In literature many authors reported different treatments of the osteochondral lesion [31
], but a true comparison between studies is difficult considering the different rating scales used, as indicated by Zengerink et al. in a meta-analysis [33
], in which so many scores as AOFAS Ankle-Hindfoot scale, Hannover score, patient satisfaction score, criteria proposed by Berndt and Harty, visual analog scale, Martin score, Alexander and Lichtman, Ogilvie Harris score, MODEMS (Musculoskeletal Outcomes Data Evaluation and Management System), Karlsson scoring scale, Tegner score, evaluation proposed by Loomer, Mazur score, Freiburg ankle score, SANE (Single Assessment Numeric Evaluation), according to Thompson and Loomer, and McCullough score are used for clinical assessment.
Traumatic cartilage fragments that have not detached from the bone can be treated with stabilization by pins or screws [41
The medial dome lesions are more common and larger than lateral, the two most common talus sites of injury being, respectively, centromedial and centrolateral. Posteromedial and anterolateral lesions are rare [34
]. Only 17% of the medial lesions and 20% of the lateral need an osteotomic access, and different studies describe medial malleolar osteotomy access [43
]. Depending on the treatment methods a precise reduction and fixation of the bone window with 1 or 2 screws is fundamental.
When cartilage remains intact on the subchondral bone lesion, retrograde drilling can be performed to protect the integrity of the articular cartilage. Outcome studies have shown good results [46
]. Some authors injected, in liquid form, calcium sulfate into the lesion after drilling, as bone substitute [49
Microfracture or microdrilling has the aim to stimulate the development of fibrocartilage increasing the serum factors on the subchondral plate that leads to fibrous tissue formation at the defect site and symptomatic relief for the patient [50
]. The new angiogenesis is by this way stimulated, bone marrow cells are introduced in the osteochondral defect, and fibrocartilaginous tissue is formed. Studies indicate this technique of bone marrow stimulation (BMS) as optimal in small lesion (diameter less than 15
mm) with chondral damage, but not subchondral bone involvement [30
Tissue transplantation today includes different techniques that are most widely used. Often the surgeons utilize perpendicular access to the injured area to allow the transplant into the talus.
For larger talar injury a Mosaicplasty proposed by Hangody et al. can be performed [53
]. The lesion must have a surface of no more than 4
cm² and about 10
mm in diameter. This technique utilizes cylindrical osteochondral plugs taken from the nonweightbearing femoral segment of the knee that are transferred to a talar dome defect. Different studies have shown good and excellent results in 94% of the cases [53
Another technique for larger cystic osteochondral lesion is Osteochondral Autologous Transfer System (OATS). When the lesion is more than 6
mm of diameter, there is the conversion from arthroscopy to open surgery, often with medial malleolar osteotomy. Also in this case good results are reported in literature [56
Osteochondral Allograft Transplantation is usually utilized for very large lesions, when the size of the lesion is more than 3
cm³. The advantage of this technique is the correct sizing of the graft, which is done intraoperatively with direct measurement. The allograft is often held in place by screw fixation [58
The ACI technique (Autologous Chondrocytes Implantation) was developed by Brittberg et al. and Peterson et al. [61
]. It includes the suture of a periosteal flap to the rim of the debrided chondral defect. We can consider MACI technique (Matrix—induced Autologous Chondrocytes Implantation) as an ACI evolution. The advantages of these 3-dimensional matrices are that they are easier to handle and apply, they are conformable to the lesion without the need of periosteal coveraging, and it is possible to apply them by an arthroscopic approach. This is the technique described in this study.
The disadvantages can be found in the need of 2 surgical steps, higher costs, more recovery time, and some limits in the treatment of deep lesions, in which an additional bone graft could be necessary, and some difficulties in new chondrocytes proliferation control [33
Our results, according to AOFAS score [37
], Van Dijk's et al. visual analogic scale (VAS) [38
], Coughlin score [39
], information about return to work or sport, and the MOCART score [40
], are comparable to the results reported in literature [20
While a preoperative subjective patients' satisfaction Coughlin score cannot be assessed, the lack of the preoperative VAS Van Dijk's score represents a limit of the study.
In the Zengerink et al. review [33
] 4 studies with the ACI technique for a total of 59 patients were discussed. In 45 of 59 cases (76%; range: 70 to 92%) a successful result was reported.
Giannini et al. with ACI technique in 8 patients and a mean follow-up of 26 months obtained an increase of the mean AOFAS score from 32,1 preoperatively to 91 postoperatively [28
According to the literature's results in prospective randomized studies, the ACI technique showed better results in cartilage lesions with a size of more than 3
cm², when compared with mosaicplasty and microfracture technique [63
There are not yet superiority evidence of the MACI technique we applied compared to the ACI technique. This may also be due to assessment methods. Most of the studies use the AOFAS score, which is very “functional” but not specific; it relates to common daily activities [37
If we judge the results based on the Van Dijk score or on Coughlin's degree of subjective satisfaction, we would see lower excellent and good results.
It is therefore still not possible to adequately compare the two surgical techniques.
Also with MACI technique, as in Brittberg et al. and Peterson et al. technique (ACI) [61
], the disadvantage are the 2 surgical steps, in which the 2nd sometimes required a malleolar osteotomy access or anterior arthrotomy, and the cost/benefits ratio of the surgical technique that, according to the different scores used in the studies, cannot be accurately validated.
There are new methods that are still under study.
Mesenchymal Stem Cells (MSCs) from bone marrow have been cultured in vitro and have been used in hybrid scaffolds to repair osteochondral defects [66
Platelet-rich plasma is characterized by red blood cells, white blood cells, and platelets in a fibrin matrix, where platelet-derived growth factor, insulin-like growth factor, and TGF-β
are included. This clot is poured into the lesion site [69
Tissue engineering has been proposed for the tissue regeneration using biomaterials, cells, and factors alone or together. Three options have been described: extraction of the patient's cells, vitro cultures, and then transplantation; utilization of biologic factors as growth factors; and use of 3-dimensional porous materials to stimulate the tissue ingrowths [71
As summarized by Van Dijk et al., ACI/MACI technique is a relatively expensive technique, while OATS gives morbidity from knee complained by up to 36% of patients in literature. On the other hand, arthroscopic excision, curettage, and BMS are relatively inexpensive, with a low morbidity, a quick recovery, and a high success rate (85%).
According to these facts and based on a non-obvious superiority of one surgical technique over the other, BMS should be still considered as the treatment of choice for type 3 and 4 osteochondral talar lesions, while in lesions with a size of more than 1,5
cm², ACI-MACI techniques should be considered in order to achieve better results with cartilage reconstruction.