Subtalar Fusion: A Nursing@2023Comprehensive Overview

Introduction

Subtalar fusion, also known as subtalar arthrodesis, is a surgical procedure that unites the bones forming the subtalar joint in the foot. This joint, located between the talus and calcaneus, plays a pivotal role in accommodating complex movements such as inversion and eversion of the hindfoot. When this joint becomes severely damaged, commonly due to arthritis, trauma, or deformity, subtalar fusion emerges as a definitive treatment intended to alleviate pain, restore function, and improve stability. This comprehensive overview delves into the indications, techniques, outcomes, and considerations surrounding subtalar fusion.

Anatomy and Function of the Subtalar Joint

The human foot is a marvel of engineering, comprising 26 bones and numerous joints that coordinate to deliver both stability and flexibility. Among these, the subtalar joint is essential for adapting the foot to uneven terrain and for maintaining balance during walking, running, or standing. The joint lies between the talus (ankle bone) and the calcaneus (heel bone), allowing for side-to-side motions and facilitating the transfer of forces during gait.

Key functions include:

• Inversion and eversion: The subtalar joint allows the sole of the foot to tilt inward (inversion) and outward (eversion).
• Shock absorption: By adjusting to irregular surfaces, the joint helps absorb shock and distribute pressure.
• Balance and propulsion: Subtalar joint movements contribute to the push-off phase in walking and running.

Indications for Subtalar Fusion

Subtalar fusion is not a first-line treatment; it is reserved for conditions where conservative therapies and less invasive interventions have failed. The most common indications include:

• Post-traumatic arthritis: Damage to the joint after fractures, dislocations, or ligament injuries can lead to persistent pain and degenerative changes.
• Primary or secondary osteoarthritis: Wear and tear, or inflammatory conditions like rheumatoid arthritis, may severely affect the subtalar joint.
• Severe hindfoot deformities: Conditions such as posterior tibial tendon dysfunction, flatfoot, or cavus foot sometimes require fusion to restore alignment and improve function.
• Failed previous surgeries: Patients with unsuccessful outcomes from prior foot surgeries may benefit from fusion.
• Chronic instability: Unremitting instability or collapse of the subtalar joint often necessitates surgical intervention.

Preoperative Evaluation

A thorough clinical assessment precedes any decision to pursue subtalar fusion. Physicians will obtain a detailed history of the patient’s symptoms, previous treatments, and functional limitations. Physical examination focuses on:

• Localization of pain
• Range of motion of the ankle and hindfoot
• Assessment for deformities and gait abnormalities
• Evaluation of neurovascular status

Radiological studies are indispensable. X-rays, CT scans, or MRI may be performed to assess the extent of joint degeneration, bone loss, and alignment. Occasionally, diagnostic injections are used to confirm the subtalar joint as the primary source of pain.

Surgical Techniques in Subtalar Fusion

Subtalar fusion can be performed using several approaches, tailored to the patient’s anatomy and pathology:

1. Open Technique

The traditional method involves a lateral or posterior incision, allowing direct visualization of the subtalar joint. The surgeon removes the remaining cartilage from the joint surfaces, prepares the bone for fusion, and aligns the foot in a functional position.

2. Minimally Invasive and Arthroscopic Techniques

Recent advancements have introduced less invasive options. Arthroscopy or smaller incisions can minimize soft tissue disruption and promote faster recovery.

3. Internal Fixation:

Regardless of approach, achieving stable fixation is critical. Screws—sometimes supplemented by plates or wires—are inserted across the joint to hold the bones in position. Modern implants and techniques help maximize the chance of successful fusion.

4. Bone Grafting:

In cases of bone loss or poor healing potential, bone grafts (autografts from the patient or allografts from donors) may be added to promote union.

Postoperative Care and Rehabilitation

Recovery from subtalar fusion demands patience and careful compliance with medical instructions. Immediately after surgery, the foot and ankle are immobilized in a cast, boot, or splint. Weightbearing is generally restricted for 6-12 weeks to allow the bones to heal.

• Physical therapy: Rehabilitation focuses on restoring muscle strength, range of motion in adjacent joints, and gait training.
• Monitoring healing: Serial X-rays are taken to confirm fusion and detect complications.
• Gradual return to activity: Depending on healing and individual progress, patients slowly reintroduce walking, standing, and eventually more strenuous activities.

Expected Outcomes

The primary aim of subtalar fusion is durable pain relief and improved function. Most patients experience a significant reduction in pain and regain the ability to walk comfortably. Success rates for attaining bony union exceed 90% in many series. However, the procedure does come with trade-offs:

• Loss of subtalar motion: Fusion eliminates inversion and eversion at the subtalar joint, which may affect adaptation to uneven surfaces.
• Risk of adjacent joint arthritis: Increased stress on remaining foot joints may accelerate wear and lead to secondary arthritis over time.
• Hardware-related discomfort: Some patients may require removal of screws or plates if they cause irritation.
• Infection, nonunion, or wound complications: Although uncommon, these risks are inherent to any orthopedic procedure.

