Radiographic assessment of leg alignment and grading of knee osteoarthritis: A critical review

Changes in spino-pelvis-lower extremity alignment in patients with knee osteoarthritis: a prospective radiographic study

PURPOSE

Osteoarthritis (OA) is a prevalent, debilitating ailment among the elderly. Humans need a correct sagittal spino-pelvis-lower extremity alignment to stand upright. Pathology in trunk or lower extremity section might disrupt this harmony, causing compensatory alterations in other segments. The aim of the present study was to evaluate spino-pelvis-lower extremity alignment and association among the various spino-pelvic, knee, and ankle radiological angles in patients with knee osteoarthritis (OA).

MATERIALS AND METHODS

This prospective study enrolled 70 adults over 50 years of age of either sex who complained of knee pain and met the American College of Rheumatology criteria for symptomatic OA of at least one knee. The radiological assessment comprised anteroposterior and lateral lower extremity full-length scans, as well as the Kellgren-Lawrence radiographic classification of OA. We measured hip, knee, ankle, and spino-pelvic angles using Horos software. We calculated descriptive statistics and linear correlation between continuous variables.

RESULTS

There was a significant association (p < 0.05) between age and the majority of the spino-pelvic, knee, and ankle angles and between age and severity of OA. Significant variables linked with 'SFA' include HKAA (p = 0.008), mLDFA (p < 0.001), TJLA, FS-TS, Cond-Plateau, and femoral bowing (p = 0.007). We found significant associations between 'PFA' and mMPTA (p = 0.005), Cond-Plateau (p = 0.005), Tibial Bowing (p = 0.003), and 'LL' with HKAA, mLDFA, FS-TS, and Cond-Plate. SSA was significantly associated with mLDFA, mMPTA, TJLA, Cond-Plateau, and HKAA; while, FI' was significantly associated with FS-TS, femoral bowing, and tibial bowing (p < 0.001). The variables 'SS' was substantially linked with TTA (p = 0.008), TT (p = 0.004), PP (< 0.001), GP (p < 0.001), and GT (p = 0.010). 'PI' was substantially linked to TT (p = 0.001), GP (p = 0.005), and GT (p = 0.042), and 'PT' to TT (p < 0.001) and GT (p = 0.012). 'SFA' and 'PFA' only correlated with TT (p = 0.012 and 0.010). Lower limb angles were significantly associated with TT, PP, GP, GT, mLDFA, and mMPTA (p = 0.031, p = 0.026, p = 0.009, p = 0.009, TT, GP, GT, p < 0.001). GP was the sole significant association for 'TJLA' (p = 0.016). 'FS-TS' substantially correlated with PP (p = 0.015), GP (p < 0.001), and GT (p < 0.001). "Femoral Bowing" was significantly linked to PP (p = 0.017), GP (p = 0.007), and GT (p < 0.001), and "Cond-Plateau" was significantly linked to GP (p = 0.002) and GT. "Tibial Bowing" was significantly linked to TTA (p < 0.001), TAS (p = 0.003), LDTA (p = 0.002), TC (p < 0.001), GP (p = 0.007), and GT (p < 0.001). Age, gender, BMI, and the severity of knee OA significantly influenced the association among these various angles.

CONCLUSION

Osteoarthritis of the knee disrupts the harmonious alignment of the spine and pelvis with the lower limbs, resulting in compensatory changes in the ankle and spine. The severity of knee osteoarthritis and the patient's gender, age, and BMI impact compensatory adaptations.

TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION

CTRI/2021/08/036088 [Registered on: 31/08/2021] - Trial Registered Prospectively.

Radiological Approach to Assessment of Lower-Limb Alignment-Coronal and Transverse Plane Analysis

Lower-limb alignment deformities constitute a significant clinical concern, as they can lead to serious complications, including progressive degenerative diseases and disabilities. Rotational deformities may give rise to conditions such as joint arthrosis, patellar instability, and the degeneration of the patellofemoral cartilage. Therefore, a comprehensive evaluation of lower-limb alignment is essential for the effective patient management, preoperative planning, and successful correction of these deformities. The primary assessment method employs full-length standing radiographs in the anteroposterior (AP) projection, which facilitates accurate measurements of the anatomical and mechanical axes of the lower limb, including angles and deviations. The outcomes of this analysis are vital for the meticulous planning of osteotomy and total knee arthroplasty (TKA). In addition, computed tomography (CT) provides a specialized approach for the precise evaluation of femoral and tibial rotation. In this area, there are potential opportunities for the implementation of AI-based automated measurement systems.

