evaluated retrospectively. A single senior surgeon evaluated the type of cartilage loss in the medial compartment intraoperatively according to the International Cartilage Repair Society classification system. Clinical outcomes were evaluated using Oxford Knee Score (OKS) and International Knee Documentation Committee (IKDC) score pre- and post-operatively at the last follow-up. Patients with PTCL and FTCL were compared in terms of their pre- and post-operative OKS and IKDC scores, and their improvements, as well as complication rates requiring reoperation and revision. The mean follow-up time was 33.1 ± 5.3 months. The PTCL (n = 80) and FTCL (n = 135) groups were statistically similar in terms of age (P = 0.41), gender (P = 0.921), body mass index (P = 0.165), bilaterality (P = 0.111), American Society of Anesthesiologists physical status (P = 0.218), Charlson Comorbidity Index (P = 0.74), and post-operative follow-up (P = 0.167). The mean pre-operative OKS and IKDC scores were improved from 24.5 ± 4.1 and 39.9 ± 5 to 40.3 ± 3.6 and 73.9 ± 7.7 at the last follow-up, respectively (P < 0.001). Pre-operative OKS and IKDC scores were superior in favor of the PTCL group. However, no significant difference was found between the groups in terms of post-operative OKS (P = 0.53) and IKDC (P = 0.975) scores, and their improvements (OKS, P = 0.953; IKDC, P = 0.536). The complication rates requiring reoperation was 5% (n = 11) in all patients. Of these, 9% (n = 7) from the PTCL group and 3% (n = 4) from the FTCL group were reoperated. Nevertheless, no significant difference was found between the groups (P = 0.105). In PTCL, medial UKA is a reliable surgery in terms of functional outcomes, the same as in FTCL; however, its complication rates requiring reoperation is higher without statistical significance. Level III, Therapeutic Study.

Comparison of the Functional, Radiological, and Gait Outcome of Imageless Navigated Mobile-Bearing vs Fixed-Bearing Medial Unicondylar Knee Arthroplasty in Patients with Symptomatic Anteromedial Osteoarthritis Using a Double-Blind Randomized Control Trial

Malhotra, Rajesh MBBS, MS, FACS; Sahu, Arpit MBBS; Manhas, Vikrant MS; Gautam, Deepak MBBS, MS Author Information

Proximal tibial bone loss in the first 2 years after unicondylar knee arthroplasty: Anatomical pattern, predictors and clinical correlation

BackgroundTibial stress fracture, anteromedial bone pain, and early subsidence could occur after unicondylar knee arthroplasty (UKA). The change in metaphyseal tibial bone density (MTBD) in the coronal and sagittal planes after UKA might be a contributing factor, but this has rarely been investigated. The aim of this study was to assess the regional and temporal change in MTBD in the coronal and sagittal planes in the first 2 years after UKA. MethodsPatients with fixed-bearing medial UKA were recruited. The change in MTBD in the first 24 months after UKA using digital radiological densitometry (DRD) was measured. Potential predictors and clinical correlations were analyzed. ResultsEighty-four cases (female 60%) were selected for review. The follow up time was 63 (±17) months. Anterior and medial regions had the largest proportion of cases with MTBD reduction (90–97%, P < 0.05). Reduction was largest at anterior and medial regions (21–29%, P < 0.05) and smallest at posterior and lateral regions (5–15%, P < 0.05). Maximal reduction occurred at 12 months for the medial region and 24 months for the anterior region. MTBDs of both regions were not significantly influenced by any confounding factors. Significant correlation was found between medial MTBD and Function Score at 6 months. ConclusionsBone loss in a zonal pattern occurs in the first 2 years after UKA with the largest loss in the anterior region below the tibial tray. It is not affected by body mass index, perioperative alignment, or angle of correction. This suggests a physiological response to trauma other than a mechanical response to the change in bone strain.

