Multiple procedures to address the different pathologies of the posterior heel are common depending on the clinical presentation including excision of the retrocalcaneal bursa, calcaneal osteotomy, or Achilles tendon debridement including all calcifications and, if necessary, reattachment of the Achilles tendon to the calcaneus.1–7 Surgical success rates for open surgery have been reported between 75% and 100% satisfactory to excellent results.8,9 Complication rates range between 11% and 19% depending on the surgery performed.10
The focus of this chapter is on revision surgical procedures for those patients who have failed their index procedure and continue to experience posterior heel pain. Surgical complications can appear at any time postoperatively, although they are most common in the immediate postoperative period. Revision surgery can be necessary for early complications, such as wound dehiscence or tendon avulsion, or it can be needed for late-stage relapse or residual equinus.
A thorough history and physical examination is critical when evaluating patients who have recurrent recalcitrant posterior heel pain after undergoing prior reconstructive surgery. A good multifactorial approach to fully understand the patient’s pathology and reason for recurrent pain is vital when developing a revision surgical plan. Patient characteristics, such as obesity, as well as compliance, may dictate surgical procedure choice as well as hardware selection and postoperative protocol. It is not well researched about the effect of body mass index (BMI) on the rate of healing postoperatively. It has been the authors’ experience that higher BMI does not preclude a patient from revision posterior heel surgery, and we have not seen an increase in wound healing issues or other postoperative complications in these patients.
Planning a secondary incision location as well as decision on suture material for closure should be considered for the patient’s ability to successfully heal a revision surgery. Obtaining the history of prior surgeries (with prior operative reports) can provide information regarding the initial procedure(s) performed. Information including bone anchors, suture material, augmentation products, as well as any prior tendon transfer is also important to know.
Isolating the primary source of pain and identifying any functional deficit is imperative when performing a physical examination on patients who are presenting with ongoing symptoms. Patients may have a chief complaint of “posterior heel pain”; however, when and where the pain is located needs to be differentiated. Reproducible pain with palpation along the Achilles tendon may need to be surgically addressed differently than if a patient presented with pain primarily with shoe gear pressure on a posterior bump. When palpating for point of maximal tenderness, it is important to specify if the majority of pain is coming from residual posterior calcaneal bump pain or from undiagnosed mid-substance tendon pain. Physical examination should rule out ankle equinus, which can be addressed during the revision surgery. A combination of a thorough physical examination can be used in conjunction with advanced imaging to ensure that the surgical plan will address the symptomatic pathology.
Posterior Heel Imaging in the Revision Patient
When examining patients who require revision surgery, it is important to discern normal findings from pathologic findings on radiographs, magnetic resonance imaging (MRI), and ultrasonography (US). Having a good understanding of what is expected will allow for a better understanding of which findings are normal postoperative findings and which are a result of a new or continued pathology. It is necessary to examine all anatomic areas including soft tissue, osseous, and any hardware used in the prior surgery. Prior tendon transfers and bone anchors may appear as unusual pathology on postoperative imaging, especially US and MRI.
Standard radiography is the most common imaging modality used following foot and ankle surgery. Although radiographs are not considered to be diagnostic for Achilles tendonitis, plain film radiographs are needed to assess for Haglund deformity, retrocalcaneal bone spurs or cavus foot structure. Radiographs are commonly the first-line imaging modality used because of the availability, cost-effectiveness, as well as the rapid images that they produce. Several radiographic angles have been described in the literature to assess pathologies of the posterior heel. Measurements have been described to better determine the root cause of the patient’s symptoms. Unfortunately, the use of these measurements is unknown in surgical planning for revision surgery, as the initial procedure oftentimes alters the morphology of the posterior and posterior-superior calcaneus. Calcaneal axial imaging is used to assess for varus deformity, but it is deficient at capturing the Haglund deformity as it does not show the superior aspect of the calcaneal tuberosity. The authors rely on the lateral oblique image to further evaluate posterior lateral heel anatomy (Figure 19.2).
