Total Knee Prosthesis Research Articles

Does Early-Period Patient Dissatisfaction Turn Into Satisfaction Over Time After Total Knee Replacement?

BackgroundTotal knee arthroplasty (TKA) is frequently used in the treatment of end-stage gonarthrosis, and the patient satisfaction rate varies. This study aimed to reveal the change in mid-term patient satisfaction results and functional scores of patients with low early postoperative satisfaction scores.Material/MethodsWe included 163 patients who underwent total knee prosthesis between September 2017 and February 2018. Among these patients, early (6 months) and mid-term (24 months) satisfaction and functional results of 34 patients with low satisfaction scores (Likert evaluations 1, 2, and 3) were evaluated. We assessed early-term functional results and satisfaction rates, mid-term analysis of patients who were not satisfied in the early period, and the relationship between functional scores and satisfaction.ResultsThe Likert score was 4 or 5 in 124 (80%) of 158 patients, and early dissatisfaction was detected in 34 patients (20%). In the early-period dissatisfied group, satisfaction scores 6 months after surgery were 1.9±1.1 (1–3) and 4.2±1 (3–5) 24 months after surgery. A statistically significant difference was observed between the dissatisfied group’s early and mid-term KSS and KS values. A correlation was observed between satisfaction scores and KS and KSS scores (P<0.05).ConclusionsPatients who do not have mechanical problems with total knee arthroplasty but are not satisfied with the surgery in the early period can be satisfied over time after regular follow-up, appropriate communication and information, and effective rehabilitation.

Designing and in vitro testing of a novel patient-specific total knee prosthesis using the probabilistic approach.

In order to prevent failure as well as ensure comfort, patient-specific modelling for prostheses has been gaining interest. However, deterministic analyses have been widely used in the design process without considering any variation/uncertainties related to the design parameters of such prostheses. Therefore, this study aims to compare the performance of patient-specific anatomic Total Knee Arthroplasty (TKA) with off-the-shelf TKA. In the patient-specific model, the femoral condyle curves were considered in the femoral component's inner and outer surface design. The tibial component was designed to completely cover the tibia cutting surface. In vitro experiments were conducted to compare these two models in terms of loosening of the components. A probabilistic approach based on the finite element method was also used to compute the probability of failure of both models. According to the deterministic analysis results, 103.10 and 21.67MPa von Mises stress values were obtained for the femoral component and cement in the anatomical model, while these values were 175.86 and 25.76MPa, respectively, for the conventional model. In order to predict loosening damage due to local osteolysis or stress shield, it was determined that the deformation values in the examined cement structures were 15% lower in the anatomical model. According to probabilistic analysis results, it was observed that the probability of encountering an extreme value for the anatomical model is far less than that of the conventional model. This indicates that the anatomical model is safer than the conventional model, considering the failure scenarios in this study.

Effect of bisphosphonates on selected markers of bone turnover in patients after total knee arthroplasty.

Osteoporosis is a problem for many patients after total knee arthroplasty (TKA). The aseptic loosening of the prosthesis is also a significant problem. Therefore, in these patients, bisphosphonates (BPs) are used that, by influencing the level of bone turnover markers, reduce the risk of osteoporotic fractures and aseptic revisions in TKA. The purpose of the study was to assess whether the Pamifos® present in bone cement has any effect on the level of selected bone turnover markers and cytokines in patients after total knee arthroplasty. The study group consisted of 30 women with degenerative changes of the knee joint, whose total knee prosthesis was stabilized with cement enriched with Pamifos®. The control group consisted of 30 women treated for degenerative changes of the knee joint without the use of bisphosphonate-enriched cement for prosthetic stabilization. In the study group, we found a decrease in tumour necrosis factor (TNF-α) levels 12weeks after surgery, whereas the control group experienced an almost twofold increase in TNF-α level. The concentration of OPG, a natural RANKL antagonist, was highest in patients of the study group sixweeks after surgery and was four times higher compared to the control group. Statistically significant differences were found in the RANKL level (P < 0.05). In the control group, there was a continuous increase in RANKL concentration from the first to the 12th week after surgery. The highest level of RANKL in patients of the study group was found sixweeks after the surgery, and 12weeks after knee arthroplasty, it was significantly lower. It was found that the concentration of osteocalcin (OC) in the study group was the lowest threeweeks after the surgery, then it increased and remained at a similar level after 12weeks. The concentrations of selected cytokines (IL-1β, IL-2, IL-6, IL-10, IL-17AF) also showed statistically significant differences. The BP-stimulated increase in the level of OPG and the decrease in the level of RANKL, as well as the impact on the level of the analyzed interleukins in the bone microenvironment, may be an important element of the mechanisms limiting bone resorption. Therefore, the use of BP-enriched cement implants appears to be justified.

