Current Concepts In Plantar Plate Repair
Do you find yourself in certain cases choosing between metatarsal realignment and plantar plate repair? Given this dilemma, these authors suggest that combining the Weil osteotomy with a dorsal approach to the anatomic plantar plate may be beneficial in addressing both plantar plate tears and metatarsalgia.
With any surgical procedure, there are problems and complications. The most commonly discussed problem associated with the Weil osteotomy is the “floating toe.” Studies had identified the floating toe to occur 15 to 50 percent of the time following a Weil osteotomy.1-3 The floating toe does not touch the floor with neutral weightbearing after undergoing a metatarsal osteotomy.
Additionally, there is weakness and decreased ability to plantarflex the toe actively. Many have theorized as to the cause of floating toe and have suggested modifications to the procedure in order to prevent its occurrence.4-7 However, most of these changes have not altered the outcome and increased other complications (transfer metatarsalgia, stiffness, edema, etc.) and disability postoperatively.
For years, we have been trying to find a solution to the problem, whether it is making sure to perform the procedure in the articular surface to prevent plantar translation, performing appropriate dorsal soft tissue release, encouraging early physical therapy (seven days postoperative), and emphasizing plantarflexion strength and night splinting of the toe. Nonetheless, floating toe still occurred, although at rates much lower than cited in the literature. In our most unstable metatarsophalangeal joints (MPJs), we started trying to repair the plantar plate in conjunction with the osteotomy but with limited success due to the difficulty of exposure from the dorsal approach.
In the fall of 2007, the lead author had given a lecture on the Weil osteotomy at a Podiatry Institute conference in Florida. Immediately following the lecture, Craig Camasta, DPM, gave a lecture on plantar plate pathology and repair. Dr. Camasta was one of the real leaders in discussing the plantar plate and he made a very compelling argument as to the role of the plantar plate in lesser metatarsophalangeal joint problems. Listening to Dr. Camasta’s rationale made the lead author strongly consider the possibility that plantar plate insufficiency may have more to do with the painful metatarsalgia entity and postoperative floating toe problems than previously appreciated. It also made him think that combining the Weil osteotomy with a plantar plate repair would be the best of both worlds.
Later in the exhibit hall, the lead author came across a company that was showing bone anchor concepts that were the standard of care for arthroscopic rotator cuff repair at the time. The delivery system for repairing the rotator cuff was something with which he was totally unfamiliar but he watched the salesman demonstrate the placement of sutures into tissue in a tight space. At that moment, he realized that he had a way to suture the plantar plate through the same dorsal exposure as the Weil osteotomy.
The following week, the lead author and his Fellow, Jason Glover, DPM, tried different combined Weil osteotomy/plantar plate repairs on cadavers and came up with a reproducible technique. They started performing the procedure for patients with the most unstable, painful metatarsalgia and closely followed the patients and their results. The lead author presented the first series of cases at the International Federation of Foot and Ankle Surgeons the following fall in Brazil with very encouraging early results showing high function and diminished incidence of floating toe.
Why Shorten The Metatarsal?
Metatarsalgia is one of the most common problems we see as foot and ankle specialists. Typically, the position and length of the second metatarsal (and occasionally the third) have created a biomechanical imbalance in the forefoot, causing pain and subsequent injury to the surrounding soft tissue structures, particularly the plantar plate. During the propulsive phase of gait, an elongated metatarsal will be overloaded with every step. Over time, that overload will cause attrition to the plantar plate and surrounding soft tissue structures, leading to pain, swelling, deviation of the joint, crossover toe deformity, hammertoe and ultimately dislocation.
Radiographically, this manifests as a subtle difference in the length of the second metatarsal in comparison to the contralateral foot (for unilateral pathology) or in comparison to the expected normal second metatarsal protrusion distance (for bilateral pathology). In our patients with unilateral plantar plate tears, the side with the plantar plate pathology had a second metatarsal protrusion distance of 4.4 ± 1.0 mm, which is 0.6 mm longer than the contralateral/non-pathological side (3.8 ± 1.0 mm).8
It is necessary to correct the underlying deformity by shortening the metatarsal. Without metatarsal shortening, soft tissue corrections will fail over time. Not correcting the metatarsal in this situation is much like addressing a posterior tendon dysfunction solely by repairing the tendon without changing the structural component with appropriate calcaneal osteotomies, arthroereisis or fusion procedures.
