Does total contact of the patella with the femoral trochlea during no thumb test significantly reduce anterior knee pain?

Internal rotational patellar resection and patella alta induced patellar maltracking in total knee arthroplasty: intraoperative measurement of the patellofemoral pressure

BACKGROUND

Anterior knee pain due to patellar maltracking following total knee arthroplasty (TKA) reduces patients' satisfaction. This study aimed to determine the patellofemoral pressure (PFP) in patients with favorable patellar tracking (FT) and impaired patellar tracking (IT) following TKA, the factors causing patellar maltracking, and the effect of lateral retinacular release (LRR) on patients with IT.

METHODS

Forty-four patients with varus knee osteoarthritis undergoing cruciate-retaining TKA were enrolled. After component implantation, patients with a separation of ≥ 2 mm of the patellar medial facet from the medial femoral trochlea throughout knee range of motion were classified into the IT group; meanwhile, the others were classified into the FT group. PFP was measured intraoperatively in three phases: (1) with the resurfaced patella (RP); (2) with the resurfaced patella and knee (RPK); and (3) when LRR was performed in IT (post-LRR). The PFPs at 0°, 90°, 120°, and 135° knee flexion were compared between FT and IT using the Mann-Whitney U test. Pairwise comparison of the PFP in IT between RPK and post-LRR was performed using the Wilcoxon signed-rank test. Correlations between PFP and pre- and postoperative radiographic parameters, such as hip-knee-ankle angle, lateral distal femoral angle, medial proximal tibial angle, anterior femoral offset, Insall-Salvati ratio (ISR), patellar tilt, and patellar resection angle (PRA), were evaluated using Spearman's rank correlation coefficients.

RESULTS

High lateral PFP in the knee flexion position led to patellar maltracking. Patients with IT (n = 24) had higher lateral and lower medial PFP than did patients with FT (n = 20) at 90°, 120°, and 135° knee flexion in RP and RPK. LRR in IT reduced the lateral PFP in the knee flexion position. PRA and ISR were correlated with the lateral PFP at no less than 90° in RP and RPK.

CONCLUSIONS

This study demonstrated that internal rotational patellar resection, which resulted in a thick medial patellar remnant and a thin lateral counterpart, and patella alta were the causative factors of high lateral PFP, which induced patellar maltracking after TKA. Surgeons should avoid internal rotational patellar resection to achieve FT and perform LRR in patients with patellar maltracking.

Different modalities of patellar management in primary total knee arthroplasty: a Bayesian network meta-analysis of randomized controlled trials

BACKGROUND

The primary management modalities for the patella in TKA include patellar resurfacing, patellar non-resurfacing, patellar resurfacing with denervation, and patellar non-resurfacing with denervation. Traditionally, meta-analyses have predominantly focused on examining comparisons between two management modalities. However, this study performed a network meta-analysis to compare all four patellar management interventions to identify the most optimal approach for patellar management in TKA.

METHODS

A computer-based search of PubMed, China National Knowledge Infrastructure (CNKI), The Cochrane Library, Web of science, Embase, and MEDLINE databases was performed to identify randomized controlled trials focusing on the four management interventions for the patella in TKA. Comparisons included two-by-two comparisons as well as those involving more than two concurrent comparisons. The search timeframe spanned from inception to June 30, 2023. Two independent authors extracted the data and evaluated the quality of the literature. The Cochrane Collaboration Risk of Bias (ROB) tool was used to evaluate the overall quality of the literature. Subsequently, a network meta-analysis was conducted using the "gemtc" package of the R-4.2.3 software. Outcome measures such as anterior knee pain (AKP), reoperation rate, and patient satisfaction rate were evaluated using odd ratio (OR) and 95% confidence intervals (CI). Additionally, the knee society score (KSS), function score (FS), and range of motion (ROM) were evaluated using mean differences (MD) with associated 95% CI. The different treatment measures were ranked using the surfaces under the cumulative ranking curves (SUCRA).

RESULTS

A total of 50 randomized controlled trials involving 9,283 patients were included in the analysis. The findings from this network meta-analysis revealed that patellar resurfacing exhibited significantly lower postoperative reoperation rate (OR 0.44, 95% CI 0.24-0.63) and AKP (OR 0.58, 95% CI 0.32-1) compared to non-resurfacing. Additionally, patellar resurfacing exhibited higher postoperative KSS clinical scores in comparison with non-resurfacing (MD: 1.13, 95% CI 0.18-2.11). However, for postoperative FS, ROM, and patient satisfaction, no significant differences were observed among the four management interventions.

CONCLUSION

Patellar resurfacing emerges as the optimal management modality in primary TKA. However, future studies should aim to reduce sources of heterogeneity and minimize the influence of confounding factors on outcomes.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023434418 identifier: CRD42023434418.

Early Clinical and Radiographic Outcomes of Robot-Assisted Versus Conventional Manual Total Knee Arthroplasty: A Randomized Controlled Study

Objective

Robot‐assisted surgery has been promoted worldwide in recent years. The development of a domestic orthopaedic robot and its clinical application are therefore of great significance. This study aimed to compare the early clinical and radiographic outcomes of domestic robot‐assisted total knee arthroplasty (RA‐TKA) with conventional manual total knee arthroplasty (CM‐TKA).

