Lateral Approach for Calcific Insertional Achilles Tendinopathy Decompression: A Masterclass

Alright fellows, let's gather around. Today, we're tackling a challenging but rewarding case: calcific insertional Achilles tendinopathy using a lateral approach. This condition is a common culprit behind posterior heel pain, often leading to significant functional impairment. Our goal today is not just to perform the surgery, but to truly understand the nuances, the anatomy, and the critical decision points that lead to a successful outcome.

Understanding the Pathology: Patient History and Physical Findings

As you know, calcific Achilles tendinopathy is the most frequent cause of posterior heel pain. Our patient today, like many others, presents with a classic history: insidious onset of posterior heel pain, consistently aggravated by activity, especially running or even just the simple friction of shoe wear against the posterior heel counter.

What we're dealing with here is an intratendinous degeneration process, where the normal tendon structure at its insertion point into the calcaneus undergoes ectopic calcification and, in some cases, frank ossification. This isn't an acute injury; it's a chronic, progressive condition.

During your physical exam, remember to be precise. Palpate directly over the Achilles insertion on the posterior aspect of the calcaneus. This localized tenderness is highly diagnostic. Be mindful that squeezing the Achilles tendon too firmly can elicit a false-positive response, so a gentle, yet firm, squeeze between your index finger and thumb is appropriate to assess for tendinosis more proximally. A thickened or painful tendon beyond the insertion warrants further investigation, typically with an MRI, to rule out extensive tendinosis that might require a tendon transfer.

We also need to consider the broader clinical picture. Inflammatory enthesopathies, such as psoriasis, Reiter syndrome, or inflammatory bowel disease, can manifest with similar symptoms, so a thorough patient history is paramount. While peritendinous swelling is rare, you might observe an increased caliber of the Achilles tendon itself. Weakness is uncommon, but an Achilles tendon contracture, or tightness, is quite prevalent. Always ensure that Achilles tightness has been thoroughly addressed with dedicated stretching protocols before considering nonoperative treatment a failure. Pain with resisted plantarflexion can indicate more extensive tendinosis beyond the insertion.

Comprehensive Surgical Anatomy: Navigating the Posterior Heel

Let's review the critical anatomy we'll be working with. The Achilles tendon, the strongest tendon in the human body, inserts onto the inferior half of the posterior calcaneal tuberosity. This inferior half has a distinct rough surface, indicative of an extensive network of Sharpey fibers, which are crucial for the robust anchoring of the tendon to bone.

Superior to this, the superior half of the posterior calcaneal tuberosity presents a smooth, almost articular surface. This smooth area is crucial because it forms the anterior boundary of the retrocalcaneal bursa, which occupies the interval between the Achilles tendon and the superior calcaneus. This bursa can extend superiorly over the posterosuperior process of the calcaneus. Understanding this relationship is key, as bursal inflammation (retrocalcaneal bursitis) often coexists with or mimics insertional tendinopathy.

The insertional calcification typically develops precisely at this insertion point, often extending proximally into the tendon itself, sometimes appearing as multiple segments.

Neurovascular Considerations: The Sural Nerve

Now, let's talk about the sural nerve, our primary neurovascular concern in this region. The sural nerve typically runs along the posterolateral aspect of the leg and foot. While our lateral approach is generally considered posterior to the main trunk of the sural nerve, there are often calcaneal branches that can cross into our surgical field. These sensory branches provide innervation to the lateral heel.

> Surgical Warning: Sural Nerve Protection
> Meticulous, sharp dissection and careful identification of these branches are absolutely paramount. Any injury to the sural nerve or its calcaneal branches can lead to distressing paresthesias, hypoesthesias, or even painful neuromas, significantly impacting patient recovery and satisfaction. Always assume a branch is present until proven otherwise.

The strongest insertion fibers of the Achilles tendon are generally found on the medial aspect of the calcaneal tuberosity. This anatomical fact is a significant advantage of the lateral approach, as it allows us to decompress the lateral and central portions of the insertion while minimizing compromise to the strongest medial fibers.

Preoperative Planning: Setting the Stage for Success

Before we even consider making an incision, thorough preoperative planning is essential.

Imaging and Diagnostic Studies

Our primary diagnostic tools are plain radiographs and MRI.

• Lateral Radiograph of the Heel: This is your initial workhorse. It allows us to directly visualize the insertional ossification, characterize the size and morphology of the posterosuperior process of the calcaneus, and identify any intratendinous calcification extending proximally. These images are crucial for templating our planned ostectomy.
  

