Essential Insights On First MPJ Implant Revision

Implants have been documented in the literature and surgeons have utilized implants over the past 50 years for the treatment of a variety of conditions including hallux rigidus, hallux valgus, osteoarthritis and rheumatoid arthritis.1,2 Total joints were originally designed to function as joint spacers to decrease pain while maintaining motion and joint alignment.1,3 Currently, a variety of products attempt to provide these characteristics. These products include silastic, polyethylene-on-metal and metal hemiarthroplasty implants. Surgeons have implanted over 2 million hinged great toe joint implants in the United States. However, there has been minimal research published on the long-term results of these implants.2 The current literature has documented an average follow-up assessment from 24 months to 13 years and patient satisfaction rates ranging from 67 to 90.7 percent.3-10 Authors have also described revisional rates for various implants ranging from 5 to 74 percent.2-10 The trend for doing total joint replacements in foot and ankle surgery continues and with the varying degrees of success, it is inevitable that many physicians will be faced with a failure at some point during their career. Revisional surgery including failed first metatarsophalangeal joint (MPJ) implants and other complex cases make up a large portion of the surgical cases at the Foot and Ankle Institute of Western Pennsylvania. With that being said, we hope to lend some insight on what we feel are some essential points that are necessary for the successful treatment of a failed first MPJ implant. Understanding The Reasons For Implant Failure Before attempting to revise a failed implant, it is imperative to understand the reasons behind the failure itself. One of the most commonly known causes of failure with silastic implants is foreign body synovitis.3,11 There have been documented reports of embedded silicone in adjacent bone and soft tissue, as well as cases of patients developing lymphadenopathy related to this silicone debris.10 In 2002, Ghalambor, et al., described this same phenomenon in identifying metal debris in affected bone and synovium from two failed titanium single stem implants.12 Lucency surrounding the implant identified on radiographs is a well documented reason for failure.6,8,10,13,14 However, one must determine the clinical correlation of implant-related lucency. In 1997, Lemon and Pupp demonstrated radiographic deterioration with various first MPJ implants but they failed to show correlation with the patient’s satisfaction.4,6,8,9,10,13 Other radiographic changes can include osteophyte production, subsidence of the implant, malalignment of implant, implant fracture, cortical fracture, lesser metatarsal fracture, cystic bone formation, osseous lucency, bone resorption and cortical thinning.4,6-8,9,15 Clinical symptoms relating to implant failure that may lead to first MPJ revision surgery include transfer lesions, chronic swelling and pain, decreased range of motion, recurrence of deformity, shortening of the first ray, instability in the first ray, hallux extensus, sesamoidal tracking and infection.3-5,12-14,16 In 1994, Papagelopoulos, et al., noted that 44 percent of all their postoperative patients had continued pain.4 These authors also related a significant correlation of age and implant failure. Researchers have found that increased activity level, younger patients and systemic diseases (including rheumatoid arthritis) all correlate with implant failure.4,6,10,14 The majority of patients with implant failure at our institution have presented with chronic pain and edema with hallux malalignment (including cock-up hallux, hallux varus, shortened first ray, and an unstable first ray), painful range of motion, and lesser metatarsalgia. Patients presenting with these symptoms have ranged from 49 to 72 years old with implants ranging from total joint metallic implants to hemi-implants. Radiographically, we have noted lucency surrounding the implant, lytic changes and subsidence or malalignment of the implant. Proper Patient Selection: What You Should Consider In The Preoperative Assessment Both the patient and the surgeon must understand that revisional surgery for a failed first MPJ implant is much more complex than the original surgery. The possible morbidity and postoperative convalescence associated with this type of procedure can be very extensive. Therefore, one must ensure a thorough preoperative workup in order to evaluate if the patient is capable of enduring such a surgery. During this time, physicians can initiate conservative care including custom orthotics with a Morton’s extension, NSAIDs and physical therapy. In addition to a thorough history and the clinical findings from the physical, the physician should evaluate the patient via radiographs. If the radiographs do not demonstrate adequate bone stock or clear visualization of the implant, one can obtain a CT scan. Advanced imaging can help identify any type of bony lesions, including cysts, as well as overall bone quality and implant alignment. Surgeons often utilize further evaluation, including pulse volume recordings of the lower extremities, to help assess tissue healing potential. A physical therapy consult is routine to help evaluate the