What is Distal Tibial Allograft Glenoid Reconstruction?
Glenoid reconstruction with distal tibial allograft is a surgical technique employed in the treatment of recurrent shoulder instability or glenohumeral instability secondary to significant glenoid bone loss and to restore the glenoid arc and maintain glenohumeral congruency.
Shoulder instability is a chronic condition that causes the frequent dislocation of the shoulder joint. A dislocation occurs when the end of the humerus (the ball portion) partially or completely dislocates from the glenoid (the socket portion) of the shoulder. A partial dislocation is referred to as a subluxation while a complete separation is referred to as a dislocation.
An allograft is a tissue such as bone, cartilage, tendon, or skin, taken from one person and surgically placed in another person to repair damaged tissue. A distal tibial allograft is a piece of tissue taken from the distal end of the tibia (shinbone) from a deceased donor to repair or replace damaged tissue in the glenoid. A section of bone tissue is removed, shaped to precisely fit the defect, and then transplanted to reconstruct the damage.
Your shoulder joint (glenohumeral joint) is a ball and socket joint made up of the upper arm bone (humerus), the shoulder blade (scapula), and the collarbone (clavicle). The head of the upper arm bone fits into the socket of the shoulder joint known as the glenoid cavity. The outer edge of the glenoid is surrounded by a strong fibrous tissue called the labrum, which provides some depth to the socket, increasing the stability of the joint. Stability is further enhanced by ligaments that form a capsule around the joint, as well as muscles and tendons which center the humeral head in the socket. Fractures or high-energy trauma to the glenoid can cause severe damage to the supporting structures of the shoulder resulting in shoulder instability.
Your surgeon may recommend distal tibial allograft glenoid reconstruction for the following conditions:
- Recurrent shoulder instability with greater than 25% glenoid defects
- Large Hill-Sachs lesions (damage to the back and outer portion of the humeral head)
- Chronic shoulder dislocation
- Bankart tear or injury
- Revision shoulder stabilization surgery
- Failure of the non-surgical treatment such as immobilization
In general, the treatment is determined by the degree of bone loss and patient factors such as level of activity, expectations, and the level of sports participation. The main objective of distal tibial allograft glenoid reconstruction is to improve stability and function to the shoulder joint and prevent recurrent dislocations.
Preparation for Distal Tibial Allograft Glenoid Reconstruction
Preoperative preparation for distal tibial allograft glenoid reconstruction may involve the following steps:
- A thorough examination is performed by your doctor to check for any medical issues that need to be addressed prior to surgery.
- Depending on your medical history, social history, and age, you may need to undergo tests such as bloodwork and imaging to screen for any abnormalities that could compromise the safety of the procedure.
- You will be asked if you have allergies to medications, anesthesia, or latex.
- You should inform your doctor of any medications, vitamins, or supplements that you are taking.
- You may need to refrain from supplements or medications such as blood thinners or anti-inflammatories for a week or two prior to surgery.
- You should refrain from alcohol or tobacco at least a few days prior to surgery.
- You should not consume solids or liquids at least 8 hours prior to surgery.
- A written consent will be obtained from you after the surgical procedure has been explained in detail.
Procedure for Distal Tibial Allograft Glenoid Reconstruction
Distal tibial allograft glenoid reconstruction is usually performed in a minimally invasive arthroscopic technique and involves the following steps:
- Anesthesia is administered to make sure you do not feel any discomfort or pain during the procedure.
- After cleaning the skin over the shoulder area, your surgeon makes a few small incisions in your shoulder joint.
- An arthroscope, a slender tubular device attached with a light and a small video camera at the end is inserted through one of the incisions into your shoulder joint.
- The video camera transmits the image of the inside of your shoulder joint onto a television monitor for your surgeon to view.
- Your surgeon then uses small surgical instruments through the other tiny incisions to perform surgical debridement of the glenoid surface (removal of damaged cartilage and bone). Care is taken to prevent damage to healthy tissue.
- A thoroughly prepared allograft bone tissue is then inserted into the section of the glenoid with bone loss or defects and allowed to grow.
- Your surgeon may also use pins, plates, or screws to secure the bone graft in place.
- Your surgeon may undertake any other repairs that may be required accordingly.
- Finally, the tiny incisions around the joint are closed and covered with a bandage.
Postoperative Care Instructions and Recovery
In general, postoperative care instructions and recovery after distal tibial allograft glenoid reconstruction involves the following steps:
- You will be transferred to the recovery area to be monitored until you are awake from the anesthesia.
- Your nurse will monitor your blood oxygen level and other vital signs as you recover.
- You may notice some pain, swelling, and discomfort in the shoulder area. Pain and anti-inflammatory medications are provided as needed.
- Antibiotics are also prescribed for risk of infection associated with surgery.
- You may also apply ice packs on the shoulder to help reduce swelling and pain.
- Your arm may be secured with assistive devices such as a sling for the first few weeks to facilitate healing.
- You are advised to walk as frequently as possible to prevent the risk of blood clots.
- Keep your surgical site clean and dry. Instructions on surgical site care and bathing will be provided.
- Refrain from smoking as it can negatively affect the healing process.
- Eating a healthy diet rich in vitamin D is strongly advised to promote healing and a faster recovery.
- Refrain from strenuous activities and lifting heavy weights for a month or two. Gradual increase in activities over a period of time is recommended.
- An individualized physical therapy protocol is designed to help strengthen your shoulder muscles and optimize shoulder function.
- You will be able to resume your normal activities in a couple of months; however, return to sports may take anywhere from 4 to 6 months.
- Refrain from driving until you are fully fit and receive your doctor’s consent.
- A periodic follow-up appointment will be scheduled to monitor your progress.
Risks and Complications
Distal tibial allograft glenoid reconstruction is a relatively safe procedure; however, as with any surgery, some risks and complications may occur, such as:
- Rejection of bone graft
- Damage to surrounding structures
- Poor bone healing
- Joint stiffness
- Failure of the bone graft
- Anesthetic complications