Introduction Patellofemoral (PF) degeneration plays an important role in knee function in the context of osteoarthritis. A specific evaluation of PF symptoms is needed to better understand the initial functional status of the knee before surgery. The aim of this study was to assess the validity of patient-related outcome measures (PROMs) for knee scores and PF scores in knee osteoarthritis. Hypothesis PF scores are more reliable for evaluating anterior knee pain than global knee scores in the context of PF degeneration in osteoarthritis. Material and methods We performed a prospective single-center study of continuous patients included between January 2017 and January 2018 in our surgical department for total knee arthroplasty (TKA) for primary knee osteoarthritis. The analysis used global knee PROMs (KOOS and new IKS) and PF-specific PROMs (HSS Patella score, Kujala score and Lille score). Floor and ceiling effects were determined for each score based on tibiofemoral and PF degeneration on radiographic views; it was considered significant when greater than 15%. Results We included 114 TKA procedures in 113 consecutive patients. According to the Iwano classification, no significant floor or ceiling effect was found for the PF preoperative scores (0–12%). The KOOS ADL and QOL scores were particularly affected by the ceiling and floor effects, whatever the patellofemoral degeneration (23–88%). In cases of severe PF degeneration (Iwano grade 3 and 4), no significant differences in the distribution of the functional scores were found. Discussion Modern knee outcome scores used to evaluate knee function do not monitor PF degeneration and related symptoms in the context of knee osteoarthritis according to the Iwano classification. PF scores do not have a floor and ceiling effects even if the severity of the PF degeneration is difficult to identify preoperatively. Physicians should be aware of this effect on the preoperative functional evaluation before TKA. Level of evidence III, comparative prospective study.

Are modern knee outcomes scores appropriate for evaluating patellofemoral degeneration in osteoarthritis? Evaluation of the ceiling and floor effects in knee outcomes scores.

Whether resurface the patella or not in total knee arthroplasty (TKA) was controversial. In 2013, we conducted a meta-analysis of randomized controlled trials (RTCs). After that, plenty of studies have been carried out, but there still existed a great deal of controversy. In order to update our previous study, we conducted this update meta-analysis to evaluate the efficacy of patellar resurfacing in TKA. Databases were searched for RCTs comparing the outcomes of patellar resurfacing and nonresurfacing in TKA. Outcomes of knee relevant indicators were analysed. To see the short- and long-term effects, we calculated the data in total and divided the patients who were followed up for ≤ 3 years and ≥ 5 years into two subgroups as well. Thirty-two trials assessing 6887 knees were eligible. There was a significant difference in terms of reoperation (in total and ≥ 5 years), Knee Society Score (KSS), function score (in total and ≥ 5 years) and noise. While no significant difference was found in the following items: reoperation (≤ 3 years), anterior knee pain (AKP), function score (≤ 3 years), range of motion (ROM), Oxford score, the Knee Injury and Osteoarthritis Outcome Score (KOOS), visual analogue score (VAS), Feller score, patellar tilt and the patients’ satisfaction. We found that patellar resurfacing could reduce the occurrence of reoperation and noise after surgery, as well as increase the KSS and function score, while it might not influence the outcomes such as AKP, ROM, Oxford score, KOOS, VAS, Feller score, patellar tilt and the patients’ satisfaction. The results are different from our previous finding in the meta-analysis. In conclusion, we prefer patellar resurfacing in TKA.

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Patellar resurfacing versus nonresurfacing in total knee arthroplasty: an updated meta-analysis of randomized controlled trials

The purpose of this study was to report outcomes of a recent anatomic trochlear-cutting patellofemoral arthroplasty (PFA) system at > 3 years. The hypothesis was that its functional scores and revision rates would be at least equivalent to those reported for other ‘trochlear-cutting’ implants in the literature. Twenty-eight consecutive patients that had received PFA using the same anatomic trochlear-cutting implant (KneeTech PFJ, Corin-Tornier, Montbonnot, France) with a dome-shaped patellar button and had systematic lateral facetectomy without lateral release were enrolled. Radiographic parameters collected pre-operatively included: trochlear dysplasia type and patellar height, TT–TG, patellar tilt and shape. Clinical scores collected pre-operatively and at > 3 years included: Oxford Knee Score (OKS) and Knee Society Score (KSS). The initial cohort comprised 23 women (82%) and five men (18%), aged 63.3 ± 14.7 years, of which 23 had trochlear dysplasia (82%). One patient (4%) could not be reached, and three (11%) were revised to TKA due to arthritic progression, aged 77, 80 and 83 years at index operation, only one of which had trochlear dysplasia (type A). At final follow-up, none of the remaining 24 patients had complications; their OKS was 35.0 ± 10.3 and KSS symptoms and function were 19.8 ± 5.0 and 71.7 ± 13.6. The anatomic trochlear-cutting PFA granted satisfactory scores and prevented mechanical complications, but the high incidence of early revisions, all due to spread of arthritis hence to improper patient selection. PFA should be restricted to patients with trochlear dysplasia, in whom arthritis was triggered by patellar instability and maltracking rather than degenerative or age-related diseases. Retrospective case series, Level IV.

