X-ray images (normally during weightbearing) can be obtained to rule out other conditions or to see if the patient also has osteoarthritis. The menisci themselves cannot be visualised with plain radiographs. If the diagnosis is not clear from the history and examination, the menisci can be imaged with magnetic resonance imaging (an MRI scan). This technique has replaced previous arthrography, which involved injecting contrast medium into the joint space. In straightforward cases, knee arthroscopy allows quick diagnosis and simultaneous treatment. Recent clinical data shows that MRI and clinical testing are comparable in sensitivity and specificity when looking for a meniscal tear.

In most cases, a physician will diagnose an ulnar collateral ligament injury using a patient’s medical history and a physical examination that includes a valgus stress test. The valgus stress test is performed on both arms and a positive test is indicated by pain on the affected arm that is not present on the uninvolved side. Physicians often utilize imaging techniques such as ultrasound, x-rays and magnetic resonance imaging or arthroscopic surgery to aid with making a proper diagnosis.

Magnetic resonance imaging (MRI) can be helpful in assessing for a ligamentous injury to the medial side of the knee. Milewski et al. has found that grade I to III classification can be seen on MRI. With a high-quality image (1.5 tesla or 3 tesla magnet) and no previous knowledge of the patient’s history, musculoskeletal radiologists were able to accurately diagnose medial knee injury 87% of the time. MRI can also show associated bone bruises on the lateral side of the knee, which one study shows, happen in almost half of medial knee injuries.

Knee MRIs should be avoided for knee pain without mechanical symptoms or effusion, and upon non-successful results from a functional rehabilitation program.

Laximetry is a reliable technique for diagnosing a torn anterior cruciate ligament.

Anterior-posterior (AP) radiographs are useful for reliably assessing normal anatomical landmarks. Bilateral valgus stress AP images can show a difference in medial joint space gapping. It has been reported that an isolated grade III sMCL tear will show an increase in medial compartment gapping of 1.7 mm at 0° of knee flexion and 3.2 mm at 20° of knee flexion, compared to the contralateral knee. Additionally, a complete medial ligamentous disruption (sMCL, dMCL, and POL) will show increased gapping by 6.5 mm at 0° and 9.8 mm at 20° during valgus stress testing. Pellegrini-Stieda syndrome can also be seen on AP radiographs. This finding is due to calcification of the sMCL (heterotopic ossification) caused by the chronic tear of the ligament.

The MRI is perhaps the most used technique for diagnosing the state of the Anterior Cruciate Ligament but it not always the most reliable. In some cases the Anterior Cruciate Ligament can indeed not be seen because of the blood surrounding it.

According to the posterior cruciate ligament injuries only account for 1.5 percent of all knee injuries (figure 2). If it is a single injury to the posterior cruciate ligament that requires surgery only accounted for 1.1 percent compared to all other cruciate surgeries but when there was multiple injuries to the knee the posterior cruciate ligament accounted for 1.2 percent of injuries.

A grade III PCL injury with more than 10mm posterior translation when the posterior drawer examination is performed may be treated surgically. Patients that do not improve stability during physical therapy or develop an increase in pain will be recommended for surgery.

If severe pain persists after the first 24hours it is recommended that an individual consult with a professional who can make a diagnosis and implement a treatment plan so the patient can return to everyday activities (Flegel, 2004). These are some of the tools that a professional can use to help make a full diagnosis;

Nerve conduction studies may also be used to localize nerve dysfunction ("e.g.", carpal tunnel syndrome), assess severity, and help with prognosis.

Electrodiagnosis also helps differentiate between myopathy and neuropathy.

Ultimately, the best method of imaging soft tissue is magnetic resonance imaging (MRI), though it is cost-prohibitive and carries a high false positive rate.

High quality MRI images (1.5 T magnet or higher ) of the knee can be extremely useful to diagnose injuries to the posterolateral corner and other major structures of the knee. While the standard coronal, sagittal and axial films are useful, thin slice (2 mm ) coronal oblique images should also be obtained when looking for PLC injuries. Coronal oblique images should include the fibular head and styloid to allow for evaluation of the FCL and popliteus tendon.

Isolated and combined posterolateral knee injuries are difficult to accurately diagnose in patients presenting with acute knee injuries. The incidence of isolated posterolateral corner injuries has been reported to be between 13% and 28%. Most PLC injuries accompany an ACL or PCL tear, and can contribute to ACL or PCL reconstruction graft failure if not recognized and treated. A study by LaPrade "et al." in 2007 showed the incidence of posterolateral knee injuries in patients presenting with acute knee injuries and hemarthrosis (blood in the knee joint) was 9.1%.