Medial unicondylar knee arthroplasty should be reserved for patients with complete joint space collapse

PurposeTo determine whether preoperative radiologic joint space width (JSW) is related to the outcome of medial unicondylar knee arthroplasty (UKA) (primary hypothesis).MethodsA retrospective comparative analysis was performed. One group was comprised of UKA patients with preoperative JSW 0–1 mm. Another group was made up of patients with preoperative JSW ≥ 2 mm (range 0–4 mm). The JSW was measured from preoperative weight-bearing Schuss-view radiographs. The clinical outcome was determined with the Western Ontario and MacMaster Universities (WOMAC) Osteoarthritis Index score preoperatively and 1 year after medial UKA. Implant survival data were obtained from the arthroplasty register of Tyrol.ResultsThere were 80 patients with a preoperative JSW 0–1 mm (age 66, BMI 27.8) and 70 patients with a preoperative JSW ≥ 2 mm (age 64, IQR 15, BMI 28.1). WOMAC total was 10 ± 10 in patients with 0–1 mm JSW and 25 ± 47 in patients with ≥ 2 mm JSW at 1 year postoperative (p = 0.052). WOMAC pain at 1 year postoperative was 7 ± 16 in patients with 0–1 mm JSW and 18 ± 46 in patients with ≥ 2 mm JSW (p = 0.047). WOMAC function at 1 year postoperative was 10 ± 9 in patients with 0–1 mm JSW and 17 ± 51 in patients with ≥ 2 mm JSW (p = 0.048). In patients with 0–1 mm JSW 5 year prosthesis survival was 92.3% and in patients with ≥ 2 mm JSW, it was 81.1% (p = 0.016).ConclusionsIn patients with preoperative complete joint space collapse (0–1 mm JSW), clinical outcome was superior to that of patients with incomplete joint space collapse. This was true for both 1 year postoperative WOMAC pain and WOMAC function and for 5 year implant survival rates. On the basis of our findings, it is recommended that ‘complete joint space collapse’ especially be used to achieve best clinical outcome in medial UKA surgery.Level of evidenceIV.

Impact of Polyethylene Thickness on Clinical Outcomes and Survivorship in Medial Mobile-Bearing Unicondylar Knee Arthroplasty

BackgroundThe thickness of the polyethylene bearing in medial unicondylar knee arthroplasty (UKA) is determined by the depth of the tibial resection, degree of correctable deformity, and balance of the knee. The purpose of this study is to evaluate whether polyethylene thickness in medial mobile-bearing UKA impacts clinical outcomes and survivorship. MethodsA retrospective review from 2004 to 2017 identified patients who underwent a primary mobile-bearing medial UKA with 2-year minimum follow-up or revision. A total of 2305 patients (3030 knees) met inclusion criteria. Patients were divided in 2 groups: thin bearing (group 1): 3-mm or 4-mm bearing and thick bearing (group 2): ≥ 5 mm. The thin group consisted of 2640 knees (87%), whereas the thick group had 390 knees (13%). Preoperative and postoperative demographics, range of motion, Knee Society scores, complications, and reoperations were evaluated. ResultsMean follow-up was 5.2 years (range, 0.5 to 12.6). There was no significant difference between groups in postoperative range of motion or Knee Society scores (P > .05). Manipulations were performed in 1.3% of patients and not significantly different between groups. The all-cause revision rate for group 1 was 4.02% and group 2 was 4.58% (P = .6). Revision rates for tibial aseptic loosening were significantly higher in group 2 (1.8%) than those in group 1 (0.7%) (P = .04). There was no significant difference in failure rates between groups for tibial collapse or fracture, femoral aseptic loosening, arthritic progression, bearing dislocation, or other cause of revision. ConclusionThis study demonstrated that thicker bearings in medial UKA increased the risk of tibial aseptic loosening, but not all-cause failures or clinical outcomes.

Occupational Outcomes and Revision Rates for Medial Unicondylar Knee Arthroplasty in U.S. Military Servicemembers.