patient’s ability to be non-weightbearing postoperatively. One must obtain medical clearance from the patient’s primary care physician or other specialists involved in the patient’s care. Surgeons must also weigh special considerations for patients affected by rheumatoid arthritis or other systemic diseases that can affect bone healing or the patient’s ability to remain nonweightbearing during the postoperative period. As with most revisional surgery, smoking cessation is paramount for an optimal surgical result. The patient’s surgical history can also be an important factor in the decision to perform revisional surgery. Previous infections, wound dehiscence and surgical techniques are all important factors to note. A previous patient that we have revised had multiple surgeries performed by another surgeon. These surgeries included placement of a silastic implant with resultant infection, removal of the implant, incision and drainage, and final placement of a titanium hemi-implant. This patient presented with a closed wound but had chronic pain at the surgical site. We obtained a bone biopsy and bloodwork to rule out any potential residual infection prior to the final surgical reconstruction of this patient. If you identify current infection in your clinical work up, you must perform extensive debridement, including the placement of an antibiotic-impregnated bone cement spacer for up to six weeks, prior to the final revisional surgery. Thorough evaluation of the patient may also reveal concomitant deformities. Pain may not only be associated with the implant itself. We have performed lesser metatarsal head resections, digital corrections and lesser metatarsal decompression osteotomies during the same reconstruction to treat coexisting deformities, and provide further pain relief and improved function. The most important part of the preoperative workup is to be thorough and communicate effectively with your patient. One must establish mutual goals and choose the correct surgical procedure for a satisfactory result to occur. Why We Advocate First MPJ Arthrodesis With Autogenic Bone Graft One of the main goals of any revisional surgery is to create a functional foot. It is our opinion that the best treatment for a failed first MPJ implant is to remove the implant and perform a first MPJ arthrodesis with an autogenic bone graft. Some believe a functional foot relies on the ability of the first MPJ to rotate through its range of motion and that surgeons should only perform a fusion as a final salvage procedure. However, it has been well documented in the literature and Lombardi, et al., clearly noted that a fusion provides a stable medial column which, in turn, provides a painless, highly functional gait.17 In 2005, Esway and Conti stated that a first MPJ arthrodesis not only provides the length and alignment needed for first MPJ revisional surgery but also facilitates a more stable and functional foot. The authors also maintained that a fusion of this type would also probably be more tolerated by younger, more active patients.1 We agree that active and/or younger individuals have a more functional foot with a stable medial column from a first MPJ fusion than other surgeries that one could consider. Keys To Bone Graft Selection First MPJ implant revisions almost always demonstrate some amount of bone lysis and erosion surrounding the implant on preoperative radiographs. This bone is devitalized and may inhibit optimal healing. Therefore, one must remove all degenerative bone before a fusion can take place. Wide debridement of the devitalized bone will result in a large defect at the surgical site. This defect would result in ineffective loadbearing if the surgeon performs an in situ fusion due to the severe shortening of the first ray.18 Therefore, a bone graft is necessary to provide the needed length and stability to this area.19 While various authors have documented the need for bone graft, there has been much discussion on the type of bone graft that is necessary.19-27 We agree with the literature that autogenic bone graft material is the preferred choice for a successful outcome of revisional surgery.21,22 Autogenic bone graft has the ability to provide osteogenic, osteoconductive and osteoinductive properties.24,25 No other type of graft provides all three characteristics. As described by Mahan and Hilstrom in 1998, the cells from the graft provide almost all new bone activity for the first eight weeks after surgery.21 As with any revisional surgery, an optimal healing environment is necessary for any chance of success. In addition, when evaluating bone grafts, one must consider structural versus cancellous grafts alone. Both provide the same healing characteristics but structural bone grafts also provide stability and length when necessary. Tricortical iliac bone is considered a structural graft. One may not only use this as a strut for cell transfer and stability, it also helps with the desired length of the first ray.26 We have also published on harvesting structural grafts from the tibia, fibula and calcaneus.24,26 One may employ cancellous bone grafts, which can be harvested from the ilium, tibia and calcaneus, for augmentation surrounding the fusion site. However, we believe these grafts do not have the capacity alone to create and maintain the length and