This work was supported by grants from National Natural Science Foundation of China (No. 81772368), Natural Science Foundation of Guangdong Province (No. 2017A030313496), and Guangdong Provincial Science and Technology Plan Project (No. 2016A020215225; No. 2017B090912007). The authors thank Dr. Fei Zhang, M.D. from the Department of Orthopaedic Surgery, The Eighth Affiliated Hospital of Sun Yat-sen University for his technical assistance during modification.

All procedures were carried out in accordance with the Guide for the Care and Use of Laboratory Animals and were approved by The Third Affiliated Hospital of Sun Yat-sen University institutional animal care and use committee (permission number: 02-165-01). All the animal experiments were performed according to the ARRIVE guidelines.
1. Preoperative preparation
NOTE: Figure 1 shows the design of the surgical procedure.
<ol>
	<li>Rigidly immobilize the knee joint with a plastic plate and two metal screws at approximately 135&#176; flexion. 
	NOTE: Perform the surgery at the proximal femur and the distal tibia without violating the joint component.</li>
	<li>Prepare materials and instruments for internal fixation.
	<ol>
		<li>Construct a medical grade polypropylene plastic plates by cutting a 5 mL syringe (Figure 2a) using a surgical scissor to fit the following dimensions: length, 25 mm; width, 10 mm; thickness, 1 mm (Figure 2b). Smooth the perimeter of the plate with a scalpel vertically. Rinse the plate with sterile saline to wash off the debris by three times.
		<ol>
			<li>Sterilize with 75% ethanol for 4 h followed by irradiating with ultraviolet light for 3 h.</li>
		</ol>
		</li>
		<li>Pre-drilling holes in the plastic plate: Prepare a hand-held low-speed electric drill with a speed of about 0-4000 rpm (Figure 2c). Drill two holes at both ends of the plate, diameters are 1 mm and 0.9 mm, respectively (Figure 2d). Match both ends of the plate with M 1.4 mm x 8 mm and M 1.2 mm x 6 mm steel screws, respectively (Figure 2e).
		<ol>
			<li>Wipe with 75% ethanol and sterilize with UV light for 3 h before use.</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>Prepare surgical instruments: 1 straight Mosquito-Type&#8194;hemostatic clamp, 1 smooth curved forceps, 2 eyelid retractors, 1 needle-holder, 1 tissue&#8194;forceps, 1 suture&#8194;scissor, 1 micro tissue&#8194;scissor and 1 scalpel (Figure 2f). Sterilize the surgical instruments by autoclaving at 121.3 &#176;C for 20 min and drying.</li>
	<li>Experimental animals
	<ol>
		<li>Use Specific Pathogen Free (SPF) grade skeletally mature male Sprague-Dawley (or Wistar) rats, weighing between 250 - 350 g in the experiment. 
		NOTE: Choose either female or male rats for the experiment.</li>
		<li>Place the rats in cages and keep in a 12 h light/12 h dark cycle-controlled laboratory room. Provide adequate food and water.</li>
	</ol>
	</li>
</ol>
2. Surgery
<ol>
	<li>Adjust the temperature. Place a warming pad on a surgical platform in a thermostatic operating room.</li>
	<li>Anesthesia and skin preparation
	<ol>
		<li>Weigh the rat with an electronic scale and record.</li>
		<li>Restrain the rat and perform an intraperitoneal injection of sodium pentobarbital (30 mg/kg) to induced anesthesia. Assessing that the animal is sufficiently anesthetized using the toe pinch22. Administer the eyes with lubricant to protect the cornea from drying during surgery.</li>
		<li>Shave the lower body of the rat including the two hind limbs with an electric clipper and disinfect with a tincture of povidone iodine twice and 75% ethanol three times.</li>
		<li>Place the rat laterally, and cover with the surgical drape exposing one side hind leg and hip.</li>
		<li>Disinfect the surgical area again with povidone iodine.</li>
	</ol>
	</li>
	<li>Immobilize the knee joint with internal fixation using a mini-invasive technique. 
	NOTE: Keep the incision properly moist with sterile saline during the operation. The surgery usually requires two surgeons.
	<ol>
		<li>Mark the direction of skin incision. At the distal end of the femur greater trochanter, draw a line along the body surface projection of the muscle gap between the vastus lateralis and biceps femoris (Figure 3a). Incise the epidermis skin along the drawing line approximate 1.5 cm (Figure 3b).</li>
		<li>Bluntly dissect the muscle gap between vastus lateralis and biceps femoris with a tissue forceps until the femoral shaft is exposed approximately 1 cm in length (Figure 3c). Use the retractor to facilitate continuous separation of the muscle gap.</li>
		<li>Incise the epidermis skin approximate 1 cm along the body surface projection of the muscle gap between the tibialis anterior and fibularis longus on the distal lower extremity (Figure 3d). Bluntly dissect the muscle gap until the tibia is exposed approximately 1 cm in length (Figure 3e).</li>
		<li>Separate the soft tissues by the retractor and the smooth forceps, keep perpendicular and drill one 1.0 mm diameter hole into the femoral shaft at a speed of 1,500 rpm using an electric drill (Figure 3f). The proper drilling position is approximate 8 mm below the lower edge of the greater trochanter. Quickly press the wound to stop bleeding. 
		NOTE: Proper drilling diameter can avoid intraoperative fractures.</li>
		<li>Drill one 0.9 mm diameter hole into the tibia approximate 4 mm below the edge of the tibiofibular fusion (Figure 4a). Perform the drilling carefully to prevent the crushing of muscles or tendons.</li>
		<li>Use the straight Mosquito-Type&#8194;hemostatic clamp to form a submuscular course from the tibia hole to femur hole. The submuscular tunnel passes below the gastrocnemius in the tibia end and above the gluteus medius, below the biceps femoris in the femur end.</li>
		<li>Use one M 1.4 mm x 8 mm steel screw to secure one end of the plastic plate (with the 1.0 mm diameter hole) in the proximal femur (Figure 4b). Use one M 1.2 mm x 6 mm steel screw to secure another end of the plastic plate (with the 0.9 mm diameter hole) in the distal tibia (Figure 4c). Ensure the knee joint without varus deformity.</li>
	</ol>
	</li>
	<li>Close the wound: Suture the myofascia, deep fasciae, and subcutaneous tissue using 4-0 absorbable sutures (Figure 4d). Close the skin with Polyamide&#160;sutures (Figure 4f).</li>
</ol>
3. Postoperative management
<ol>
	<li>Apply postoperative analgesia through subcutaneous injection of Buprenorphine (0.03 mg/mL) at 0.05 mg/kg . Add 5 mg/mL Neomycin into drinking water for 5 days after the surgery.</li>
	<li>Inject the analgesia mixture (Buprenorphine and Carprofen) respectively at 0.05mg/kg and 5 mg/kg subcutaneously twice a day for at least 72 hours post-operation.</li>
	<li>Check whether the hind limb had over-edema in case of vascular injury. Made sure that the rats can walk normally in the case of nerve injury during surgery.</li>
</ol>
4. Postoperative examination
<ol>
	<li>Observe the healing of the surgical incision and physically examine the knee joint to evaluate early signs of infection every other day postoperatively. Check the degree of swelling of the ankle and metacarpophalangeal joint in case of continuous edema. 
	NOTE: Early postoperative infection can cause wound exudate, leg swelling, and delayed wound healing.</li>
	<li>Perform X-ray imaging of the hindlimb to ensure that correctly placed the screws on the first postoperative day. 
	NOTE: A Micro-CT scan analysis is another alternative option to display the proper location and the direction of the steel screws.</li>
	<li>Measure the passive range of motion (ROM) to evaluate the development of contracture. Take a knee joint ROM measurement at different time cohorts postoperatively as described previously20.
	<ol>
		<li>In brief, euthanize the rats and skin the hindlimbs. Remove the immobilizer and measure the knee joint angle using a mechanical arthrometer at two torques (667 or 1,060 g/cm)23.</li>
		<li>Calculate the ROM as a result of the total contracture, the myogenic contracture, and the arthrogenic contracture separately based on the investigation objectives24. 
		NOTE: Set different time cohorts (i.e., 1, 2, 4, 8, 16, and 32 weeks) according to the research objectives. The contralateral knee joint (non-operative or sham-operated) can serve as a control2.</li>
	</ol>
	</li>
	<li>Histological analysis of the posterior knee joint capsules.
	<ol>
		<li>Prepare the joint tissues. Dissect the knee joint tissue and fix it with 4% paraformaldehyde. Decalcify and embed it in paraffin as previously reported25. Cut the sections (5 &#956;m) at the medial midcondylar level in the sagittal plane. 
		NOTE: Choose to perform different evaluating staining including HE, aldehyde-fuchsin-Masson Goldner (AFMG), Elastica&#8211;Masson, or Immunohistochemistry staining for histological study in the joint capsule based on your study objectives15,26.</li>
		<li>Observe histomorphometric changes in the posterior knee joint capsules. Photograph the posterior region of the knee joint. Observe fibrous deposition and adhesion changes between the diaphysis-synovium junction and the meniscus6. 
		NOTE: Pathological changes of joint capsule are considered to be a pathogenic factor for knee joint contracture. Measure the length, the thickness, and the capsular areas of the posterior capsule as previously described according to the research content27.</li>
	</ol>
	</li>
</ol>

