Addressing Hallux Rigidus In The Presence Of Metatarsus Primus Elevatus
Given
the common nature of hallux rigidus and the challenges of concomitant metatarsus primus elevatus, these authors share key diagnostic insights, explore possible surgical options and discuss two illuminating case studies.
Hallux rigidus is degenerative arthritis of the first metatarsophalangeal joint (MPJ) and is the most common form of osteoarthritis of the foot.1 Hallux rigidus is characterized as a progressive condition that causes a severely painful and rigid great toe joint, leading to debilitating pain.2
There is debate as to the exact etiology of hallux rigidus. Some state that inadequate shoe gear and a tight Achilles tendon are to blame.3,4 Authors have also suggested that hallux rigidus can occur due to hypermobility of the first ray, immobilization of the first ray, an excessively long first metatarsal, an elevated first ray, degenerative joint disease or trauma.5,6
McMaster postulated that a subchondral defect develops on the articular surface of the first metatarsal head, causing a subchondral lesion. This lesion is also located beneath the dorsal lip of the proximal phalanx of the hallux. If jamming continues, degenerative changes will lead to joint narrowing, flattening of the first metatarsal head and the development of osteophytes.7 The hallux needs to dorsiflex 65 to 70 degrees for normal locomotion.5,7,8 The patient’s gait may become antalgic as the MPJ stiffens and there is a transfer of weight to the lateral border of the foot.9
Lambrinudi originally described the theory of an elevated first metatarsal as a variation in the sagittal plane of the first ray being elevated in relation to the lesser metatarsals.6 The etiology of metatarsus primus elevatus is either structural or functional. Structural etiology occurs from a congenital malformation or first metatarsal fracture, usually toward the base of the metatarsal. Functional elevatus is due to some form of muscle or biomechanical imbalance, or a combination of both. The peroneus longus is the prime stabilizer of the first ray and any interference with the peroneus longus resulting in paralysis or weakness will lead to the onset of functional elevatus.10
Essential Diagnostic Insights
Initially, patients complain of pain localized to the first MPJ, often with a history of an arthritic condition secondary to injury.9,11 Patients with a complaint of acute onset of symptoms need evaluation for gout, calcium pyrophosphate dihydrate crystal deposition disease, septic arthritis, stress fracture of the sesamoids and soft tissue masses. Early hallux rigidus consists of pain only at the end range of motion while patients with end-stage hallux rigidus may be pain-free due to ankylosis of the first MPJ. The most common finding on physical examination is a dorsal bunion.9,11
Radiographic evaluation of hallux rigidus should include dorsoplantar, lateral and oblique views of the foot.9 X-rays usually show dorsal osteophytes at the head of the metatarsal, joint space narrowing, subchondral cyst formation and sclerosis. During early stages, these findings are confined to the dorsal aspect of the joint but extend as the disease continues to spread. It is necessary to evaluate the parabola of the metatarsal and specifically the length of the first metatarsal. Lateral views show dorsal osteophytic spurring but this view tends to underestimate the size.9,11 Radiographic findings are characteristic of arthritic changes of the joint.12
The radiographic relationship between hallux rigidus and elevatus is a subject of debate due to a lack of agreement on the appropriate measurement between the first and second metatarsal. Some authors have evaluated elevatus by measuring the distance from the dorsal distal metaphyseal flare of the first metatarsal to the dorsal aspect of the second metatarsal perpendicular to the ground.2,13-15
There are several classification systems for the evaluation and categorization of hallux rigidus. Vanore and colleagues proposed a four-stage classification system based on clinical and established radiographic criteria.12 Stage one consists of plantar subluxation of the proximal phalanx and metatarsus primus elevatus. Joint dorsiflexion may be normal non-weightbearing but with ground reactive forces, joint dorsiflexion elevates the first metatarsal, limiting motion with no degenerative joint changes on radiographs.