TOTAL DİZ PROTEZİ UYGULANAN HASTALARDA OBESİTE VARLIĞININ İNTRAOPERATİF VE ERKEN POSTOPERATİF (HASTANEDE) KOMPLİKASONLAR ÜZERİNE OLAN ETKİSİ

OBJECTIVE: Due to the increase in both obesity and total knee prosthesis arthroplasty (TKA), the number of TKA applications in obese patients has increased in recent years. However, it is debatable whether obesity is a risk factor for the complications observed in TKA. The aim of this study is to investigate the effect of obesity on intraoperative and early postoperative (in hospital) complications in patients with TKA.MATERIAL AND METHODS: Patients were divided into 2 groups according to body mass index; Group 1: obese patients (Body mass index: BMI&amp;gt; 30 kg/m2), Group 2: non-obese patients (BMI≤30 kg/m2). Patient files were examined from 4 different perspectives (Demographic data, Preoperative features, Intraoperative features, Postoperative features). T-test was used in the analysis of parametric data, and Chi-square test was used in the analysis of non-parametric data. A value of P&amp;lt;0.05 was considered significant.RESULTS: There was no statistically significant difference between the obese and non-obese patients in respect of the length of hospital stay, the operation time, the tourniquet time, the number of blood transfusions, presence of ischemic heart disease, diabetes, ASA scores, local skin complications, and systemic complications such as deep vein thrombosis, sepsis, pulmonary embolism and mortality. However, a statistically significant difference was found in presence of hypertension, hypothyroidism, and obstructive sleep apnea in the obese group.CONCLUSIONS: There is no difference in terms of local and systemic complications in obese and non-obese patients undergoing TKA.

Definition of post-traumatic outcomes of operated and unoperated knee fractures

Knee fractures include fractures of the tibial plateau, distal femur, and patella. The most frequent complication of these fractures is post-traumatic osteoarthritis, defined as secondary osteoarthritis that develops as a result of direct damage or trauma to a specific joint. According to the available data, 23-36% of people who have suffered an intra-articular knee fracture will develop secondary osteoarthritis. The average age at which it develops is 9-14 years before the average age at which primary osteoarthritis develops in the general population. Analysis of the literature shows that treatment of knee fractures must be chosen according to various parameters such as age, state of health, and degree of activity of the patient as well as the extent of damage to the joint surface. In young patients, there is an indication for open reduction and internal fixation treatments, corrective osteotomies, or osteoarticular reconstruction, while in elderly patients with low functional demands the use of total knee prostheses should be considered. It must be taken into account, however, that poor functional results of prostheses are reported when used in cases of high complexity of joint deformity, especially if they involve both the femur and tibia and in case of compromised soft tissues that require reconstruction.

Long Term Results of a Rotating Hinge Total Knee Prosthesis With Carbon-Fiber Reinforced Poly-Ether-Ether-Ketone (CFR-PEEK) as Bearing Material.