<ol>
	<li>Akeson, W. H., Amiel, D., Woo, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immobility+effects+on+synovial+joints+the+pathomechanics+of+joint+contracture.">Immobility effects on synovial joints the pathomechanics of joint contracture.</a> Biorheology. 17 (1-2), 95-110 (1980).</li><li>Trudel, G., Uhthoff, H. K., Brown, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extent+and+direction+of+joint+motion+limitation+after+prolonged+immobility:+an+experimental+study+in+the+rat.">Extent and direction of joint motion limitation after prolonged immobility: an experimental study in the rat.</a> Archives of Physical Medicine and Rehabilitation. 80 (12), 1542-1547 (1999).</li><li>Arsoy, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Joint+contracture+is+reduced+by+intra-articular+implantation+of+rosiglitazone-loaded+hydrogels+in+a+rabbit+model+of+arthrofibrosis.">Joint contracture is reduced by intra-articular implantation of rosiglitazone-loaded hydrogels in a rabbit model of arthrofibrosis.</a> Journal of Orthopaedic Research. , (2018).</li><li>Glaeser, J. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anti-Inflammatory+Peptide+Attenuates+Edema+and+Promotes+BMP-2-Induced+Bone+Formation+in+Spine+Fusion.">Anti-Inflammatory Peptide Attenuates Edema and Promotes BMP-2-Induced Bone Formation in Spine Fusion.</a> Tissue Engineering. Part A. , (2018).</li><li>Fergusson, D., Hutton, B., Drodge, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+epidemiology+of+major+joint+contractures:+a+systematic+review+of+the+literature.">The epidemiology of major joint contractures: a systematic review of the literature.</a> Clinical Orthopaedics and Related Research. 456, 22-29 (2007).</li><li>Wong, K., Trudel, G., Laneuville, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Noninflammatory+Joint+Contractures+Arising+from+Immobility:+Animal+Models+to+Future+Treatments.">Noninflammatory Joint Contractures Arising from Immobility: Animal Models to Future Treatments.</a> BioMed Research International. 2015, 848290 (2015).</li><li>Clavet, H., Hebert, P. C., Fergusson, D., Doucette, S., Trudel, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Joint+contracture+following+prolonged+stay+in+the+intensive+care+unit.">Joint contracture following prolonged stay in the intensive care unit.</a> CMAJ : Canadian Medical Association Journal. 178 (6), 691-697 (2008).</li><li>Dehail, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Joint+contractures+and+acquired+deforming+hypertonia+in+older+people:+Which+determinants?.">Joint contractures and acquired deforming hypertonia in older people: Which determinants?.</a> Annals of Physical and Rehabilitation Medicine. , (2018).</li><li>Watanabe, M., Kojima, S., Hoso, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+low-intensity+pulsed+ultrasound+therapy+on+a+rat+knee+joint+contracture+model.">Effect of low-intensity pulsed ultrasound therapy on a rat knee joint contracture model.</a> Journal of Physical Therapy Science. 29 (9), 1567-1572 (2017).</li><li>Goto, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+and+progression+of+immobilization-induced+skin+fibrosis+through+overexpression+of+transforming+growth+factor-ss1+and+hypoxic+conditions+in+a+rat+knee+joint+contracture+model.">Development and progression of immobilization-induced skin fibrosis through overexpression of transforming growth factor-ss1 and hypoxic conditions in a rat knee joint contracture model.</a> Connective Tissue Research. 58 (6), 586-596 (2017).</li><li>Sasabe, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+joint+immobilization+on+changes+in+myofibroblasts+and+collagen+in+the+rat+knee+contracture+model.">Effects of joint immobilization on changes in myofibroblasts and collagen in the rat knee contracture model.</a> Journal of Orthopaedic Research. 35 (9), 1998-2006 (2017).</li><li>Sakakima, H., Yoshida, Y., Sakae, K., Morimoto, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Different+frequency+treadmill+running+in+immobilization-induced+muscle+atrophy+and+ankle+joint+contracture+of+rats.">Different frequency treadmill running in immobilization-induced muscle atrophy and ankle joint contracture of rats.</a> Scandinavian Journal of Medicine &amp; Science in Sports. 14 (3), 186-192 (2004).</li><li>Nagai, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Contributions+of+biarticular+myogenic+components+to+the+limitation+of+the+range+of+motion+after+immobilization+of+rat+knee+joint.">Contributions of biarticular myogenic components to the limitation of the range of motion after immobilization of rat knee joint.</a> BMC Musculoskeletal Disorders. 15, 224 (2014).</li><li>Matsuzaki, T., Yoshida, S., Kojima, S., Watanabe, M., Hoso, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+ROM+Exercise+on+the+Joint+Components+during+Immobilization.">Influence of ROM Exercise on the Joint Components during Immobilization.</a> Journal of Physical Therapy Science. 25 (12), 1547-1551 (2013).</li><li>Kaneguchi, A., Ozawa, J., Kawamata, S., Yamaoka, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+arthrogenic+joint+contracture+as+a+result+of+pathological+changes+in+remobilized+rat+knees.">Development of arthrogenic joint contracture as a result of pathological changes in remobilized rat knees.