Hallux Rigidus Treatment & Management

Nonsurgical techniques can often be used to successfully treat patients with varying degrees of severity of hallux rigidus. However, when the condition is refractory to nonoperative treatment methods, there are a number of procedures that can be employed as treatment. The choice of operation depends on the degree of involvement, the range-of-motion (ROM) limitations, the individual's activity level, and the surgeon's and patient's preference. Options include the following:

• Joint-sparing procedures, such as cheilectomy, with or without proximal phalanx osteotomy (Moberg procedure)
• Metatarsal (MT) osteotomy
• Joint arthroplasty
• Arthrodesis

Dorsal cheilectomy is indicated in patients with mild-to-moderate arthritic changes with less than 50% involvement of the joint surface. ^[43] A proximal phalangeal osteotomy can be added in patients in whom sufficient dorsiflexion (DF) is not obtained (if plantarflexion [PF] is sufficient).

Excisional arthroplasty, or the Keller procedure, is associated with a number of potential complications and is not generally recommended. ^[44] Capsular interposition arthroplasty, however, can provide good pain relief in select individuals with advanced degenerative disease.

Metatarsophalangeal (MTP) arthrodesis is an excellent procedure that is indicated in most cases of advanced hallux rigidus. The benefits of MT osteotomies are theoretical, and these procedures are not recommended for the treatment of uncomplicated hallux rigidus.

Silicone-implant arthroplasty probably has no place in the treatment of hallux rigidus. It is not clear that current metallic hemiarthroplasty and total arthroplasty have significant advantages over capsular interposition arthroplasty, and the techniques have many reported complications. ^[45]

The use of a polyvinyl alcohol (PVA) hydrogel implant to treat hallux rigidus has received substantial attention. Early studies suggested results similar to those of arthrodesis. ^[46]  A limited number (< 10%) of patients who underwent this joint-sparing procedure required conversion to arthrodesis within 5 years. ^[47]  Additionally, successful later conversion to arthrodesis is not prohibitively difficult. ^[48]  High levels of patient satisfaction can be achieved. ^[49]

An absolute contraindication for operative treatment is poor peripheral circulation. Active infection should be considered a relative contraindication.

Pharmacologic options include analgesics and nonsteroidal anti-inflammatory drugs (NSAIDs).

Mechanical methods to limit the motion of the first MTP joint are helpful. The use of in-shoe orthotics with medial stiffness, stiff-soled shoes with a rocker bottom, shoes with a wide toe box, low-heeled shoes, and shoe modifications (eg, a steel shank placed along the entire medial side) may be beneficial. Activity modifications include avoiding extremes of DF of the great toe, such as those caused by kneeling or squatting with the toes in an extended position.

Solan et al reported on the use of manipulation and injection of the joint, but this was noted to be helpful only in grade 1 or 2 hallux rigidus. ^[50] Patients with grade 1 changes obtained symptomatic relief for a median of 6 months. Little symptomatic relief was seen in patients with grade 3 arthritis.

Surgical options include joint-sparing procedures, such as cheilectomy, with or without proximal phalanx osteotomy (the Moberg procedure), as well as MT osteotomy, joint arthroplasty, and arthrodesis. ^{[51, 52]}

Cheilectomy

Cheilectomy involves the excision of all irregular bony spurs that limit motion. ^[43] These spurs are primarily dorsal, but excision of impinging medial and lateral spurs, if present, is usually part of the procedure as well. Most authors recommend dorsal cheilectomy for patients with mild to moderate radiographic changes, particularly young or active patients who have less than 50% articular cartilage loss, as seen at surgery.

The procedure can be performed through a 5- to 6-cm dorsal midline or medial incision centered over the first MTP joint. The dorsomedial cutaneous nerve is protected. A longitudinal capsulotomy exposes the joint, and all excessive synovial tissue is debrided.

The joint is explored for any loose bodies and joint abnormalities. Often, the articular surface of the MT head shows erosions down to bone in the dorsal half. Occasionally, erosive changes of the proximal phalanx surface also are present. An osteotome or saw is used to resect the large dorsal osteophyte on the MT head and, sometimes, the dorsal base of the proximal phalanx. As much as one third of the dorsal joint surface of the MT head is excised. Usually, most of the eroded surface is excised. (See the image below.)

Medial and lateral bone spurs are excised flush with the joint, and the ROM is checked. The goal is to achieve at least 60º of MTP DF intraoperatively. A Freer elevator is used to free any plantar adhesions between the MT head and the sesamoids. In addition, the plantar capsule is released, if necessary, to achieve improved ROM.

Postoperatively, the patient may bear weight as tolerated in a postoperative shoe. Passive motion exercises are started in 1 week if the wound is dry.

Proximal phalanx osteotomy

Bonney et al first described proximal phalanx osteotomy for the treatment of hallux rigidus in 1952. ^[53] In 1958, Kessel et al reported on the use of the procedure in 10 adolescents, and in 1979, Moberg discussed its use in eight patients. ^{[54, 55]} Moberg popularized the proximal phalanx osteotomy, and his name is commonly associated with this operation.