Stage two entails pain on end range of motion, flattening of the first metatarsal head, small dorsal exostosis and subchondral eburnation. Stage three manifests in crepitus with pain on full range of motion, severe flattening of the first metatarsal head, osteophytosis, asymmetric narrowing of the joint space and subchondral cysts. Stage four reveals complete obliteration of joint space, exuberant osteophytosis with loose bodies within the joint space or capsule, total ankylosis and local pain most likely secondary to skin irritation or bursitis.12
A Closer Look At Conservative Treatment
Conservative treatment may provide some decrease in pain. Patients should avoid activities that aggravate symptoms, flexible shoes and non-supportive shoes. We recommend that patients wear rocker bottom shoes as this results in a propulsive gait with limited dorsiflexion of the first MPJ. Shoes with a wider toe box will allow more room for an enlarged metatarsophalangeal joint. Oral and topical non-steroidal anti-inflammatory drugs (NSAIDs) can be beneficial in reducing associated pain. Also consider corticosteroids in the form of intra-articular injections and tapered oral doses.11,12
Smith and colleagues evaluated a small series of symptomatic patients who had non-operative treatment.16 The treatment included increasing the room in the toebox, avoidance of high heels and a change in activities. After follow-up of an average of 14.4 years, there was a measurable loss of cartilage space in 67 percent of patients. Only one in 22 patients reported worsening pain since treatment and nearly 75 percent stated they would still choose non-operative treatment again.
What The Literature Reveals About Surgical Procedures
There is a wide spectrum of procedures that one can use to treat hallux rigidus with metatarsus primus elevatus. Goals for surgical treatment are to relieve pain, improve first MPJ range of motion and prevent progression of the degenerative process.17 We can divide these operations into two categories: joint salvage and joint destructive procedures. Joint salvage procedures include cheilectomy, metatarsal or phalangeal osteotomies. Joint destructive procedures include resection arthroplasty, implant arthroplasty and arthrodesis.
Cheilectomies involve resection of the dorsal osteophytes and the degenerative portion of cartilage from the metatarsal head. Cheilectomy has become a popular procedure for the treatment of hallux rigidus by relieving pain while preserving motion and stability.1 Usually, surgeons remove 25 to 33 percent of the dorsal portion of the metatarsal head.13 The goal is to increase dorsiflexion of the joint by removing bone fragments. The removal of bone depends on the size of the bony proliferation, the change of articular cartilage and the amount of dorsiflexion.1 Easley and colleagues reported on results of cheilectomy in 68 cases of hallux rigidus with a five-year follow-up.18 They recorded a 90 percent satisfaction rate and an average increase in dorsiflexion of the MPJ of 19 degrees.
Bonney and MacNab first described a dorsal closing wedge osteotomy of the proximal phalanx in 1952 for treatment of hallux rigidus in adolescents.19 The procedure shifted the MPJ motion dorsally and placed the hallux into a more dorsiflexed position, allowing for improved movement and function.
Authors have also described several osteotomies of the first metatarsal. These procedures focus on decompressing the joint by shortening the metatarsal, realigning the articular surface to bring the metatarsal in a more functional position and correcting metatarsus primus elevatus by plantarflexing the first ray.1,6,8-11 In 1927, Waterman described a procedure for patients with limitation of dorsiflexion at the first MPJ. He advocated the use of a dorsally based wedge trapezoidal osteotomy at the metatarsal neck to preserve the functional articular cartilage at the first metatarsal head in an adolescent.5,20
The Green-Waterman osteotomy involves excising a rectangular section of bone from the dorsal aspect of the metatarsal neck while maintaining a plantar arm. This redirects healthy plantar articular cartilage dorsally. Dickerson and colleagues retrospectively reviewed 32 patients treated with the Green-Waterman osteotomy for four years and reported that 94 percent of patients had a significant reduction in pain.21
Youngswick described a modification of the Austin bunionectomy for the treatment of metatarsus primus elevatus. The osteotomy allows the head of the metatarsal to plantarflex, achieving relative reduction of the elevatus and shortening of the metatarsal length, allowing more dorsiflexion at the MPJ. One usually combines the procedure with an Austin bunionectomy for treatment of hallux abducto valgus deformity but may use this when only dealing with metatarsus primus elevatus.22 All of these osteotomies usually occur with a cheilectomy.11
A recent review evaluated four studies involving 93 isolated periarticular first metatarsal osteotomies with hallux rigidus and found an average increase of 10.4 degrees with dorsiflexion of the first MPJ.23 The same author prospectively evaluated 19 patients who had decompressive osteotomies, which included Austin-Youngswick, Green-Waterman, Weil or telescoping scarf osteotomies.17 Most of the patients indicated that they would have the same surgery again even though investigators found radiographically significant worsening of the lateral talar-first metatarsal angle, progressive medialization of the second digit and persistent metatarsus primus elevatus. The authors determined that the shortening of the first metatarsal consequently led to medial column instability.17 The surgeon must not remove too much bone from the osteotomy site as this can result in overcorrection of the elevatus.10
Joint destructive procedures include arthroplasty, implant arthroplasty and arthrodesis of the first MPJ. Arthroplasty creates increased space between the first metatarsal and proximal phalanx to allow motion at the joint. The most ideal patients for arthroplasty are sedentary patients with the treatment goal of improving symptoms and allowing them to perform activities of daily living.12 Keller resection arthroplasty of the base of the proximal phalanx was once a standard procedure in older patients with severe hallux rigidus and valgus. Originally described in 1904, the procedure is still in use to preserve the first metatarsal head.24
Implant arthroplasty of the first MPJ has been in successful use for over 50 years. Hemi-implant resurfacing endoprosthesis replaces the articular surface of the base of the proximal phalanx and leaves all conjoined tendons that insert onto the base of the proximal phalanx.