</a> Journal of Orthopaedic Research. 35 (7), 1414-1423 (2017).</li><li>Hargreaves, D. G., Drew, S. J., Eckersley, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kirschner+wire+pin+tract+infection+rates:+a+randomized+controlled+trial+between+percutaneous+and+buried+wires.">Kirschner wire pin tract infection rates: a randomized controlled trial between percutaneous and buried wires.</a> Journal of Hand Surgery. 29 (4), 374-376 (2004).</li><li>Trudel, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differentiating+the+myogenic+and+arthrogenic+components+of+joint+contractures.+An+experimental+study+on+the+rat+knee+joint.">Differentiating the myogenic and arthrogenic components of joint contractures. An experimental study on the rat knee joint.</a> International Journal of Rehabilitation Research. 20 (4), 397-404 (1997).</li><li>Evans, E. B., Eggers, G. W. N., Butler, J. K., Blumel, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+Immobilization+and+Remobilization+of+Rat+Knee+Joints.">Experimental Immobilization and Remobilization of Rat Knee Joints.</a> Journal of Bone and Joint Surgery. 42 (5), 737-758 (1960).</li><li>Hagiwara, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expression+patterns+of+collagen+types+I+and+III+in+the+capsule+of+a+rat+knee+contracture+model.">Expression patterns of collagen types I and III in the capsule of a rat knee contracture model.</a> Journal of Orthopaedic Research. 28 (3), 315-321 (2010).</li><li>Trudel, G., Uhthoff, H. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Contractures+secondary+to+immobility:+is+the+restriction+articular+or+muscular?+An+experimental+longitudinal+study+in+the+rat+knee.">Contractures secondary to immobility: is the restriction articular or muscular? An experimental longitudinal study in the rat knee.</a> Archives of Physical Medicine and Rehabilitation. 81 (1), 6-13 (2000).</li><li>Hagiwara, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increased+elasticity+of+capsule+after+immobilization+in+a+rat+knee+experimental+model+assessed+by+scanning+acoustic+microscopy.">Increased elasticity of capsule after immobilization in a rat knee experimental model assessed by scanning acoustic microscopy.</a> Upsala Journal of Medical Sciences. 111 (3), 303-313 (2006).</li><li>Adelsperger, A. R., Bigiarelli-Nogas, K. J., Toore, I., Goergen, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+a+Low-flow+Digital+Anesthesia+System+for+Mice+and+Rats.">Use of a Low-flow Digital Anesthesia System for Mice and Rats.</a> Journal of Visualized Experiments. (115), (2016).</li><li>Trudel, G., O'Neill, P. A., Goudreau, L. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+mechanical+arthrometer+to+measure+knee+joint+contracture+in+rats.">A mechanical arthrometer to measure knee joint contracture in rats.</a> IEEE Transactions On Rehabilitation Engineering. 8 (1), 149-155 (2000).</li><li>Campbell, T. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+a+Knee+Arthrometer+to+Evaluate+Tissue-specific+Contributions+to+Knee+Flexion+Contracture+in+the+Rat.">Using a Knee Arthrometer to Evaluate Tissue-specific Contributions to Knee Flexion Contracture in the Rat.</a> Journal of Visualized Experiments. (141), (2018).</li><li>Moriyama, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Alteration+of+knee+joint+connective+tissues+during+contracture+formation+in+spastic+rats+after+an+experimentally+induced+spinal+cord+injury.">Alteration of knee joint connective tissues during contracture formation in spastic rats after an experimentally induced spinal cord injury.</a> Connective Tissue Research. 48 (4), 180-187 (2007).</li><li>Onoda, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Joint+haemorrhage+partly+accelerated+immobilization-induced+synovial+adhesions+and+capsular+shortening+in+rats.">Joint haemorrhage partly accelerated immobilization-induced synovial adhesions and capsular shortening in rats.</a> Knee Surgery, Sports Traumatology, &amp; Arthroscopy. 22 (11), 2874-2883 (2014).</li><li>Trudel, G., Jabi, M., Uhthoff, H. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Localized+and+adaptive+synoviocyte+proliferation+characteristics+in+rat+knee+joint+contractures+secondary+to+immobility.">Localized and adaptive synoviocyte proliferation characteristics in rat knee joint contractures secondary to immobility.</a> Archives of Physical Medicine and Rehabilitation. 84 (9), 1350-1356 (2003).</li><li>Jiang, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endoplasmic+reticulum+stress-dependent+ROS+production+mediates+synovial+myofibroblastic+differentiation+in+the+immobilization-induced+rat+knee+joint+contracture+model.">Endoplasmic reticulum stress-dependent ROS production mediates synovial myofibroblastic differentiation in the immobilization-induced rat knee joint contracture model.</a> Experimental Cell Research. 369 (2), 325-334 (2018).</li><li>Pithioux, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+Efficient+and+Reproducible+Protocol+for+Distraction+Osteogenesis+in+a+Rat+Model+Leading+to+a+Functional+Regenerated+Femur.">An Efficient and Reproducible Protocol for Distraction Osteogenesis in a Rat Model Leading to a Functional Regenerated Femur.</a> Journal of Visualized Experiments. (128), (2017).</li></ol>

