AC Joint Repair Surgery Using Pin Method

humility image by Jake Hellbach from

The acromioclavicar (AC) joint is where the collarbone attaches to the shoulder blade. Surgery is not usually needed when this joint becomes separated. However, in cases of severe separation, surgery may be necessary. Pins are used during AC surgery to strengthen and improve the stability of the joint.


When the AC joint becomes separated, the severity of the separation is given a grade.

A Grade 1 separation means that the ligaments that hold the joint together have been partially torn. When the ligament is completely torn, the separation is considered a Grade 2 separation. In a Grade 3 separation, the joint is completely separated. and the shoulder sinks with the weight of the arm.

The collarbone moves over the shoulder blade in a Grade 4 separation. A Grade 5 separation is the same as a Grade 3 separation, but the pull of the arm causes the gap between the joints to be larger. In a Grade 6 separation, all the bones involved are completely ruptured. A pin will be needed to support the damaged arm in the last three grades.


Most AC separations do not require invasive treatment, but a Grade 4 to Grade 6 separation is serious enough to warrant surgery. Some Grade 3 separations might require treatment, and surgery might also be required if the ligaments have been severely damaged. Surgery is used to draw the collarbone and the shoulder blade back together to allow the ligaments between them to heal properly. A number of methods are used to hold the joint in place, including pinning, screws, and bioabsorbable or nonbioabsorbable devices passed through a drilled hole in the bone.


Once the collarbone and shoulder blade have been brought back together during surgery, a pin is used to connect the bones to each other and support the joint as it heals. While the pin does strengthen the damaged joint, this does not mean that the joint will be able to bear as much weight as it did before being separated.

Pins are placed through the acromion (the protrusion at the top of the shoulder blade), across the joint itself and then down the clavicle. This also increases the stability of the damaged joint.


After the AC joint has been pinned, the patient can expect the arm of the damaged shoulder to be in a sling for at least two weeks. After this time, four weeks of physiotherapy and movement exercises are performed on the shoulder. In between sessions, the arm must remain in a sling.

After the first six weeks, an operation will be performed to remove the pins from the joint. Heavy lifting is prohibited for at least another six weeks.


It is important to remember not to put any strain on your shoulder after having your AC joint pinned. Consult your doctor immediately if you notice any pain or notice any protrusions from your shoulder during recovery, as it may indicate that the joint has separated again despite being pinned.

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