Patellofemoral morphology is not related to pain using three-dimensional quantitative analysis in an older population: data from the Osteoarthritis Initiative

Sexual dimorphism in peri-articular tissue anatomy - More keys to understanding sex-differences in osteoarthritis?

Objective

Osteoarthritis prevalence differs between women and men; whether this is the result of differences in pre-morbid articular or peri-articular anatomical morphotypes remains enigmatic. Albeit sex within humans cannot be reduced to female/male, this review focusses to the sexual dimorphism of peri-articular tissues, given lack of literature on non-binary subjects.

Methods

Based on a Pubmed search and input from experts, we selected relevant articles based on the authors' judgement of relevance, interest, and quality; no "hard" bibliometric measures were used to evaluate the quality or importance of the work. Emphasis was on clinical studies, with most (imaging) data being available for the knee and thigh.

Results

The literature on sexual dimorphism of peri-articular tissues is reviewed: 1) bone size/shape, 2) subchondral/subarticular bone, 3) synovial membrane and infra-patellar fad-pad (IPFP), 4) muscle/adipose tissue, and 5) peri-articular tissue response to treatment.

Conclusions

Relevant sex-specific differences exist for 3D bone shape and IPFP size, even after normalization to body weight. Presence of effusion- and Hoffa-synovitis is associated with greater risk of incident knee osteoarthritis in overweight women, but not in men. When normalized to bone size, men exhibit greater muscle, and women greater adipose tissue measures relative to the opposite sex. Reduced thigh muscle specific strength is associated with incident knee osteoarthritis and knee replacement in women, but not in men. These observations may explain why women with muscle strength deficits have a poorer prognosis than men with similar deficits. A "one size/sex fits all" approach must be urgently abandoned in osteoarthritis research.

Using Dual-Orthogonal Fluoroscopy and CT to Assess the Relationship Between Knee Morphology and Patellar Kinematics in Patients With Patellofemoral Pain

INTRODUCTION

Patellofemoral pain (PFP) is one of the most common knee overuse injuries, with studies suggesting PFP as a precursor for early knee osteoarthritis. The etiology of PFP is multi-factorial; however, patellar mal-tracking has been regarded as a primary mechanism. Details of this multi-factorial mechanism have been unclear because of the limitations in evaluating in-vivo, three-dimensional (3D) patellofemoral joint movement during dynamic activities accurately. Alternatively, studies have demonstrated the high accuracy and repeatability of dual fluoroscopy and CT/MRI for measuring knee joint motion.

OBJECTIVE

This study uses dual fluoroscopy and CT to investigate the associations between joint morphology and patellar kinematics in healthy controls and subjects with PFP.

METHODS

Eight PFP females (29.7±10.6 years) and 10 healthy females (25.0±7.7 years) were recruited and screened by a sports medicine physician. CT imaging was performed on participants in a supine with the knee extended, and ankle and hip in neutral alignment. Dual-orthogonal fluoroscopy measured patellar movement while participants performed a lunge task. A calibration algorithm was used to register the 3D CT model to 2D fluoroscopy image to calculate the relative position and angles of the patella based on the clinical definition of patellar motion. Measures of patellar and trochlear morphology were generated and correlated to kinematic data.

RESULTS AND CONCLUSION

There was a significant difference in the patellar-to-trochlear width ratio; however, no other significant differences in CT morphology measurements were present between groups. For PFP patients in the weight-bearing extended position, there was a moderate positive correlation between the patellar-to-trochlear width ratio and medial-lateral patellar shift (τ = 0.643, p = 0.026). Healthy controls in this position demonstrated a moderate positive correlation between the lateral-trochlear inclination angle and medial-lateral patellar shift (τ = 0.600, p = 0.016) and moderate negative correlation between medial trochlear inclination angle and medial-lateral patellar shift (τ = -0.511, p = 0.040). The findings suggest that, for this cohort, there is correlation between morphology and patellar kinematics. Passive and active stabilizers likely have a role in mal-tracking.

Osteoarthritic knees have a highly variable patellofemoral alignment: a systematic review

PURPOSE

This systematic review aimed to evaluate the variability of patellofemoral (PF) alignment and trochlear morphology in osteoarthritic knees.

METHODS

PF alignment of the knee was defined by the following parameters: the sulcus angle (SA), femoral trochlear depth (FTD), patellar tilt angle (PTA), lateral patellofemoral angle (LPFA), lateral femoral trochlear inclination (LFTI) and tibial tubercle-trochlear groove distance (TT-TG). The electronic databases MEDLINE and EMBASE were searched from database inception to the search date (February 19, 2019) and were screened for relevant studies. The PRISMA guidelines were followed. Articles reporting PF alignment measurements of osteoarthritic knees in patients over 40 years old were included. Data were extracted and methodological quality was assessed using a 14-item checklist.

RESULTS

A total of 8 studies met the inclusion criteria. The studies reported mean values ± SD between 120° and 141.1° ± 7.7 for the SA; 5.8 mm ± 1.4 for the FTD; between - 0.1° ± 3.3 and 10.3° ± 5.7 for the PTA; between 5.8° ± 5.4 and 17° for the LPFA; between 23.2° ± 5.0 and 27.1° ± 4.4 for the LFTI; and 5.8 mm ± 5.4 for the TT-TG.