The authors have nothing to disclose.

This study aimed to elucidate a step-by-step knee joint immobilization method using a mini-invasive technique that permits rapid postoperative rehabilitation in animals after surgery. Conventionally, the muscle-gap separation approach is thought to be a minimally invasive technique in orthopedic surgery. As expected, we found that rats can return to a normal diet and activities just one day postoperatively, which was consistent with the previous study. Moreover, no artery or nerve injury occurred after the surgery, evide...

Joint contractures are defined as a restriction in the passive range of motion (ROM) of a diarthrodial joint1,2. The current therapies aiming to prevent and treat joint contracture have achieved some success3,4. However, the underlying molecular mechanism of acquired joint contracture remains largely unknown5. The etiology of joint contractures in different social communities is highly diverse and includes genetic factors, posttraumatic states, chronic diseases, and prolonged immobility6. It is widely accepted that immobility is a critical issue in the development of acquired joint contracture7. People who suffer from major joint contracture may ultimately result in physical disability8. Thus, a stable and reproducible animal model is necessary for investigating the potential pathophysiological mechanisms of acquired joint contracture.
The currently built immobilization-induced knee joint contracture models are mostly achieved by utilizing non-invasive plaster casts, external fixations, and internal fixations. Watanabe et al. reported the possibility of the use of plaster cast immobilization on rat knee joints9. By wearing a special jacket, one side of the lower limb joint of the rat is immobilized by a cast. The rat knee joint can remain fully flexed without any surgical trauma10,11. However, both the hip and ankle joint movements are also affected by this form of immobilization, which may increase the degree of muscle atrophy in quadriceps femoris or gastrocnemius12. In addition, edema and congestion of the hind limbs must be avoided by replacing the cast at set time points, which may affect the continuity of immobility. Another accepted method for the establishment of a knee joint contracture model is using external surgical fixation. Nagai et al. combined Kirschner wire and steel wire into an external fixator, which immobilized the knee joint to approximately 140&#176; of flexion13. In this method, a resin is used to cover the surface to prevent skin scratches. Although external fixation immobilization is robust and reliable14,15, percutaneous Kirschner wire pin tracks may increase the risk of infection16. In our own experience, using the external fixation technique may reduce the daily activity of rats due to an increase in the conditioned lick behavior.
Alternatively, Trudel et al. described a well-accepted model of joint contracture in the rat knee joint based on a surgical internal fixation17 (this method was modified from the one used by Evans and colleagues18). Notably, this method highlights the importance of utilizing a mini-incision technique to minimize the surgical wounds. The efficient development of joint contracture has been proved in this model19. However, the protocol on how to perform a minimal dissection to expose the bone surface is still unclear20. Also, the precise position where the screw is drilling is not fully understood. The implantation of the internal fixation through a subcutaneous or submuscular way is still controversial21. To solve these problems, we have modified this method by including an appropriate muscle-gap separation modus, which allows a mini-invasive exposure of the bone surface and the placement of the implantation through a submuscular channel. This protocol led to rapid postoperative rehabilitation in rats after surgery. Animals developed a limited joint range of motion after joint immobilization, which was consistent with morphological changes of capsular adhesion obtained from the histological analysis. We also describe an exact possible location of the drilled screws as confirmed by X-ray analysis or micro-CT analysis. Thus, this study aimed to describe in detail a minimal-invasive technique in a knee joint contracture model that was established by a muscle-gap separation modus combined with a mini-incision method. We believe that minimally invasive techniques can both reduce animal trauma and effectively mimic the pathological process of joint flexion contracture.