Why Repair The Plantar Plate?
The earliest description of the plantar plate can be credited to Cruveilhier, who described the plantar plate as a static structure that served to “protect” the lower portion of the lesser MPJ while increasing joint space area.9 More recently, authors have theorized the plantar plate to serve as both a static and dynamic structure having attachments to the deep transverse intermetatarsal ligament, the lateral collateral ligaments and the plantar fascia.10
The plantar plate is one of the main stabilizers of the lesser metatarsophalangeal joint. In concert with the collateral ligament complex, sagittal and transverse plane deformity (including dislocation) are resistant at the level of the MPJ. Sectioning of the plantar plate will decrease the amount of force necessary to dislocate the MPJ by 30 percent.11 Sectioning of the collateral ligaments will decrease the amount of force to dislocate the MPJ by 45 percent. Sectioning of both structures will decrease the amount of force needed to dislocate the MPJ by 79 percent.
It stands to reason, therefore, that pathology of the plantar plate needs repair in order to restore stability to the lesser MPJ. This concept is similar to that of a Brostrom procedure for lateral ankle stabilization. When the primary stabilizing structure of a joint undergoes repair, the joint becomes more stable.
How Common Is Plantar Plate Pathology?
In the experience of our institution, plantar plate pathology is responsible for much of the lesser MPJ pain/metatarsalgia in our patients. As many as 50 percent of our patients with metatarsalgia present to our clinic seeking a second opinion as they had previously seen physicians who diagnosed another pathology (generally capsulitis or a second interspace neuroma) that was resistant to treatment.
Interestingly, while conducting a cadaveric study earlier this year aimed at elucidating the cross-sectional anatomy of the metatarsal neck and the proximal attachment of the plantar plate, researchers found 80 percent (16 of 20) of these randomly selected specimens had one of four types of plantar plate tears (see the table “What A Cadaveric Study Reveals About Plantar Plate Pathology” below).12
How To Determine Plantar Plate Pathology
A thorough clinical examination can isolate the possibility of plantar plate pathology. Patients will typically present with pain to the ball of the foot that is progressive in nature. They may complain of some numbness in the area, which is likely due to swelling putting pressure on the nerves in the area. The toe may be changing position over time by becoming more dorsally aligned or with lateral or, more commonly, medial deviation. There can be concomitant first ray pathology (hallux valgus or hallux rigidus), but this is not always present.
In the most severe cases, there may be a crossover toe deformity or MPJ dislocation. Hammertoe deformities may or may not be present. In early manifestations of disease, swelling at the plantar aspect of the MPJ may be present. However, in the situation of complete tear, this may be absent. There will be pain at the plantar aspect of the MPJ or distal aspect of the metatarsal head. A modified drawer test may yield instability in comparison to the contralateral foot or in comparison to the “expected normal” when bilateral disease is present. A drawer test will be painful in the patient with an incomplete tear but is often painless with complete tear. There may be weakness of plantarflexion of the affected toe.
X-ray findings of bilateral weightbearing films will often show an altered metatarsal pattern with the second metatarsal being slightly longer in comparison to the contralateral foot, transverse plane deviation of the digits, splaying of the digits and a subtly increased metatarsus adductus angle. Interestingly, 60 percent of our patients had splaying of the second and third digits, and did not have an interdigital neuroma. In the past, advanced diagnostics were inconsistent at best. Magnetic resonance images (MRI) of a MPJ would rarely provide more than one or two slices through the joint and visualization of the plantar plate was inadequate. More recently, MRI techniques have allowed a much higher level of appreciation of the MPJ.
