Tension pneumothorax is a life threatening condition in which air leaks outside of the lung, and the air is trapped between the pleura and the lung. This is a medical emergency. Air leaks outside of the lung into the pleural cavity. The air is trapped between the pleura and the lung. The air in the pleural space cannot exit. This condition prevents expansion of that lung and its oxygenation. This condition leads to hypoxia and cardiopulmonary collapse. The patient will have acute unilateral chest pain, dyspnea, respiratory distress, tachypnea, and tachycardia. The patient will also have unilateral decreased or absent breath sounds. As air pushes against the lung, it deviates the trachea to the other side. To treat, do needle decompression. Insert the needle at the 2nd intercostal space, mid clavicular line followed by insertion of a chest tube.
Q Angle of the Knee
A well-functioning knee is important for mobility. The knee must be able to support the weight of the body during activities such as walking or running. A normal alignment of the knee is important for its function. The Q-angle of the knee provides useful information about the alignment of the knee joint. The Q-angle is the angle between the quadriceps tendon and the patellar tendon. An increased Q-angle is a risk factor for patellar subluxation. The Q-angle (quadriceps angle) is formed in the frontal plane by two line segments. The first line drawn is drawn from the anterior superior iliac spine (ASIS) to the center of the patella. A second line is drawn from the center of the patella to the tibial tubercle. The angle is formed by the two lines is called the Q-angle. Find the patella and its border; find the center of the patella; find the tibial tubercle; draw a line from the ASIS to the center of the patella and a second line from the tibial tubercle through the center of the patella. The normal Q-angle is variable. In extension, the normal Q-angle for males is usually 14 degrees, and in females it is approximately 17 degrees. The normal Q-angle in flexion is approximately 8 degrees. A wider pelvis and increased Q-angle in females is linked to knee pain, patellofemoral pain, and ACL injury. The alignment of the patellofemoral joint is affected by the patellar tendon length and the Q-angle. It is best to measure the Q-angle with the knee in extension as well as flexion. Larger Q-angle plus a strong quadriceps contraction can dislocate the patella. The Q-angle is increased by genu valgum, external tibial torsion, femoral anteversion, lateral positioned tibial tuberosity, and tight lateral retinaculum. CT scan study of the patellofemoral articulation is found to be very helpful. An increased Q-angle in the knee will lead to an increase in lateral subluxation forces on the patella which may lead to pain, wear of the implant, and mechanical symptoms. When doing a total knee replacement, avoid the techniques that will cause increased Q-angle, such as internal rotation of the femoral component of the tibial component. Avoid medialization of the femoral component. Avoid lateral placement of the patellar component. The patellar prosthesis should be placed either in the center or slightly medial. You will put the patella slightly medial, but you will put the femoral component opposite to that; it will be slightly lateral. Terms used to describe a triad of anatomic features or findings which will increase the Q-angle include excessive femoral anteversion, genu valgum, and external tibial torsion or pronated feet. Symptoms for miserable malalignment syndrome include anterior knee pain, pain under the patella, and stiffness of the knee joint. When examining a patient for patellofemoral pain, alignment is important, including rotational alignment.