This study evaluates return to work and revision rates for medial unicondylar knee arthroplasty (UKA) in a high-demand military cohort. Patient demographic and clinical variables were isolated from the medical records of active-duty military servicemembers with at least 2 years of postoperative follow-up and correlated with return to work, medial UKA survivorship, and perioperative complications. The medial UKA annual revision rate was calculated as the percentage of implants revised per observed component year. A total of 39 servicemembers underwent 46 primary medial UKAs (32 unilateral and 7 bilateral) with a mean follow-up of 3.9 (2.0-6.6) years. At a minimum of 2 years postoperatively, 33 (85%) servicemembers returned to military service or successfully completed their service obligation. Older servicemembers (odds ratio [OR] = 0.67; 95% confidence interval [CI]: 0.45, 0.99) had a significantly decreased OR for knee-related medical separation. Nine servicemembers (20%) had conversion to TKA at an average of 2.4 (range, 0.6-5.6) years with a medial UKA annual revision rate of 5%. When compared with Navy/Air Force, Army/Marine servicemembers had an increased TKA conversion rate (OR = 5.40; 95% CI: 1.13, 25.81). Older age decreased the likelihood of medical separation and Army/Marines service was the sole risk factor associated with conversion to TKA. The level of evidence is IV, therapeutic case series.

Outcomes of Combined Unicondylar Knee Arthroplasty and Anterior Cruciate Ligament Reconstruction.

Young and more active patients with medial compartmental osteoarthritis (OA) in conjunction with anterior cruciate ligament (ACL) deficiency are challenging for orthopaedic surgeons. The aim of the present study was to examine the early-mid clinical and radiological outcomes of combined Oxford unicondylar knee arthroplasty (UKA) and ACL reconstruction for the patients presenting ACL deficiency and concomitant medial compartment symptomatic OA. Twelve patients were included in the study. All patients were treated by combination of ACL reconstruction with medial UKA. The varus-valgus angles of the tibial and femoral components, and pathological radiolucent lines were measured on anteroposterior and lateral knee radiographs. Clinical evaluations include knee osteoarthritis outcome score (KOOS pain, symptom, daily life, sports, and quality of life), Oxford knee score (OKS), EQ-5D-3L, and EQ-visual analog scale (VAS). All the patients were followed up for an average of 45.6 months. The leg alignment showed 3.6 degrees ± 1 of varus deformity before surgery and 2.6 degrees ± 1 of valgus after surgery. With the exception of KOOS sports (p > 0.001), the KOOS pain, symptom, daily life, and quality of life, OKS, EQ-5D-3L, and EQ-VAS improved significantly after surgery (p < 0.001). Preoperative knee instability showed anterior translation of 5 to 10 mm in eight patients and >10 mm in four patients. There were no complications at follow-up. The early-mid clinical data have shown that UKA in conjunction with ACL reconstruction has revealed promising results. However, long-term follow-up studies are required to confirm the combined procedure in these patients.

Robotic-arm assisted medial unicondylar knee arthroplasty versus jig-based unicompartmental knee arthroplasty with navigation control: study protocol for a prospective randomised controlled trial

BackgroundThere remains a paucity of clinical studies assessing how any differences in accuracy of implant positioning between robotic-arm assisted unicompartmental knee arthroplasty (RO UKA) and conventional jig-based unicompartmental knee arthroplasty (CO UKA) translate to patient satisfaction, functional outcomes, and implant survivorship. The objectives of this study are to compare accuracy of implant positioning, limb alignment, patient satisfaction, functional outcomes, implant survivorship, cost-effectiveness, and complications in CO UKA versus RO UKA. Computer navigation will be used to assess intraoperative knee kinematics in all patients undergoing CO UKA.Methods and analysisThis prospective randomised controlled trial will include 140 patients with symptomatic medial compartment knee arthritis undergoing primary UKA. Following informed consent, patients will be randomised to CO UKA (control group) or RO UKA (investigation group) at a ratio of 1:1 using an online random number generator. The primary objective of this study is to compare accuracy of implant positioning in CO UKA versus RO UKA. The secondary objectives are to compare the following outcomes between the two treatment groups: limb alignment, surgical efficiency, postoperative functional rehabilitation, functional outcomes, quality of life, range of motion, resource use, cost effectivness, and complications. Observers will review patients at regular intervals for 2 years after surgery to record predefined study outcomes pertaining to these objectives. Ethical approval was obtained from the London-Bloomsbury Research Ethics Committee, UK. The study is sponsored by University College London, UK.DiscussionThis study compares a comprehensive and robust range of clinical, functional, and radiological outcomes in CO UKA versus RO UKA. The findings of this study will provide an improved understanding of the differences in CO UKA versus RO UKA with respect to accuracy of implant positioning, patient satisfaction, functional outcomes, implant survivorship, cost-effectiveness, and complications.Trial registrationClinicalTrials.gov NCT04095637. Registered on 19 September 2019.