  
  
  

• Magnetic Resonance Imaging (MRI): MRI is indicated when the Achilles tendon appears thickened, tender, or significantly calcified on physical exam or radiograph. The critical information we glean from MRI is whether greater than 50% of the cross-sectional area of the Achilles tendon is involved with degenerative tendinosis. If this threshold is met, a flexor hallucis longus (FHL) tendon transfer reconstruction of the Achilles tendon will be necessary, a procedure beyond the scope of today's discussion but a crucial preoperative decision point. MRI also helps differentiate retrocalcaneal bursitis from pure insertional tendinosis.

Patient Preparation and Counseling

• Crutch Training: For patients who anticipate prolonged non-weight-bearing, preoperative crutch training can significantly ease their transition into the postoperative period.
• Realistic Expectations: It is vital to counsel patients that recovery from this surgery can be a lengthy and often frustrating process. Maximum improvement often takes 12 to 18 months, particularly in non-athletic individuals. While recurrent prominence of the heel can occur in up to 50% of cases, it is rarely symptomatic.
• Nonoperative Management: Remember, nonoperative management is successful in at least 50% of cases. Our typical protocol involves an initial period in a removable walker boot with 2-3 Achilles wedges for two weeks. We then remove one wedge every two weeks, continuing boot use for two weeks after the last wedge is removed, with weight-bearing as tolerated in the boot. Corticosteroid injections are strictly contraindicated in Achilles tendinopathy due to the risk of tendon rupture.

Patient Positioning: Optimizing Exposure

For this procedure, we have two primary options for patient positioning: lateral decubitus or prone.

• Lateral Decubitus Position: This is often preferred for older or heavier patients, as it provides excellent access to the heel while managing potential anesthesia concerns more easily than prone positioning. The operative leg is prepped and draped freely, allowing for full range of motion during the procedure.
• Prone Position: This also offers excellent access, particularly if a bilateral procedure is contemplated or if the surgeon prefers this orientation.

Regardless of the position chosen, ensure the neurovascular status of the foot is accurately assessed and documented preoperatively. Inspect for any previous incisional scars that might influence our approach.

Once the patient is positioned, a thigh tourniquet will be applied. After the leg is prepped and draped in a sterile fashion, we will exsanguinate the limb with an Esmarch bandage and inflate the tourniquet to an appropriate pressure, typically 250-300 mmHg, or 100 mmHg above systolic pressure, to maintain a bloodless field.

Step-by-Step Intraoperative Execution: The Lateral Approach

Now, fellows, let's begin. We're scrubbed in, the patient is prepped, draped, and the tourniquet is up.

1. Incision Planning and Execution

We will utilize a longitudinal incision along the lateral heel. Observe the landmarks carefully.

• Incision Line: The incision should run anterior to the anterior margin of the Achilles tendon itself. It needs to extend distally, almost to the plantar surface of the heel, and proximally, superior to the retrocalcaneal bursa. This allows for ample exposure of the calcaneal tuberosity and the insertional pathology.
  

  
  
  

• Initial Dissection: Using a #15 surgical blade, we make our skin incision. Immediately, we begin our sharp dissection through the subcutaneous tissues. The key here is to create full-thickness flaps. This means dissecting down to the deep fascia and periosteum, ensuring that the skin and subcutaneous tissue are lifted as a robust unit. This minimizes the risk of wound edge necrosis and dehiscence, especially in areas of compromised vascularity like the posterior heel.

> Surgical Warning: Sural Nerve Identification and Protection
> As we proceed with this initial dissection, our vigilance for the sural nerve and its calcaneal branches is paramount. These branches can be quite superficial. Use fine dissecting scissors and blunt probes to carefully sweep and identify any neural structures. Once identified, gently retract them with vessel loops or small malleable retractors, ensuring they are protected throughout the entire procedure. Avoid blind or aggressive blunt dissection in this area.

2. Exposure of the Retrocalcaneal Bursa and Calcaneal Periosteum

Once our full-thickness flaps are established, we'll continue our dissection.

• Periosteal Incision: We will make a longitudinal periosteal incision, extending it proximally through the retrocalcaneal bursa. This incision should be just anterior to the Achilles tendon insertion.
• Bursal Excision: Now, using fine dissecting scissors and forceps, we will meticulously excise the retrocalcaneal bursa. This is often inflamed and thickened in these patients. Complete excision ensures adequate decompression and removal of the inflammatory nidus.
• Periosteal Elevation: With a small, sharp periosteal elevator, such as a Freer or a small Cobb, we will carefully elevate the periosteum. Start by elevating the periosteum anteriorly from the calcaneus. This anterior flap will be crucial for our later Achilles tendon repair. Then, continue to elevate the periosteum posteriorly, carefully separating it from the insertional Achilles tendon fibers.