Background: The use of rotating hinge (RH) prostheses for severe primary as well as revision arthroplasty is widely established. Due to the steadily increasing number of RH prostheses, we aimed to assess the complication frequencies, complication types and clinical outcomes of a modern RH hinge prosthesis using a new bearing material with a minimum follow-up of 7 years. Methods: Fifty-six consecutive patients who received the EnduRo® RH prosthesis using carbon-fiber reinforced poly-ether-ether-ketone (CFR-PEEK) as bearing material were included in this prospective study: 21 patients (37.5%) received the prosthesis as a primary total knee arthroplasty (TKA) and 35 patients (62.5%) underwent revision total knee arthroplasties (rTKA). Clinical and radiographic examinations were performed preoperatively, postoperatively after three and 12 months and annually thereafter. Clinical scores were documented for each patient. Competing risk analysis was assessed with respect to indication and failure mode. Results: Knee Society Score (KSS), Western Ontario and McMaster Osteoarthritis Index (WOMAC), Oxford Knee Score (OKS) and range of motion (ROM) improved significantly compared to preoperative values (p < 0.0001). The overall cumulative incidence for revision surgery was 23.6% at 7 years and the cumulative incidence for complications associated with failure of the prothesis was 5.6% at 7 years, respectively. Complications occurred more frequently in the revision group (p = 0.002). Conclusion: The evaluated RH prosthesis provided reliable and durable results for a minimum follow-up of 7 years. Prosthesis survival was successful considering the complexity of the cases. The use of this RH system in primary patients showed high survival rates and long-term functional outcomes and clinical outcomes proved to be satisfying in both revision and primary cases. No adverse events were associated with the new bearing material CFR-PEEK.

199 The Influence of Pre-Operative Factors on Patient Length of Stay After Total Knee Replacement

Abstract Aim This study aims to assess the impact of pre-operative factors on the length of stay in patients following total knee replacement at our institution. Method A total of 478 patients following total knee replacement between January 2017-Decemeber 2019 are included in this study. All patients underwent total knee replacement with a medial rotating total knee prosthesis (MRK; Matt Ortho UK). Data for each patient was collated retrospectively and included the following: Patient demographics (age and sex), American Society of Anaesthesiology (ASA) score, pre-operative range of movement (ROM), Body Mass Index (BMI), and pre-operative haemoglobin. Each factor was then compared with the length of stay for all 478 patients. Statistical significance was sort for each pre-operative factor for both men and women. Results Our cohort of patients includes 291 females and 187 males. Patients ranged from 39 to 90 years with an average age of 68. The average BMI of the cohort was 31.3(18.6–56.56) and the average ASA grade was 2. Preoperative hemoglobin and the Age of the patient at the time of surgery were the only two factors which had a statistically significant impact on the length of hospital stay (p&amp;lt;0.05). BMI, Pre- operative range of motion and ASA scores had no statistically significant effect on the length of hospital stay in our cohort. Conclusions Low pre-operative hemoglobin and increasing age have significant effects on length of stay after total knee replacement. The BMI, pre-operative range of movement and ASA scores do not influence the length of hospital stay.

The effect of patient and prosthesis factors on revision rates after total knee replacement using a multi-registry meta-analytic approach.

