Percutaneous Flexor Tenotomy: A Viable Alternative For Distal Digital Ulceration?

Combining a compelling case study with insights from the literature, this author discusses how the flexor tenotomy can be a treatment option for ulcerations on the distal tips of the toes in patients with diabetic neuropathy.

A 57-year-old female presented to the emergency department with a chief complaint of ulcerations to the distal tips of the right second and third toes. The patient reported having routine foot care approximately three weeks prior when she sustained an iatrogenic cut. The patient had been soaking her feet in Epsom salts twice daily and had not sought medical attention prior to her presentation to the emergency department.

The patient reported no pain and was ambulating without restriction in normal shoe gear. Her pertinent past medical history included a diagnosis of diabetes 10 years prior to her current presentation. The patient denied tobacco use.

Upon presentation, the patient was afebrile with stable vital signs. A focused examination of the right foot revealed biphasic signals on Doppler exam. Protective sensation was absent. There was reducible extension and free range of motion without pain or crepitus to all five metatarsophalangeal joints (MPJ). The second to fifth interphalangeal joints were plantarflexed. The proximal interphalangeal joints (PIPJs) were semi-reducible and the distal interphalangeal joints (DIPJ) were reducible.

A full-thickness ulceration was present at the distal tips of toes two and three. The second toe wound measured 4 x 6 mm, had a slight hyperkeratotic rim with a red granular base and was positive for probing to bone. The third toe wound measured 5 x 4 mm, had a hyperkeratotic margin with a red granular base and there was no probing to bone. There were no signs of infection to either digit. Pertinent radiographic findings were cortical disruption of the distal aspect of the second digit distal phalanx, which was concerning for osteomyelitis. A white blood cell count, erythrocyte sedimentation rate and C reactive protein were all within normal limits. The patient’s HgbA1c was 10.5%.

Both wounds were debrided and dressed with a silver-containing collagen dressing. She received toe sleeves to offload the ulcerations. The patient started on oral antibiotics and got a referral to the Limb Preservation Service for continued treatment.

Upon presentation to the Limb Preservation Service, the patient continued with conservative modalities and we discussed surgical options, including percutaneous flexor tenotomy, partial digital amputation and corrective hammertoe surgery. The patient gave her consent for in-office percutaneous flexor tenotomies of the right second and third toes. At the first post-procedure appointment, the wound on the second toe had decreased to 3 x 2 mm and no longer probed to bone. The wound on the third toe remained stable. Both the second and third digits were in near rectus alignment. One week later, both wounds were healed.

Subsequently, the patient had an ulceration develop at the distal aspect of the fifth digit due to the adductovarus deformity. I performed a percutaneous flexor tenotomy on both the fourth and fifth digits to aid in healing of the fifth digit wound and as a prophylactic procedure on the fourth digit to prevent a future wound due to the adductovarus deformity. The wound to the fifth digit healed one week later. All the lesser digits remain without ulceration and in near rectus alignment at 12 months.

A Closer Look At The Literature On Digital Amputation

The triad of diabetic peripheral neuropathy, hammertoe deformity and repetitive trauma resulted in ulceration in this patient.¹ Podiatrists commonly encounter this clinical presentation. Conservative treatment most often consists of offloading (i.e., crest or buttress pads, orthotics, immobilization) and local wound care. Unfortunately, healing of these ulcerations is difficult. Osteomyelitis often results, leading to digital amputation.

Digital amputation is currently the most common level of foot amputation surgeons perform.² While this procedure can eradicate infection with a minimally complicated postoperative recovery course and is cost-effective in comparison to extended medical treatment, it is not without complications, particularly in the long-term.^1,3-5 Authors have found digital amputation to be a significant indicator of future limb loss, even in the face of successful revascularization when needed.⁴ Loss of a digit leads to alternation of the osseous architecture of the foot, resulting in changes to pressure distribution about the foot. These changes can lead to the development of new areas of osseous prominence, resulting in increased pressure, ulceration and the risk for infection and amputation.^3,5,6

Studies have shown postoperative re-ulceration, hospitalization, re-amputation and mortality rates to increase each year following digital amputation.^5,7,8 The one-, three- and five-year rates of re-ulceration are reportedly about 30, 60 and 70 percent respectively.⁵ The one-, three- and five-year rates of re-amputation are reportedly about 20 percent, 20 to 40 percent and 50 percent respectively.^4,5,9 The one-, three- and five-year mortality rates are reportedly 6, 15 and 33 percent respectively.⁵