Our previous Fellow, Wenjay Sung, DPM, led our ACFAS Research Grant Award to determine MRI correlation to intraoperative findings of plantar plate pathology. The overall accuracy of MRI in determining if plantar plate pathology was present was 96 percent. This study also revealed a sensitivity of 95 percent, a specificity of 100 percent, a positive predictive value of 100 percent and a negative predictive value of 67 percent. This MRI study occurred without IV contrast and without intra-articular contrast, as had been done previously in the literature.13,14 Sung’s MRI study was the 2011 poster award winner at the American Orthopedic Foot and Ankle Surgeons Annual Summer Meeting, and will be published in the Journal of Foot and Ankle Surgery in 2012.15
We also have an ongoing study looking at diagnostic ultrasound in comparison to MRI findings and intraoperative findings. The early results from this study suggest that ultrasound evaluation of the plantar plate is highly technician dependent. Although the ability of the ultrasound and technician to detect the presence of plantar plate pathology is relatively high (75 percent), the ability to accurately detect the location of the plantar plate pathology is very low (31 percent).
A Guide To Performing The Combined Plantar Plate Repair And Weil Osteotomy
To rectify plantar plate pathology and metatarsal deformity, we have developed a combined procedure to perform a dorsal approach anatomic plantar plate repair and a Weil osteotomy.
Make a linear incision overlying the extensor apparatus extending from the distal third of the metatarsal shaft to the midshaft of the proximal phalanx centering over the MPJ. After performing dissection down to the extensor apparatus, create an incision between the extensor digitorum longus and brevis to the level of bone from the distal metatarsal to the proximal phalanx shaft. Place a self-retaining retractor deep to the extensor tendons and expose the MPJ. Reflect the medial and lateral collaterals off the proximal phalanx base, making sure to preserve their metatarsal head attachments.
Then carefully place a small or medium McGlamry type elevator into the MPJ and advance it proximally (hugging the bone) to release adhesions and mobilize the proximal plantar plate attachment at the metatarsal neck. This allows improved exposure to the plantar plate in later steps. Only use the elevator plantarly and do not carry it to the medial or lateral side of the metatarsal head. This helps maintain collateral attachments as these attachments provide the most important blood supply to the metatarsal head.
Perform a Weil osteotomy in the affected metatarsal. The osteotomy starts in the dorsal (2 to 3 mm) articular surface of the metatarsal. The angle of the osteotomy is as close to parallel to the weightbearing surface as possible. This angle is important to prevent plantar displacement of the metatarsal head as one creates shortening.
After completing the osteotomy, use a metatarsal pushing device to push the metatarsal head proximally 7 to 15 mm and temporarily fixate it with a 1.6-mm threaded K-wire.
Place a mini-joint distraction device over the pin to fixate the metatarsal head and then place a second pin from dorsal to plantar, 5 mm distal to the base of the proximal phalanx. After placing the distractor, open it to gain dorsal access to the MPJ and visualize the plantar plate.
One can confirm plantar plate pathology with direct visualization of this structure. We have observed several different types of plantar plate injuries. These injuries include attenuation/attrition, longitudinal buttonhole tears, partial transverse tears or complete ruptures (see the table “What A Cadaveric Study Reveals About Plantar Plate Pathology” above). The most common pattern, in cadavers and our patients alike, is the incomplete transverse tears at the attachment into the proximal phalanx. These tears can be visible at the medial plantar plate attachment or, more commonly, the lateral plantar plate attachment. With more advanced disease, the entire plantar plate will be torn. Coughlin and colleagues published an anatomic study of plantar plate tears and a modified version of our grading scale.12,16
If the plantar plate has pathology, one must carefully dissect the entirety of the plantar plate off the base of the proximal phalanx. The flexor tendons run in close plantar (deep) proximity to the plantar plate at this level and one must take care not to cut them. After resecting the plantar plate off the phalanx, carry dissection proximally to create a full thickness flap of the plantar plate for advancement. A Freer elevator may be helpful to maintain a consistent level of tissue during this dissection.
After completely mobilizing the plantar plate, utilize a Mini-Scorpion device from the Complete Plantar Plate Repair System (Arthrex) to create a wide three-stitch mattress. Remove the distraction device and place a right angle towel clamp around the sides of the proximal phalanx. Perform manual distraction/plantarflexion to expose the base of the proximal phalanx. Remove any soft tissue attachments on the plantar surface of the proximal phalanx base. Using a small curette, roughen the plantar bony surface to facilitate plantar plate reattachment.