Background and purposeCharacteristics of patients receiving total knee arthroplasty (TKA) and prostheses used vary between regions and change with time. How these practice variations influence revision remains unclear. We combined registry data for better understanding of the impact of variation, which could potentially improve revision rates.Patients and methodsWe used data from 2003 to 2019 for primary TKA from arthroplasty registries of Sweden (SKAR), Australia (AOANJRR), and Kaiser Permanente (KPJRR). We included 1,072,924 TKA procedures for osteoarthritis. Factors studied included age, sex, ASA class, BMI category, prosthesis constraint, fixation, bearing mobility, patellar resurfacing, and polyethylene type. Cumulative percentage revision (CPR) was calculated using Kaplan–Meier estimates, and unadjusted Cox hazard ratios were used for comparisons. Random-effects generic inverse-variance meta-analytic methods were used to determine summary effects.ResultsWe found similarities in age and sex, but between-registry differences occurred in the other 7 factors studied. Patients from Sweden had lower BMI and ASA scores compared with other registries. Use of cement fixation was similar in the SKAR and KPJRR, but there were marked differences in patellar resurfacing and posterior stabilized component use. Meta-analysis results regarding survivorship favored patients aged ≥ 65 years and minimally stabilized components. There were inconsistent results with time for sex, fixation, and bearing mobility, and no differences for the patellar resurfacing or polyethylene type comparisons.InterpretationMarked practice variation was found. Use of minimally stabilized and possibly also cemented and fixed bearing prostheses is supported.

Long-Term Effects of Metal-on-Metal Cobalt-Chromium-Containing Prostheses Used in Total Knee Arthroplasty on Hearing and Tinnitus.

ObjectivesWe aimed to determine the long-term effects of metal-on-metal (MoM) cobalt (Co)-chromium-containing prostheses used in total knee arthroplasty (TKA) on hearing and tinnitus.MethodsA total of 88 patients with the normal otoscopic examination and normal blood B12 levels, consisting of 44 patients who had been using MoM Co-chromium-containing total knee prosthesis for more than 5 years, and 44 non-implanted patients with similar demographic characteristics, were randomly selected and included in the study. Patients with previous ear surgery, chronic middle ear disease, or conductive hearing loss were excluded from the study. All participants were evaluated with pure-tone audiometry (PTA), distortion product otoacoustic emission (DPOAE), tinnitus handicap inventory (THI), and tinnitus reaction questionnaire (TRQ).ResultsThe mean age of the 88 patients was 67.22±10.4 years. The mean age of 44 patients who underwent TKA at least 5 years ago was 72.89±7.18 years, 75% of these patients had bilateral prostheses, and the mean prosthesis duration was 11.00±5.08 years (range 5–25). The two groups were compared statistically using PTA, DPOAE, THI, and TRQ scores. When the patient groups with and without prostheses were compared in terms of hearing and tinnitus, we did not find a significant difference between the two groups (p>0.05).ConclusionIn our study, we observed that the long-term use of MoM Co-chromium total knee prostheses did not have an ototoxic effect, contrary to what was believed. We also found that prolonged prosthesis duration or undergoing bilateral surgery did not worsen hearing and tinnitus.

Prevencija tromboembolije u ortopedskoj hirurgiji - primena rivaroksabana kod artroplastičnih procedura

Arthroplastic surgeries, the installation of total hip and knee prostheses are expanding, as a consequence of the increasing elderly population and the consequent increase in degenerative joint diseases. Prolonged life expectancy has also increased the number of patients with hip fractures requiring surgical treatment. In both groups of patients there is a marked risk of developing deep vein thrombosis (DVT) and pulmonary embolism (PE), which as serious complications, both during and after hospitalization, can be fatal. Therefore, prevention of DVT is necessary in all these patients. This article presents widely used methods of mechanical prophylaxis in orthopedic practice, along with essential methods of pharmacological prophylaxis, which include aspirin, vitamin K antagonists, unfractionated heparin (UFH), and also more modern low molecular weight heparins (LMWH), as well as new preparations - direct oral anticoagulants (DOAC), with special reference to rivaroxaban. It is recommended that in patients with hip fractures and patients after arthroplastic procedures, DVT prophylaxis is applied for 42 days before and after the operation.

An Imaging Measurement Study of Normal Knee Parameters in Southeast China.