Townley and Taranow evaluated the results of 279 hemi-metallic base implants with a follow-up between eight months and 33 years. Of all the cases, 93.1 percent reported excellent results while only 4.7 percent were unsatisfactory. The failures occurred with patients who either received concomitant hallux valgus correction, metatarsal osteotomies or had rheumatoid arthritis.25 Authors have reported improvement of range of motion and a reduction in pain in studies of patients not only with arthritis of the proximal phalanx but also double-sided joint disease.26 Metallic implants to resurface the metatarsal head can also resurface damaged articular bone and restore a patient’s geometry with minimal bone resection with success.27 With implants, reactive synovitis, increase in lateral column pressure, implant loosening and cost are concerns.28
The hinged silastic total first MPJ implant has successfully relieved the symptoms of hallux rigidus. It provides a reduction in pain, ease of shoe fitting and allows a wide range of activity levels consistent for five years postoperatively. The results are especially consistent with patients 60 years or older with active lifestyles.29 One potential complication with using joint replacements, whether they are silastic or another type of implant, is the difficulty to convert failed implants to arthrodesis if needed. If the implants fail, fusion becomes difficult due to the loss of bone, requiring bone grafting.11
In patients with painful advanced stage hallux rigidus, researchers have considered arthrodesis as the standard treatment.9,28,30-32 Surgeons usually reserve arthrodesis of the first MPJ for patients with stage II or IV hallux rigidus. When performing arthrodesis of the first metatarsophalangeal joint, the optimal position of the hallux after fusion should be 10 to 15 degrees of dorsiflexion and 10 to 20 degrees of valgus.1 Researchers have noted that the procedure provides stable osteosynthesis with a less than 5 percent complication rate.13,32 Inadequate dorsiflexion may create pressure and a source of pain to the distal aspect of the toe.13
The disadvantages of arthrodesis include the possibility of nonunion or malunion, prolonged postoperative time, transfer metatarsalgia and loss of joint motion.11 Arthrodesis has a high success rate in pain relief and restoration of function although certain disadvantages to consider are loss of joint motion, difficulty wearing shoes, long recovery time and metatarsalgia.9,30,31 Patients should also take into consideration limitations in sports and physical activity.33
Case Study One: Using A Cheilectomy For A First MPJ With No Motion
A 62-year-old female presented to the office complaining of pain and stiffness of the first MPJ of her left foot. The pain developed approximately one year earlier, had been progressively increasing and on a typical day, she graded the pain at a 7 out of 10. The stiffness had been present for years and she could only wear shoes with a low heel. The pain was located around the joint but the greatest pain was on the dorsal aspect of the first metatarsal head where she had an osseous prominence that had localized edema and erythema. 
Upon examination, her foot structure was within normal limits and neurovascular status was intact. Reflexes and motor function were also intact. Musculoskeletal evaluation revealed a tight Achilles tendon and no motion at the first MPJ.
Radiographs revealed significant narrowing at the first metatarsophalangeal joint with multiple bone spurs and subchondral sclerosis at the base of the proximal phalanx and first metatarsal head. The dorsoplantar view revealed that the first metatarsal was very long and equal in length to the second metatarsal. On the lateral view, the first metatarsal was elevated 10 mm over the second metatarsal as measured at the metatarsal neck. 
The patient had declined conservative care and requested surgery. Due to her limited time for healing, we selected a cheilectomy procedure and would use a hemi metallic implant if we found significant loss of articular cartilage. During surgery, after resection of the spurs, we noted that approximately 80 percent of the metatarsal head had no cartilage.
We resected the base of the proximal phalanx and inserted the hemi-joint implant. Evaluation of motion revealed improvement but her extension was still restricted. We resected a larger portion of the dorsal surface of the first metatarsal head and beveled it until hallux extension with the foot loaded was approximately 40 degrees.
