Os Trigonum: Should You Treat It Surgically?
- Volume 22 - Issue 9 - September 2009
- 45514 reads
- 1 comments
In my practice, patients usually present three to four days after injury with pain and swelling of the posterior ankle joint. A majority of these patients are under the age of 40. After a thorough history and physical, I will attempt to recreate the position of the foot and ankle at the time of injury. This produces pain along the posterior ankle joint. I take three views of the ankle to rule out a fracture and confirm the presence of an os trigonum. I also take contralateral views for comparison.
After diagnosing os trigonum syndrome, I place the patient into a CAM walker and crutches if needed. I will start the patient immediately on a standard nonsteroidal anti-inflammatory (NSAID) medication. The patient may remove the CAM walker for bathing and applying ice to the ankle. However, I instruct the patient to wear it at all times while weightbearing. Patients wear the CAM walker for four to six weeks.
At that time, if they continue to have residual pain and swelling of the posterior ankle joint, then I will recommend a cortisone injection. I use 1 cc of 10 mg/mL of triamcinolone (Kenalog, Bristol Myers-Squibb) with 1 cc of 0.25% marcaine plain injected posterior lateral behind the fibula and peroneal tendons into the posterolateral aspect of the joint. Patients wear the CAM walker for an additional two to three weeks after the injection.
Once symptoms have resolved, I have the patient initiate a physical therapy program for strengthening and range of motion exercises. At this time, patients have returned to regular sneakers without any assistance.
In order to prevent further injury and reoccurrence, patients wear an ankle brace for walking and athletic activities. It is important to identify and address biomechanical faults of the foot and ankle that may contribute to patient symptoms. I will usually prescribe a rigid orthotic with rearfoot extrinsic posting to vertical and neutral forefoot posting.
I find that most patients are asymptomatic with conservative treatment in six to eight weeks. Preventing re-injury decreases the possible need for surgical excision.
When Is Surgery Recommended?
It is difficult to find studies that document the success of conservative treatment versus surgical excision. There is a general consensus and agreement to start with conservative treatment for an undefined length of time. This eventually proceeds to surgical excision once conservative treatment has failed.
However, a vast majority of patients who present with an initial injury respond well with conservative treatment. These patients rarely require surgical excision since their symptoms are due to a single traumatic event.
If patients continue to have reoccurrence of injury or fail to respond to conservative treatment, then surgical excision is recommended.
Like all surgical procedures, surgical excision of the os trigonum has associated risks and complications. Incision approaches for removal of the os trigonum include a posterior medial or posterior lateral ankle incision. Podiatric surgeons most commonly employ the posterior lateral incision in order to avoid injury to the neurovascular structures of the tarsal tunnel.
The main complication with this approach is injury to the sural nerve, which can result in sural neuritis, reflex sympathetic dystrophy syndrome, and sensory loss of the lateral ankle joint.5 While these complications are rare, they may cause permanent disability to the patient if they occur.
Patients who present with an initial injury and first time occurrence of os trigonum syndrome respond well to conservative treatment. One would only consider surgical excision if these conservative measures fail to alleviate symptoms or if the symptoms reoccur. Correcting the faulty biomechanics with a custom orthosis is imperative to prevent further injury and reoccurrence.
Dr. Sekel is board qualified in forefoot and rearfoot surgery by the American Board of Podiatric Surgery. He practices in Chambersburg, Pa. and Hagerstown, Md.