stability needed for a functional foot.26 Surgeons may also utilize bone graft substitutes for augmentation purposes. Although we recommend autogenic structural graft as the preferred bone graft for revisions of this kind, we do understand that many physicians may find themselves at an institution without the support needed to harvest a graft of this kind. With this consideration, structural allograft may be your first consideration. In 2000, Myerson described his success in eight patients with the use of a femoral head allograft for first MPJ fusions.23 Myerson’s results were impressive with a 100 percent fusion rate for the allograft group and a 21 percent nonunion rate for the autogenic group. Myerson agrees that a structural graft was needed to maintain the length of the first ray for adequate function postoperatively. In 2005, Raikin, et al., described the use of calcaneal bone graft for a revisional first metatarsophalangeal arthrodesis. In their paper, they found a 100 percent satisfaction rate with only minor complications including initial incision sensitivity and sural neuritis.28 A Few Thoughts About Iliac Crest Bone Graft At the Western Pennsylvania Hospital, we are fortunate to have a strong working relationship with our plastic and orthopedic surgeons. They have outstanding techniques when performing a superior harvest of a tricortical iliac bone graft. The incision placement and dissection techniques cause minimal soft tissue disruption, and have accordingly resulted in a low complication rate. Researchers have described donor site complications in the literature such as seromas, hematomas, nerve damage, infection, fracture and hernias.21,26,29-32 Minor complication rates range from 0.5 to 18 percent with residual pain being the most consistent factor.26,29,31,32 Our patients have noted that the donor site is often more painful immediately after the surgery than the primary surgical site. However, to date, these patients have not had any chronic residual pain. Their symptoms generally resolve within the first two weeks. Overall, with sound surgical techniques, we have had a minimal number of minor surgical complications and no major complications to date. Step By Step Insights On Surgical Technique When first approaching this procedure, one would perform initial incision placement and dissection in normal fashion. Once you have identified the implant, remove it as well as any surrounding soft tissue or bone which appears diseased or devitalized. Proceed to prepare both the metatarsal head and base, and the proximal phalanx, including curettage and fenestration to bleeding cancellous bone. Following resection, measure the gap and harvest the appropriate sized tricortical iliac bone graft. The surgeon can place cancellous bone graft as well as bone graft substitutes within the medullary canals of both the proximal phalanx and metatarsal where one has removed debridement from the implants. Proceed to prepare the iliac graft for placement. On average, there is 0.5 cm to 1 cm difference in height dorsal to plantar of the metatarsal to the proximal phalanx depending on the phalangeal remnant. One must cut the iliac graft accordingly in an oblique manner from proximal to distal. This will provide proper contact of the graft to the metatarsal while avoiding the remaining plantar prominence distally at the graft to phalanx interface. Placing the graft with the central cortical side dorsally helps prevent graft collapse when one places the hardware. The primary concern with graft placement is coadapted bone to bone interfaces and surgical alignment of the first ray. Surgeons may utilize temporary fixation to hold the surgical site and graft in place while evaluating the placement. However, this is often not necessary due to the tight fit of the graft. There is no algorithm for alignment so one must assess each case individually. Surgeons can assess the alignment by loading the forefoot in the OR suite. The first ray should appear aligned with the lesser rays and one should note an approximate thumb’s distance between the hallux and the loading surface. This allows appropriate toe clearance and push off during the gait cycle. This is a salvage procedure and the preferred outcome is to provide a functional limb. Since there is overall loss of length of the first ray, calculated placement of the hallux, as described in the literature for primary arthrodesis, is not as significant in importance in revisional procedures. Fixation has ranged from various holed dorsal plates to Steinman pin fixation with favorable results. Generally, a low profile dorsal plate is the most common fixation type for these revision. Once one has placed the fixation and removed the temporary fixation, the surgeon should evaluate the fusion sites for any remaining micromotion. If motion is evident, you need to reassess your fixation as it is not yet adequate. Surgeon may also perform any adjunct surgical procedures at this time. One would subsequently close the soft tissues in normal fashion and place the patient in a posterior splint. How To Ensure Appropriate Post-Op Care It is imperative that all postoperative patients remain non-weightbearing until there is evidence of clinical healing and radiographic union. To enhance bony healing, surgeons often prescribe the use of a bone