<table><tbody><tr><td>Anerdian</td><td>Shanghai Likang Ltd.</td><td>310173</td><td>antibacterial</td></tr><tr><td>Buprenorphine&amp;nbsp;</td><td>Shanghai Shyndec Pharmaceutical Ltd.</td><td>/</td><td>analgesia&amp;nbsp;</td></tr><tr><td>Carprofen</td><td>MCE</td><td>HY-B1227</td><td>analgesia&amp;nbsp;</td></tr><tr><td>Cross screwdriver</td><td>STANLEY</td><td>PH0*125mm</td><td>tighten the screws</td></tr><tr><td>Electric drill</td><td>WEGO</td><td>185</td><td>drill hole(with stainless steel drill 0.9mm;1.0mm)</td></tr><tr><td>Microsurgical instruments</td><td>RWD</td><td>/</td><td>Orthopaedic surgical instruments for animals</td></tr><tr><td>Neomycin</td><td>Sigma</td><td>N6386</td><td>antibacterial</td></tr><tr><td>Sodium pentobarbital</td><td>Sigma</td><td>P3761</td><td>&amp;nbsp;anaesthetize</td></tr><tr><td>Stainless Steel screws</td><td>WEGO</td><td>m1.4*8; m1.2*6</td><td>screw(part of internal fixation)&amp;nbsp;</td></tr><tr><td>Syringe&amp;nbsp;</td><td>WEGO</td><td>3151474</td><td>use for plastic plate(part of internal fixation)&amp;nbsp;</td></tr><tr><td>&amp;mu;-CT&amp;nbsp;</td><td>ALOKA</td><td>Latheta LCT-200</td><td>in vivo CT scan</td></tr></tbody></table>

a mini-invasive internal fixation technique for studying immobilization-induced knee flexion contracture in rats

Joint contracture, resulting from a prolonged joint immobilization, is a common complication in orthopedics. Currently, utilizing an internal fixation to restrict knee joint mobility is a widely accepted model to generate experimental contracture. However, implanting application will inevitably cause surgical trauma to the animals. Aiming to develop a less invasive approach, we combined a muscle-gap separation modus with a previously reported mini-incision skill during the surgical procedure: Two mini skin incisions were made on the lateral thigh and leg, followed by performing muscle-gap separation to expose the bone surface. The rat knee joint was gradually immobilized by a preconstructed internal fixation at approximately 135&#176; knee flexion without interfering essential nerves or blood vessels. As expected, this simple technique permits rapid postoperative rehabilitation in animals. The correct position of the internal fixation was confirmed by an x-ray or micro-CT scanning analysis. The range of motion was significantly restricted in the immobilized knee joint than that observed in the contralateral knee joint demonstrating the effectiveness of this model. Besides, histological analysis revealed the development of fibrous deposition and adhesion in the posterior-superior knee joint capsule over time. Thus, this mini-invasive model may be suitable for mimicking the development of immobilized knee joint contracture.

We observed that rats received minimally invasive surgery can return to the regular diet just one day postoperatively. In particular, the surgical incision has scarred without exudate (Figure 5a). The swelling of the ankle and metacarpophalangeal joints in the operative hindlimb has almost wholly disappeared two days postoperatively (Figure 5b) when compared with the contralateral side (Figure 5c). N...

Watch this Scientific Journal Video about A Mini-Invasive Internal Fixation Technique for Studying Immobilization-Induced Knee Flexion Contracture in Rats at JoVE.com

A Mini-Invasive Internal Fixation Technique for Studying Immobilization-Induced Knee Flexion Contracture in Rats

Here, we present a protocol to describe a minimally invasive technique for knee joint immobilization in a rat model. This reproducible protocol, basing on muscle-gap separation modus and the mini-incision skill, is suitable for studying the underlying molecular mechanism of acquired joint contracture.

Joint contracture, resulting from a prolonged joint immobilization, is a common complication in orthopedics. Currently, utilizing an internal fixation to ...

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Universidad de Cartagena UDEC

Research

JoVE Journal

Developmental Biology

7.9K Views.  The Third Affiliated Hospital of Sun Yat-sen University. Here, we present a protocol to describe a minimally invasive technique for knee joint immobilization in a rat model. This reproducible protocol, basing on muscle-gap separation modus and the mini-incision skill, is suitable for studying the underlying molecular mechanism of acquired joint contracture.

Video: A Mini-Invasive Internal Fixation Technique for Studying Immobilization-Induced Knee Flexion Contracture in Rats

An in vivo Rodent Model of Contraction-induced Injury and Non-invasive Monitoring of Recovery

Muscle strains are one of the most common complaints treated by physicians. A muscle injury is typically diagnosed from the patient history and physical exam alone, however the clinical presentation can vary greatly depending on the extent of injury, the patient's pain tolerance, etc. In patients with muscle injury or muscle disease, assessment of muscle damage is typically limited to clinical signs, such as tenderness, strength, range of motion, and more recently, imaging studies. Biological markers, such as serum creatine kinase levels, are typically elevated with muscle injury, but their levels do not always correlate with the loss of force production. This is even true of histological findings from animals, which provide a "direct measure" of damage, but do not account for all the loss of function. Some have argued that the most comprehensive measure of the overall health of the muscle in contractile force. Because muscle injury is a random event that occurs under a variety of biomechanical conditions, it is difficult to study. Here, we describe an in vivo animal model to measure torque and to produce a reliable muscle injury. We also describe our model for measurement of force from an isolated muscle in situ. Furthermore, we describe our small animal MRI procedure.

