Chronic exertional compartment syndrome (CECS) of the lower leg can be a disabling condition in active individuals. CECS is characterized by cramping or aching pain of the affected extremity with physical activity, frequently running. Symptoms resolve with rest. Usually, it is bilateral, affecting one or more of the compartments of the lower leg, with findings of increased intracompartmental pressure. Most commonly, the anterior compartment is affected, followed by the lateral compartment. Although recent studies have demonstrated improvements with a change in running style, nonoperative management is generally ineffective in controlling symptoms if the patient continues to engage in the inciting activity. An elective fasciotomy of the affected compartment either through a medial (deep and superficial posterior compartments) or lateral incision (anterior and lateral compartments) may provide relief to the affected individuals. Proper patient selection for surgical management increases the likelihood of success, with relief of symptoms upon return to sport or recreation. Patients are usually able to return to or exceed preoperation activity levels with decreased pain. However, the rate of positive outcomes is significantly lower than those for other elective orthopaedic operations. Evidence varies regarding success rates, recurrence of symptoms, and return to activity. Approximately 75% of patients are satisfied with their outcome upon return to their pre-CECS level of activity and would do it all over again. The incidence of postoperative complications is up to 15% in athletes and military personnel.

Background

The repair of osteochondral lesions remains a challenge due to its poor vascularity and limited healing potential. Micronized cartilage matrix (MCM) is dehydrated, decellularized, micronized allogeneic cartilage matrix that contains the components of native articular tissue and is hypothesized to serve as a scaffold for the formation of hyaline-like tissue. Our objective was to demonstrate in vitro that the use of MCM combined with mesenchymal stem cells (MSCs) can lead to the formation of hyaline-like cartilage tissue in a single-stage treatment model.

Design

In group 1 (no wash), 250 µL MCM was reconstituted in 150 µL Dulbecco's phosphate-buffered saline (DPBS) for 5 minutes. Group 2 (saline wash) included 250 µL MCM washed in 20 mL DPBS for 30 minutes, then aspirated to remove all DPBS and reconstituted in 150 µL DPBS. Group 3 (serum wash): 250µL MCM washed in 20 mL DPBS for 30 minutes, then aspirated and reconstituted in 150 µL fetal bovine serum. Each group was then added to 50 µL solution of MSC suspended in DPBS at a concentration of 1.2 × 10⁶ cells/350 µL. After 3 weeks, the defects were extracted and sectioned to perform viability and histologic analyses.

Results

Stem cells without rehydration of the MCM showed almost no viability whereas near complete cell viability was seen after rehydration with serum or saline solution, ultimately leading to chondrogenic differentiation and adhesion to the MCM particles.

Conclusion

We have shown in this proof-of-concept in vitro study that MCM can serve as a scaffold for the growth of cartilage tissue for the treatment of osteochondral lesions.