Radiographic Assessment of Bone Union in Proximal Tibia and Distal Femur Osteotomies: A Systematic Review

Background

Osteotomies around the knee are a well-established treatment option for early and moderate unicompartmental osteoarthritis combined with a lower extremity malalignment. Moreover, osteotomies are often combined with cartilage treatment. Current image-based bone union assessments lack an accepted definition despite widespread use in research and clinical settings. The aim of this systematic review was to identify definitions and classification systems for bone union on radiographs after a proximal tibia or distal femur osteotomy.

Methods

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we systematically searched MEDLINE and Embase database, applying specific inclusion and exclusion criteria. Two independent reviewers screened abstracts and full-texts. The modified Cochrane Risk of Bias Tool and Risk of Bias in Nonrandomized Studies of Interventions tool were used. Data extraction included study characteristics, imaging modality, bone union definition, classification systems, assessment of gap fillers, use of modifiers, and osteotomy type.

Results

Of the 1,180 screened titles and abstracts, 105 studies were included, with the majority (69 studies [65.7%]) using a retrospective design. Fifty-five studies (52.4%) defined bone union based on one or more criteria, while 50 studies (47.6%) used a classification system. There were 13 different criteria for bone union and 9 different classification systems. Interestingly, none of the classification systems incorporated negative criteria, such as hardware failure. Notably, 137 studies (49.1%) described bone union as either a primary or secondary outcome but do not describe a system for assessing bone union.

Conclusion

This systematic review highlights the lack of consensus in the literature in defining bone union after a proximal tibia or distal femur osteotomy, revealing many criteria and different classifications. None of the classification systems were applicable to osteotomies with and without gap filler. This systematic review shows the need for a straightforward, reproducible, and accurate method to assess bone union after a proximal tibia or distal femur osteotomy.

Level of Evidence

Level III. See Instructions for Authors for a complete description of levels of evidence.

Management Considerations for Unicompartmental Osteoarthritis in Athletic Populations: A Review of the Literature

Unicompartmental osteoarthritis in the young athlete poses a challenge for both patients and providers. Coronal plane malalignment is frequently a concomitant finding that adds to the complexity of management. Military surgeons are presented unique challenges, in that they must consider optimal joint-preservation methods while returning patients to a high-demand occupational function. Management options range from lifestyle changes to surgical interventions. We present a concise review of the available literature on this subject, with a specific focus on indications and outcomes within the military and young athletic population.

Automated Radiographic Measurements of Knee Osteoarthritis

OBJECTIVE

Herewith, we report the development of Orthopedic Digital Image Analysis (ODIA) software that is developed to obtain quantitative measurements of knee osteoarthritis (OA) radiographs automatically. Manual segmentation and measurement of OA parameters currently hamper large-cohort analyses, and therefore, automated and reproducible methods are a valuable addition in OA research. This study aims to test the automated ODIA measurements and compare them with available manual Knee Imaging Digital Analysis (KIDA) measurements as comparison.

DESIGN

This study included data from the CHECK (Cohort Hip and Cohort Knee) initiative, a prospective multicentre cohort study in the Netherlands with 1,002 participants. Knee radiographs obtained at baseline of the CHECK cohort were included and mean medial/lateral joint space width (JSW), minimal JSW, joint line convergence angle (JLCA), eminence heights, and subchondral bone intensities were compared between ODIA and KIDA.

RESULTS

Of the potential 2,004 radiographs, 1,743 were included for analyses. Poor intraclass correlation coefficients (ICCs) were reported for the JLCA (0.422) and minimal JSW (0.299). The mean medial and lateral JSW, eminence height, and subchondral bone intensities reported a moderate to good ICC (0.7 or higher). Discrepancies in JLCA and minimal JSW between the 2 methods were mostly a problem in the lateral tibia plateau.

