Emerging Insights On The First MPJ Arthrodesis

Arthrodesis of the first metatarsophalangeal joint (MPJ) was first advocated in 1894 by Clutton for severe, painful hallux valgus.1 McKeever refined the technique in 1952 using intramedullary screw fixation, which is currently the gold standard for treatment of advanced arthritis and/or significant deformities of the hallux.2 Common indications for arthrodesis include stage 3 hallux rigidus (osteoarthritis), rheumatoid arthritis, failed first MPJ implants, severe hallux valgus deformities and post-traumatic arthritis.3,4

   Joint preparation, position, internal fixation and stabilization of the first MPJ are critical to the success of this procedure. While some fixation methods are favored over others, no consensus exists on the optimal technique. Fixation methods include Kirschner wires/Steinmann pins, two crossing screws, dorsal plates or memory staples.4-7 Union rates continue to increase as technique and fixation methods continue to improve. Current studies report fusion rates greater than 90 percent.3-5,7,8

   In 2005, Gibson and Thomson performed a randomized control trial to compare the clinical outcomes of arthrodesis with total joint arthroplasty in 63 patients with first MPJ osteoarthritis.9 All patients who underwent arthrodesis fused with few complications while six of the 39 patients in the arthroplasty group required implant removal postoperatively.

   At 24 months, there was a significantly greater reduction in pain in the arthrodesis group.9 Overall, only 3 percent of patients in the arthrodesis group said they would not have undergone the same surgery again in comparison to 40 percent of patients in the arthroplasty group.

   Functionally, a big concern with patients is the maintenance of their activity level after surgery. In 2005, Brodsky and co-workers followed up with 53 patients 12 months after first MPJ arthrodesis with screw fixation.10 Ninety-eight percent of patients returned to their preoperative jobs/activities with no restrictions and 94 percent could kneel and squat without difficulty.

   In another study by Van Doeselaar and colleagues, 62 patients with hallux rigidus underwent successful treatment with fusion of the first MPJ.8 After a median follow-up of 30 months, all patients received the Dutch Foot Function Index (FFI) questionnaire to measure foot function as well as a Visual Analogue Score (VAS) to evaluate pain and patient satisfaction. The FFI scores improved significantly from 38 to 8 and the median VAS pain and VAS satisfaction scores were 6.5 and 5.5 respectively.

   According to these studies, first MPJ arthrodesis provides patients with the level of activity, relief of pain and postoperative satisfaction they desire.

   Recent literature advocates the use of screw fixation with or without a dorsal plate. In 2008, Sharma and co-workers compared the use of a single interfragmental compression screw versus a screw supplemented with plate fixation in regard to clinical and radiologic fusion of the first MPJ.7

   The authors found that the addition of the dorsal plate did not confer any increase in stability or shorten the time to fusion.7 They also noted no difference of statistical significance in patient satisfaction or complications between the two methods. Using a single screw alone provided a union rate of 100 percent in the study.

   Hyer and colleagues performed a cost comparison of the crossed screw technique versus dorsal plating for first MPJ arthrodesis while also analyzing fusion rates and complications.3 This series included 45 patients with a 20 month follow-up. There were no statistically significant differences between techniques in regard to the proportion of patients achieving fusion, time to fusion or prevalence of complications. The mean cost for crossed screws was $374.05 (± 76.30), which was significantly lower than the mean cost for the dorsal plating technique, which was $603.57 (± 234.70). The authors concluded that screw fixation incurs less cost without compromising clinical results.

Salient Insights On Surgical Technique

Surgeons typically perform the procedure with the patient under regional or general anesthesia. The senior author prefers to utilize tourniquet control of the field and notes that an ankle tourniquet is appropriate in the case of first MPJ arthrodesis. In cases of revisional bunions, failed implant arthroplasty or non-unions, one should consider the potential need for bone grafting, particularly if a structural graft is indicated to re-establish or maintain length.

   The senior author prefers a medial approach as it allows for ease in fixation with crossing screws and provides a more acceptable cosmetic result for the patient. Create a medial capsular incision and elevate the capsule and periosteum from the medial aspect of the first metatarsal and the base of the proximal phalanx. One should limit dissection around the metatarsophalangeal joint in order to prevent unnecessary stripping of the soft tissue and blood supply to the fusion site.

   Using power and hand instrumentation, proceed to resect all loose bodies and spurring surrounding the MPJ. One may then use mini-Hohmann retractors to provide better exposure to both the metatarsal head and the base of the proximal phalanx. Curettage can remove any remaining cartilage. Use a high-speed 2 mm burr to resect and amalgamate the subchondral plate.

   Surgeons can then fenestrate the joint surfaces via a K-wire, drill bit or fish scaling with a small osteotome. While power reamers are available, the senior author cautions surgeons about using these due to potential excessive shortening of the first ray and the increased exposure required to introduce the instrumentation.