growth stimulator during the postoperative period. It is vital to inform your patients that it may take eight to 16 weeks for bony consolidation and that varies from case to case. In the recent literature, researchers have documented the average time to fusion being from 10 to 14 weeks with salvage union rates ranging from 75 to 82 percent.1,18,20,23,33 When appropriate, one may transfer patients to partial weightbearing and subsequently full weightbearing. Physicians should also advise patients preoperatively that they may not be returning to full activity for up to six months or longer after the surgery. The surgical procedure may be painful and more than one surgical site may need to heal. However, the convalescence period is often more difficult for the patient to handle. Addressing Potential ComplicationsAs with any surgery, complications may occur and they include the more common findings of infection, residual pain, painful hardware and nonunion. Close patient observation during the initial postoperative period will enhance one’s chances to identify and address any complications that could develop. The majority of complications that we have dealt with are primarily related to painful hardware, including the migration of pins and the dorsal plate and screws. To date, we have had two documented cases of incomplete fusions that we noted on advanced imaging. However, these patients were pain free and displayed no clinical signs of delayed healing. For these patients, we prescribed rocker bottom shoes and orthotics for long-term support. We also had one patient present to our institution after multiple surgeries from another surgeon had left her with a shortened fused first ray. We successfully lengthened the ray through a metatarsal corticotomy and the placement of an M-100 mini-rail. Through gradual lengthening, the patient had a functional first ray at the final follow-up visit. One must always discuss with patients that there is always a risk of further surgery and that the risk increases with the increased complexity of each case. What About Adjunctive Procedures? We evaluate each case on an individual basis. Accordingly, we consider additional or adjunctive surgical procedures when appropriate. In elderly patients with limited physical demands and a questionable ability to remain nonweightbearing, one may consider a Keller procedure. While this procedure provides relief from the failed implant, it does not stabilize the first ray. Furthermore, researchers have documented that the Keller procedure may cause lesser metatarsalgia, cock-up toe deformity, hallux varus and hallux valgus deformity, and excess hallux shortening.33,34 Surgeons should only consider this procedure with a select patient population type. In 1992, Kitaoka, et al., described a similar procedure performed on a limited, select number of patients. They removed the implant and only performed a synovectomy. They showed that seven out of 10 patients had an excellent clinical result with a primary complication of lateral column overloading.35 In Conclusion First MPJ implant revisional surgery is complex in nature and requires a detailed perioperative assessment for success. Achieving a functional limb and decreased pain is realistic with proper patient and procedure selection. With all this taken into account, podiatrists should consider revisional surgery due to the high rate of success. However, our profession must evaluate the failures of these implants and use this information to educate our colleagues so they can critically assess their patients prior to employing revisional surgery to help minimize the failures which are more common than one may believe. In regard to first MPJ implants, we recall a discussion at an academic meeting many years ago. “Implants have their indications but not nearly at the level of usage currently performed,” noted the colleague. “Often we as doctors do what the patient wants versus what he or she needs. An implant is a much easier procedure to consult a patient for versus an arthrodesis. Keep that in mind every time you consider an implant. The revision is no easy undertaking and should not be described to a patient as we all have heard, namely that if it does not work, we can just remove it or fuse it. This is not as simple as just removing it or doing a primary fusion so when consulting with a patient for an implant, it is your responsibility to provide the patient with a realistic scenario of what would need to be done in the event of failure.” We believe that implants can be very successful but one should not consider them in all cases of hallux rigidus or first MPJ arthritis. Physicians should critically evaluate each case on an individual basis. This in turn will lead to fewer failures and greater surgical successes. Dr. Murphy is a second-year resident at the Western Pennsylvania Hospital in Pittsburgh. Dr. Mendicino is Vice Chairman of the Department of Surgery and is the Chief of Foot and Ankle Surgery at the Western Pennsylvania Hospital in Pittsburgh. He is a Fellow and Past President of the American College of Foot and Ankle Surgeons. Dr. Catanzariti is an Attending Surgeon and the Director of the Residency Training Program at the Western Pennsylvania Hospital in Pittsburgh. He is a Fellow of the American College of Foot and Ankle Surgeons.  