An in vivo Rodent Model of Contraction-induced Injury and Non-invasive Monitoring of Recovery

An in vivo animal model of injury is described. The method takes advantage of the subcutaneous position of the fibular nerve. Velocity, timing of muscle activation, and arc of motion are all pre-determined and synchronized using commercial software. Post injury changes are monitored in vivo using MR imaging/spectroscopy.

Muscle strains are one of the most  common complaints treated by physicians. A muscle injury is typically diagnosed from the patient history and  physical ...

Medicine

Adjustable Stiffness, External Fixator for the Rat Femur Osteotomy and Segmental Bone Defect Models

The mechanical environment around the healing of broken bone is very important as it determines the way the fracture will heal. Over the past decade there has been great clinical interest in improving bone healing by altering the mechanical environment through the fixation stability around the lesion. One constraint of preclinical animal research in this area is the lack of experimental control over the local mechanical environment within a large segmental defect as well as osteotomies as they heal. In this paper we report on the design and use of an external fixator to study the healing of large segmental bone defects or osteotomies. This device not only allows for controlled axial stiffness on the bone lesion as it heals, but it also enables the change of stiffness during the healing process in vivo. The conducted experiments have shown that the fixators were able to maintain a 5 mm femoral defect gap in rats in vivo during unrestricted cage activity for at least 8 weeks. Likewise, we observed no distortion or infections, including pin infections during the entire healing period. These results demonstrate that our newly developed external fixator was able to achieve reproducible and standardized stabilization, and the alteration of the mechanical environment of in vivo rat large bone defects and various size osteotomies. This confirms that the external fixation device is well suited for preclinical research investigations using a rat model in the field of bone regeneration and repair.

One constraint of preclinical research in the field of bone repair is the lack of experimental control over the local mechanical environment within a healing bone lesion. We report the design and use of an external fixator for bone repair with the ability to change fixator stiffness in vivo.

The mechanical environment around the healing of broken bone is very important as it determines the way the fracture will heal. Over the past decade there ...

An Efficient and Reproducible Protocol for Distraction Osteogenesis in a Rat Model Leading to a Functional Regenerated Femur

This protocol describes the use of a newly developed external fixator for distraction osteogenesis in a rat femoral model. Distraction osteogenesis (DO) is a surgical technique leading to bone regeneration after an osteotomy. The osteotomized extremities are moved away from each other by gradual distraction to reach the desired elongation. This procedure is widely used in humans for lower and upper limb lengthening, treatment after a bone nonunion, or the regeneration of a bone defect following surgery for bone tumor excision, as well as in maxillofacial reconstruction. Only a few studies clearly demonstrate the efficiency of their protocol in obtaining a functional regenerated bone, i.e., bone that will support physiological weight-bearing without fracture after removal of the external fixator. Moreover, protocols for DO vary and reproducibility is limited by lack of information, making comparison between studies difficult. The aim of this study was to develop a reproducible protocol comprising an appropriate external fixator design for rat limb lengthening, with a detailed surgical technique that permits physiological weight-bearing by the animal after removal of the external fixator.

This study describes a reproducible and detailed protocol using a newly developed external fixator for distraction osteogenesis (DO) in a femoral rat model which permits physiological weight-bearing by the animal after removal of the external fixator.

This protocol describes the use of a newly developed external fixator for distraction osteogenesis in a rat femoral model. Distraction osteogenesis (DO) ...

Bioengineering

Rat Model of Adhesive Capsulitis of the Shoulder

This proposal aims to create an in vivo rat model of adhesive capsulitis for researching potential treatment options for this condition and other etiologies of comparable arthrofibrosis. The model includes extra-articular fixation of the shoulder in rats via scapular to humeral suturing, resulting in a secondary contracture without invading the intra-articular space and resulting in decreased rotational ROM and increased joint stiffness.
We used 10 Sprague-Dawley rats for the purpose of this study. Baseline ROM measurements were taken before glenohumeral immobilization. The rats were subjected to 8 weeks of immobilization before the fixation sutures were removed and changes in ROM and joint stiffness were evaluated. To evaluate whether immobilization resulted in a significant reduction in ROM, changes in kinematics were calculated. ROM was measured at each time point in the follow-up period and was compared to the baseline internal and external ROM measurements. In order to evaluate the stiffness, joint kinetics were calculated by determining the differences in torque (text and tint ) needed to reach the initial external rotation of 60&#176; and initial internal rotation of 80&#176;.
After the removal of the extra-articular suture fixation on follow-up day 0, we found a 63% decrease in total ROM compared to baseline. We observed continuous improvement until week 5 of follow-up, with the progress slowing down around a 19% restriction. On week 8 of follow-up, there was still an 18% restriction of ROM. Additionally, on follow-up day 0, we found the torque increased by 13.3 Nmm when compared to baseline. On week 8, the total torque was measured to be 1.4 &#177; 0.2 Nmm higher than initial measurements. This work introduces a rat model of shoulder adhesive capsulitis with lasting reduced ROM and increased stiffness.

This protocol presents an in vivo rat model of adhesive capsulitis. The model includes an internal fixation of the glenohumeral joint with extra-articular suture fixation for an extended time, resulting in a decreased rotational range of motion (ROM) and increased joint stiffness.

This proposal aims to create an in vivo rat model of adhesive capsulitis for researching potential treatment options for this condition and other ...

