In recent years, cell therapy for bone regeneration has been found to have different indications in orthopaedic surgery, such as delayed fracture consolidation and the treatment of bone cysts and osteonecrosis.
The aims of regenerative medicine are to obtain healing in the shortest possible time, to use a mini-invasive approach and to reduce management costs.
Delayed consolidation can be defined radiographically as a fracture callus that is poorly evident or absent six months after osteosynthesis and its incidence ranges from 5 to 10% of long-bone fractures; to demonstrate the efficacy of regenerative therapy, we treated six patients aged between 19 and 53 years (mean 39 years) using a mini-invasive technique, preparing the fracture rim and applying, to the site, demineralised bone matrix (DBM) and mesenchymal stem cells (MSCs) obtained by harvesting bone marrow blood from the iliac crest. The sites treated were the tibia and the femur. Osteosynthesis was performed using an endomedullary nail in one case, an external fixing device in two, and a plate in three. Before our treatment, carried out between 4 and15 months after osteosynthesis (mean 8 months), all the patients were experiencing pain and none was completely loading the limb. The follow-up duration ranged from 3 to 18 months (mean 6 months) with checkups performed at 3, 6 and 12 months. Three months after the operation, five of the patients were completely loading the treated limb without pain and showed inter-fragment thickening on radiographic examination that allowed removal of the external fixing device in the two patients in whom it had been used, and at 12 months’ follow up showed complete clinical-radiographic healing.
The application of DBM and MSCs through mini-invasive surgery, performed a short time after osteosynthesis, reduced the healing time in patients with delayed consolidation and considerably reduced the costs of managing the condition itself.
Another field of application for regenerative medicine is the treatment of simple bone cysts, benign bone lesions that regress spontaneously when skeletal maturity is reached; nevertheless, their treatment is justified by the high risk of pathological fracture. To date, numerous techniques have been proposed to treat this disease, from curettage and bone grafting to cycles of cortisone injections. However, these techniques have limitations; either they are highly invasive or they involve a number of procedures carried out in close succession.
In 2007, we began a study comparing two groups of patients: the first treated with multiple cortisone injections and the second with a single injection of DBM associated with MSCs. The minimum follow up was 12 months. The mean follow up was 48 months (range 12–120 months) in the first group, and 19 months (range 12–29 months) in the second. The sites treated were the humerus (137 and 44 respectively) and femur (42 and 16 respectively).
At the end of the treatment, only 38% of the patients treated with cortisone could be defined healed, compared with 67% of those treated with DBM and MSCs. The treatment with a single injection of DBM and MSCs was thus found to be more effective in reducing healing times in patients with simple bone cysts.
Regenerative medicine is also indicated in hip osteonecrosis (ON). We treated 15 patients aged between 17 and 50 years (mean 32 years) with a mini-invasive technique involving decompression of the necrotic area and infiltration of DBM, MSCs and platelet-rich fibrin (PRF). Using the Ficat staging system, the ON was graded IIa–IIb in eight patients and III–IV in seven, with follow up lasting a mean of 6 months (range 3–14); checkups were scheduled at 3, 6 and 12 months. The mean Harris Hip Score showed an improvement: the score of the patients graded IIa–IIb rose from the 61 recorded preoperatively to 75 at 3 months, 82 at 6 months, and 98 at 12 months, whereas that of the patients graded III–IV rose from 57 preoperatively to 75 at 3 months, 76 at 6 months, and 86 at 12 months.
Even though the follow ups conducted are still short and the sample of patients small, the preliminary results of this study on the use of MSCs associated with DBM and PRF are promising.
All this suggests that the use of cells, in regenerative medicine, might be considered an effective and economic treatment possibility in orthopaedics.