Nehler and colleagues found that 50 percent of their patients who successfully healed a digital amputation developed a new ulceration.⁷ The authors reported an overall 70 percent success rate once the study included those patients who eventually healed after multiple hospitalizations and re-operations. While these are the rates following total digital amputation, partial digital amputation does not fare much better. Authors of a retrospective review of in-office distal Symes procedures performed on 48 patients (48 distal digital tip ulcerations) reported a 4 percent incidence of an adjacent digital ulceration, all of which became infected and necessitated inpatient management.¹ Given these poor outcomes, the toes should be a major area of concern with a focus on preventive efforts and procedures that could result in wound healing without amputation.^5,9-11

Pearls For Performing The Percutaneous Flexor Tenotomy

Percutaneous flexor tenotomy is reportedly a safe and effective treatment for these types of ulcerations when the deformity is flexible.¹ A systematic review of percutaneous flexor tenotomies in patients with diabetes and a neuropathic ulceration found that the procedure provided digital realignment with fewer complications than those reported following digital amputation or hammertoe correction.¹² Subsequent studies report a 92 to 100 percent success rate. While there may not be complete correction of the deformity, there is often enough pressure relief for healing to occur.¹⁶ Postoperative complications consist of transfer ulceration (21 percent), ulcer recurrence (2-18 percent), postoperative infection (5 percent) and amputation (2 percent).^13-16 As the procedure only addresses the individual toe one is treating at that time, the high rate of transfer ulceration is not unexpected.

Authors have advocated the percutaneous flexor tenotomy as the first procedure of choice in cases of transfer ulceration and there is reportedly a 100 percent success rate using it as a prophylactic procedure to prevent callus formation, which could lead to ulceration.^13-16 I employed both of these tenets in the case presented here with success. While I do not recommend performing the procedure when signs of soft tissue infection are present, the presence of osteomyelitis is not a contraindication. Studies have shown that the presence of osteomyelitis will either lead to prolonged but eventual healing or result in no change in the definitive procedure of digital amputation.^15,16

The patient may remain seated or can be in a reclined or supine position based on comfort choice. A digital block is often not required as a majority of patients are neuropathic. No tourniquet is required.

Grasp the affected digit by the non-dominant hand with the index finger on the dorsum of the proximal interphalangeal joint and the thumb on the plantar distal aspect of the digit, and then extend the digit to expose the plantar toe sulcus. Insert a 6400 beaver blade vertically and perpendicular to the skin at the level of the toe sulcus until reaching bone. Performing the procedure at this level will ensure transection of both the long and short flexors.

Then turn the blade 90 degrees and transect half of the tendons. Rotate the blade 180 degrees to transect the other half of the tendons. Bring the blade vertical again for removal from the percutaneous stab incision site. Then hyperextend the toe. One can ask the patient to actively plantarflex the digit to determine if the tenotomy is complete.

One can perform the procedure again in the same manner if there is suspicion that transection of both tendons has not occurred. The patient can also continue to plantarflex the digit while the surgeon repeats the procedure to ensure transection of both flexors. The digit should be in a more rectus position once one transects both tendons.

Apply skin adhesive to the plantar distal and dorsal aspects of the digit and the dorsal aspect of the corresponding MPJ. Apply a ½ inch Steri-Strip to the plantar distal aspect of the digit and along the dorsum of the digit and MPJ to help maintain its rectus alignment. Roll a silver alginate dressing and place it under the digits to maintain digital alignment and serve as a dressing for the stab incision, which remains open to heal by secondary intention. Apply a small Coban dressing to the forefoot to keep the dressing in place. Instruct the patient to leave the dressing in place and ambulate freely in normal shoe gear until the first post-procedure visit in seven to 10 days.

Final Words

Percutaneous flexor tenotomy is a quick, simple, and effective procedure with minimal risk of complication that results in wound healing, even with the presence of osteomyelitis.^14-17 One can perform the procedure in the clinic, often without local anesthesia, and patients can freely ambulate in their normal shoe gear upon completion of the procedure. Should the procedure fail, one can still perform a hammertoe correction or partial or total digit amputation, if required.

Dr. Schade is a Fellow of the American College of Foot and Ankle Surgeons, and the American College of Foot and Ankle Orthopedics and Medicine.

References

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