A Reliable and Reproducible Critical-Sized Segmental Femoral Defect Model in Rats Stabilized with a Custom External Fixator

Orthopedic research relies heavily on animal models to study mechanisms of bone healing in vivo as well as investigate the new treatment techniques. Critical-sized segmental defects are challenging to treat clinically, and research efforts could benefit from a reliable, ambulatory small animal model of a segmental femoral defect. In this study, we present an optimized surgical protocol for the consistent and reproducible creation of a 5 mm critical diaphyseal defect in a rat femur stabilized with an external fixator. The diaphyseal ostectomy was performed using a custom jig to place 4 Kirschner wires bicortically, which were stabilized with an adapted external fixator device. An oscillating bone saw was used to create the defect. Either a collagen sponge alone or a collagen sponge soaked in rhBMP-2 was implanted into the defect, and the bone healing was monitored over 12 weeks using radiographs. After 12 weeks, rats were sacrificed, and histological analysis was performed on the excised control and treated femurs. Bone defects containing only collagen sponge resulted in non-union, while rhBMP-2 treatment yielded the formation of a periosteal callous and new bone remodeling. Animals recovered well after implantation, and external fixation proved successful in stabilizing the femoral defects over 12 weeks. This streamlined surgical model could be readily applied to study bone healing and test new orthopedic biomaterials and regenerative therapies in vivo.

In vivo mammalian models of critical-sized bone defects are essential for researchers studying healing mechanisms and orthopedic therapies. Here, we introduce a protocol for the creation of reproducible, segmental, femoral defects in rats stabilized using external fixation.

Orthopedic research relies heavily on animal models to study mechanisms of bone healing in vivo as well as investigate the new treatment techniques. ...

An Intramedullary Locking Nail for Standardized Fixation of Femur Osteotomies to Analyze Normal and Defective Bone Healing in Mice

Bone healing models are essential to the development of new therapeutic strategies for clinical fracture treatment. Furthermore, mouse models are becoming more commonly used in trauma research. They offer a large number of mutant strains and antibodies for the analysis of the molecular mechanisms behind the highly differentiated process of bone healing. To control the biomechanical environment, standardized and well-characterized osteosynthesis techniques are mandatory in mice. Here, we report on the design and use of an intramedullary nail to stabilize open femur osteotomies in mice. The nail, made of medical-grade stainless steel, provides high axial and rotational stiffness. The implant further allows the creation of defined, constant osteotomy gap sizes from 0.00 mm to 2.00 mm. Intramedullary locking nail stabilization of femur osteotomies with gap sizes of 0.00 mm and 0.25 mm result in adequate bone healing through endochondral and intramembranous ossification. Stabilization of femur osteotomies with a gap size of 2.00 mm results in atrophic non-union. Thus, the intramedullary locking nail can be used in healing and non-healing models. A further advantage of the use of the nail compared to other open bone healing models is the possibility to adequately fix bone substitutes and scaffolds in order to study the process of osseous integration. A disadvantage of the use of the intramedullary nail is the more invasive surgical procedure, inherent to all open procedures compared to closed models. A further disadvantage may be the induction of some damage to the intramedullary cavity, inherent to all intramedullary stabilization techniques compared to extramedullary stabilization procedures.

This protocol describes an osteosynthesis technique using an intramedullary locking nail for standardized fixation of femur osteotomies, which can be used to analyze normal and defective bone healing in mice.

Bone healing models are essential to the development of new therapeutic strategies for clinical fracture treatment. Furthermore, mouse models are becoming ...

Using a Knee Arthrometer to Evaluate Tissue-specific Contributions to Knee Flexion Contracture in the Rat

Normal knee range of motion (ROM) is critical to well-being and allows one to perform basic activities such as walking, climbing stairs and sitting. Lost ROM is called a joint contracture and results in increased morbidity. Due to the difficulty of reversing established knee contractures, early detection is important, and hence, knowing risk factors for their development is essential. The rat represents a good model with which the effect of an intervention can be studied due to the similarity of rat knee anatomy to that of humans, the rat's ability to tolerate long durations of knee immobilization in flexion, and because mechanical data can be correlated with histologic and biochemical analysis of knee tissue.
Using an automated arthrometer, we demonstrate a validated, precise, reproducible, user-independent method of measuring the extension ROM of the rat knee joint at specific torques. This arthrometer can be used to determine the effects of interventions on knee joint ROM in the rat.

The goal of the protocol is to measure the extension range of motion of the rat knee. The effects of various diseases that increase the stiffness of the knee joint and the effectiveness of treatments can be quantified.

Normal knee range of motion (ROM) is critical to well-being and allows one to perform basic activities such as walking, climbing stairs and sitting. Lost ...

The Generation of Closed Femoral Fractures in Mice: A Model to Study Bone Healing

Bone fractures impose a tremendous socio-economic burden on patients, in addition to significantly affecting their quality of life. Therapeutic strategies that promote efficient bone healing are non-existent and in high demand. Effective and reproducible animal models of fractures healing are needed to understand the complex biological processes associated with bone regeneration. Many animal models of fracture healing have been generated over the years; however, murine fracture models have recently emerged as powerful tools to study bone healing. A variety of open and closed models have been developed, but the closed femoral fracture model stands out as a simple method for generating rapid and reproducible results in a physiologically relevant manner. The goal of this surgical protocol is to generate unilateral closed femoral fractures in mice and facilitate a post-fracture stabilization of the femur by inserting an intramedullary steel rod. Although devices such as a nail or a screw offer greater axial and rotational stability, the use of an intramedullary rod provides a sufficient stabilization for consistent healing outcomes without producing new defects in the bone tissue or damaging nearby soft tissue. Radiographic imaging is used to monitor the progression of callus formation, bony union, and subsequent remodeling of the bony callus. Bone healing outcomes are typically associated with the strength of the healed bone and measured with torsional testing. Still, understanding the early cellular and molecular events associated with fracture repair is critical in the study of bone tissue regeneration. The closed femoral fracture model in mice with intramedullary fixation serves as an attractive platform to study bone fracture healing and evaluate therapeutic strategies to accelerate healing.