Complications and Risk Management

Despite its effectiveness, subtalar fusion carries certain risks that must be acknowledged:

• Nonunion: Failure of the bones to fuse may necessitate revision surgery.
• Infection: Superficial or deep infections can impact healing, sometimes requiring antibiotics or further procedures.
• Nerve injury: The proximity of nerves in the area means there is a small risk of numbness or tingling after surgery.
• Malalignment: Poor positioning can result in ongoing pain or difficulty with gait.

Careful surgical planning, meticulous technique, and patient adherence to postoperative instructions are vital to minimizing these risks.

Alternatives to Subtalar Fusion

Before committing to surgery, patients and healthcare providers should consider alternative treatments:

• Conservative management: Physical therapy, custom orthotics, bracing, and anti-inflammatory medications can sometimes control symptoms.
• Joint-sparing procedures: In select cases, realignment (osteotomy), arthroscopic debridement, or injection therapies may be useful.
• Other fusions: When additional joints are involved, triple arthrodesis (fusion of subtalar, talonavicular, and calcaneocuboid joints) may be indicated.

Patient Selection and Prognosis

Not every patient is an ideal candidate for subtalar fusion. Factors influencing selection include:

• Severity and location of joint damage
• Overall health and comorbidities (e.g., diabetes, poor circulation)
• Functional goals and lifestyle needs
• Previous surgeries or treatments

When performed for the right indications, in appropriate candidates, subtalar fusion is a reliable solution providing lasting pain relief and improved quality of life.

Nursing Care of the Patient with Subtalar Fusion

The nursing care of these patients is crucial for successful surgical outcomes and for minimizing complications, ensuring comfort, and promoting optimal recovery.

Preoperative Nursing Care

• Patient Assessment: Conduct a thorough assessment of the patient’s health history, including comorbidities, medications, allergies, and previous surgical experiences. Assess for risk factors that may affect healing, such as diabetes, smoking, or vascular disease.
• Patient Preparation: Educate the patient on the nature of the procedure, expected outcomes, and the importance of adhering to postoperative instructions. Address any anxieties or questions to reduce preoperative stress.
• Preoperative Testing: Ensure all necessary laboratory and imaging studies are completed, including blood tests, ECG, and foot/ankle X-rays or CT scans.
• Infection Prevention: Instruct the patient on preoperative skin cleansing protocols and ensure prophylactic antibiotics are administered as ordered before surgery.
• Venous Thromboembolism (VTE) Prophylaxis: Assess the patient’s risk for VTE and implement preventive measures as prescribed, such as compression stockings or pharmacologic prophylaxis.

Immediate Postoperative Nursing Care

• Monitoring Vital Signs: Closely monitor vital signs in the immediate postoperative period to detect early signs of complications such as hemorrhage, shock, or infection.
• Neurovascular Assessment: Regularly assess the neurovascular status of the affected limb, including color, temperature, capillary refill, sensation, movement, and pulses, to ensure there is no compromise due to swelling or tight splints/casts.
• Pain Management: Administer prescribed analgesics as needed and assess pain levels frequently. Employ both pharmacologic and non-pharmacologic pain relief strategies, such as elevation and ice packs, while protecting the surgical site.
• Wound Care: Inspect the surgical site for signs of bleeding, drainage, or infection. Maintain a clean and dry dressing, and change dressings as ordered. Document the appearance of the wound and report any concerns promptly.
• Casting/Splint Care: Ensure that the cast or splint is in good condition and educate the patient on signs of complications, such as increased pain, numbness, tingling, or swelling beyond the cast or splint.
• Mobility and Positioning: Maintain the operated limb in an elevated position to minimize swelling and promote venous return. Instruct the patient to avoid placing any weight on the operative foot unless otherwise directed by the surgical team.
• Fluid and Nutrition: Encourage adequate hydration and nutrition to support healing. Monitor intake and output, and address any postoperative nausea or vomiting.