CONCLUSION

PF alignment in the osteoarthritic knee is more variable than expected. This finding should encourage surgeons to consider the individual preoperative PF alignment more precisely with the aim of reducing anterior knee pain (AKP) after TKA. 3D-CT imaging might be of great value to analyse the PF alignment in an appropriate way.

LEVEL OF EVIDENCE

Level III.

Associations of trochlea morphology and patellofemoral alignment with prevalent radiographic patellofemoral osteoarthritis

OBJECTIVE

To investigate the relation of trochlea morphology and patellofemoral alignment to prevalent radiographic patellofemoral osteoarthritis (PFOA).

DESIGN

A within-person knee-matched case-control study was performed. Participants with unilateral radiographic PFOA were selected from the Multicenter Population-based Osteoarthritis Study (MPOA) in three towns in northern China that was approved by Peking University Health Science Center Ethics Committee (2018PHB166-01). Radiographic PFOA, radiographic tibiofemoral OA, sulcus angle, patellofemoral index and patella displacement were assessed using posterio-anterior and skyline views of the knee. We classified sulcus angle, patellofemoral index and patella displacement into quarters and investigated the relation of each of these measures to prevalent radiographic PFOA.

RESULTS

Among 451 participants (mean age: 65.2 years, women: 66.8%) with unilateral radiographic PFOA, a reverse J-shaped relationship was observed between sulcus angle and prevalent radiographic PFOA (P = 0.039 for quadratic term). Both higher patellofemoral index and patella displacement were associated with higher prevalent radiographic PFOA. Adjusted odds ratios (ORs) of prevalent radiographic PFOA in the highest quarter of patellofemoral index and patella displacement were 4.69 and 3.60 (P for trend <0.001), respectively, compared with the lowest quarter of each measurement. A similar relationship was observed between sulcus angle with either prevalent radiographic lateral or medial PFOA. Higher values of patellofemoral index and patella displacement were statistically significantly associated with higher prevalent radiographic lateral (ORs = 5.07 and 4.59, respectively), but not medial PFOA (ORs = 0.58 and 0.76, respectively).

CONCLUSION

Extreme sulcus angles as well as higher values of patellofemoral index and patella displacement were associated with higher prevalent radiographic PFOA.

Evaluation of predicted patellofemoral joint kinematics with a moving-axis joint model

The main objectives of this study were to expand the moving-axis joint model concept to the patellofemoral joint and evaluate the patellar motion against experimental patellofemoral kinematics. The experimental data was obtained through 2D-to-3D bone reconstruction of EOS images and segmented MRI data utilizing an iterative closest point optimization technique. Six knee model variations were developed using the AnyBody Modeling System and subject-specific bone geometries. These models consisted of various combinations of tibiofemoral (hinge, moving-axis, and interpolated) and patellofemoral (hinge and moving-axis) joint types. The newly introduced interpolated tibiofemoral joint is calibrated from the five EOS quasi-static lunge positions. The patellofemoral axis of the hinge model was defined by performing surface fits to the patellofemoral contact area; and the moving-axis model was defined based upon the position of the patellofemoral joint at 0° and 90° tibiofemoral-flexion. In between these angles, the patellofemoral axis moved linearly as a function of tibiofemoral-flexion, while outside these angles, the axis remained fixed. When using a moving-axis tibiofemoral joint, a hinge patellofemoral joint offers (-5.12 ± 1.23 mm, 5.81 ± 0.97 mm, 14.98 ± 2.30°, -4.35 ± 1.95°) mean differences (compared to EOS) while a moving-axis patellofemoral model provides (-2.69 ± 1.04 mm, 1.13 ± 0.80 mm, 12.63 ± 2.03°, 1.74 ± 1.46°) in terms of lateral-shift, superior translation, patellofemoral-flexion, and patellar-rotation, respectively. Furthermore, the model predictive capabilities increased as a direct result of adding more calibrated positions to the tibiofemoral model (hinge-1, moving-axis-2, and interpolated-5). Overall, a novel subject-specific moving-axis patellofemoral model has been established; that produces realistic patellar motion and is computationally fast enough for clinical applications.

Osteoarthritis year in review 2018: imaging

PURPOSE

To provide a narrative review of the most relevant original research published in 2017/2018 on osteoarthritis imaging.

METHODS

The PubMed database was used to recover all relevant articles pertaining to osteoarthritis and medical imaging published between 1 April 2017 and 31 March 2018. Review articles, case studies and in vitro or animal studies were excluded. The original publications were subjectively sorted based on relevance, novelty and impact.

RESULTS AND CONCLUSIONS

The publication search yielded 1,155 references. In the assessed publications, the most common imaging modalities were radiography (N = 708) and magnetic resonance imaging (MRI) (355), followed by computed tomography (CT) (220), ultrasound (85) and nuclear medicine (17). An overview of the most important publications to the osteoarthritis (OA) research community is presented in this narrative review. Imaging studies play an increasingly important role in OA research, and have helped us to understand better the pathophysiology of OA. Radiography and MRI continue to be the most applied imaging modalities, while quantitative MRI methods and texture analysis are becoming more popular. The value of ultrasound in OA research has been demonstrated. Several multi-modality predictive models have been developed. Deep learning has potential for more automatic and standardized analyses in future OA imaging research.