The murine closed femoral fracture model is a powerful platform to study fracture healing and novel therapeutic strategies to accelerate bone regeneration. The goal of this surgical protocol is to generate unilateral closed femoral fractures in mice using an intramedullary steel rod to stabilize the femur.

Bone fractures impose a tremendous socio-economic burden on patients, in addition to significantly affecting their quality of life. Therapeutic strategies ...

Protocol for Developing a Femur Osteotomy Model in Wistar Albino Rats

Fracture healing is a physiological process resulting in the regeneration of bone defects by the coordinated action of osteoblasts and osteoclasts. Osteoanabolic drugs have the potential to augment the repair of fractures but have constraints like high costs or undesirable side effects. The bone healing potential of a drug can initially be determined by in vitro studies, but in vivo studies are needed for the final proof of concept. Our objective was to develop a femur osteotomy rodent model that could help researchers understand the development of callus formation following fracture of the shaft of the femur and that could help establish whether a potential drug has bone healing properties. Adult male Wistar albino rats were used after Institutional Animal Ethics Committee clearance. The rodents were anesthetized, and under aseptic conditions, complete transverse fractures at the middle one-third of the shafts of the femurs were created using open osteotomy. The fractures were reduced and internally fixed using intramedullary K-wires, and secondary fracture healing was allowed to take place. After surgery, intraperitoneal analgesics and antibiotics were given for 5 days. Sequential weekly x-rays assessed callus formation. The rats were sacrificed based on radiologically pre-determined time points, and the development of the fracture callus was analyzed radiologically and using immunohistochemistry.

Here, we present a protocol to iatrogenically fracture the shaft of the femur of Wistar albino rats and follow up on the development of the callus. This femur osteotomy model can help researchers evaluate the process of fracture healing and to study how a drug could influence fracture healing.

Fracture healing is a physiological process resulting in the regeneration of bone defects by the coordinated action of osteoblasts and osteoclasts. ...

Visualization of Knee Joint Degeneration after Non-invasive ACL Injury in Rats

Source: Lindsey K. Lepley1,2, Steven M. Davi1, Timothy A. Butterfield3,4 and Sina Shahbazmohamadi5,
1Department of Kinesiology, University of Connecticut, Storrs, CT; 2Department of Orthopaedic Surgery, University of Connecticut Health Center, Farmington, CT; 3Department of Rehabilitation Sciences, University of Kentucky, Lexington, KY; 4Center for Muscle Biology, Department of Physiology, University of Kentucky, Lexington, KY; 5Biomedical Engineering Department, University of Connecticut, Storrs, CT
Anterior cruciate ligament (ACL) injury to the knee dramatically increases the risk of post-traumatic osteoarthritis (PTOA), as approximately one-third of individuals will demonstrate radiographic PTOA within the first decade following ACL injury. Though ACL reconstruction (ACLR) successfully restores knee joint stability, ACLR and current rehabilitation techniques do not prevent the onset of PTOA. Therefore, ACL injury represents the ideal model to study the development of PTOA after traumatic joint injury.
Rat models have been used extensively to study the onset and effect of ACL injury on PTOA. The most widely used model of ACL injury is ACL transection, which is an acute model that surgically destabilizes the joint. Though practical, this model does not faithfully mimic human ACL injury due to the invasive and non-physiological injury procedures that mask the native biological response to injury. To improve the clinical translation of our results, we have recently developed a novel non-invasive model of ACL injury where the ACL is ruptured through a single load of tibial compression. This injury closely replicates injury conditions relevant to humans and is highly reproducible.
Visualization of joint degeneration through micro-computed tomography (&#181;CT) provides several major advancements over traditional OA staining techniques, including rapid, high-resolution, non-destructive 3D imaging of whole joint degeneration. The goal of this demonstration is to introduce the state of the art non-invasive ACL injury in a rodent model and use &#181;CT to quantify knee joint degeneration.

Knee Joint Degeneration after Non-invasive Anterior Cruciate Ligament Injury

Source: Lindsey K. Lepley1,2, Steven M. Davi1, Timothy A. Butterfield3,4 and Sina Shahbazmohamadi5,
1Department of Kinesiology, University of Connecticut, ...

A Mini-Invasive Internal Fixation Technique for Studying Immobilization-Induced Knee Flexion Contracture in Rats

Summary

Explore More Videos

Chapters in this video

An in vivo Rodent Model of Contraction-induced Injury and Non-invasive Monitoring of Recovery

Adjustable Stiffness, External Fixator for the Rat Femur Osteotomy and Segmental Bone Defect Models

An Efficient and Reproducible Protocol for Distraction Osteogenesis in a Rat Model Leading to a Functional Regenerated Femur

Rat Model of Adhesive Capsulitis of the Shoulder

A Reliable and Reproducible Critical-Sized Segmental Femoral Defect Model in Rats Stabilized with a Custom External Fixator

An Intramedullary Locking Nail for Standardized Fixation of Femur Osteotomies to Analyze Normal and Defective Bone Healing in Mice

Using a Knee Arthrometer to Evaluate Tissue-specific Contributions to Knee Flexion Contracture in the Rat

The Generation of Closed Femoral Fractures in Mice: A Model to Study Bone Healing

Protocol for Developing a Femur Osteotomy Model in Wistar Albino Rats

Visualization of Knee Joint Degeneration after Non-invasive ACL Injury in Rats