Create crossed bone tunnels in the proximal phalanx from distal dorsal medial to proximal plantar lateral. Create a second tunnel by drilling from distal dorsal lateral to proximal plantar medial. Then pass the sutures attached to the plantar plate from plantar to dorsal through the bone tunnels in the phalanx.
Proceed to remove the temporary fixation for the metatarsal head and pull the metatarsal head to its desired length. It is rare to shorten more than 3 mm. After achieving accurate alignment, fixate the osteotomy with one or two Snap-Off screws.
Plantarflex the phalanx to approximately 15 to 20 degrees. Then pull the sutures tightly to advance the plantar plate into the base of the proximal phalanx. Tie the sutures dorsally to secure the plantar plate position. The toe will appear plantarflexed. Then reapproximate deep tissue and skin, and apply a bulky compressive bandage to hold the second toe in plantarflexion. This bandage should remain in place for seven to 10 days with guarded partial weightbearing in a surgical shoe.
After removing the bandages, instruct the patient to return to a supportive athletic shoe with guarded weightbearing. The patient receives a night brace to reduce swelling. This brace (AFTR DC brace with osteotomy strap, BioSkin) will serve as a night splint to hold the toe in plantarflexion. This night splinting technique helps prevent dorsal contracture and scar tissue formation that can lead to limited postoperative plantarflexion.
Aggressive physical therapy begins at seven to 10 days postoperatively with particular emphasis on plantarflexion strength. Passive and active range of motion of the short and long flexor tendons — often under the direction of a physical therapist — two to three times a week is often included in the postoperative regimen.
Patients are able to return to normal shoe gear six to eight weeks postoperatively and begin aggressive weightbearing activities.
How Patients Have Fared Following The Procedure
Our early results of this procedure were published in Foot and Ankle Specialist in 2011.17 Postoperative visual analogue scale pain scores decreased from 7.3 + 1.6 to 1.7 + 1.8. Eighty-five percent of patients reported improved function and 77 percent of patients were satisfied or very satisfied with the outcome of the procedure. For this group of patients, there were two complications: painful hardware and continued metatarsalgia. There were no incidences of dehiscence, malunion, non-union or recurrent MPJ subluxation or dislocation.
Since the time of that study’s publication, we have performed many more procedures, all with similar and significant reduction in pain level postoperatively. There have been a few patients who have sustained significantly painful post-op stiffness that has resolved after a joint manipulation with the patient under anesthesia. Further results will be available with longer follow-up of this larger cohort of patients.
Through our research, we conclude that the incidence of plantar plate pathology is far more prevalent than commonly appreciated. In a randomized group of 20 cadavers, 80 percent of specimens had plantar plate tears.12 Anytime we see a painful metatarsalgia with plantar swelling at the MPJ, we suspect a plantar plate tear.
An appropriate clinical exam and radiographs can help detect plantar plate problems. Magnetic resonance imaging and ultrasound can help accurately define the presence and location of plantar plate deficits.
Previously, surgeons would have to choose whether to realign the metatarsal position or repair the plantar plate. Both procedures provide successful outcomes but have limitations as neither addresses the entire pathology involved. The dorsal approach for anatomic plantar plate repair provides a combined alternative to fully correct the complex nature of both a plantar plate repair and metatarsal deformity. The dorsal approach of this procedure allows the surgeon appreciation of both severe and subtler plantar plate injuries that may not be clearly evident from a plantar approach. This approach also allows for metatarsal realignment and prevention of a plantar scar.
We believe that with further attention and research, we can better understand, diagnose and treat plantar plate problems to provide surgeons and patients alike with the most optimal results.
Dr. Weil is the President and Fellowship Director of the Weil Foot, Ankle and Orthopedic Institute. He also serves as the Editor of Foot and Ankle Specialist. Dr. Weil is a Fellow of the American College of Foot and Ankle Surgeons.
Dr. Klein is the Reconstructive Foot and Ankle Surgical Fellow at the Weil Foot, Ankle and Orthopedic Institute.
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