Jones Tendon Transfer: A Comprehensive Overview
The Jones tendon transfer procedure, also known as Jones Tenosuspension, was first described in 1916 by Sir Robert Jones, a British orthopedic surgeon. Originally developed as a solution for the treatment of clawed hallux (the big toe in a flexed position) in individuals with pes cavovarus (a foot deformity), this technique has evolved over the years to include several modifications for more effective outcomes. This article will provide an in-depth review of the Jones tendon transfer procedure, elaborating on the indications, procedure, adjunct procedures, and postoperative management, while presenting a layman’s understanding of the technical aspects involved.
What is Clawed Hallux?
Clawed hallux is a condition in which the big toe becomes deformed, with extension at the metatarsophalangeal joint (MTPJ) and flexion at the interphalangeal joint (IPJ). This deformity can lead to pain, difficulty walking, and poor footwear fit, causing ulcers or calluses under the foot. The imbalance in the muscles acting on the big toe, particularly the extensor hallucis longus (EHL), flexor hallucis longus (FHL), and peroneus longus (PL), is believed to be the primary cause of this deformity】.
Why is Jones Tendon Transfer Needed?
The purpose of the Jones tendon transfer is to correct the deforming forces on the big toe caused by this muscular imbalance. In essence, the procedure involves transferring the EHL tendon to the first metatarsal, a technique designed to alleviate the contracture and deformity. Additionally, the procedure is commonly combined with a fusion of the IPJ to ensure that the toe remains straight and stable after the tendon transfer.
In some cases, the procedure also addresses issues such as excessive plantarflexion of the first metatarsal (the bone in the forefoot that connects to the big toe), which may require further intervention such as an osteotomy to reposition the bone. The Jones tendon transfer is typically performed on patients with either idiopathic (unknown origin) or neurologic causes of the deformity.
Procedure Overview
The modified Jones procedure is performed under general or regional anesthesia. The patient is placed in a supine position, and an incision is made along the medial side of the big toe, extending from the base of the first metatarsal to the hallux IPJ. This allows the surgeon to access and release the EHL tendon, which is then rerouted through a small hole drilled in the neck of the first metatarsal.
Once the tendon has been passed through the hole, it is sutured back onto itself under appropriate tension to restore the alignment of the toe. In cases where there is a fixed deformity of the first metatarsal, a dorsiflexory wedge osteotomy is performed to reposition the bone. Following this, a fusion of the IPJ is done to prevent further bending of the toe. The procedure may also involve additional interventions, such as a plantar fascia release or a subtalar joint fusion, depending on the complexity of the deformity.
Adjunct Procedures
In many cases, the Jones tendon transfer is combined with other procedures to address more severe deformities. For example, in patients with a fixed plantarflexed first ray (the first metatarsal), a dorsiflexory wedge osteotomy is performed to elevate the bone before the tendon transfer. Other potential adjunct procedures include:
- Tendon Transfers: Tibialis anterior or posterior tendon transfers to correct additional deformities in the foot.
- Plantar Fascia Release: A technique to relieve tension in the plantar fascia, which can be contributing to the deformity.
- Midfoot or Hindfoot Arthrodesis: Surgical fusion of joints in the foot to improve stability and alignment.
Postoperative Care
Postoperatively, the patient is placed in a splint and then a below-the-knee cast for around four weeks. Weight-bearing is restricted during this period to prevent damage to the newly positioned tendon and bones. After the first few weeks, limited weight-bearing is allowed to avoid stress on the foot, particularly under the first metatarsal head.
A follow-up assessment is essential to ensure the success of the surgery. This includes monitoring for potential complications such as tendon rupture, stress fractures, or recurrence of the deformity.
Expected Outcomes
The results of the Jones tendon transfer are generally favorable, especially when combined with other procedures. A study by de Palma and colleagues found that 79% of feet treated with this procedure showed good or fair outcomes. However, complications such as pain under the first metatarsal head or nonunion of the IPJ fusion may occur. These are more likely in patients with idiopathic cavovarus deformities compared to those with neurologic causes.
Conclusion
The Jones tendon transfer is a valuable surgical technique for the correction of hallux malleus and related deformities, especially when combined with IPJ fusion. It offers significant benefits in terms of improving function and reducing pain, although it may not be effective in all cases, particularly when the deformity is fixed. A thorough evaluation of the patient’s condition, including radiographs and clinical examination, is critical to determine the most appropriate approach for each individual.
This procedure remains an essential tool in treating foot deformities related to muscular imbalances and continues to evolve with new modifications to improve patient outcomes.