Prior high tibial osteotomy is not a contraindication for medial unicompartmental knee arthroplasty.

To report on the outcome and complications of minimal invasive medial unicondylar knee arthroplasty (UKA) after failed prior high tibial osteotomy (HTO) as treatment for medial osteoarthritis in the knee. The hypothesis was that good results can be achieved, if no excessive postoperative valgus alignment and abnormal proximal tibial geometry is present. All medial UKAs after failed prior HTO (n = 30), performed between 2010 and 2018 were retrospectively reviewed. The patients were followed for revision surgery and survival of the UKA (defined as revision to TKA). Clinical examination using the Knee Society Score (KSS), Oxford Knee Score (OKS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), as well as radiological examination was performed. Radiographs were studied and the influence of the demographic factors and the radiographic measurements on the survival and the clinical outcome was analysed. After a follow-up of 4.3 ± 2.6years (2.1-9.9) 27 UKAs were available. The survival rate was 93.0%. Two UKAs were revised to TKA (excessive valgus alignment and tibial loosening with femoropatellar degeneration). Two further patients had revision surgery (hematoma and lateral meniscus tear). Follow-up clinical and radiological examination was performed in 21 cases: KSS 82.9 ± 10.1 (54.0-100.0), KSS (function) 93.3 ± 9.7 (70.0-100.0); OKS 42.7 ± 6.0 (25.0-48.0); WOMAC 7.9 ± 15.6 (0.0-67.1). No significant influence of demographic factors or radiological measurements on the clinical outcome was present. Prior HTO is not a contraindication for medial UKA, because good-to-excellent results can be achieved in selected patients with medial osteoarthritis and previous HTO, treated with medial UKA, in a midterm follow-up. Excessive mechanical valgus axis should be avoided; therefore, patient selection and accurate evaluation of medial laxity, preoperative mechanical axis, joint line convergence and proximal tibial geometry are important. III.

Does the overhang of tibial component in fixed bearing medial unicondylar knee arthroplasty affect 1-year results?

Aim: Unicondylar knee arthroplasty (UKA) is an effective treatment for single-compartment knee arthrosis. The compatibility of the size of the components with the bone is one of the factors determining patient satisfaction. With this study we aimed to investigate the effect of size concordance of the tibial component and bone in fixed bearing UKA on functional scores and pain.Methods: Demographic data, preoperative and postoperative 1-year visual analog pain scale (VAS) and Oxford Knee Scores (OKS) were collected from 43 patients operated by a single surgeon with a fixed bearing UKA implant (Zimmer UKA, Warsaw USA) for this prospective cohort study. Patients were then grouped according to radiological compliance of the tibial component to the bone as perfect match or overhang, and the groups were compared in terms of pain and functional scores. Results: Among 43 patients included in the study, 9 (20.9%) were males and 34 (79.1%) were females. The mean age of the patients was 62.1 (8.1) years. The median VAS and OKS scores of the patients before surgery were 6 (3-8) and 26 (21-30), respectively. Postoperatively, VAS score decreased to 1 (0-2), while OKS increased to 44 (37-48) (P&lt;0.001 for both). There were only 3 patients with underhang. Twenty-two (52.1%) patients had perfect match and 18 (41.9%) had an overhang from the bone surface. There was no patient with an overhang greater than 3mm. The VAS and OKS scores at post-operative 1-year of 18 patients with overhang and 22 patients without bone overhang were similar (P=0.674 and P=0.873, respectively).Conclusion: The overhang of the tibial component in fixed bearing unicondylar knee arthroplasty is common, however, this does not affect functional results in 1-year follow-up. Nevertheless, the sizing of the component should be checked by adequate means.

Unicondylar vs. total knee arthroplasty in medial osteoarthritis: a retrospective analysis of registry data and functional outcome.