Methods

A total of 77 patients who underwent primary single‐sided TKA from June to December 2020 were prospectively enrolled; resulting in the inclusion of 72 patients. The patients were randomly divided into the RA‐TKA group (37 cases, with TKA being assisted by the Yuanhua Orthopaedic Robotic System) and the CM‐TKA group (35 cases, with TKA being performed using conventional tools). Knee function was evaluated by the knee range of motion (ROM), the American Knee Society Score (KSS), and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Postoperative radiographic results were evaluated by full‐length weight‐bearing X‐rays of the lower limb and anteroposterior and lateral X‐rays of the knee were obtained preoperatively and at 90 days postoperative. The operative duration, blood loss, postoperative knee function, radiographic outcomes, and incidence of complications were compared by Student's t‐test, Mann–Whitney U test, or chi‐square test. Serum levels of inflammatory markers before the operation and 1, 3, and 30 days after the operation were recorded and compared between the two groups.

Results

The operation was significantly longer in the RA‐TKA group than in the CM‐TKA group (154.3 vs 115.2 min, p < 0.001). There was no significant difference in blood loss (933 vs 863 ml, p = 0.519) between the two groups. The knee ROM, KSS, and WOMAC were significantly improved in both groups 90 days after the operation compared with before the operation (p < 0.05), but there were no significant differences between the two groups (p > 0.05). The incidence of postoperative deep vein thrombosis was not statistically different between the two groups. In the radiographic findings at 90 days postoperatively we found the frequency of lateral tibial component (LTC) angle outliers was significantly lower in the RA‐TKA group (3.0% vs 29.4%, p = 0.003). The neutrophil‐to‐lymphocyte ratio (NLR) was significantly lower in the RA‐TKA group than in the CM‐TKA group on day 1 after surgery (9.9 vs 12.7, p = 0.024).

Conclusions

RA‐TKA requires more time than CM‐TKA, which may be related to the learning curve and intraoperative registration. The short‐term postoperative knee functional outcomes had no differences between the two groups, and RA‐TKA improved the accuracy of tibial component alignment. Further follow‐up studies are required to investigate the long‐term outcomes.

Patellar Resurfacing Does Not Improve Clinical Outcome in Patients with Symptomatic Tricompartmental Knee Osteoarthritis. An RCT Study of 40 Patients Receiving Primary Cruciate Retaining Total Knee Arthroplasty

There is some evidence that patellofemoral (PF) joint osteoarthritis (OA) causes anterior knee pain (AKP) after total knee arthroplasty (TKA). We hypothesized that patellar resurfacing in primary TKA for patients with symptomatic tricompartmental knee OA yields better clinical results after 2 years than non-resurfacing. A single center randomized controlled clinical trial comparing 40 patients receiving 42 cruciate retaining TKAs with (n = 21) or without patellar resurfacing (n = 21) was conducted. Primary outcome was the specific PF joint score HSS Baldini and secondary outcomes were the Knee Society Score (KSS) and the Knee Osteoarthritis Outcome Scale (KOOS). After 2 years no significant differences between both groups and between the groups in time for HSS Baldini, KSS, and KOOS were found. HSS Baldini score improved significantly after 6 weeks in both groups (p < 0.001) and did not improve in time afterward. At final follow-up the HSS Baldini mean score improved from a preoperative mean of 39 to 88 (difference of 49 points; p < 0.001)) for without patellar resurfacing group, and from a preoperative mean of 37 to 81 for patellar resurfacing group (difference of 47 points; p < 0.001). One patient in the patellar resurfacing group underwent a soft tissue re-alignment procedure because of patellar subluxation. Two patients in without patellar resurfacing group received secondary patellar button placement. Patellar resurfacing in primary TKA for patients with symptomatic tricompartmental OA has no beneficial effect over non-resurfacing and seems unnecessary. A special PF joint outcome measurement tool (HSS Baldini) and common knee scores showed no better knee function or AKP outcomes for with patellar resurfacing over without patellar resurfacing group in time and after 2 years of follow-up.

A Simple, Stepwise, Outside-in Technique for Lateral Retinacular Release for Management of Patellar Maltracking During Total Knee Arthroplasty

Lateral retinacular release is done to correct patellar maltracking in total knee arthroplasty. The inside-out technique is widely used but has associated risks. Our video describes a simple outside-in technique, done stepwise, and titrated according to the grade of maltracking that maximizes preservation of the superior lateral geniculate artery and preserves the synovium, avoiding complications such as hematoma formation, skin tenting, and wound discolouration. The technique is also effective in all severities of maltracking and with all types of implants.

Literature review of the causes of pain following total knee replacement surgery: prosthesis, inflammation and arthrofibrosis

Adverse knee pain occurs in 10–34% of all total knee replacements (TKR), and 20% of TKR patients experience more pain post-operatively than pre-operatively. Knee pain is amongst the top five reasons for knee replacement revision in the United Kingdom. The number of TKRs is predicted to continue increasing due to the ageing population.

A narrative literature review was performed on the different causes of pain following TKR. A database search on Scopus, PubMed, and Google Scholar was conducted to look for articles related to TKR, pain, and cause. Articles were selected based on relevance, publication date, quality of research and validation. Relevant sections were added to the review.

One hundred and fourteen articles were identified and potential causes of TKR pain included: arthrofibrosis, aseptic loosening, avascular necrosis, central sensitization, component malpositioning, infection, instability, nerve damage, overstuffing, patellar maltracking, polyethylene wear, psychological factors and unresurfaced patella.

It is important to tailor our approach to address the individual causes of pain. Certain controllable risk factors can be managed pre-operatively to minimize post-operative pain. Risk factors help to predict adverse pain outcomes and identify specific causes.

There are multiple causes of pain following TKR. Some factors will require further extensive studies, and as pain is a commonly attributed reason for TKR revision, its underlying aetiologies should be explored. Understanding these factors helps to develop effective methods for diagnosis, prevention and management of TKR pain, which help to improve patient outcomes.

Cite this article: EFORT Open Rev 2020;5:534-543. DOI: 10.1302/2058-5241.5.200031