Midsubstance Achilles Tendinosis

Christopher Diefenbach, Christopher Kreulen, and Eric Giza

Abstract

Midsubstance Achilles tendonosis is a painful chronic condition that has many associated factors. This chapter details a concise and thorough review of the pathology, appropriate workup and conservative management, operative technique including pertinent tips/tricks/bailouts, postoperative rehabilitation, and outcomes of midsubstance Achilles tendonosis treatment. Operative repair is indicated after thorough evaluation and work-up, and the patient has failed conservative management, which occurs in approximately 24 to 45% of cases. The goals of open excision and repair of midsubstance Achilles tendinopathy are to excise fibrotic adhesions, remove degenerated nodules, identify and resect intratendinous lesions, and restore vascularity to remaining healthy tendinous tissue to help stimulate a healing response. The ultimate goal is to restore function and strength of the Achilles tendon. The operative technique described within this chapter reflects the most current knowledge of the disease process and optimal technique for complete resolution of symptomatology, restoration of function, and timely rehabilitation. Excellent patient outcomes and satisfaction can be obtained, and hinge on the extent of disease as well as meticulous surgical technique followed by thorough rehabilitation.

Keywords: midsubstance Achilles tendinosis, Achilles tendon, tendinosis, tendinopathy, operative repair, open repair, surgical technique, Achilles rehabilitation, Achilles repair

34.1 Indication and Pathology

• Tendinopathy of the midsubstance of the Achilles tendon.

• Associated factors (not necessarily causative).

• Intrinsic: overuse vascularity, gastrocnemius–soleus dysfunction, age, gender, BMI (body mass index), metabolic factors, foot malalignment, ankle instability.

• Extrinsic: quinolone antibiotics, training pattern changes, poor technique, footwear, environmental training factors (hard, slippery, slanted surface).¹

34.1.1 Clinical Evaluation

• Pain localized 2 to 6 cm proximal to the calcaneal insertion, particularly with exercise (Fig. 34.1).

• Pain increased at the beginning and end of exercise sessions, with intermediate period of minimized discomfort.

• Hindfoot inspected for malalignment, deformity, tendon asymmetry, thickening, Haglund’s deformity, previous scarring.

• Palpable tenderness, heat, thickening, nodularity, crepitus.

• “Painful range of motion” characterized by movement of the nodule within paratenon during plantar/dorsiflexion.²^–⁷

34.1.2 Radiographic Evaluation

• Plain film lateral radiograph is useful because it may show an associated bony abnormality or intrasubstance calcification (Fig. 34.2).

• Magnetic resonance imaging (MRI)/ultrasound provides information on the internal tendon morphology and is useful for preoperative planning, extent of degeneration, peritendinitis versus tendinosis.

• Sagittal and axial MRI images are helpful to determine the percentage of tendon involvement as augmentation may be necessary if greater than 50% of the tendon is removed (Fig. 34.3).

• Disorganized tissue appears as intrasubstance intermediate signal intensity.

34.1.3 Nonoperative Options

• A trial of conservative treatment is typically recommended prior to indicating a patient for surgical intervention.

Fig. 34.1 Clinical photograph demonstrating a fusiform swelling of an Achilles tendon 4 cm proximal to the calcaneus (large arrow) contrasted with the normal width of the Achilles tendon (small arrow).

Fig. 34.2 Lateral radiograph of the ankle demonstrating an intrasubstance calcification in the center of an area of midsubstance tendinopathy (arrow).

Fig. 34.3 Sagittal T1-weighted MRI (magnetic resonance imaging) demonstrating a thickened Achilles tendon with altered signal intensity within the central tendon.

• Boot immobilization.

• Nonsteroidal anti-inflammatory drugs can help alleviate acute symptoms.

• Eccentric loading and low-energy shockwave therapy show comparatively beneficial results.⁸^,⁹

• Other controversial options: gastrocnemius–soleus recession, peritendinous aprotinin, or topical glyceryl trinitrate.¹⁰^–¹²

• Platelet-rich plasma injection can provide pain relief and decreased tendon circumference for many patients, and remains an option prior to surgical intervention. The injection is best performed under ultrasound guidance to provide direct visualization of the diseased fibers.¹³

34.1.4 Contraindications

• Elderly or sedentary patients.