References:

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Foot Ankle Int 2006;27(4):299-302. 19. Catanzariti, A. Graft-enhanced arthrodesis. J Foot Ankle Surg 1996;35(5):463-473. 20. Hecht P, Gibbons M, Wapner K, Cooke C, Hoisington S. Arthrodesis of the first metatarsophalangeal joint to salvage failed silicone implant arthroplasty. Foot Ankle Int 1997;18(7):383-390. 21. Mahan K, Hillstrom H. Bone grafting in foot and ankle surgery, a review of 300 cases. JAPMA 1998;88(3):109-118. 22. Brodsky J, Ptaszek A, Morris S. Salvage first MTP arthrodesis ultilizing ICBG: Clinical evaluation and outcome. Foot Ankle Int 2000;21(4):290-296.23. Myerson M, Schon L, McGuigan F, Oznur A. Result of arthrodesis of the hallux metatarsophalangeal joint using bone graft for restoration of length. Foot Ankle Int 2000;21(4):297-306. 24. Saltrick K, Caron M, Grossman J. Utilization of autogenous corticocancellous bone graft from the distal tibia for reconstructive surgery of the foot and ankle. J Foot Ankle Surg 1996;35(5):406-412. 25. Cypher T, Grossman J. Biological principles of bone graft healing. J Foot Ankle Surg 1996;35(5):413-417. 26. Mendicino RW, Leonheart E, Shromoff P. Techniques for harvesting autogenous bone grafts of the lower extremity. J Foot Ankle Surg 1996;35(5):428-435. 27. Catanzariti A, Karlock L. The application of allograft bone in foot and ankle surgery. J Foot Ankle Surg 1996;35(5):440-451. 28. Raikin S, Brislin K. Local bone graft harvested from the distal tibia or calcaneus for surgery of the foot and ankle. Foot Ankle Int 2005;26(6):449-453. 29. DeOrio J, Farber D. Morbidity associated with anterior iliac crest bone grafting in foot and ankle surgery. Foot Ankle Int 2005;26(2):147-151. 30. Scranton P. Use of bone graft substitutes in lower extremity reconstructive surgery. Foot Ankle Int 2002;23(8):689-692. 31. Tessier P, Kawamoto H, Posnick J, Raulo Y, Tulasne J, Wolfe S. Complications of harvesting autogenous bone grafts: A group experience of 20,000 cases. Plast Reconstr Surg 2005;116:72-73. 32. Boone D. Complications of iliac crest graft and bone grafting alternatives in foot and ankle surgery. Foot Ankle Clin N Am 2003;8:1-14. 33. Baumhauer J, DiGiovanni B. Salvage of first metatarsophalangeal joint arthroplasty complications. Foot Ankle Clin N Am 2003;8:37-48. 34. Trnka H. Arthrodesis procedures for salvage of the hallux metarsophalangeal joint. Foot Ankle Clin N Am 2000;5(3):673-686. 35. Kitaoka H, Holiday A, Chao E, Cahalan T. Salvage of failed first metatarsophalangeal joint implant arthroplasty by implant removal and synovectomy: Clinical and biomechanical evaluation. Foot Ankle 1992;13(5):243-250.Editor’s note: For further reading, see “How To Salvage A Failed First MPJ Implant” in the May 2005 issue of Podiatry Today. For other related articles, visit the archives at www.podiatrytoday.com.