Osteoarthritis between the radius bone and the carpals is indicated by a "radiocarpal joint space" of less than 2mm.

X-rays can be very helpful in diagnosing and differentiating between SNAC and SLAC wrists. On the other hand, X-rays are not always sufficient to distinguish between different stages. It is important to note that both hands need to be compared. Therefore, two X-rays are needed: one from the left and one from the right hand. When the X-ray is inconclusive, wrist arthroscopy can be performed.

SLAC

Because the scapholunate ligament is ruptured, the scaphoid and lunate are not longer connected. This results in a larger space between the two bones, also known as the Terry Thomas sign. A space larger than 3 mm is suspicious and a space larger than 5 mm is a proven SLAC pathology. Scaphoid instability due to the ligament rupture can be stactic or dynamic. When the X-ray is diagnostic and there is a convincing Terry Thomas sign it is a static scaphoid instability. When the scaphoid is made unstable by either the patient or by manipulation by the examining physician it is a dynamic instability.

In order to diagnose a SLAC wrist you need a posterior anterior (PA) view X-ray, a lateral view X-ray and a fist view X-ray. The fist X-ray is often made if there is no convincing Terry Thomas sign. A fist X-ray of a scapholunate ligament rupture will show a descending capitate. Making a fist will give pressure at the capitate, which will descend if there is a rupture in the scapholunate ligament.

SNAC

In order to diagnose a SNAC wrist you need a PA view X-ray and a lateral view X-ray. As in SLAC, the lateral view X-ray is performed to see if there is a DISI.

Computed tomography (CT) or Magnetic Resonance Imaging (MRI) are rarely used to diagnose SNAC or SLAC wrist osteoarthritis because there is no additional value. Also, these techniques are much more expensive than a standard X-ray. CT or MRI may be used if there is a strong suspicion for another underlying pathology or disease.

A meniscal tear can be classified in various ways: by anatomic location, by proximity to blood supply, etc. Various tear patterns and configurations have been described. These include:

- Radial tears;

- Flap or parrot-beak tears;

- Peripheral, longitudinal tears;

- Bucket-handle tears;

- Horizontal cleavage tears; and

- Complex, degenerative tears.

These tears can then be further classified by their proximity to the meniscus blood supply, namely whether they are located in the “red-red,” “red-white,” or “white-white” zones.

The functional importance of these classifications, however, is to ultimately determine whether a meniscus is repairable. The repairability of a meniscus depends on a number of factors. These include:

- Age/strength

- Activity level

- Tear pattern

- Chronicity of the tear

- Associated injuries (anterior cruciate ligament injury)

- Healing potential

The diagnosis of a sprain relies on the medical history, including symptoms, as well as making a differential diagnosis, mainly in distinguishing it from strains or bone fractures. The Ottawa ankle rule is a simple, widely used rule to help differentiate fractures of the ankle or mid-foot from other ankle injuries that do not require x-ray radiography. It has a specificity of nearly 100%, meaning that a patient who tests negative, according to the rule almost certainly does not have an ankle fracture.

X-ray of the affected wrist is required if a fracture is suspected. Anteroposterior (AP), lateral, and oblique views can be used together to describe the fracture. X-ray of the uninjured wrist should also be taken to determine if there are any normal anatomic variations. Investigation of a potential distal radial fracture includes assessment of the angle of the joint surface on lateral X-ray (volar/dorsal tilt), the loss of length of the radius from the collapse of the fracture (radial length), and congruency of the distal radioulnar joint (DRUJ). Displacement of the articular surface is the most important factor affecting prognosis and treatment. CT scan is often performed to further investigate the articular anatomy of the fracture, especially if surgery is considered. MRI can be considered to evaluate for soft tissue injuries, including damage to the TFCC and the interosseous ligaments.

RSIs are assessed using a number of objective clinical measures. These include effort-based tests such as grip and pinch strength, diagnostic tests such as Finkelstein's test for De Quervain's tendinitis, Phalen's Contortion, Tinel's Percussion for carpal tunnel syndrome, and nerve conduction velocity tests that show nerve compression in the wrist. Various imaging techniques can also be used to show nerve compression such as x-ray for the wrist, and MRI for the thoracic outlet and cervico-brachial areas.