> Surgical Pearl: Preserving the Achilles Sleeve
> During subperiosteal exposure of the insertional ossification, it is critical to perform careful dissection to preserve the Achilles sleeve. This "sleeve" refers to the intact, healthy fibers of the Achilles tendon that are not involved in the calcification, particularly the lateral and medial expansion of the tendon over the tuberosity. Our goal is to remove the pathology while maintaining as much healthy tendon attachment as possible.

3. Extensive Subperiosteal Dissection and Pathology Identification

Now, we need to fully expose the pathology.

• Medial Extension: We will continue the sharp elevation of the calcaneal periosteum and the Achilles tendon insertion expansion medially along the posterior calcaneal tuberosity. Our goal is to achieve subperiosteal exposure all the way to the medial aspect of the tuberosity. This extensive exposure allows us to address the full width of the insertional calcification, which often extends medially.
• Degenerative Tendinosis Resection: At this point, we will carefully inspect the Achilles tendon itself. If preoperative MRI demonstrated significant degenerative tendinosis (greater than 50% cross-sectional area involvement), then an FHL tendon transfer would have been indicated and performed (as described elsewhere). However, if there are smaller, localized areas of degenerative tendinosis within the Achilles tendon, we will resect these areas using a #15 blade, debriding the unhealthy tissue while preserving as much viable tendon as possible.

4. The Calcaneal Ostectomy: Decompression and Resection

This is the core of our decompression. We need to resect the posterosuperior process of the calcaneus along with the insertional calcification.

• Defining the Osteotomy: We will use a small oscillating saw or an osteotome. The osteotomy line is crucial: it should extend from inferior to the insertional ossification to anterior to the posterosuperior process of the calcaneus.
  

  
  
  

> Surgical Pearl: Avoiding the Subtalar Joint
> When performing the ostectomy, be absolutely certain to stay anterior to the posterior facet of the subtalar joint. Violation of this joint can lead to significant postoperative pain and arthrosis. Use fluoroscopy if there is any doubt about the depth or trajectory of your osteotomy. The goal is to remove the prominent bone and calcification, not to alter the subtalar joint mechanics.

• Bone Resection: Carefully resect the bone block containing the posterosuperior process and the insertional calcification. Once the bone is removed, inspect the remaining calcaneal surface and the Achilles tendon for any residual calcification or impingement.
• Rounding Edges: After the ostectomy, the remaining calcaneal bone edges can be sharp. Using a bone rasp or a small rongeur, meticulously round over all sharp edges, both medially and laterally. This prevents future impingement on the Achilles tendon and soft tissues.

5. Achilles Tendon Repair and Closure

With the decompression complete, we now need to re-establish the Achilles tendon's secure attachment to the calcaneus.

• Suture Anchor Placement: We will place two suture anchors into the cancellous bone that remains after the ostectomy. These anchors should be positioned strategically to provide a robust reattachment of the Achilles tendon. Drill the pilot holes under constant fluoroscopic guidance if necessary, ensuring proper depth and avoiding penetration of the anterior cortex of the calcaneus. Insert the anchors firmly.
• Tendon Repair: Using the sutures from the anchors, we will meticulously repair the Achilles tendon to the calcaneus. A strong, secure repair is paramount to allow for early motion and minimize the risk of early avulsion. We typically use a locking stitch configuration, ensuring broad contact between the tendon and the prepared bone bed.
• Periosteal Repair: Once the Achilles tendon is reattached, we will carefully repair the elevated periosteal flap laterally over the repair site. This provides an additional layer of soft tissue coverage and helps to reinforce the repair.
• Wound Closure: With the deep layers secured, we will proceed with meticulous layered closure of the incision. Close the subcutaneous tissues with absorbable sutures to obliterate dead space. Finally, close the skin with non-absorbable sutures or staples.
• Dressing and Immobilization: Apply a sterile dressing. Immediately following closure, we will apply a plaster posterior mold splint with the ankle held in a position of resting plantarflexion. This position offloads tension on the repaired Achilles tendon, protecting the repair during the initial healing phase.

Postoperative Care and Complication Management

Our job isn't done until the patient has fully recovered. Postoperative care is as critical as the surgery itself.

Immediate Postoperative Period

• Non-Weight-Bearing: The patient will remain strictly non-weight-bearing on the operative limb for the first 4 weeks postoperatively. This is crucial for initial tendon healing.
• Splint Management: At 2 weeks post-surgery, once the incision has healed, the posterior plaster splint will be removed, and the patient will be transitioned into a removable walker boot. This boot will include an Achilles wedge, similar to what we use for nonoperative treatment.
• Early Motion: Once the incision is well-healed, typically around 2 weeks, we can begin active, nonresistive ankle and hindfoot range-of-motion exercises while still in the boot. This helps prevent stiffness and promotes tendon gliding.
• DVT Prophylaxis: Given the immobilization, deep venous thrombosis (DVT) prophylaxis is essential, typically with low-molecular-weight heparin or aspirin, depending on patient risk factors and institutional protocols.

