® Integra CASE STUDY Integra® Allograft in Lower Extremity Orthopedic Surgery Integra® Allograft in Lower Extremity Orthopedic Surgery

Dr. Shane Hollawell Orthopaedic Institute of Central Jersey

Patient: MG

The patient presented as a 53-year-old male with a history of left medial ankle and foot pain. He had a progressive area of edema over the plantar medial arch and medial ankle. He noted a decrease in the height of his foot. He described it as becoming “more flat.” He described a general feeling of weakness in the medial aspect of his foot and ankle.

The patient has been treated for his symptoms and progressive positional foot changes with: rest, orthotics, physical therapy, anti-inflammatory medication, and ankle bracing.

His foot condition deteriorated over a number of years in spite of the conservative treatment. He was ultimately taken to the O.R. to correct a progressive adult acquired flatfoot deformity secondary to a long history of posterior tibial tendon dysfunction.

He had a past medical history of psoriatic arthritis, benign prostatic hypertrophy, and hypercholesterolemia. Current medications were denied. He has no known drug allergies. His social history was negative for tobacco use. Alcohol consumption was moderate. He is a self-employed builder.

Examination

The clinical examination was consistent with a pes planovalgus foot type. There was a decrease in longitudinal arch height, significant heel eversion, and midtarsal abduction, hammer toe deformity of digits two, three, and four in the sagittal plane, without transverse plane deviation of the forefoot. He was unable to perform the single toe test on his left foot. Edema was present along the course of the posterior tibial tendon, from its insertion into the navicular to behind the medial malleolus. A palpable thickening of the tendon was present just proximal to the navicular insertion. The rearfoot valgus and forefoot varus were flexible and reducible with manipulation.

X-Ray Evaluation

Decreased calcaneal inclination angle, increased talar declination angle, abnormal Meary’s line, uncovering of the talar head (“talar escape”), decreased ankle joint spacing, decreased subtalar joint spacing, mild calcaneal spurring (Figure A).

Figure A. Introduction

Adult-acquired flatfoot deformity formally referred to as posterior tibial tendon dysfunction or insufficiency, entails a spectrum of deformities resulting in medial arch pain, swelling, and weakness. Initially described as a posterior tibial tendon failure, an adult-acquired flatfoot deformity also encompasses a failure of the ligament complex of the medial arch. This combination leads to a progressive deformity of the midtarsal and forefoot joints. The posterior tibial tendon enlarges in width and length and becomes insufficient. This dysfunction places increased stresses upon the spring ligament complex and leads to further instability of the talonavicular joint, allowing for progressive arch flattening, pain, and functional limitations.

In addition to the rearfoot valgus and forefoot varus deformity, a concomitant equinus soft tissue contracture often develops as the flatfoot deformity progresses.

The degeneration of posterior tibial tendon mostly occurs in the hypovascular region of the tendon, as it courses behind the medial malleolus and progress toward its insertion into the navicular. Although the etiology of adult-acquired flatfoot deformity is not entirely clear, it is thought to be a multi-factorial entity related to obesity, gender, age, activity, and systemic disease.

There are generally four accepted stages of adult-acquired flatfoot deformity.

When pain and deformity persist in spite of conservative treatment, then surgical intervention is indicated. The surgeon must address and correct all planes of deformity through osseous realignment and soft tissue balancing.

Surgical Technique

Attention was first given to the Achilles tendon contracture. A percutaneous lengthening was performed with an #11 scalpel blade in a three-incision manner. Two incisions are placed posterior medially and one posterior laterally in the midsubstance of the Achilles tendon. Once the percutaneous cuts are made, the foot is dorsiflexed and supinated upon the leg to lengthen the tendon. Once adequate dorsiflexion has been achieved at the ankle, the percutaneous incisions are closed in a simple interrupted fashion, typically with a prolene or nylon suture.

Attention is then given to the hindfoot valgus and midtarsal joint abduction deformity. A lateral semi-extensile curvilinear incision is made over the lateral wall of the calcaneus. The incision is placed inferior to the peroneal tendons and the sural nerve. The incision is made perpendicular to the long axis of the calcaneus in the sagittal plane. The sural nerve and peroneal tendons are elevated off the lateral wall of the calcaneus. The flap is raised full thickness as one entire unit.

With the sural nerve and the peroneal tendons retracted superiorly, the osteotomy is then performed with a microsagittal saw or osteotome and mallet. The osteotomy is performed anterior to the tuber of the calcaneus and posterior to the posterior facet of the subtalar joint. The osteotomy position should be confirmed via intra operative imaging prior to initiating. The osteotomy is typically greensticked at the medial cortex to avoid damage to the neurovascular bundle in the tarsal canal.

Once the medial slide (Koutsogiannis) osteotomy is complete, the calcaneus is translated medially and plantar flexed to correct for the malalignment in both the frontal and sagittal planes.

DISCLAIMER: As a manufacturer, Integra LifeScience Corporation does not practice medicine and does not recommend any specific technique for use on a patient. Actual results may vary.

2 A 6-mm, 8-mm, or 10-mm Integra calcaneal step-off plate can be utilized for osteotomy fixation. The osteotomy is typically stabilized with a posterior to anterior Steinman pin. The plate is placed onto the lateral calcaneal wall centrally over the area of osteotomy. The plate can be secured temporarily to the bone with an olive or K-wire (Figure 1).

Figure 1. Figure 2.