   Then position the fusion site and temporarily fixate it with 0.062 inch K-wires. In cases of hallux rigidus, one can obtain the optimum position with the toe completely derotated, 5 to 10 degrees of abduction and approximately 15 degrees of dorsiflexion. One may slightly increase dorsiflexion if necessary, particularly in females who may desire to wear up to a 2-inch heel.

   Positioning is difficult in the sagittal plane intraoperatively. Surgeons can utilize the tray lid from the small fragment screw set to help determine proper hallux positioning, allowing approximately one finger’s breadth to pass between the hallux and the lid as the lid loads the foot.

   In cases of hallux valgus, particularly longstanding cases or in patients with rheumatoid arthritis, take care not to “over-straighten” the hallux as it may serve as a long lever and prove difficult for the patient to ambulate.

   Fixation typically occurs with two crossing 3.5 mm cortical screws. Place one screw from proximal-medial to distal-lateral and the second from distal-medial in the phalanx into the proximal-lateral aspect of the first metatarsal. Place the screws using a lag technique. Be sure to provide considerable compression and stable fixation when placing the screws in a bicortical fashion. Stack the screws on top of one another to provide uniform fixation throughout the fusion site. Surgeons may utilize other types of screw fixation using a similar construct based on surgeon preference.

   The senior author recommends capsular closure using a running 3-0 vicryl and skin closure using a 4-0 nylon stitch. One should ensure limited subcutaneous closure in order to prevent soft tissue irritation medially. Patients wear a controlled ankle motion (CAM) boot postoperatively and stay non-weightbearing for at least four weeks. In weeks four through eight, patients typically may bear weight on the heel only in a CAM boot. At or around eight weeks, the patient progresses to regular shoe gear based on radiographic healing.

In Conclusion

When it comes to considering first MPJ arthrodesis in the management of hallux rigidus, one should carefully weigh the patient’s age, overall health status, prior surgeries and exhaustion of conservative efforts. For the active patient whose quality of life is deteriorating due to first MPJ osteoarthritis and for whom conservative treatments have failed, we recommend first MPJ arthrodesis with crossed screw fixation.

   It is clear from the current literature that first MPJ arthrodesis is a cost-effective method of reducing first MPJ pain and gaining overall patient satisfaction. With constant advances in fixation techniques and materials, union rates are very high.

   More importantly, first MPJ arthrodesis maintains postoperative function and quality of life, and the procedure offers reproducible and predictable results.

   Ms. Swanson is a third-year podiatric medical student at the College of Podiatric Medicine and Surgery at Des Moines University in Des Moines, Iowa.

   Ms. Dyack is a third-year podiatric medical student at the College of Podiatric Medicine and Surgery at Des Moines University in Des Moines, Iowa.

   Dr. Lee is in private practice at Capital Orthopaedics and Sports Medicine, PC. He is an Associate Clinical Professor at the College of Podiatric Medicine and Surgery at Des Moines University in Des Moines, Iowa. Dr. Lee is a Fellow and Past President of the American College of Foot and Ankle Surgeons.

References
1. Clutton HH. The treatment of hallux valgus. St. Thomas Rep. 1894;22:1.
2. McKeever D. Arthrodesis of the first metatarsophalangeal joint for hallux rigidus and metatarsus primus varus. J Bone Joint Surg. 1952;34:129.
3. Hyer CF, Glover JP, Berlet GC, Lee TH. Cost comparison of crossed screws versus dorsal plate construct for first metatarsophalangeal joint arthrodesis. J Foot Ankle Surg. 2008; 47(1):13-18.
4. Bennett GL, Sabatta J. First metatarsophalangeal joint arthodesis: evaluation of plate and screw fixation. Foot Ankle Int. 2009; 30(8):752-7.
5. Wassink S, van den Oever M. Arthrodesis of the first metatarsophalangeal joint using a single screw: retrospective analysis of 109 feet. J Foot Ankle Surg. 2009; 48(6):653-61.
6. Bennett GL, Kay DB, Sabatta J. First metatarsophalangeal joint arthrodesis: an evaluation of hardware failure. Foot Ankle Int. 2005; 26(8):593-6.
7. Sharma H, Bhagat S, DeLeeuw J, Denolf F. In vivo comparison of screw versus plate and screw fixation for first metatarsophalangeal arthrodesis: does augmentation of internal compression screw fixation using a semi-tubular plate shorten time to clinical and radiologic fusion of the first MTPJ? J Foot Ankle Surg. 2008; 47(1):2-7.
8. Van Doeselaar DJ, Heesterbeek PJC, Louwerens JWK, Swierstra BA. Foot function after fusion of the first metatarophalangeal joint. Foot Ankle Int. 2010; 31(8):671-5.
9. Gibson JN, Thomson C. Arthrodesis or total replacement arthroplasty for hallux rigidus: a randomized controlled trial. Foot Ankle Int. 2005; 26(9):689-90.
10. Brodsky JW, Passmore RN, Polio FE, Shabat S. Functional outcome of arthrodesis of the first metatarsophalangeal joint using parallel screw fixation. Foot Ankle Int. 2005; 26(2):140-6.