Evaluation of structures in the posterior heel by MRI is warranted in a high percentage of revision scenarios, as it can evaluate both soft tissue and osseous structures. It provides further investigation of the patient’s anatomy for surgical planning. Standard T1-weighted and T2-weighted imaging in all 3 planes of the ankle are used for optimal visualization of the posterior heel and related structures. A change in signal intensity may be a result of pathologic changes or artifact. Detailed information supplied to the reading radiologist will result in a more detailed report, which is helpful in these challenging revision cases. Careful interpretation and correlation of physical examination findings is important to fully understand the changes that are seen, particularly in the area of the Achilles tendon where suture repair was performed.
The use of MRI in evaluation of the postoperative patient can be challenging. Depending on the prior surgery and the hardware construct that was used, it can be difficult to determine if the patient’s current symptoms are a result of a new pathology or due to pathologies that were not addressed in the prior surgery. Knowing what prior surgical procedure was performed allows for changes in orientation of specific tendons to be interpreted as normal rather than pathologic. Soft tissue reconstruction, whether it is a primary end-to-end anastomosis or use of an allograft for augmentation, can also be evaluated on MRI. Insufficient resection or recurrent ossification of the Achilles tendon is manifested as areas of marrow signal within the tendon (Figure 19.4). If the patient continues to have a chronic wound or persistent infection, MRI should be obtained to evaluate for potential abscess formation as well as osteomyelitis along with standard laboratory workup.
Although US has the reputation to hold a steep learning curve and be dependent on the operator, it holds a high positive predictive value when examining the Achilles tendon.11 The images produced by US can assist the physician in determining the exact pathologic process, location of symptoms, and surgical planning in an immediate image produced in the office. Owing to the Achilles tendon location, size, as well as orientation, it is a structure that is favorable to view with US imaging. Immediate information about the tendon, its insertion, as well as the surrounding bursae can be visualized. Fractures, Achilles tendon ruptures and rupture hematomas, calcific changes in the Achilles tendon, as well as osseous projections can all be seen on longitudinal and transverse imaging of the calcaneus.
Is Ankle Equinus Present?
Proper evaluation of equinus when working up a patient presenting with recurrent posterior heel pain is important not only during the physical examination in the clinic setting but also in the operating room once the patient is under anesthesia. Hill found the incidence of equinus to be 96.5% for patients with a foot or ankle disorder.12 Patients often times have a tight gastrocnemius and soleus complex prior to their primary procedure, and if it is not adequately addressed, they may continue to tighten up in the postoperative period. Surgeons should be mindful of this when determining their postoperative protocol with casting, bracing, or pneumatic walkers to avoid equinus recurrence after release. It is also possible for the patient to have adequate length of the gastrocnemius and soleus complex preoperatively; however, if too much bone is resected off of the calcaneus during a retrocalcaneal procedure, or if too much distal Achilles tendon is resected, it may be difficult for the surgeon to reattach the Achilles tendon without creating an equinus contracture. Utilizing the Silfverskiold maneuver to differentiate gastrocnemius equinus from gastrocnemius and soleus equinus is standard clinical approach for proper procedural selection. The surgeon should assume that equinus is a factor in revision surgery until proven otherwise by careful examination.
Revision surgery for posterior heel pain is more likely to involve release of equinus contracture when compared with the index surgery. If the equinus contracture appears to be the main complicating factor, it could be performed as an isolated procedure. The surgeon might elect to perform a minimally invasive ambulatory lengthening, to see if that successfully treats the patient’s residual pain at the Achilles insertion. More invasive procedures could always be addressed at a later date. Contracture secondary to an isolated gastrocnemius equinus is typically treated with a proximal lengthening, above the conjoined tendon, such as a Baumann or high Strayer. When a patient’s equinus contracture is secondary to a combined gastrocnemius and soleus contracture, it is generally treated with a more distal procedure, at or below the level of the conjoined tendon, including a Vulpius or tongue-type lengthening procedure. Distal Z-lengthening can be performed at the Achilles repair site when performing side-to-side retubularization in cases involving longitudinal tears.