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Current Treatment Methods for Articular Cartilage Injury
critically important to facilitate a physically active lifestyle. microfracture technique. In experimental studies the addition of
Maintaining an active lifestyle has significant medical benefits, such growth factors such as transforming growth factor-beta 3 (TGF-β3)
as reducing the risk of serious medical conditions like heart disease, and bone morphogenetic protein-7 (BMP-7) was able to induce
hypertension, and diabetes. Since injuries to articular cartilage have chondrogenic marker gene expression for type II and IX collagen,
been shown to present one of the most common causes of cartilage oligometric matrix protein (COMP) and aggrecan with both
permanent disability, their management has important long-term qualitative and quantitative improvement of the repair cartilage after
implications.
13,14
Treatment of articular cartilage injuries has microfracture.
25,26
Besides directly stimulating the chondrogenic
traditionally presented a significant therapeutic challenge. However, differentiation, a different approach involves enhancement of the
development of first-generation surgical techniques has created microfracture repair by modulation of the potential negative effect of
considerable clinical and scientific enthusiasm for articular cartilage cytokines on the repair tissue. Recent long-term experimental data
repair.
15–18
Based on the source of the cartilage repair tissue, these have shown promise by demonstrating increased proteoglycan and
new surgical techniques can generally be categorised into three type II collagen content in the microfracture repair tissue after
groups: marrow-stimulation-based techniques, osteochondral stimulating local production of interleukin-1 receptor antagonist
transplantation techniques and cell-based repair techniques. Each of protein (IL-1 ra) by in vivo gene therapy.
27
However, while these
the existing cartilage repair techniques is associated with unique approaches are scientifically plausible and the results are promising,
advantages and limitations. New treatment options are being their transition to clinical application is still pending.
explored that integrate modern tissue engineering and genetic
augmentation techniques to further improve the quantity and quality By contrast, clinical evaluation has started for other microfracture-
of the repair cartilage generated by the currently existing cartilage based cartilage repair techniques that use scaffold-guided in situ
restoration methods. chondroinduction.
28,29
These technologies use 3D scaffolds to enhance
the initial stability and peripheral adhesion of the microfracture clot,
Marrow Stimulation Methods thereby reducing the risk for early clot displacement. In situ
Microfracture Chondroplasty solidification of the microfracture clot with chitosan–glycerol
Due to its limited invasiveness, low associated morbidity and phosphate (BST-CarGel, Bisosyntec Inc, Laval, Quebec, Canada), a
relatively short post-operative rehabilitation, microfracture has thrombogenic and adhesive polysaccharide polymer, has been shown
become a popular treatment option for articular cartilage lesions. By to improve cartilage repair volume and biochemical composition after
penetration of the subchondral plate this technique results in filling experimental microfracture.
43,45
Preliminary clinical data from 33
the cartilage defect with a blood clot that contains pluripotent patients have demonstrated the safety of this technique with
marrow-derived mesenchymal stem cells, which subsequently improvement of Western Ontario and McMaster Universities
produce a mixed fibrocartilage repair tissue that contains varying Osteoarthrisis Index (WOMAC) scores after 12–24 months.
31
amounts of type II collagen.
19,20
Improved knee function has been
reported in 58–95% after microfracture with significantly increased Other authors have developed a novel method that uses
activity scores. Return to sports was demonstrated in 44–77% after microfracture with a combination of a multifunctional chondroitin
microfracture, in 57% of them at the pre-operative level.
20–22
sulphate for peripheral adhesion and injectable biodegradable
hydrogel scaffold to enhance microfracture repair (Chondux, Cartilix
Several factors have been found to influence the results after Inc, San Carlos, CA). Photopolymerisation of the hydrogel allows for
microfracture. The time between injury and microfracture has a rapid stabilisation of the combined cellular implant
29
(see Figure 1). In
significant effect on outcome, emphasising the critical role of early clinical trials this minimally invasive technique has shown reduction
surgical treatment of articular cartilage lesions for successful of pain in 92%, significantly improved International Knee
outcome.
20–22
Microfracture is most effective as a first-line procedure in Documentation Committee (IKDC) scores, excellent repair cartilage fill
patients under 40 years of age with lesion size ≤2cm
2
.
20–23
Following volume in 93% and peripheral intergration on MRI at 12 months after
initial functional improvement, deterioration of knee function has been implantation. Prospective, randomised, long-term comparisons with
described in 47–80% after 24 months.
23,24
While the exact reasons for microfracture are needed to further evaluate the promising new
this functional decline are unknown, some studies suggest that repair technologies, specifically in the demanding athletic population.
cartilage volume plays a critical role in durability, as deterioration of
knee function occurs primarily with poor repair cartilage fill.
23,20
Post- Osteochondral Transplantation Methods
operative magnetic resonance imaging (MRI) demonstrates depressed Osteochondral Autograft Transfer
repair cartilage morphology and incomplete peripheral integration in The use of osteochondral autografts (mosaicplasty/osteochondral
53–96% and subchondral bony overgrowth in 25–40%.
23
Lack of autograft transfer system [OATS]) for repair of focal chondral and
peripheral integration and relative thinning of the repair cartilage osteochondral lesions has been popularised by Hangody.
32
This
increases mechanical stress on the repair cartilage and promotes technique provides a hyaline cartilage repair by harvesting cylindrical
repair cartilage degeneration, and may contribute to the observed osteochondral grafts from areas of limited weight-bearing and
functional deterioration in the demanding athletic population. transfering them into small to mid-size (1–4cm
2
) defects of the weight-
bearing cartilage using a press-fit technique. Prospective studies have
Next-generation Microfracture Techniques shown up to 95% good or excellent results with significantly improved
Despite its current limitations, recent data has shown that the knee function scores.
32–34
Macroscopic International Cartilage Repair
microfracture technique provides multipotent stem-cell-like Society (ICRS) scores and MRI demonstrated 84 and 94% good to
mesechymal progenitor cells with a high chondrogenic differentiation excellent ratings, respectively. Return to athletic activity was reported in
potential.
25
This has prompted the investigation of new technologies 61–93%, as early as six to nine months post-operatively. Longer pre-
that can help to enhance the results from the first-generation operative symptoms, age >30 years and pre-operative radiographic
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