The Use of Autologous Matrix-Induced Chondrogenesis as a Surgical Treatment for Patients with the First Metatarsophalangeal Joint Osteoarthritis: Immediate and Medium-Term Results

Microscale strain concentrations in tissue-engineered osteochondral implants are dictated by local compositional thresholds and architecture

Tissue-engineered osteochondral implants manufactured from condensed mesenchymal stem cell bodies have shown promise for treating focal cartilage defects. Notably, such manufacturing techniques have shown to successfully recapture the bulk mechanical properties of native cartilage. However, the relationships among the architectural features, local composition, and micromechanical environment within tissue-engineered cartilage from cell-based aggregates remain unclear. Understanding such relationships is crucial for identifying critical parameters that can predict in vivo performance. Therefore, this study investigated the relationship among architectural features, composition, and micromechanical behavior of tissue-engineered osteochondral implants. We utilized fast-confocal microscopy combined with a strain mapping technique to analyze the micromechanical behavior under quasi-static loading, as well as Fourier Transform Infrared Spectroscopy to analyze the local compositions. More specifically, we investigated the architectural features and compositional distributions generated from tissue maturation, along with macro- and micro-level strain distributions. Our results showed that under compression, cell-based aggregates underwent deformation followed by body movement, generating high local strain around the boundaries, where local aggrecan concentration was low and local collagen concentration was high. By analyzing the micromechanics and composition at the single aggregate length scale, we identified a strong threshold relationship between local strain and compositions. Namely at the aggrecan concentration below 0.015 arbitrary unit (A.U.) and the collagen concentration above 0.15 A.U., the constructs experienced greater than threefold increase in compressive strain. Overall, this study suggests that local compositional features are the primary driver of the local mechanical environment in tissue-engineered cartilage constructs, providing insight into potential quality control parameters for manufacturing tissue-engineered constructs.

Autologous matrix induced chondrogenesis plus peripheral blood concentrate (AMIC+PBC) in chondral defects of the first metatarsophalangeal joint - 5-year follow-up

BACKGROUND

The aim of the study was to assess the 5-year-follow-up (5FU) after Autologous Matrix Induced Chondrogenesis plus Peripheral Blood Concentrate (AMIC+PBC) in chondral defects at the first metatarsophalangeal joint (MTP1).

MATERIAL AND METHODS

In a prospective consecutive non-controlled clinical follow-up study, all patients with chondral lesion at MTP1 that were treated with AMIC+PBC from July 17, 2016 to May 31, 2017 were included. Size and location of the chondral lesions, the Visual-Analogue-Scale Foot and Ankle (VAS FA) and the EFAS Score before treatment and at 5FU were analysed and compared with previous 2-year-follow-up (2FU). Peripheral Blood Concentrate (PBC) was used to impregnate a collagen I/III matrix (Chondro-Gide, Wolhusen, Switzerland) that was fixed into the chondral lesion with fibrin glue.

RESULTS

One hundred and ninety-eight patients with 238 chondral defects were included. In 21 % of patients no deformities in the forefoot were registered. The average degree of osteoarthritis was 2.2. The chondral defect size was 1.0 cm² on average. The most common location was metatarsal dorsal (33 %), and in most patients one defect was registered (74 %). Corrective osteotomy of the first metatarsal was performed in 79 %. 176 (89 %)/164 (83 %) patients completed 2FU/5FU. VAS FA/EFAS Score were preoperatively 46.8/11.9 and improved to 74.1/17.1 at 2FU and 75.0/17.3 at 5FU on average. No parameter significantly differed between 2FU and 5FU.

CONCLUSIONS

AMIC+PBC as treatment for chondral defects at MTP1 as part of joint preserving surgery led to improved and high validated outcome scores at 2FU and 5FU. The results between 2FU and 5FU did not differ.

[Description of a technique that uses Lapidus arthrodesis plus osteochondral autotransplantation in the treatment of severe hallux rigidus]

OBJECTIVE

The objective of this technique is the treatment a severe hallux rigidus deformity by reorientation of an elevated first metatarsal using arthrodesis of the first tarsometatarsal joint and performing a one-step transplantation of an osteochondral graft, which is harvested from the first cuneiform, to the head of the first metatarsal bone.

INDICATIONS

Severe arthritis of the first metatarsophalangeal joint (MTP) stage 3 and 4 in the Vanore classification.

CONTRAINDICATIONS

General contraindications for a foot surgery; ankylosis of MTP joint; severe arthritis of the sesamoid joint; osteonecrosis; short first metatarsal; previous infection in the metatarsophalangeal joint; large cysts at the head of the first metatarsal.

SURGICAL TECHNIQUE

The first step is the preparation of the metatarsophalangeal and the first tarsometatarsal joint. After mobilizing the first metatarsal in a medioplantar direction, a cartilage-bone cylinder is removed from the articular surface of the medial cuneiform using special osteochondral autograft transfer system (OATS) instruments (Small Joint OATS, Arthrex medical instruments GmbH, Munich, Germany). This is followed by the arthrodesis of the first tarsometatarsal joint with reorientation of the position of the first metatarsal bone. Then the removed osteochondral cylinder is implanted into the articular surface of the first metatarsal head. After that the capsule is closed and the skin sutured.

POSTOPERATIVE MANAGEMENT

Postoperative management is guided mainly by the requirements of the first tarsometatarsal arthrodesis. When a plantar plate is used pain orientated full weightbearing is allowed in a postoperative shoe with a stiffened sole for 6-8 weeks. Physiotherapy is prescribed to exercise the first metatarsophalangeal joint.

RESULTS

In the study, 5 patients were treated with the method described in the years 2011-2012 and were followed up for a period of 2 years. All of these patients were subjectively satisfied with the outcome of the operation. There were no relevant surgery-associated complications.

[Cartilage chip transplantation for cartilage defects of the first metatarsophalangeal joint]

OBJECTIVE

Treatment of circumscribed cartilage defects in the first metatarsophalangeal joint (MTP1) using autologous cartilage fragments.

INDICATIONS

Full thickness cartilage defects (ICRS IV) or focal osteoarthritis in combination with hallux rigidus.

CONTRAINDICATIONS

Pre-existing ankylosis of the metatarsophalangeal joint; global osteoarthritis of the joint; advanced osteoarthritis of the sesamoidal articulation; osteonecrotic cysts in the head of the first metatarsal bone.

SURGICAL TECHNIQUE

Preparation of the metatarsophalangeal joint. Mobilization of the first metatarsal head. Harvesting of the cartilage fragments from the dorsal rim portion as part of the cheilectomy. Mincing the cartilage fragments with a 3.0 mm shaver in sterile conditions. Augmenting the cartilage fragments with autologous conditioned plasma (ACP). Preparing the defect area and creation of a "contained" defect. Replantation of the resulting minced cartilage mass into the defect of the articular surface on the first metatarsal head.

POSTOPERATIVE MANAGEMENT

Immobilization of the MTP1 for 48 h. Intensive physiotherapy for 3 months. Full weight bearing after reduced swelling.

RESULTS

In 2020, 5 patients were treated with the method described and followed up for a period of 1 year. All patients were subjectively satisfied with the result of the operation. There were no relevant surgery-associated complications.