Imaging measurement of distal femur and proximal tibia has been the hot point in the research of total knee arthroplasty and prosthesis development, which is an important treatment for patients with advanced knee joint disease. This study retrospectively investigated the digital imaging measurement of normal knee parameters in southeast China and evaluated their clinical value. From February 2010 to May 2014, and in accordance with the inclusion criteria, a total of 677 knees (334 female knees and 343 male knees) were categorized into 3 age groups. Clinical and digital imaging data, including the distal Femoral Condyle Diameter (FCD), Tibial Plateau Diameter (TPD), the distance between the medial tibial plateau and fibular head (DPF), tibiofemoral valgus angle, distal femoral valgus angle, Proximal Tibia (PT) varus angle and the angle from femoral condyle to tibial perpendicular (FT), were measured by using AutoCAD 10.0 software. All measured variables were statistically analyzed by SPSS statistical software (version 18.0). Data are presented as the mean ± standard deviation. The normal female and male femoral condyle diameter was (7.69 ± 0.46) cm and (8.68 ± 0.55) cm, while the normal female and male tibial plateau diameter was (7.66 ± 0.46) cm and (8.60 ± 0.55) cm, respectively. The normal female and male DPF was (0.76 ± 0.36) cm and (0.79 ± 0.36) cm. For females and males, the tibiofemoral valgus angle and distal femoral valgus angle were (3.89 ± 2.20) ° and (3.29 ± 2.12) °, (9.03 ± 2.18) ° and (8.25 ± 2.20) °. As the two methods to measure tibial plateau varus angle, PT angle of normal female and male was (4.29 ± 1.86) ° and (4.84 ± 2.23) °, while the normal female and male FT angle was (5.34 ± 1.95) ° and (5.52 ± 2.07) °. Based on the data obtained, we found significant differences between the two genders in terms of the femoral condyle diameter and tibial plateau diameter in all age groups (P < 0.01). The DPF parameter showed an obvious difference between the young group and the middle-aged group (P < 0.05), and no significant difference was observed between the sides and genders (P > 0.05). The distal femoral valgus angle showed statistical differences between genders in the left side of the young group and middle-aged group (P < 0.05), while angle PT and FT showed no significant difference (P > 0.05). A large number of knee measurements was obtained, and a local knee database was developed in this study. Imaging measurement prior to total knee arthroplasty is clinically important for increasing the accuracy and long-term efficacy of total knee arthroplasty. These data can also provide useful information for knee surgery and sports medicine as well as prosthesis development.

Is conventional knee radiograph reliable enough to assess the anatomical knee alignment and total knee prosthesis position in Indian population?

Is conventional knee radiograph reliable enough to assess the anatomical knee alignment and total knee prosthesis position in Indian population?

Simultaneous Bilateral Versus Staged Bilateral Total Knee Arthroplasty: Risks and Benefits

Randomized single-blinded controlled clinical trial. Patients and methods: This study was carried out on 40 patients diagnosed with end-stage osteoarthritis and underwent TKA. Patients are randomly allocated into 2 equal groups: Simultaneous bilateral total knee group and staged bilateral total knee group. All patients were operated on through a universal midline approach of the knee and posterior cruciate stabilized cemented bi compartmental total knee prosthesis was inserted.

Proximal partial fibular resection instead of total knee prosthesis in a patient with metal allergy

Joint Diseases and Related Surgery (JDRS), the official journal of the Turkish Joint Diseases Foundation, is an international, peer-reviewed, immediate open access journal. All published articles in JDRS has been free for everyone, without embargo, since 1990.

Distal femoral arthropometry in Nigerians and its correlation to total knee replacement implants.