Sir Robert Jones (British Surgeon) sustained an acute fracture at the base of the fifth metatarsal bone while dancing, and the fracture was then named after him. The Jones fracture occurs at the metaphyseal/diaphyseal junction, and it extends into the intermetatarsal joint proximal to the metatarsocuboid joint. One joint articulates with the cuboid bone (metatarsocuboid) and the second joint (intermetatarsal) articulates with the 4th metatarsal. For the Jones fracture to be called “Jones Fracture”, the fracture must enter the intermetatarsal joint (fracture must be distal to the metatarsocuboid joint and must enter the intermetatarsal joint). The Jones fracture occurs about 1 ½ cm distal to the tuberosity of the 5th metatarsal bone. The 5th metatarsal bone is divided into the head and shaft. Jones fractures of the proximal fifth metatarsal occurs in the watershed area within 1.5cm of the tuberosity. The area where the Jones fracture occurs is an area of limited blood supply. There are multiple metaphyseal arteries in the tuberosity. Nutrient artery with intramedullary branches provides retrograde blood flow to the proximal fifth metatarsal. Fracture distal to the tuberosity will disrupt the nutrient artery supply resulting in relative avascularity. The Peroneus Tertius tendon is inserted into the dorsal metaphysis of the 5th metatarsal bone. The Peroneus Brevis tendon is inserted into the tuberosity of the 5th metatarsal bone. The plantar fascia is connected to the fifth metatarsal bone. When a Jones fracture occurs, the tendons will pull the fracture apart and prevent healing. This fracture could be mistaken for a sprain because a sprain is common on this side of the foot. There are three types of fractures at the proximal fifth metatarsal: Zone I, Zone II, and Zone III. Zone I fractures are avulsion fractures (pseudo Jones Fracture) and occur at the Peroneus Brevis insertion site; they require conservative treatment. Zone II fractures are acute fractures that occur at the metaphyseal-diaphyseal junction and involve the 4th and 5th metatarsal articulation. Zone III stress fractures are chronic fractures that occur distal to the 4th and 5th metatarsal articulation and may be associated with cavovarus foot deformity. In children, it is important not to make the wrong diagnosis of a fracture of the proximal 5th metatarsal base while looking at a normal growth plate. The growth plate is usually present between the ages of 9-14 years of age, and it is parallel and lateral to the metatarsal. X-rays will show the fracture and its location. An acute Jones fracture will have sharp margins with no intramedullary sclerosis. A stress fracture will have a wide fracture line with medullary sclerosis. With nondisplaced fractures, use a boot or a cast and be non-weight bearing for 6-8 weeks. 75% of fractures will heal. For athletes or a displaced fracture, do a screw fixation of the fracture (very popular technique). In the lateral view, the canal appears to be straight and narrow. In the AP view, the 5th metatarsal appears to be curved (lateral bow). Lateral bow of the 5th metatarsal may cause complications during surgery. There is vulnerability at the midshaft for perforation of the medial cortex. The canal is narrower in the dorsal plantar dimension, which is narrow in the lateral view. The point of entry for the wire or the screw is not centered. The fifth metatarsocuboid joint blocks the proximal canal projection, and this situation can cause complications. Each patients metatarsal should be evaluated individually for proper screw selection. Drill parallel with the shaft in the lateral plane and avoid the plantar direction. Avoid the sural nerve. You will probably need to use a 4.5 mm cancellous screw. The appropriate length of the screw that should be used is usually around 40-50mm. The diameter of the screw depends on the width of the canal. The screw threads must cross the fracture site. Failure of the procedure is attributed to poor blood supply or return of the athlete to activity before complete radiographic union.
Anatomy of the Pronator Teres Muscle
The pronator teres is a muscle located in the forearm. The pronator teres muscle has two heads. The superficial head, which is the humeral head, arises from the medial epicondyle of the humerus and a deep head, which is the ulnar head, which arises from the medial border of the coronoid process of the ulna. The muscle is inserted into the middle of the lateral surface of the shaft of the radius. The function of the pronator teres is to pronate the forearm (along with the pronator quadratus) so that the palm turns posterior or down. It functions to pronate the forearm. The pronator teres also assists in flexion of the forearm at the elbow. When fractures occur below the insertion of the pronator teres muscle, the proximal fragment is usually pulled into pronation. The forearm has a normal range of 160-180 degrees. Sometimes a decrease in rotation motion by 50 degrees may not be noticed; however, every attempt should be made to reduce the forearm fracture well, especially fracture of the proximal radius (prone to malrotation). The bicipital tuberosity of the radius is used as a guide to the rotation of the proximal radius. Compare the position of the thumb to the position of the radial tuberosity. The pronator teres muscle is innervated by the median nerve. In the condition of high radial nerve palsy is helped by transfer of the pronator teres muscle. Extension of the wrist, which is impaired by high radial nerve palsy (wrist drop), is improved by transfer of the pronator teres to the extensor carpi radialis brevis muscle. The median nerve passes between the two heads of the pronator teres. The ulnar head (deep hard) separates the median nerve from the ulnar artery. The median nerve runs above the deep head while the ulnar artery runs below the deep head. It seems like when a nerve enters the forearm, it goes between two heads of a muscle. The posterior interosseous nerve enters the extensor compartment of the forearm between the two heads of the supinator muscle. The ulnar nerve enters the forearm by passing through the two heads of the flexor carpi ulnaris muscle. The median nerve enters the forearm by passing through the two heads of the pronator teres muscle. The condition of pronator teres syndrome can occur due to entrapment of the median nerve between the two heads of the pronator teres muscle. Other causes may cause pronator teres syndrome, however, entrapment of the median nerve between the two heads of the pronator teres is an important cause.