• Significant medical comorbidities including diabetic neuropathy and severe vascular disease.

34.2 Goals of Surgical Procedure

Operative repair is indicated after the patient has failed 6 months of conservative management, which occurs in approximately 24 to 45% of cases.¹⁰ The goals of open excision and repair of midsubstance Achilles tendinopathy are to excise fibrotic adhesions, remove degenerated nodules, identify and resect intratendinous lesions, and restore vascularity to remaining healthy tendinous tissue to help stimulate a healing response. The ultimate goal is to restore function and strength of the Achilles tendon.⁹

34.3 Advantages of Surgical Procedure

The advantages of an open midsubstance Achilles tendinopathy repair can be attributed to the resultant healing response to the operative procedure in general, as well as the specific technique. Operative repair has been shown to yield successful results in patients who have otherwise failed conservative management. Complete debridement of tendinopathic tissue allows for viable tendon healing and restoration of function and strength. This meticulous technique maintains the soft-tissue envelope as much as possible. This confers less scar and adhesion formation and significantly decreased incidence of wound complications. Less peritendinous disruption may enhance speed of healing and quality of tissue through preserved circulation. Ensuring that the procedure is performed inside the paratenon also reduces the chance of sural nerve injury. This method offers the benefit of operative intervention while minimizing the associated risks, and thus maximizing patient benefit and satisfaction.¹⁴

34.4 Key Principles

• Meticulous skin and soft-tissue handling.

• Preservation of the paratenon.

• Excision of all diseased tissue.

• Construct stability via durable suture fixation.

• Postoperative protocol that allows for healing and revascularization of viable tendon.

34.5 Preoperative Preparation and Patient Positioning

• Following diagnosis and appropriate workup, the preoperative preparation is crucial for optimal patient outcomes. A compressive elastic or cohesive tape wrap can be placed for significant swelling. Allow ambulation in a CAM walker boot to promote circulation and prevent venous thrombosis. Preoperative imaging will guide incision placement. Ensure resolution of any existing wounds near this area.

• Once in the operating room, proper patient positioning is important. The patient is positioned prone with an Achilles bump or over the edge of the table, allowing for plantar flexion and dorsiflexion of the ankle during the procedure.

• Pillows are not recommended given they can soften during the procedure and make exposure difficult.

• The operation is performed under anesthesia with use of a thigh tourniquet.

• The resting tension of the uninjured side should be noted in case a segment of tendon requires resection.

• Intravenous antibiotics and regional anesthesia is administered.

• Place well-padded thigh tourniquet prior to prone positioning.

• Proper positioning on the operating table in a prone position with all bony prominences padded.

• Position legs with Achilles bump or over the edge of the table, resting position (Fig. 34.4).

• The operative extremity is prepped and draped in standard sterile fashion.

• The area of diseased tissue is palpated and correlated to pre-operative imaging for site and length of incision.

34.6 Operative Technique

• Posterior incision slightly medial to the midline is utilized to minimize risk of injury to sural nerve, saphenous vein, and discomfort from external pressure.

• Full-thickness flaps are developed to expose and preserve the paratenon.

• The use of excessive or constant retraction with rakes or self-retainers is avoided to prevent tension on the skin, which could lead to wound complications.

• The paratenon is then incised and an attempt is made to dissect the paratenon as a separate layer for closure at the completion of the procedure (Fig. 34.5).

• Coexisting paratendinopathy or scarring will require excision of the scarred and thickened tissue.

• Any adhesions are then released from the paratenon using a small Cobb elevator or freer for blunt dissection. Dissection on the ventral surface is performed only when there is severe scar of the tendon to the paratenon. If the tendon still glides, the ventral paratenon can be preserved to aid in blood flow to the tendon (Fig. 34.6).

• The tendon is then incised longitudinally in line with its fibers directly overlying the diseased segment (Fig. 34.7).

The longitudinal tenotomy should follow the 90-degree rotation of tendon fibers as they course distally.

• Tendinopathic tissue is identified by disorganized fiber bundles, “crab meat appearance” (Fig. 34.8).

• Thorough intraoperative tendon evaluation is essential for complete disease elimination. Visualization of the axial MRI during the procedure can help find the diseased tendon given the pathologic fibers are not always apparent on initial visual inspection.