A Surgical Method to Establish a Murine Model of Knee Osteoarthritis using a Modified Hulth Procedure

Summary

This protocol outlines the refined surgical steps of the modified Hulth model, providing a standardized, reproducible method for inducing experimental osteoarthritis.

Abstract

Knee osteoarthritis (KOA) is a chronic degenerative joint disease characterized by articular cartilage degeneration, subchondral bone remodeling, osteophyte formation, and synovitis, which is the most common type of osteoarthritis.

This protocol presents a surgical method to establish a murine model of knee osteoarthritis using a modified Hulth procedure. Compared to injection-induced or conventional surgical models such as destabilization of the medial meniscus (DMM) and anterior cruciate ligament transection (ACLT), the modified Hulth model induces an earlier disease onset and more severe joint inflammation. By transecting the medial collateral ligament, medial meniscus, and anterior cruciate ligament, this method disrupts the mechanical alignment of the knee joint, thereby promoting OA progression. This model is particularly suitable for studying acute OA pathology and evaluating potential therapeutic interventions. To evaluate arthritis severity, we used small-animal ultrasound combined with three-dimensional (3D) reconstruction of the joint cavity to quantify its volume and assess synovial fluid accumulation. In addition, safranin-O/fast green staining of histological sections was performed for Osteoarthritis Research Society International (OARSI) scoring to evaluate cartilage destruction.

Introduction

Knee osteoarthritis (OA) is a common, chronic, degenerative joint disease characterized clinically by pain, stiffness, limited range of motion, and muscle weakness around the knee. Its prevalence is higher in women than in men. If inadequately controlled, OA can lead to progressive loss of physical capacity, sleep disturbance, chronic fatigue, and eventual disability. As global populations age, the incidence of knee OA continues to rise, posing a substantial challenge to health-care systems and economies worldwide^1,2.

Pathophysiologically, cartilage loss represents the central featu....

Protocol

All experimental procedures were approved by the Animal Ethics Committee of Shanghai University of Traditional Chinese Medicine. Male C57BL/6 mice aged 6-8 weeks and weighing approximately 20 g were purchased from commercial vendors (see Table of Materials) (Ethics approval number: PZSHUTCM2312210005).

1. Preoperative care

1. Allow mice to acclimate for at least 1 week before surgery.
2. Sterilize all surgical instruments before surgery and disinfect the surgical workspace.
3. Turn on the gas anesthesia machine, and place the mouse in an induction chamber for 5 min using 2-3% isoflura....

Results

Longitudinal scans of the knee joint were performed using a micro-ultrasound⁸ system with a scan step of 4 mm and an axial resolution of 0.04 mm. On postoperative day 7, 3D reconstruction revealed a marked increase in joint-cavity volume in the model group compared with the sham group (Figure 2A,B). Rotarod fatigue testing^10,11 corroborated this finding, demonstrating a significant reduction i.......

Discussion

Comparison with other surgery modelling methods, like the destabilization of the medial meniscus (DMM) and anterior cruciate ligament transection (ACLT) models, the modified Hulth model induces osteoarthritis through combined ligamentous and meniscal injury. The specific structural disruption determines alterations in joint biomechanics across different planes. ACLT⁴ compromises rotational stability (internal and external rotation) and reduces anteroposterior stability, resulting in positive drawe.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
1 mL injection syringe	/	/	Specifications: 30 G × 0.13 mm
3D Ultrasound Vevo 3100 Imaging System	Optic	Vevo 2100	A high-frequency ultrasound imaging system integrated with Vevo LAB software for data analysis.
4-0 nylon suture	/	/
75% ethanol	Shanghai Titan Scientific Co., Ltd.	G73537O
C57BL/6J male mice (6-8 weeks old)	Shanghai Jiesijie Laboratory Animal Co., Ltd.	/
Depilatory cream	Veet	Lot: C021123001
Iodine tincture	/	/
Isoflurane	RWD	R650-IE
Micro forceps	RWD	F12013-10
Micro scissors	RWD	S11035-08
Modified Safranin O and Fast Green Stain Kit	Solarbio	G1371
Needle holder	RWD	F21001-12
Surgical blades (10#)	RWD	S31010-01
Surgical microscope	Olympus	SZ61