Total Knee replacement (TKR) is performed to relieve pain and restore both the mechanical axis and joint line whenever indicated. Most of prostheses being used for TKR were manufactured using dimensions from Caucasians' measurements. This study documented the dimensions of distal femora of Nigerians and correlated the dimensions with different TKR prostheses. Fifty-six matured femora were measured. Dimensions of distal femora from other regions were retrieved from published articles. The dimensions of TKR prosthesis were extracted from product monographs. Analyses were done with Microsoft excel 2010 (Microsoft Corporation, Redmond, Washington, United States) and STATA version 13 (StataCorp, Texas. USA). Statistical significance was set at p ≤ 0.05. The average Mediolateral dimension was 79.3 ± 4.4 mm. The anterioposterior dimensions of the medial and lateral condyles were 63.7 ± 3.6 mm and 64.9 ± 3.3 mm respectively. There were no significant differences between the left and right distal femur. The average aspect ratio calculated was1.23 ± 0.05. There was a mismatch of aspect ratio of the distal femora and those of the prostheses. Equations that can be useful both clinically and in forensic medicine were generated. This study has provided measurements that can be considered when the designing of a suitable femoral component of total knee prosthesis for Nigerians. This study also provided equations that can be used to estimate the dimensions of the medial and the lateral condyles and femoral length from parts of distal femur in forensic medicine. Self-funded.

Does the anatomic design of total knee prosthesis allow for a better component fit than its nonanatomic predecessor? A matched cohort Study.

BackgroundTotal knee arthroplasty (TKA) is considered the most efficient treatment of end-stage osteoarthritis. There is an ongoing debate about proper implant designs and articulation types. One of the considered causes of unsatisfactory outcome and patients’ dissatisfaction is femoral or tibial component overhanging, which can lead to chronic knee pain and restricted motion. The aim of this study is to compare radiological outcomes of TKA using an anatomic PERSONA Posterior-Stabilized (PS) knee design with its nonanatomic predecessor, the NexGen LPS.MethodsA group of 39 patients who received the PERSONA PS system and 33 patients who received the NexGen LPS was included. PERSONA patients were matched to NexGen patients using a 0.1 propensity score threshold with priority given to exact matches. Anteroposterior, lateral, and long-leg radiographs were taken preoperatively and at 6 weeks postoperatively to perform radiological and statistical analysis.ResultsThe PERSONA subgroup had statistically higher posterior condylar offset. There is no statistically significant difference in posterior condylar offset ratio. There were less cases of femoral notching, femoral overhang, and placing tibial baseplate in the medial overhang in the PERSONA PS subgroup than in the NexGen subgroup (each statistically significant). Occurrence of tibial underhang was not statistically significant.ConclusionRadiological assessment in short-term follow-up showed excellent results for PERSONA knee design with better fit to native femur and tibia. In comparison to its predecessor, it also spares more bone tissue. As the aforementioned parameters are risk factors of lesser clinical outcomes, the PERSONA design gives high hopes for improvement of TKA satisfaction rate.

The Fate of Failed Debridement, Antibiotics, and Implant Retention in Infected Knee Arthroplasties: Nothing to Lose.

PurposeThe frequency of periprosthetic knee infections increases yearly because of the popularity of the total knee prostheses. Revision knee arthroplasty is an annoying problem for both the surgeons and the patients. Debridément, antibiotics, and implant retention (DAIR) is a popular alternative for the treatment of periprosthetic knee infections. Little is known about the fate of the failed DAIR patients. This study aims to investigate the effect of the failed DAIR on the clinical result after two-staged revision arthroplasty.MethodNinety-nine two-staged revision arthroplasties and 85 DAIR patients from two reference clinics were retrospectively analyzed. The minimum follow-up was 36 months. Patients were grouped according to the treatment as, two-staged revision without DAIR, two-staged revision after failed DAIR, and successful DAIR. Their Knee Society Scores (KSS), functional KSS (KSS-f) and Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores were analyzed and compared.ResultsDAIR has a 52.9% success rate for the treatment of infection. Elevated erythrocyte sedimentation rates and C-reactive peptide levels are not risk factors for failure, but the time passed since the index surgery is a risk factor for worse outcome scores. Failed DAIR is not a risk factor for reinfection after two-staged revision. Last KSS after failed DAIR, successful DAIR, and two-staged revision were 83.98±7.033, 91.89±4.386, and 91.38±4.735, respectively. Last KSS-f after failed DAIR, successful DAIR, and two-staged revision were 86.25±9.524, 94.56±8.106, and 94.85±5.996, respectively. Last WOMAC after failed DAIR, successful DAIR, and two-staged revision were 86.16±7.745, 94.750±4.964, and 93.319±5.961, respectively. ConclusionFailed DAIR is associated with lesser, but still good, or excellent clinical scores. DAIR is suggested as a promising treatment option for periprosthetic knee infections in well-selected patients.

