[Advances in the Treatment of Osteochondral Lesions of the Talus]

Osteochondral lesion of the talus (OLT) is a localized cartilage and subchondral bone injury of the talus trochlea. OLT is caused by trauma and other reasons, including osteochondritis dissecans of the talus (OCD) and talus osteochondral tangential fracture. OLT can develop from being asymptomatic to subchondral bone cysts accompanied by deep ankle pain. OLT tends to occur on the medial and lateral sides of the talar vault. OLT seriously affects the patients' life and work and may even lead to disability. Herein, we reviewed advances in the treatment of OLT and the strengths and weaknesses of various treatments. Different treatment methods, including conservative treatments and surgical treatments, can be adopted according to the different subtypes or clinical symptoms of OLT. Conservative treatments mostly relieve symptoms in the short term and only slow down the disease. In recent years, it has been discovered that platelet-rich plasma injection, microfracture, periosteal bone grafting, talar cartilage transplantation, allograft bone transplantation, reverse drilling under robotic navigation, and other methods can achieve considerable benefits when each of these treatment methods is applied. Furthermore, microfracture combined with platelet-rich plasma injections, microfracture combined with cartilage transplantation, and various other treatment methods combined with anterior talofibular ligament repair have all led to good treatment outcomes.

Basic fibroblast growth factor and agarose gel promote ​the ability of immune privilege of allogeneic cartilage transplantation in rats

Objective

Allogeneic cartilage transplantation is used to treat severe osteochondral defects or cartilaginous injury. However, acute immune rejection has been a key problem interfering with graft healing.

Methods

Full-thickness osteochondral defects were performed in Sprague Dawley rats. The allograft implants were set into the defect region. Blood and spleen samples from Postoperative Day 3 onward were collected for inflammatory cell analysis, including analysis of monocytes, natural killer cells, CD4⁺CD25⁺Foxp3⁺ regulatory T cells, CD4⁺ T cells, and CD8⁺ T cells. Gross observation and histologic staining (hematoxylin and eosin, toluidine blue) were carried out at the same time point to assess the repair effect of the cartilage graft and the degree of immune rejection.

Results

Treatment with basic fibroblast growth factor, agarose gel, and allogeneic cartilage was similar to that of the autologous group. The percentage of monocytes in allografts was at a higher level in the spleen and blood; the frequency of CD4⁺ T cells in the allogeneic group was higher than in the autologous group and the other agarose groups at 6 weeks after transplantation. The number of regulatory T cells in the autograft was increased from Postoperative Week 1; similar results were observed in groups containing basic fibroblast growth factor beginning at Postoperative Week 3.

Conclusions

Allogeneic cartilage transplantation induces acute immune rejection, which compromises the validity of the implant. The combination of basic fibroblast growth factor and agarose gel facilitates the goal of immune privilege and promotes the success of the allograft tissues.

The translational potential of this article

This study investigated the combination of basic fibroblast growth factor (bFGF) and agarose gel facilitates promotes the success of the allograft tissues transplantation. This work may help clinicians find a new way to repair articular cartilage damage. This will affect the treatment of articular cartilage movement injuries and arthritis.

Histological study of costal cartilage after transplantation and reasons for avoidance of postoperative resorption and retention of cartilage structure in rats

BACKGROUND

Limited information is available on the biological status of transplanted cartilage from which the perichondrium has been removed. This article describes the histological and three-dimensional structural picture of cartilage, using green fluorescent protein (GFP) transgenic rats and normal wild rats.

METHODS

Three sections of costal cartilage were harvested from 10-week-old wild rats. One section was used as a specimen while two were subcutaneously collected from the dorsal region of 10-week-old GFP rats at 4 and 8 weeks post-transplant. The experiment was performed in two randomized groups. The perichondrium was removed from transplanted cartilage in the first group and perichondrium of transplanted cartilage remained intact in the second group. Histology and focused ion beam/scanning electron microscope (FIB/SEM) tomography were used to evaluate the transplanted cartilage.

RESULTS

All 40 transplanted sections were harvested and no infections, exposure or qualitative change of cartilage matrix were seen following transplant. Histological analyses showed that the surface layer of the GFP-negative transplanted cartilage was replaced with GFP-positive chondrocytes 8 weeks post-transplant in the first group. A three-dimensional layer of perichondrium-like tissue reconstructed around the cartilage at 8 weeks was confirmed, resembling normal perichondrium. However, the GFP-positive chondrocytes were not replaced in the second group.

