Pectus carinatum (PC) is a deformity of the anterior chest wall which is a common pediatric condition, characterized by an idiopathic overgrowth of the costal cartilages resulting in protrusion of the sternum. There are two subtypes of PC: the chondro-gladiolar variant, which is the most common type, and presents with protrusion of the sternal body, and the chondro-manubrial variant, showing protrusion of the component of the sternum (manubrium). PC usually involves the lower sternal costal cartilages, pushing the sternum forwards and can be symmetrical (bilateral) or often asymmetrical (unilateral) with the right for some reason being more obviously affected. PC may occur as a solitary abnormality or in association with other genetic disorders or syndromes (eg, trisomy 18, Marfan syndrome, homocystinuria, Morquio syndrome, and Ehlers-Danlos syndrome). Of the musculoskeletal abnormalities, scoliosis is most frequently associated with PC.

Chest pain or discomfort, especially when lying in prone position, increased respiratory effort during exercise, scoliosis, impaired shoulders and kyphotic position are some of the physical signs and symptoms. Unlike pectus excavatum, PC is rarely associated with significant cardiopulmonary involvement except in severe cases. Pectus carinatum is not just a simple aesthetical problem. It can be responsible of physical signs and symptoms and also has significant psychological impact. Deformity and its psychological impact tend to worsen during pubertal rapid phases of growth and even during adult life. It has been demonstrated that patients with PC are at risk for a disturbed body image and reduced quality of life and many patients refer feelings of discomfort, shame, shyness, anxiety, and even depression.

The classical management of pectus deformities, both carinatum and excavatum, has been primarily surgical. Modification of the Ravitch technique involves resection of the deformed costal cartilages along with sternal osteotomy. Because the results of this technique resulted in worse cosmetic results, a new less invasive procedure, the Nuss procedure was developed. Nuss procedure includes remodeling of the chest wall cartilage with an internal support bar. These techniques have demonstrated the plasticity of the chest wall and led clinicians to hypothesize that carinatum defects would also remodel in response to chronic pressure, leading to a cosmetically superior, nonoperative technique: compression brace. Compression brace is a dynamic orthosis which is custom-fitted, rigid aluminum brace that is adjustable to any thoracic shape. Complications of brace use include uncommon (4.6%), mild and easy to resolve: back pain, hematoma and skin ulceration. Pressure of correction is the pressure applied to the patient, in the most protruding area of the chest, needed to accomplish a proper shape of the thorax. It is an indirect parameter of the chest wall's flexibility. It can be measured with a pressure measuring device in pounds per square inches (PSI). Some special designed braces contain a part in which pressure measuring device can be docked. This enables measuring of pressure of treatment. Pressure of treatment can be different from pressure of correction since skin breakdown occurs with corrections at high pressure.

In the Calgary protocol, wearing brace 23 hours a day during the correction phase until the development of the axial skeleton is completed and afterwards 8 hours of wear is recommended in the continuation phase.Martinez-Ferro et al developed pressure measuring device and special designed braces contain a part in which pressure measuring device can be docked. They suggested that patients with pressure of correction \<10 should be braced. De Beer et al. also recommended the surgical treatment in the presence of chondro-manubrial type PC and pressure of correction \> 10 PSI. However, recommendations are based on prospective or retrospective cohort studies other than randomized controlled trials which corresponds to low level of evidence.

Despite the fact that patients with PC have impaired posture, exercise intolerance and increased scoliosis occurrence, there is no consensus on the exercise program for patients with PC. Postural impairment aggravates psychological burden caused by disease itself. Patients with pectus carinatum may get benefit from exercises to improve posture. Also, disease itself or compression brace use may result in abdominal flare and increased lateral diameter of chest wall as an unwanted effect. Strengthening of abdominal muscles may prevent from abdominal flare. Strengthening of chest wall muscles, strengthening the pectoralis and sacrospinalis muscles as well as expanding the chest through deep breathing, strengthening core muscles including abdominal muscles, increasing flexibility of muscles, manipulation and mobilization of costae may lead improvements in the management of PC.

There is no consensus about exercises, and there is not enough scientific evidence about the wear time of orthosis. The existing treatment protocols are non-standardized protocols developed by the researchers of previous studies investigating the effectiveness of orthosis. Martinez-Ferro et al., the developer of the dynamic compression brace, recommends the daytime wear of orthosis for patients with low pressure of correction. They recommend duration of clothing to be shorter and the pressure of treatment should be kept lower in patients with high pressure of correction. However, every compression brace may not contain dock and pressure of treatment cannot be measured. In the present study we aimed to investigate the effects of exercises and compression brace in children with PC. Also, safety and feasibility of the orthosis will be evaluated. Patients with chondro-gladiolar, symmetrical or asymmetric, compressible PC (compression test positive) and with correction pressure ≤10 PSI, aged 5-18 years old will be included to study. They will be randomized to three groups using closed envelope system. All groups will be given exercises to strengthen the muscles of the respiratory muscles of the posture exercises, deep breathing exercises, ribs manipulation and mobilization exercises and core exercises for 1 hour a day, five days a week for 3 weeks. The first group will use the orthosis for 8 hours during the night and the second group for 23 hours except for sports activities, exercise and bath. The control group who will receive exercise therapy only will be selected from the wait-in list for the orthosis. Pectus carinatum protrusion, pressure of correction, anteroposterior and lateral diameter of thorax at the most protruded part of deformity, Haller index, Cobb and kyphosis angle, Pectus Evaluation Questionnaire will be assessed at before treatment and after treatment, 1 month and 3 months and 6 months after treatment.