Whether the Partial Knee Arthroplasty is Worthwhile: Estimation of Orthopedic Surgeons from Large Arthroplasty Center

Background. Despite several proven advantages of the partial knee arthroplasty (PKA) over the total knee arthroplasty (TKA) in selected patients with osteoarthritis (OA) or osteonecrosis (ON), there is still no consensus regarding the feasibility of this procedure among practitioners all over the world. The purpose of the study to perform comprehensive analysis of the preferences of knee surgeons, regarding the feasibility of partial arthroplasty for modern orthopedic practice. Materials and Methods. A special questionnaire was developed that includes 4 sections devoted to personal surgical experience, understanding of indications/contraindications to PKA, attitude to potential advantages and disadvantages, as well as the reasons limiting the use of this technology in the daily practice. Using the institutional register of knee arthroplasty there were identified 37 orthopedic surgeons who perform more than 20 knee replacements annually. All of them agreed to participate in the survey. All surgeons were men with average age 43.1 years (min 31, max 64, moda 41, SD = 8.9). The total number of knee arthroplasties performed by all respondents during the last year was 3094 . Results. The surgeons divided into two groups: 17 (46%) performed PKA but majority did not (20 (54%)). The average age of the surgeons of the 1st group was less than in the 2nd one (41.8 and 44.1 years (p0.05)). The surgeons from group 1 significantly often respond in a positive way regarding the advantages of PKA compared to TKA (p0.01). The significant differences among surgical estimations regarding PKA noted in the questions related to the speed of rehabilitation (p0.05), the achievement of the forgotten knee phenomenon (p0.01) and the frequency of postoperative complications (p0.01). There was a trend that the more often a surgeon utilized PKA, the more he believes in its advantages over TKA. Only 1 respondent consider PKA fully unreliable, and 6 surgeons reported that they are unfamiliar with surgical technique. Interestingly that all surgeons, except one in the second group, met right candidates for PKA in their daily practice. There was no correlation between the studied parameters and surgeons age, experience, as well as annual caseload. Conclusions. Every second surgeon (54%) who regularly performs knee replacement ignores PKA as a method of choice for selected patients with OA or ON despite evidence-based literature data even in a large orthopedic center. For PKA users among the most significant advantages of this approach there are the faster rehabilitation (p0.05), ability to reach the forgotten knee (p0.01), as well as lower incidence and severity of postoperative complications (p0.01).

The compartmental approach to revision of partial knee arthroplasty results in nearer-normal gait and improved patient reported outcomes compared to total knee arthroplasty

Purpose This study investigated the gait and patient reported outcome measures of subjects converted from a partial knee arthroplasty to combined partial knee arthroplasty, using a compartmental approach. Healthy subjects and primary total knee arthroplasty patients were used as control groups. Methods Twenty-three patients converted from partial to combined partial knee arthroplasty were measured on the instrumented treadmill at top walking speeds, using standard gait metrics. Data were compared to healthy controls (n = 22) and primary posterior cruciate-retaining total knee arthroplasty subjects (n = 23) where surgery were performed for one or two-compartment osteoarthritis. Groups were matched for age, sex and body mass index. At the time of gait analysis, combined partial knee arthroplasty subjects were median 17 months post-revision surgery (range 4–81 months) while the total knee arthroplasty group was median 16 months post-surgery (range 6–150 months). Oxford Knee Scores and EuroQol-5D 5L scores were recorded at the time of treadmill assessment, and results analysed by question and domain. Results Subjects revised from partial to combined partial knee arthroplasty walked 16% faster than total knee arthroplasty (mean top walking speed 6.4 ± 0.8 km/h, vs. 5.5 ± 0.7 km/h p = 0.003), demonstrating nearer-normal weight-acceptance rate (p < 0.001), maximum weight-acceptance force (p < 0.006), mid-stance force (p < 0.03), contact time (p < 0.02), double support time (p < 0.009), step length (p = 0.003) and stride length (p = 0.051) compared to primary total knee arthroplasty. Combined partial knee arthroplasty subjects had a median Oxford Knee Score of 43 (interquartile range 39–47) vs. 38 (interquartile range 32–41, p < 0.02) and reported a median EQ-5D 0.94 (interquartile range 0.87–1.0) vs. 0.84 (interquartile range 0.80–0.89, p = 0.006). Conclusion This study finds that a compartmental approach to native compartment degeneration following partial knee arthroplasty results in nearer-normal gait and improved patient satisfaction compared to total knee arthroplasty. Level of evidence III.

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

Aims Joint 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. Methods Classification 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. Results Four 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). Conclusion The 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.

Contemporary knee arthroplasty: one fits all or time for diversity?