Ongoing Postoperative Nursing Care

• Infection Surveillance: Monitor for signs of systemic or local infection, including increased redness, warmth, swelling, purulent drainage, or fever. Educate the patient and family on infection prevention measures.
• Thromboembolism Prevention: Reinforce the importance of not bearing weight on the affected limb, and encourage gentle range-of-motion exercises for the non-affected limbs to prevent venous stasis. Administer anticoagulants if prescribed and assess for signs of deep vein thrombosis (DVT).
• Pressure Ulcer Prevention: Assess skin integrity around the cast or splint. Reposition the patient regularly and use protective padding as necessary, especially in patients with decreased sensation or limited mobility.
• Pain and Comfort Management: Adjust pain management strategies as the patient transitions from inpatient to home care. Provide guidance on safe use of medications and alternative pain relief techniques.
• Rehabilitation Support: Collaborate with physical therapy to initiate rehabilitation as appropriate. Encourage exercises to maintain strength in the unaffected limb and upper body for mobility aids (e.g., crutches, walker).
• Psychosocial Support: Offer emotional support to the patient and family, acknowledging the impact of limited mobility and the recovery process on mental health. Provide resources for psychological counseling if needed.
• Patient Education: Educate the patient extensively on signs of complications, wound and cast care, the importance of keeping the limb elevated, and the timeline for weight-bearing progression.

Patient Education and Discharge Planning

Effective education and discharge planning are essential for a smooth transition from hospital to home care. The following key points should be covered:

• Activity Restrictions: Explain restrictions on weight-bearing and the use of mobility aids. Instruct on safe transfer techniques, and the use of crutches or a walker.
• Wound and Cast Care: Demonstrate how to keep the wound and cast dry, how to monitor for signs of infection, and when to seek medical attention.
• Pain Management: Review the prescribed pain medications, their dosages, side effects, and safe usage. Discuss alternative pain management strategies.
• Follow-Up Appointments: Stress the importance of attending scheduled follow-up visits for wound assessment, suture removal, and imaging to monitor bone fusion.
• Signs and Symptoms of Complications: Teach the patient and caregivers to recognize and report severe pain, numbness, tingling, increased swelling, signs of infection, fever, or any color changes in the toes or foot.
• Home Environment Preparation: Advise on modifications to the home to reduce fall risks, such as removing loose rugs, securing handrails, and ensuring adequate lighting.
• Nutritional Support: Encourage a diet rich in protein, vitamins, and minerals to support bone healing. Highlight the importance of avoiding smoking and limiting alcohol consumption.
• Assistive Devices Training: Provide hands-on training in the use of assistive devices and clarify the correct technique for safe mobility.

Prevention and Management of Complications

Complications following subtalar fusion can include infection, delayed or non-union of the bones, hardware failure, DVT, pressure ulcers, and chronic pain. Nurses play a vital role in early detection and intervention:

• Infection: Meticulous wound care, aseptic technique during dressing changes, and prompt reporting of abnormal findings are fundamental.
• Non-union or Delayed Union: Monitor for persistent pain, swelling, or instability at the surgical site. Report concerns to the surgical team for timely imaging and evaluation.
• Hardware Complications: Observe for pain or swelling over the hardware site and report any abnormalities or hardware exposure.
• DVT and Pulmonary Embolism: Ensure adherence to prescribed prophylactic measures and monitor for calf pain, swelling, redness, or sudden shortness of breath.
• Pressure Ulcers: Conduct frequent skin assessments, especially in areas at risk due to immobilization, and implement preventive interventions.

Interdisciplinary Collaboration

Optimal nursing care of the patient with a subtalar fusion requires coordinated teamwork with surgeons, physical therapists, occupational therapists, pharmacists, social workers, and case managers. Effective communication ensures seamless care, reduces hospital stay duration, and enhances patient satisfaction.

Psychosocial Considerations

Recovery from subtalar fusion can be lengthy, often requiring months before full weight-bearing is permitted. This period of restricted mobility can lead to frustration, anxiety, or depression. Nurses should provide encouragement, help set realistic expectations, and connect patients with peer support groups or counseling services as needed.

REFERENCES

1. American Academy of Orthopaedic Surgeons. Rheumatoid Arthritis of the Foot and Ankle. https://orthoinfo.aaos.org/en/diseases–conditions/rheumatoid-arthritis-of-the-foot-and-ankle/. Last reviewed 9/2017.
2. American Orthopaedic Foot & Ankle Society. Subtalar Arthroscopy. https://www.footcaremd.org/conditions-treatments/ankle/subtalar-arthroscopy.
3. Subtalar Joint Fusion, https://roh.nhs.uk/services-information/foot-and-ankle/subtalar-joint-fusion
4. American Podiatric Medical Association. When is Foot Surgery Necessary?. https://www.apma.org/Patients/FootHealth.cfm?ItemNumber=1560
5. Chambers AR, Dreyer MA. Triple Arthrodesis. https://www.ncbi.nlm.nih.gov/books/NBK551713/. 2023 Jun 5. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan.
6. Jennison T, Dalgleish J, Taher S, et al. Subtalar Arthrodesis Union Rates With and Without Adjacent Ankle Arthrodesis. https://pubmed.ncbi.nlm.nih.gov/35869646/. Foot Ankle Int. 2022;43(10):1295-1299
7. Physiopedia. Subtalar Joint. https://www.physio-pedia.com/Subtalar_Joint.

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