The four screws can be placed into the plate in a non-locking or locking fashion from lateral to medial.

Once the plate is properly secured to the bone, then the temporary Steinman pin fixation is removed and the wound is irrigated (Figure 2).

Figure 3A.

The Evans osteotomy can be performed through the anterior aspect of the lateral incision or through a separate incision. The osteotomy is performed with a microsagittal saw approximately, 1 -1.5 cm proximal to the calcaneal cuboid joint (Figure 3a). The medial cortex is left intact to aid in osteotomy stability and the calcaneo-cuboid ligaments should not be disturbed. The osteotomy is gradually opened and a laminar spreader is placed into it. The desired correction is dialed in via the laminar spreader (Figure 3b).

Figure 3B. Figure 3C.

3 A 6-mm to 12-mm pre-contoured bone graft wedge, Integra LifeSciences, Plainsboro, NJ (Figure 3C) is ideal and can be used and to correct the transverse midtarsal abduction deformity. The most typical size wedge used for the Evans osteotomy is 8 or 10 mm. The pre-contoured bone wedge is placed into the open osteotomy (Figure 3D). The graft is gently tamped into place until it is even with the lateral cortex of the calcaneus (Figure 3E). The smooth laminar spreader is gently tamped out of the osteotomy with careful attention being paid to avoid any disruption to the bone graft (figure 3F). The wound is irrigated and packed temporarily with a wet gauze until the closure is performed.

Figure 3D. Figure 3E. Figure 3F.

The final extra-articular osteotomy is performed to correct the forefoot varus deformity. The Cotton osteotomy is made in the medial cuneiform. A 2-3 cm longitudinal incision is placed dorsally over the body of the medial cuneiform immediately next to the EHL tendon. Blunt dissection is carried down to the level of the periosteal tissue. The Periosteal tissue is incised and elevated medially and laterally. The tibialis anterior tendon and EHL tendons are retracted. The osteotomy is performed transversely in the central aspect of the medial cuneiform from dorsal to plantar. The plantar cortex is left intact to aid in the stability of the osteotomy. The osteotomy is typically performed with a microsagittal saw or osteotome and mallet. The osteotomy is opened with a smooth laminar spreader or distracting device of the surgeon’s preference. (Figure 4) The Cotton osteotomy is typically grafted with a pre-contoured bone graft wedge.

Figure 4.

4 The graft is placed from dorsal to plantar into the open osteotomy (Figure 4a). It is gently tamped into place until the allograft wedge is equal to the dorsal cortex of the medial cuneiform (Figure 4b). The laminar spreader is gently removed from the operative site with careful attention being paid to avoid any injury to the allograft bone.

Figure 4A. Figure 4B.

The lateral extensile and dorsal midfoot incisions are then closed in a layered fashion. The deeper tissue is closed using 2-0 Vicryl, followed by subcutaneous closure with 3-0 Vicryl and skin approximation in an interrupted, mattress or running fashion with either prolene , nylon, or monocryl suture.

A Final incision was made along the course of the posterior tibial tendon from the medial malleolus to its insertion of the navicular. The incision is deepened with a #15 scalpel exposing the posterior tibial tendon sheath. The tendon sheath is opened longitudinally with a dissecting scissor to expose the posterior tibial tendon.

The tendon was thickened, nodular with an area of intrasubstance tear several centimeters proximal to its insertion in the navicular. The diseased tendon was debrided with a scalpel, pickup, and scissor. After tendon debridement was complete, a primary repair was performed with a 4.0 looped non-absorbable FiberWire suture (Arthrex, Naples, FL).

Of note, a flexor digitorum longus tendon transfer can be performed in conjunction with the corrective osteotomies and posterior tibial tendon repair if the quality of the posterior tibial tendon is non-amenable for primary repair.

5 Postoperative Results

X-ray findings demonstrated a increased calcaneal inclination angle, elevated talar declination angle, normal Meary’s line, corrected midtarsal abduction, and rectus alignment of the talonavicular joint (Figures 5 and 6).

Figure 5. Figure 6.

The clinical results were consistent with calcaneal frontal plane correction, increased dorsiflexion ROM of the ankle, correction of the “too many toes” sign/midfoot abduction. There was a significant improvement in the medial longitudinal arch height, improved posterior tibial tendon strength. The patient demonstrated greater ability to single toe raise on his left foot. Pain was substantially reduced and he was able to significantly increase his activity level.

Postoperative Course

The patient was followed both radiographically and clinically. The patient had no adverse effects to the allograft bone or the internal fixation. The patient did not experience any wound complications or postoperative infection.

The patient maintained a non-weight bearing status for approximately six weeks. Passive range of motion began at the four-week interval postoperatively. The patient began protected weight bearing at six weeks and formalized physical therapy began at eight weeks postoperatively.

Radiographs were taken at two, four, six, and twelve weeks postoperatively. Radiographs demonstrated complete consolidation across the osteotomy and bone grafting sites. There was no evidence of bone graft failure or collapse. The position of correction was maintained radiographically and clinically.

Discussion

The extra-articular triple osteotomy approach for adult-acquired flatfoot deformity has proven to be a very effective method and a technically less demanding procedure to correct a flexible pes planovalgus foot condition, when compared to other surgical approaches. The triple osteotomy approach allows the surgeon to correct all planes of deformity by achieving proper joint alignment, without the need for autograft bone harvesting while simultaneously maintaining flexibility and promoting maximum foot function.

6 Integra® Allograft

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