Introduction Total knee arthroplasty (TKA) has historically been the preferred solution for any type of knee osteoarthritis, independently of the number of compartments involved. In these days of patient-specific medicine, mono-compartmental disease could also be approached with a more individualized treatment, such as partial knee arthroplasty (PKA). Off-the-shelf (OTS) implants are often the compromise of averages and means of a limited series of anatomical parameters retrieved from patients and the pressure of cost control by limited inventory. Personalized medicine requires respect and interest for the individual shape and alignment of each patient. Materials and methods A Pubmed and Google Scholar search were performed with the following terms: “patient-specific knee” and “arthroplasty” and “custom implant” and “total knee replacement” and “partial knee replacement” and “patellofemoral knee replacement” and “bicompartmental knee replacement”. The full text of 90 articles was used to write this narrative review. Results Unicondylar, patellofemoral and bicompartmental knee arthroplasty are successful treatment options, which can be considered over TKA for their bone and ligament sparing character and the superior functional outcome that can be obtained with resurfacing procedures. For TKA, where compromises dominate our choices, especially in patients with individual variations of their personal anatomy outside of the standard, a customized implant could be a preferable solution. Conclusion TKA might not be the only solution for every patient with knee osteoarthritis, if personalized medicine wants to be offered. Patient-specific mono-compartmental resurfacing solutions, such as partial knee arthroplasty, can be part of the treatment options proposed by the expert surgeon. Customized implants and personalized alignment options have the potential to further improve clinical outcome by identifying the individual morphotype and respecting the diversity of the surgical population.

Comparison of Iatrogenic Soft Tissue Trauma in Robotic-Assisted versus Manual Partial Knee Arthroplasty

Partial knee arthroplasty (PKA) is performed to treat end-stage osteoarthritis in a single compartment. There are minimal data characterizing soft-tissue injuries for PKA with robotic and manual techniques. This cadaver study compared the extent of soft-tissue trauma sustained through robotic-arm assisted PKA (RPKA) and manual PKA (MPKA). Five surgeons prepared 24 cadaveric knees for medial PKA, including six MPKA controls and 18 RPKA assigned into three different workflows: RPKA-LB (six knees) – RPKA with legacy burr; RPKA-NB (six knees) – RPKA with new burr design; and RPKA-NBS (six knees) – RPKA with new burr design and oscillating saw. Two surgeons estimated trauma to the patellar tendon, quadriceps tendon, anterior cruciate ligament (ACL), medial collateral ligament (MCL), medial capsule, posterior capsule, and posterior cruciate ligament (PCLs) using a five-grade system: Grade 1 – complete soft tissue preservation; Grade 2 – ≤25%; Grade 3 – 26 to 50%; Grade 4 – 51 to 75%; and Grade 5 – ≥76% trauma. A total trauma grade was assigned by summing the grades. Kruskal-Wallis statistical tests were used to assess outcomes. When compared to the MPKA group, all RPKA subgroups had lower total trauma grading (p<0.01), lower posterior capsular damage (p<0.01), and less severe ACL damage (p<0.01). The analysis demonstrated no significant difference between the three RPKA workflows. As this study was performed using cadaveric specimens, additional investigations are necessary to determine associations between robotic or manual-assisted technique, observed soft tissue damage, and postoperative clinical outcomes following PKA.

Validation of joint space narrowing on plain radiographs and its relevance to partial knee arthroplasty

Aims To explore the clinical relevance of joint space width (JSW) narrowing on standardized-flexion (SF) radiographs in the assessment of cartilage degeneration in specific subregions seen on MRI sequences in knee osteoarthritis (OA) with neutral, valgus, and varus alignments, and potential planning of partial knee arthroplasty. Methods We retrospectively reviewed 639 subjects, aged 45 to 79 years, in the Osteoarthritis Initiative (OAI) study, who had symptomatic knees with Kellgren and Lawrence grade 2 to 4. Knees were categorized as neutral, valgus, and varus knees by measuring hip-knee-angles on hip-knee-ankle radiographs. Femorotibial JSW was measured on posteroanterior SF radiographs using a special software. The femorotibial compartment was divided into 16 subregions, and MR-tomographic measurements of cartilage volume, thickness, and subchondral bone area were documented. Linear regression with adjustment for age, sex, body mass index, and Kellgren and Lawrence grade was used. Results We studied 345 neutral, 87 valgus, and 207 varus knees. Radiological JSW narrowing was significantly (p < 0.01) associated with cartilage volume and thickness in medial femorotibial compartment in neutral ( r = 0.78, odds ratio (OR) 2.33) and varus knees ( r = 0.86, OR 1.92), and in lateral tibial subregions in valgus knees ( r = 0.87, OR 3.71). A significant negative correlation was found between JSW narrowing and area of subchondral bone in external lateral tibial subregion in valgus knees ( r = −0.65, p < 0.01) and in external medial tibial subregion in varus knees ( r = −0.77, p < 0.01). No statistically significant correlation was found in anterior and posterior subregions. Conclusion SF radiographs can be potentially used for initial detection of cartilage degeneration as assessed by MRI in medial and lateral but not in anterior or posterior subregions. Cite this article: Bone Joint Res 2021;10(3):173–187.