Progressive Rehabilitation

• Boot Weaning: The removable walker boot will be continued for a total of 6 weeks after the splint removal, meaning a total of 8 weeks of immobilization from the date of surgery. During this boot phase, we will gradually remove the Achilles wedges, typically one every two weeks, to slowly bring the ankle into a more neutral position.
• Physical Therapy: Upon completion of the removable walker boot immobilization, formal physical therapy will be initiated. This will focus on a structured program of progressive strengthening, including eccentric closed-chain strengthening exercises, which are vital for Achilles tendon recovery and remodeling.

Potential Complications and Management

Despite our best efforts, complications can occur. It's important to anticipate and manage them effectively.

• Delayed Wound Healing: This is a particular concern in diabetic and overweight patients due to compromised microcirculation. Meticulous wound care, strict blood glucose control, and nutritional support are essential. In severe cases, wound VAC therapy or even plastic surgery consultation for flap coverage may be necessary.
• Paresthesias and Hypoesthesias: These are typically due to sural nerve irritation or injury. Most mild symptoms resolve over time. Persistent or severe symptoms may warrant nerve block, medication, or in rare cases, surgical exploration and neurolysis. This emphasizes the importance of our intraoperative diligence in nerve protection.
• Achilles Avulsion: This is a devastating complication, usually due to premature or excessive loading on the repaired tendon. A secure surgical repair and strict adherence to the non-weight-bearing and rehabilitation protocols are our best defense. If avulsion occurs, reoperation with a stronger repair, possibly augmented with an FHL transfer, is usually required.
• Recurrence: While our goal is definitive treatment, recurrence of symptoms or calcification can happen, albeit rarely symptomatic even if prominent. This reinforces the need for thorough patient counseling on the chronicity of the underlying pathology.
• Deep Venous Thrombosis (DVT): As mentioned, prophylaxis is key. If DVT is suspected (swelling, pain, warmth), immediate diagnostic imaging (ultrasound) and anticoagulation are necessary.

Fellows, this procedure, when performed meticulously with a deep understanding of the anatomy and biomechanics, offers excellent outcomes for patients suffering from disabling insertional Achilles tendinopathy. Remember the pearls, anticipate the pitfalls, and always prioritize patient safety and functional recovery. Let's proceed.

REFERENCES

1. Alfredson H, Bjur D, Thorsen K, et al. High intratendinous lactate levels in painful chronic Achilles tendinosis: an investigation using microdialysis technique. J Orthop Res 2002;20:934–938.

2. Astrom M, Rausing A. Chronic Achilles tendinopathy: a survey of surgical and histopathologic findings. Clin Orthop Relat Res 1995; 316:151–164.

3. Maffulli N, Reaper J, Ewen SW, et al. Chondral metaplasia in calcific insertional tendinopathy of the Achilles tendon. Clin J Sports Med 2006;16:329–334.

4. Maffulli N, Testa V, Capasso G, et al. Surgery for chronic Achilles tendinopathy yields worse results in nonathletic patients. Clin J Sports Med 2006;16:123–128.

5. Rufai A, Ralphs JR, Benjamin M. Structure and histopathology of the insertional region of the human Achilles tendon. J Orthop Res 1995; 13:585–593.

6. Shalabi A, Kristoffersen-Wilberg M, Svensson L, et al. Eccentric training of the gastrocnemius-soleus complex in chronic Achilles tendinopathy results in decreased tendon volume and intratendinous signal as evaluated by MRI. Am J Sports Med 2004;32: 1286–1296.

7. Watson AD, Anderson RB, Davis WH. Comparison of results of retrocalcaneal decompression for retrocalcaneal bursitis and insertional Achilles tendinosis with calcific spur. Foot Ankle Int 2000; 21:638–642.

8. Physical therapy begins 8 weeks after surgery.

OUTCOMES
- Fifty to 85% of patients report good or excellent results 2 years after surgery. 4,7

• The percentage of good or excellent results is higher in athletic than nonathletic patients. 4

• Radiographically recurrent insertional calcification occurs in 50% of patients, but symptoms do not always recur with radiographic recurrence. 7

• Some patients have recurrent symptoms without radiographic recurrence. 7

• Maximum symptomatic relief may not occur until 12 to 18 months after surgery.

• A 1to 2-month period of temporary symptomatic recurrence often occurs 7 to 10 months after the surgery. 7

COMPLICATIONS
- Superficial or deep infection is especially common in diabetic and overweight patients.