Distal Femoral Pin Tracker Placement Prevents Pin Tract-induced Fracture in Robotic-Assisted Total Knee Arthroplasty.

The purpose of this study was to determine the effectiveness of the placement of pin trackers in the medial sagittal plane of the distal femur in robotic-assisted total knee arthroplasty (TKA) over a minimum follow-up period of 3 months. From August 2020 to October 2020, a consecutive series of 81 TKAs were performed in 59 patients using the Triathlon posterior-stabilized total knee prosthesis with a robotic-assisted system (Mako) at our hospital. Patient charts were reviewed for complications associated with the pin sites, including fracture, infection, thigh pain, and the need for reoperation. No patients had any minor or major complications associated with distal femoral pins. This technique, which used pin trackers in the medial sagittal plane of the distal femur, could be a useful option for surgeons performing robotic-assisted TKA. This is a Level IV study.

Letter to the Editor: "Early Survivorship of Newly Designed Highly Porous Metaphyseal Tibial Cones in Revision Total Knee Arthroplasty".

We read with interest the article by Chalmers et al. [1] and congratulate them on their work. They present the early (minimum 2 years) survival of 3D-printed titanium tibial metaphyseal cones used during revision total knee arthroplasty for a case series of 163 patients. However, there are limitations due to the heterogenicity of the cohort assessed, that may not be fully addressed by their regression model, and the problems of reporting survival of an augment when used in combination with total knee prosthesis.

The revision partial knee classification system: understanding the causative pathology and magnitude of further surgery following partial knee arthroplasty.

AimsJoint registries classify all further arthroplasty procedures to a knee with an existing partial arthroplasty as revision surgery, regardless of the actual procedure performed. Relatively minor procedures, including bearing exchanges, are classified in the same way as major operations requiring augments and stems. A new classification system is proposed to acknowledge and describe the detail of these procedures, which has implications for risk, recovery, and health economics.MethodsClassification categories were proposed by a surgical consensus group, then ranked by patients, according to perceived invasiveness and implications for recovery. In round one, 26 revision cases were classified by the consensus group. Results were tested for inter-rater reliability. In round two, four additional cases were added for clarity. Round three repeated the survey one month later, subject to inter- and intrarater reliability testing. In round four, five additional expert partial knee arthroplasty surgeons were asked to classify the 30 cases according to the proposed revision partial knee classification (RPKC) system.ResultsFour classes were proposed: PR1, where no bone-implant interfaces are affected; PR2, where surgery does not include conversion to total knee arthroplasty, for example, a second partial arthroplasty to a native compartment; PR3, when a standard primary total knee prosthesis is used; and PR4 when revision components are necessary. Round one resulted in 92% inter-rater agreement (Kendall’s W 0.97; p < 0.005), rising to 93% in round two (Kendall’s W 0.98; p < 0.001). Round three demonstrated 97% agreement (Kendall’s W 0.98; p < 0.001), with high intra-rater reliability (interclass correlation coefficient (ICC) 0.99; 95% confidence interval 0.98 to 0.99). Round four resulted in 80% agreement (Kendall’s W 0.92; p < 0.001).ConclusionThe RPKC system accounts for all procedures which may be appropriate following partial knee arthroplasty. It has been shown to be reliable, repeatable and pragmatic. The implications for patient care and health economics are discussed.Cite this article: Bone Jt Open 2021;2(8):638–645.