Postoperatively, she bore weight as tolerated and got instructions to perform flexion and extension exercises of the first MPJ to prevent adhesions and scar tissue from developing, which could result in limited motion. On the patient’s six-week evaluation, she had no pain at the surgical site and had 20 degrees of dorsiflexion and 5 degrees of plantarflexion with no crepitation. At one-year follow-up, she remained asymptomatic with no complaints and the patient maintained the same motion that she had at her six-week postoperative evaluation.
Case Study Two: Combining A Cheilectomy With A Youngswick Osteotomy
A 40-year-old male presented to the Foot and Ankle Clinic complaining of pain and stiffness at the first MPJ of his right foot. The patient originally injured his great toe when he slipped and fell while walking through a small waterfall. If he stood or walked for over one hour, he had pain and swelling that limited his daily activities. The pain had been present for six years, was progressively increasing and he graded the pain at 5 out of 10 on a typical day. 
The examination revealed a normal foot structure and his neurovascular status was intact. He had a prominence over the first metatarsal head and a moderate bunion deformity. The musculoskeletal examination revealed barely a total of 5 degrees of motion at the great toe joint.
The X-rays showed a long elevated first metatarsal with joint narrowing and subchondral sclerosis. The arthritic changes were not fully developed and the limited dorsiflexion was primarily due to the elevated metatarsal. The first metatarsal was elevated 8 mm above the second metatarsal. 
The patient requested surgery after having failed conservative treatment, which included offloading, oral medications and steroid injections. We performed a cheilectomy to remove the bone spurs and the medial bunion, and a Youngswick osteotomy to shorten the metatarsal and reduce the elevatus. On the operating table, we were able to dorsiflex the great toe to 45 degrees of extension. A bone plate and locking screws ensured stabilization of the osteotomy site so the patient could begin early range of motion exercises. In addition, we applied a cast with the distal aspect ending just proximal to the metatarsophalangeal joint.
After the osteotomy site healed, we removed the cast and the patient continued more aggressive range of motion exercises at home and began walking as part of his rehabilitation. He was unable to participate in physical therapy due to financial issues. Four months following surgery, he had 25 degrees of extension and 5 degrees of plantarflexion. Although motion was limited, he had no pain and no restriction of his activities. At one-year follow-up, first MPJ extension was only 20 degrees but he had no pain and returned to all of his activities.
Key Tips And Pearls On Treatment
1. Recognize the importance of the elevatus. If one does not address this with a plantarflexory first metatarsal osteotomy either distally or proximally, or an aggressive resection of the dorsal aspect of the metatarsal head, the surgery may fail.
2. When using a cast, the distal aspect of the cast should not extend beyond the metatarsophalangeal joint to permit early range of motion exercises. In some reliable patients, one can use a removable controlled ankle motion boot to permit manipulation of the joint. 
3. Recognize that postoperative fibrosis, adhesions and scar tissue are always going to form, can develop quickly, become severe and result in a failed surgical procedure. If one does not perform an osteotomy, we encourage early ambulation with aggressive range of motion exercises, ideally by physical therapy. Many patients cannot perform adequate self-manipulation because of their fear of pain. For patients who decline physical therapy initially, if we do not see a significant increase in motion, especially extension, in a two-week period, they go to physical therapy.
4. In our experience, postoperatively, patients usually lose about 50 percent of their intraoperative extension. For this reason, we will attempt to obtain as much extension as possible during the procedure and our goal is at least 40 degrees. We have found that if patients end up with at least 20 degrees of postoperative extension, this is usually adequate to result in pain-free ambulation.
Dr. Andrews is a third-year resident at Oakwood Hospital-Wayne in Wayne, Mich.
Dr. Fallat is the Program Director of Podiatric Surgical Residency at Oakwood Hospital-Wayne in Wayne, Mich. He is a Fellow of the American College of Foot and Ankle Surgeons.
References
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28. Gibson A, Thomson CE. Arthrodesis or total replacement arthroplasty for hallux rigidus. Foot Ankle Int. 2005; 26(9):680-690.
29. Pontell D, Gudas C. Retrospective analysis of surgical treatment of hallux rigidus/limitus: clinical and radiographic follow-up of hinged, Silastic implant arthroplasty and cheilectomy. J Foot Surg. 1988; 27(6):503-510.
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For further reading, see “Current And Emerging Techniques For Hallux Rigidus” in the July 2013 issue of Podiatry Today, “Point-Counterpoint: Hallux Rigidus Surgery In Active Adults: Implant Arthroplasty Or First MPJ Arthrodesis?” in the July 2011 issue or “How To Treat Hallux Rigidus In Runners” in the April 2009 issue.