Diagnosis may be evident clinically when the distal radius is deformed but should be confirmed by X-ray.

The differential diagnosis includes scaphoid fractures and wrist dislocations, which can also co-exist with a distal radius fracture. Occasionally, fractures may not be seen on X-rays immediately after the injury. Delayed X-rays, X-ray computed tomography (CT scan), or Magnetic resonance imaging (MRI) will confirm the diagnosis.

Pain along the inside of the elbow is the main symptom of this condition. Throwing athletes report it occurs most often during the acceleration phase of throwing. Closing the hand and clenching the fist has also been shown to reproduce the painful symptoms. The injury is often associated with an experience of a sharp “pop” in the elbow, followed by pain during a single throw. In addition, swelling and bruising of the elbow, loss of elbow range of motion, and a sudden decrease in throwing velocity are all common symptoms of a UCL injury. If the injury is less severe, pain can be minimal with complete rest.

In all injuries to the tibial plateau radiographs (commonly called x-rays) are imperative. Computed tomography scans are not always necessary but are sometimes critical for evaluating degree of fracture and determining a treatment plan that would not be possible with plain radiographs. Magnetic Resonance images are the diagnositic modality of choice when meniscal, ligamentous and soft tissue injuries are suspected. CT angiography should be considered if there is alteration of the distal pulses or concern about arterial injury.

Ankle sprains can occur through either sports or activities of daily living, and individuals can be at higher or lower risk depending on a variety of circumstances including their homeland, race, age, sex, or profession In addition, there are different types of ankle sprains such as eversion ankle sprains and inversion ankle sprains. Overall, the most common type of ankle sprain to occur is an inversion ankle sprain, where excessive plantar flexion and supination cause the anterior talofibular ligament to be affected. A study showed that for a population of Scandinavians, inversion ankle sprains accounted for 85% of all ankle sprains Most ankle sprains occur in more active people, such as athletes and regular exercisers.

To assess an olecranon fracture, a careful skin exam is performed to ensure there is no open fracture. Then a complete neurological exam of the upper limb should be documented. Frontal and lateral X-ray views of the elbow are typically done to investigate the possibility of an olecranon fracture. A true lateral x-ray is essential to determine the fracture pattern, degree of displacement, comminution, and the degree of articular involvement.

OSD may result in an avulsion fracture, with the tibial tuberosity separating from the tibia (usually remaining connected to a tendon or ligament). This injury is uncommon because there are mechanisms that prevent strong muscles from doing damage. The fracture on the tibial tuberosity can be a complete or incomplete break.

Type I: A small fragment is displaced proximally and does not require surgery.

Type II: The articular surface of the tibia remains intact and the fracture occurs at the junction where the secondary center of ossification and the proximal tibial epiphysis come together (may or may not require surgery).

Type III: Complete fracture (through articular surface) including high chance of meniscal damage. This type of fracture usually requires surgery.

This test can see various warning signs that predict if OSD might occur. Ultrasonography can detect if there is any swelling within the tissue as well as cartilage swelling. Ultrasonography's main goal is to identify OSD in the early stage rather than later on. It has unique features such as detection of an increase of swelling within the tibia or the cartilage surrounding the area and can also see if there is any new bone starting to build up around the tibial tuberosity.

Examination will often show tenderness at the radioscaphoid joint (when palpated or while moving the radioscaphoid joint), dorsal radial swelling and instability of the wrist joint. Notice that people may say they have trouble with rising from a chair when pressure is exerted on the hands by pushing against the handrail. Younger people may complain about not being able to do push-ups anymore because of a painful hand.

There are a number of tests and actions that can be performed when a patient is suspected of having osteoarthritis caused by SLAC or SNAC.

SLAC:

- Tenderness 1 cm above Lister’s Tubercle

Tests:

- Watson's test

- Finger extension test

SNAC:

- Tenderness at the anatomical snuff box

- Painful pronation and supination when performed against resistance

- Pain during axial pressure

Segond and reverse Segond fractures are characterized by a small avulsion, or "chip", fragment of characteristic size that is best seen on plain radiography in the anterior-posterior plane. The chip of bone may be very difficult to see on the plain x-ray exam, and may be better seen on computed tomography. MRI may be useful for visualization of the associated bone marrow edema of the underlying tibial plateau on fat- saturated T2W and STIR images, as well as the associated findings of ligamentous and/or meniscal injury.