Minimally Invasive Plantar Capsule Release and Flexor Tenotomy for Rigid Diabetic Hammer Toe: A Technique Tip

Abstract

Graphical Abstract.

Introduction

Hammer toes, a prevalent toe deformity, can result in significant morbidity, particularly in individuals with diabetes. This condition often leads to altered gait, painful calluses, and ulcerations, posing an increased risk of infection, osteomyelitis, and amputation. ⁶ Rigid hammer toes are characterized by nonreducible flexion deformity at the proximal interphalangeal (PIP) joint, with varying degrees of metatarsophalangeal (MTP) joint deformity. ⁵ Their pathology is thought to stem from a combination of intrinsic muscle atrophy, imbalance between flexor and extensor tendons, and eventual contractures of surrounding soft tissue structures, including the joint capsule. ⁵

Conventional treatments for rigid hammer toes, such as PIP joint arthrodesis or resection arthroplasty, often require surgical hardware like wires or implants. ⁵ Although effective, these interventions carry significant risks, particularly in diabetic populations where wound healing complications and infections are prevalent. ⁸ Minimally invasive techniques, such as percutaneous tenotomy, have shown promise for neuropathic flexible hammer toes, with high success rates for ulcer prevention and healing. ⁷ However, this technique alone is insufficient for rigid deformities due to severe soft tissue contractures at the PIP joint.

To address the limitations of current interventions, we propose combining a plantar capsule release of the PIP joint with percutaneous flexor tenotomy. This combination targets the soft tissue contractures responsible for rigidity in diabetic hammer toe deformities. This technique tip describes a minimally invasive method for plantar capsule and flexor tendon release to correct rigid hammer toe deformity in patients with diabetes, particularly those with chronic plantar ulceration, to promote toe extension and wound healing.

Indications and Contraindications

Plantar capsule release combined with percutaneous tenotomy is indicated for correcting mild to moderately rigid hammer toe deformities, particularly in diabetic patients with existing or impending ulcerations at the dorsal PIP joint or the tip of the toe. This technique is especially suitable for individuals at high risk of complications from traditional surgical interventions, such as those with neuropathy, poor wound healing, or a history of infections. It is also ideal for patients who require a minimally invasive, outpatient procedure.

Contraindications include active infection at the surgical site and severe vascular insufficiency in the affected toe. Additionally, severe rigid deformities of the PIP joint where the articular surfaces are substantially worn or deformed pose a block to reduction following soft tissue release. Furthermore, this technique may not be sufficient for patients with fixed deformities of the metatarsophalangeal joint, and additional surgical intervention may need to be considered. Finally, this technique results in significant loss of toe flexion strength, which is typically well tolerated in the neuropathic population. However, it does not restore active toe flexion or normal toe biomechanics.

Technique

The patient is placed supine with the foot at the end of the bed, allowing optimal access and visualization. Local anesthesia is administered using either a toe block or an ankle block, depending on whether multiple toes are being operated, with 1% lidocaine containing epinephrine.

A single plantar incision is used for this procedure. A beaver blade is inserted just proximal to the PIP joint flexor crease, ensuring a midline approach to avoid injury to the neurovascular structures of the toe (eg, plantar medial and lateral digital arteries; Supplemental Video 1). The blade is inserted at an angle that is perpendicular to the middle phalanx of the toe (Figure 1). Initially, the long and short flexor tendons are released. As expected for a rigid deformity, this step does not typically result in improvement in alignment. The plantar capsule of the PIP joint is subsequently released by advancing the blade into the joint (Figure 2). The entry into the joint can be detected through tactile feedback. The blade is angled medially and laterally to ensure the entire plantar capsule is addressed. During this maneuver, care is taken to always maintain contact with the bony surface and avoid releasing the soft tissues medial or lateral to the surface of the phalanges.

Figure 1.

Demonstration of landmarking and blade angle of approach before percutaneous flexor tenotomy.

Figure 2.

Following flexor tenotomy, advancement of the beaver blade into the PIP joint plantar capsule to release the rigid hammer toe deformity.

Once the plantar capsule is fully released, significant improvement in toe alignment and range of motion is achieved (Figure 3, A and B). The incision is closed using a single interrupted 3-0 Monocryl suture, and a sterile dressing is applied. The patient is allowed to bear weight as tolerated with a postoperative sandal and scheduled follow-up 3 weeks postoperatively.

Figure 3.

(A) Preoperative and (B) postoperative range of motion following the percutaneous flexor tenotomy and plantar capsule release of a rigid diabetic hammer toe.

Complications

Although the combination of plantar capsule release and percutaneous tenotomy is a minimally invasive technique, potential complications include neurovascular injury, incomplete correction of the deformity, recurrence of the hammer toe, or a floating toe deformity. Neurovascular injury of plantar medial and lateral arteries can be mitigated by maintaining a midline approach during the procedure and avoiding excessive medial or lateral deviation of the blade. Incomplete correction may occur if the plantar capsule is not fully released; careful intraoperative assessment of toe alignment and range of motion is essential to ensure adequate release. Although recurrence is a potential long-term complication, we have not observed it during our short-term follow-up. Finally, because of the extent of release at the PIP joint, a floating toe can occur following this procedure. In the diabetic neuropathic population, this has not caused pain, functional limitation, or transfer lesions.

Discussion

Rigid hammer toe deformities are traditionally managed through surgical methods such as PIP joint arthrodesis or resection arthroplasty, which often require wires or implants. ⁵ These approaches, although effective, are associated with risks such as infection, nonhealing, and amputation, particularly in high-risk populations like individuals with diabetes and neuropathy. ⁸ Additionally, these procedures often necessitate operating room facilities, increasing health care costs and wait times.

Percutaneous flexor tenotomy is a well-established technique for correcting flexible hammer toes in diabetics, offering high rates of ulcer prevention and healing in an outpatient setting.^1,2,7 However, this approach is insufficient for rigid deformities because of the presence of severe contractures at the PIP joint capsule. ⁴ Other minimally invasive techniques, such as selective long or short flexor tenotomy, PIP joint arthrolysis, and osteotomies of the phalanges, also exist. ³ In this technique tip, we expand on the previously established flexor tenotomy by adding a plantar PIP joint capsule release, allowing effective correction of more rigid deformities through a simple, outpatient procedure that avoids the risks of internal fixation, particularly suitable for impending or established neuropathic ulcerations.

In our center, this technique has been used in patients with diabetes and a rigid hammer toe with either existing or impending ulceration at the dorsal PIP joint or the tip of the toe. Most patients experienced rapid recovery and subjective improvement in the alignment of the toe. This leads to effective resolution of the impending or existing ulceration, defined as complete wound healing and confirmed by physical examination. Finally, a contracture at the level of the MTP joint can coexist in rigid hammer toes. In the majority of cases, this was not addressed as the position of the toe was sufficiently corrected following combined flexor tenotomy and plantar PIP joint capsule release. In patients where MTP deformity is also felt to place the toe at risk, percutaneous extensor tenotomy and dorsal MTP capsular release can be considered.

The technique described is an effective alternative to traditional surgical interventions described for the treatment of a mild to moderately rigid hammer toe in the diabetic population. Future studies should validate these findings in larger, diverse cohorts and explore long-term outcomes, including recurrence rates and patient-reported satisfaction. By integrating this approach into clinical practice, surgeons can expand treatment options for rigid hammer toes in patients with diabetes and neuropathy, offering patients a less invasive and more accessible solution.