It was the aim of our study to compare the functional outcome (WOMAC score, range of motion) achieved with unicondylar knee arthroplasty (UKA) and total knee arthroplasty (TKA). It was hypothesized that UKA and TKA would differ with regard to the WOMAC function scale (hypothesis 1) and the WOMAC total scale (hypothesis 2). It was assumed that the groups would differ with respect to changes in range of motion (ROM) over time (hypothesis 3). A retrospective comparative study was conducted to analyze data available from the federal state's Arthroplasty Registry (WOMAC score) and from clinical routine (ROM). Patients who underwent UKA or TKA between 2008 and 2015 were considered. ANOVAs for repeated measurements were applied, adjusted for age, to test hypotheses 1-3. The UKA group was comprised of 112 patients (age 65, BMI 29). The TKA group included 330 cases (age 69, BMI 29). Regarding hypothesis 1, the amount of improvement in WOMAC function was not influenced by the surgical group (no significant group*time interactions, p = 0.608). Similarly, for hypothesis 2, the amount of improvement in the WOMAC total score was not influenced by the surgical group (no significant group*time interactions, p = 0.392). Regarding hypothesis 3, we found no significant group*time interaction for the ROM data (p = 0.731). On the basis of our findings, it is concluded that whether knee osteoarthritis is treated with either medial UKA or TKA has no influence on the WOMAC total score or any of the WOMAC subscales. It has no effect on early or late ROM gain.

Current Trends in Clinical Practice for the Minimal Invasive Medial Unicondylar Knee Arthroplasty

Unicondylar Knee Arthroplasty (UKA) is an early alternative surgical procedure for the unicondylar osteoarthritis or damaged knee joint with artificial prosthesis for the release of disabling painful condition and restoring the normal knee functions. Minimally UKA is one of the recent and the majority successful procedures in modern orthopedics for the osteoarthritis which is spreading throughout the worldwide. Recently, many orthopedic surgeons are expanding their abilities in this field. However, it needs good knowledge and well experience for the successful clinical outcomes. The minimal invasive approach is more efficient for short hospital stay and faster postoperative recovery with low morbidity of the patients after UKA. The aim of this article is to emphasize the steps in UKA based on modern facts: function of knee joint, diagnosis, less invasive approach for medial condylar replacement, radiographic evaluation, and earlier recovery, selecting the patient and implant survivorship with review of surgery.

Continuous Adductor Canal Block used for postoperative pain relief after medial Unicondylar Knee Arthroplasty: a randomized, double-blind, placebo-controlled trial

BackgroundPeripheral nerve block and local infiltration analgesia (LIA) provide good analgesia after knee replacement. This study evaluated the additional analgesic efficacy of continuous adductor canal block (ACB) added to single-dose LIA after medial unicondylar knee arthroplasty (UKA). We hypothesized ACB would lower pain scores and facilitate postoperative ambulation.MethodsForty-six patients were enrolled into this double-blind, randomized, placebo-controlled trial. UKA was performed and all patients received single-dose LIA intraoperatively. Patients were randomized into two groups: Group RP receiving 0.2% ropivacaine or Group Con receiving normal saline. A flow at 6 mL/h was administered for 48 h through a catheter in the adductor canal. Primary outcome was movement pain score at 24 h using the numeric rating scale (NRS-11). Secondary outcomes included serial postoperative pain scores, rate of patients with NRS>3 at rest and movement within 24 and 48 h postoperatively, time to breakthrough pain, quadriceps motor strength, ambulated distance, catheter related infection and patient satisfaction.ResultsForty-two patients were analyzed. Pain scores with movement at 24 h postoperatively were significantly lower in Group RP than that in Group Con (3 vs. 5 NRS, P<0.001). Compared with Group Con, breakthrough pain occurred later in Group RP (18.5 vs 10.0 h, P = 0.002), serial pain scores at rest and with movement and rate of patients with NRS>3 with movement after surgery were significantly lower. Quadriceps motor strength was equivalent, however, ambulated distance on postoperative day 1 and 2 in Group Con was significant less (19.7 vs 37.3 m, P = 0.046; 33.4 vs 59.5 m, P = 0.002).ConclusionsContinuous adductor canal block added to single-dose LIA offered better analgesia and facilitated ambulation without motor weakness after medial UKA.Trial registrationClinical Trial Registration: ChiCTR-IOR-16008720; Registered 25 June 2016.