Platelet-rich plasma (PRP) is a biological therapy that uses the patient's own blood to obtain products with a higher platelet concentration than in blood. It provides a transient fibrin scaffold as a controlled drug delivery system of growth factors suitable for regenerative medicine. PRP has been used as medical strategy to treat diverse types of injuries in the field of orthopedics, including peripheral nerve lesions. In vitro and in vivo studies showed the neuroprotective, neurogenic and neuroinflammatory modulator effect of PRP. In addition, it has been demonstrated clinically that PRP infiltrations improve clinical symptoms and enhance the sensory and motor functional nerve muscle unit recovery. Potential effects of PRP could be applied in treatments for neuropathies, as conservative treatment by means of nerve ultrasound-guided infiltrations or as biological adjuvant during surgery.

In some surgical techniques like femoral derotation osteotomy, accuracy is a key factor that often is not optimal because of the lack of appropriate technology. 3D printing is emerging in many professional areas and its use in the medical field may enhance the results of certain surgeries. This case describes a patient who underwent an intramedullary nail fixation to treat a femoral shaft fracture. After nine months, the patient presented hip pain and "in toe" walking caused by a malrotation produced during the surgery. To address the consequent femoral derotation osteotomy, 3D technology was used throughout the whole process. A 3D model of the patient's femur was created to conduct a real and accuracy assessment of femoral anteversion. Then, a customized surgical guide was designed and printed to ensure the proper alignment during surgery. Given the success of this surgery, 3D printing can be considered a quick and inexpensive tool to improve surgical results.

Femoral shaft fractures are one of the most common injuries in trauma patients. The gold standard treatment consists of closed reduction and intramedullary nailing, providing a high fracture healing rate and allowing early mobilization. However, rotational malalignment is a well-known complication following this procedure, and excessive femoral anteversion or femoral retroversion can trigger functional complaints. In order to achieve the ideal degree of femoral rotation, a 3D planning and printing cutting guides procedure was developed to correct femoral malrotation. A patient series with malalignment after a femoral diaphyseal fracture was operated on with the customized guides and evaluated in this study. Computed tomography scans were performed to accurately determine the number of degrees of malrotation, allowing the design of specific and personalized surgical guides to correct these accurately. Once designed, they were produced by 3D printing. After surgery with the customized guides to correct femoral malrotation, all patients presented a normalized anteversion angle of the femur (average −10.3°, range from −5° to −15°), according to their contralateral limb. These data suggest that the use of customized cutting guides for femoral osteotomy is a safe and reproducible surgical technique that offers precise results when correcting femoral malrotation.

Platelet-Rich Plasma (PRP) is a biologic therapy that uses the patient's own blood to obtain products with a higher platelet concentration than in blood. This technology provides a controlled drug delivery system of growth factors suitable for regenerative medicine. The biological effects of PRP mimic and influence biological processes such as inflammation, analgesia, and cell stimulation, providing this therapy with promising therapeutic potential. All these processes participate in maintenance, correct function, and homeostasis of the joint, where all tissues are involved. Alterations in one joint element have impact on the rest, outstanding the cellular and molecular interaction between the cartilage and subchondral bone. Therefore, the joint is an optimal therapeutic target for PRP therapy, which favors biological environment for joint repair. This chapter collects the basic concepts of joint function and the biological processes that participate in its degeneration, the definition and obtention of PRP, as well as its therapeutic potential and clinical translation.

Objective: Addressing the subchondral bone through intraosseous infiltrations of Platelet-Rich Plasma (PRP) may improve the effectiveness of this technique for severe hip osteoarthritis (HOA). Methods: Forty patients with HOA degree 2 and 3 according to the T€ onnis scale were recruited for this study. They were susceptible to a total hip arthroplasty, without response to previous treatment based on intraarticular infiltrations of PRP. Patients received a combination of intraosseous injections into the acetabulum and the femoral head, as well as intraarticular PRP infiltrations. The clinical outcome was evaluated at 2, 6 and 12 months using the Hip Osteoarthritis Outcome Score (HOOS) and the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index. Results: At 2, 6 and 12 months, patients had significant pain improvement according to HOOS pain, WOMAC pain, and VAS scores. After the treatment, the percentage of patients with minimal clinically important improvement was 40% (16 over 40 patients) at 2 months, 37.5% (15 over 40) at 6 months, and 40% (16 over 40) at 12 months. Conclusion: The combination of intra-articular and intra-osseous infiltrations of PRP showed a pain reduction and improvement in hip joint functionality up to 12 months in patients with severe HOA, with no severe adverse effects.