Early outcomes of an anatomic trochlear-cutting patellofemoral arthroplasty: patient selection is key.

Isolated patellofemoral osteoarthritis (PF-OA) is a common subtype of knee osteoarthritis, leading to a huge economic burden on health care systems. Although previous studies have shown that patellofemoral arthroplasty (PFA) and total knee arthroplasty (TKA) have good clinical effects, it remains largely unclear which treatment is more effective for patients with isolated PF-OA. We aimed to compare postoperative function, complications, revision rates, level of physical activity, and satisfaction rate between the two surgical techniques. Our study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Search of literature was conducted in MEDLINE, EMBASE, Cochrane Library, and Web of Science until November 2020. The included studies were those that provided direct comparison of postoperative outcomes between PFA and TKA. Data were extracted from eligible studies and combined to calculate the pooled odds ratio (OR) and 95% confidence interval (CI). Sensitivity analysis and subgroup analysis were conducted to evaluate heterogeneity between the two groups. A total of 7 eligible studies (3 recent randomized controlled trials and 4 nonrandomized controlled trials) were included in this meta-analysis. The pooled results showed that both the PFA group and the TKA group had improved postoperative indicators, suggesting that the two operation modes could improve the knee function and quality of life of patients. Throughout the first 2 years postoperatively, higher activity level, and better functional recovery were observed for PFA compared with TKA in this study; moreover, the differences between the two operation modes were statistically significant (p < 0.05). We found no significant difference in complications, revision rates, and satisfaction rate between the two procedures. Although there was no observed difference in the complications, revision rates, and satisfaction rate between PFA and TKA, PFA was superior to TKA in terms of knee function and physical activity in the first 2 years postoperatively. Therefore, PFA is a safe, effective, and less invasive treatment for patients with isolated PF-OA. Our findings are consistent with the systematic review of current evidence that PFA may be more suitable for younger patients with high activity needs. Patient selection is, therefore, thought to be of paramount importance. Individualized surgical plan should be designed according to the patient’s age, BMI, KOA site, and activity level and combined with the doctor’s personal experience.

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Patellofemoral arthroplasty versus total knee arthroplasty for isolated patellofemoral osteoarthritis: a systematic review and meta-analysis.

We aimed to compare second-generation patellofemoral arthroplasty (2G PFA) with total knee arthroplasty (TKA) in treating isolated patellofemoral osteoarthritis (PFOA) by assessing the percentages of revisions, complications, and patient-reported outcome measures (PROMs). Studies that compared the outcomes of 2G PFA and TKA in the treatment of isolated PFOA were searched in electronic databases, including MEDLINE, Embase, and Web of Science. Two researchers independently identified eligible studies, extracted the data, and evaluated the quality of the literature. Pooled risk ratios (RRs) or weighted mean differences with 95% confidence intervals were calculated using either fixed or random effects models. Descriptive analysis was used when data could not be pooled. A total of six studies were included in the review. For the revision percentage and complications, there were no significant differences between 2G PFA and TKA (RR = 2.29, 95% CI 0.69–7.58, P = 0.17; RR = 0.56, 95% CI 0.23–1.40, P = 0.22, respectively). Second, the results demonstrated that the differences in the Oxford Knee Score (OKS) and the University of California, Los Angeles (UCLA) activity score between 2G PFA and TKA were not significant (WMD −4.68, 95% CI −16.32 to 6.97, p = 0.43; WMD 0.16, 95% CI −1.21 to 1.53, P = 0.82). The Knee Injury and Osteoarthritis Outcome Score (KOOS), the American Knee Society Score (AKSS), and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were presented in a narrative form due to methodological heterogeneity. For isolated PFOA, 2G PFA demonstrated similar results to TKA with respect to the percentages of revisions, complications, and PROMs.

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The short-term effectiveness and safety of second-generation patellofemoral arthroplasty and total knee arthroplasty on isolated patellofemoral osteoarthritis: a systematic review and meta-analysis

Background Incongruity in the evaluation of outcomes between patients and surgeons has led to an increasing utilization of patient-reported outcome measures (PROMs) as an evaluation method of outcome. Objective The aim of this study was to compare Oxford Knee Score (OKS), KOOS-PS and Kujala Score results in patients who received either PFA or TKA with and without patella resurfacing in the tretament of knee osteoarthritis. Methods A total of 50 patients (PFA = 19 patients; TKA with patelloplasty = 15 patients; TKA with patellar resurfacing = 16 patients) undergone surgery between 2011 and 2014 and were included for final analysis. Results No statistical significance was found for OKS, KOOS-PS and Kujala scores between the three groups. However, although patients with PFA experienced higher levels of pain. Conclusions According to our results, it is essential to discuss the treatment options and quality of life expectations with the patient prior joint replacement surgery in order to reduce patient dissatisfaction. Level of evidence Level III, retrospective comparative study.

Steffen Baron

Papers

Patient-reported outcome measures (PROMs) in patients undergoing patellofemoral arthroplasty and total knee replacement: A comparative study.