CONCLUSIONS

The current ODIA tool provides important measurements of OA parameters in an automated manner from standard radiographs of the knee. Given the automated and computerized methodology that has very high reproducibility, ODIA is suitable for large epidemiological cohorts with various follow-up time points to investigate structural progression, such as CHECK or the Osteoarthritis Initiative (OAI).

Feasibility and 3D Planning of a Novel Patient-Specific Instrumentation Technique in Medial Opening-Wedge High Tibial Osteotomy

A novel approach for opening-wedge high tibial osteotomy (OWHTO) with patient-specific instrumentation (PSI) was evaluated for its safety, feasibility, and accuracy. Next, the mechanical medial proximal tibial angle (mMPTA) was assessed as a potential planning angle by investigating the relation with the mechanical femorotibial angle (mFTA). Ten OWHTO cases were 3D planned using the mMPTA and operated with a customized 3D-printed wedge and cast which resembled the intended osteotomy opening. Patients were closely monitored for intraoperative and postoperative complications up to 1 year after surgery. Radiological assessment was conducted on full leg standing radiographs and supine lower limb computed tomography-scans preoperatively and 3 months after surgery. No intraoperative complications or logistical issues during PSI processing were observed. Absolute accuracy outcomes showed a correction error of 1.3° ± 1.1 mMPTA and 0.9° ± 0.6 mFTA with all osteotomies falling in (-2°; + 2°) mFTA around the target. The mMPTA and mFTA were found to have a strong correlation in both 3D (r = 0.842, p = 0.002) and 2D (r = 0.766, p = 0.01) imaging for effective correction. The study confirmed the development of a safe and feasible PSI technique in OWHTO with excellent accuracy outcomes. The strong correlation between the mMPTA and mFTA indicated that soft tissue changes after OWHTO are of minor significance to the final alignment in ligament-stable patients. Finally, the mMPTA was found to be a reliable planning angle in 3D software for obtaining the intended lower limb realignment and its use can therefore be recommended in modern OWHTO planning.

Radiological assessment of lower limb alignment

The full-length standing radiograph in an anteroposterior projection is the primary tool for defining and measuring limb alignment with definition of the physiological axes and mechanical and anatomic angles of the lower limb.

We define the deformities of the lower limb and the importance of correct surgical planning and execution.

For patients with torsional malalignment of the lower limb, computerized tomography scan evaluation is the gold standard for preoperative assessment.

Cite this article: EFORT Open Rev 2021;6:487-494. DOI: 10.1302/2058-5241.6.210015

Assessing Radiographic Knee Osteoarthritis: An Online Training Tutorial for the Kellgren-Lawrence Grading Scale

INTRODUCTION

Knee osteoarthritis (OA) is a degenerative form of arthritis commonly diagnosed in older adults. It presents clinically with patient complaints of pain and impaired function, which are thought to result from cartilage degeneration and other skeletal changes. These changes can by examined radiographically and quantified using the semiquantitative grading scale known as the Kellgren-Lawrence (KL) scale. Currently, no standard training exists for KL grading, which may explain the unsatisfactory reliability of this tool in OA research. Therefore, the objective of this project was to develop a training tutorial for KL grading of knee OA to educate assessors on possible areas of inconsistency in grading.

METHODS

The tutorial was developed in an e-learning authoring tool, Articulate Presenter. The content focuses on the poor reliability of KL grading, normal anatomy of a knee radiograph, and multiple examples of bony changes within the knee and their relation to different grades of the KL scale. The tutorial was presented to a group of health sciences graduate students at the University of Colorado Denver.

RESULTS

Students were able to complete the training and an associated assessment in under an hour and reported improved confidence with assessing radiographic knee OA. Furthermore, they demonstrated favorable inter- and intrarater reliability scores in applying KL grading.

DISCUSSION

To our knowledge, this is the first attempt to standardize training in KL grading for knee OA and to examine the effects of this training on reliability.