CONCLUSIONS

The cell renewal of chondrocytes is necessary for subcutaneously transplanted cartilage to maintain its tissue composition over a long period of time. The histological and ultrastructural analyses revealed that cells from recipient tissue generated new chondrocytes even when cartilage was implanted after removing the perichondrium.

Two-stage late reconstruction with a fresh large osteochondral shell allograft transplantation (FLOCSAT) for a large ostechondral defect in a non-union after a lateral tibia plateau fracture 2-year follow up

This is the description of a 58-year-old female patient presenting 8 months after a horse riding accident with significant pain and inability to walk independently. Imaging revealed a large osseous defect of the lateral tibia plateau which was not united posteriorly. The patient refused knee replacement and we developed a patient specific two-step procedure for her. Step 1: Filling of the defect with a large cortico-cancellous autograft from the posterior iliac crest; step 2: Transplantation of a fresh large osteochondral shell allograft (FLOCSAT). The postoperative protocol included continuous passive motion (CPM), partial weight bearing for three months, and physiotherapy. Based on the concept of immuno-privileged cartilage tissue, the patient did not get any immuno-suppressive therapy. Pain-, activity of daily living, Lysholm and Tegner scores were evaluated before defect filling surgery with autograft, before allograft transplantation, and at 12 and 24 months after allograft transplantation. There were no complications. Radiographic analyses with plain films and CT scans revealed solid osseous integration within 3 month. The patient regained excellent functionality in both, activities of daily living and sports (back to horse riding, trampolin jumping). Knee arthroscopy after 1year showed excellent condition of the lateral meniscus and the cartilage of the lateral tibia plateau. Chimerism/DNA analysis of a cartilage biopsy showed, that at 1year 32% of the donor cells have been already replaced by the patient's own cells. To our knowledge, this is the first case of a patient who sustained such a large defect during a tibia plateau fracture, and got successfully treated with a fresh large osteochondral shell allograft transplantation in a two-step procedure.

Practical execution of defect preparation prior to surgical cartilage intervention: results from a representative meeting survey among experts

During a specialised orthopedic meeting held on ‘the state of the art in cartilage defect repair’, all previously fully-registered participants were requested to participate in an electronic survey by the use of a moderator-presented “Power Point Presentation-based” 9-item questionnaire. The aim of this survey was to assess indication, approach, and treatment execution of cartilage defect debridement prior to planned microfracture (MFX) or autologous chondrocyte implantation (ACI). All participants completed the questionnaire (n = 146) resulting in a return rate of 100 %. An uncertainty exists as to whether the removal of the calcifying layer prior to cartilage repair must be carried out or not. The same was true for the acceptability of subchondral bleeding prior to microfracturing and its handling prior to autologous chondrocyte implantation. There is a degree of unanimity among experts regarding the management of osteophytes and bone marrow edema. In a homogenous society collective of consultants that frequently deal with cartilage defective pathologies, there still remain a significant heterogeneity in selected topics of defect debridement.

Revision cartilage cell transplantation for failed autologous chondrocyte transplantation in chronic osteochondral defects of the knee

The management of failed autologous chondrocyte implantation (ACI) and matrix-assisted autologous chondrocyte implantation (MACI) for the treatment of symptomatic osteochondral defects in the knee represents a major challenge. Patients are young, active and usually unsuitable for prosthetic replacement. This study reports the results in patients who underwent revision cartilage transplantation of their original ACI/MACI graft for clinical or graft-related failure. We assessed 22 patients (12 men and 10 women) with a mean age of 37.4 years (18 to 48) at a mean of 5.4 years (1.3 to 10.9). The mean period between primary and revision grafting was 46.1 months (7 to 89). The mean defect size was 446.6 mm(2) (150 to 875) and they were located on 11 medial and two lateral femoral condyles, eight patellae and one trochlea. The mean modified Cincinnati knee score improved from 40.5 (16 to 77) pre-operatively to 64.9 (8 to 94) at their most recent review (p < 0.001). The visual analogue pain score improved from 6.1 (3 to 9) to 4.7 (0 to 10) (p = 0.042). A total of 14 patients (63%) reported an 'excellent' (n = 6) or 'good' (n = 8) clinical outcome, 5 'fair' and one 'poor' outcome. Two patients underwent patellofemoral joint replacement. This study demonstrates that revision cartilage transplantation after primary ACI and MACI can yield acceptable functional results and continue to preserve the joint.