The Moberg procedure involves increasing the DF by translating the arc of motion from plantar to dorsal, thereby increasing the functional ROM of the MTP joint to a more dorsal position because of a more dorsiflexed position of the toe. This position decreases pushoff stress on the hallux and provides decompression of the dorsal joint space.

A prerequisite to the procedure is the presence of adequate PF. Proximal phalanx osteotomy is always accompanied by dorsal joint cheilectomy/decompression. Reported complications are relatively few but have included nonunion or malunion, tendon injury, neuritis or neuroma, progressive DJD, and decreased pushoff power. Most reports of this procedure show functional improvement with low complication rates. They also show that this procedure can be added to dorsal cheilectomy when sufficient DF is not attained with cheilectomy alone in cases of mild-to-moderate hallux rigidus (particularly in running athletes), provided that preoperative PF is adequate.

The technique involves a medial longitudinal or a dorsal incision over the base of the proximal phalanx, with protection of the dorsal and plantar medial cutaneous nerves and the flexor and extensor tendons. A dorsal closing-wedge greenstick osteotomy is performed with a saw or osteotome just distal to the MTP joint. The plantar cortex is maintained, and 2-6 mm of dorsal cortex is cut, depending on the degree of hallux PF and joint stiffness. The goal is to attain 20-30° of DF relative to the first MT.

The osteotomy can be stabilized with a Kirschner wire (K-wire), a small screw, or a staple to allow early DF at 1-2 weeks and PF at 3-4 weeks. Full weightbearing is usually allowed.

Arthroscopy

Although not commonly performed, arthroscopic removal of the dorsal osteophytes in hallux rigidus has been reported. Arthroscopy of the great-toe MTP joint requires the availability of small arthroscopic equipment (1.9 mm) and the use of digital equipment. The role of arthroscopy in the treatment of various grades of hallux rigidus and its benefits compared with those of open cheilectomy have not been defined. Fast rehabilitation and prompt return to work are the advantages of this arthroscopic procedure.

Metatarsal osteotomy

MT osteotomies are based on the premise that metatarsus elevatus or a long first MT are the underlying causes of hallux rigidus. Therefore, a number of different osteotomies to cause PF and/or to shorten the first MT have been described.

Most authors define indications for osteotomy in lower grades of hallux rigidus. Proximal and distal osteotomies have been described. Various authors, including Suppan in 1921, Hohman in 1924, Waterman in 1927, Lambrinudi in 1938, Youngswick in 1982, Pittman and Burns in 1984, and Davies in 1989, have described different methods of MT osteotomy. These include wedge-, oblique-, or crescentic-type osteotomies, performed at the base or neck to result in PF and/or shortening of the first MT. Waterman's dorsal closing-wedge osteotomy with removal of the dorsal osteophytes in effect rotates the articular surface dorsally for a more functional arc of motion.

Saur conducted a retrospective cohort study (N = 72; average age, 57 ± 9 y; 87 feet) evaluating 4-year outcomes (mean follow-up, 51 mo) of oblique distal osteotomy of the first MT for stage 1-3 hallux rigidus. ^[56] In 22 of the 87 feet, the first metatarsal surgery was performed in isolation; in the remaining 65, other forefoot procedures were performed concomitantly (Akin phalangeal osteotomy, n = 31; Moberg phalangeal osteotomy, n = 34).

In this study, ^[56] the American Orthopaedic Foot and Ankle Society (AOFAS) score increased from 54.2 ± 11.3 preoperatively to 92.2 ± 7.8 postoperatively. Patient-reported outcomes were excellent or good in 95.4% of cases. The score on the 40-point self-reported pain subscale improved from 19.6 ± 10.0 preoperatively to 37.4 ± 5.4 postoepratively. Overall ROM increased from 61 ± 21º preoperatively to 69 ± 17º postoperatively. The mean first-MT shortening rate was 9.6%. At 6-month follow-up, 15 patients had transfer metatarsalgia, compared with five at final follow-up, without need for another surgical procedure.

Arthrodesis

Arthrodesis eliminates all motion across the first MTP joint; it is a reliable and reproducible procedure with a high percentage of good results. ^[57] This procedure is indicated in severe cases of hallux rigidus and as a salvage procedure ^[58] when other surgical methods fail. Preoperative considerations are whether enough bone stock is available for an in situ fusion and whether an interposition bone block is necessary for a shortened first ray. ^[11]

The procedure involves a dorsomedial or medial exposure of the first MTP joint, as well as the removal of the articular cartilage to create opposable, cancellous surfaces and stabilization using one of a number of different devices, including pins, screws, or plates. The medial exposure has the benefit of avoiding a scar contracture involving the dorsomedial cutaneous nerve.

A number of different techniques have been described for preparation of bone ends and for fixation of the toe. Conical reamers can be used to allow continued good apposition throughout the range of positions of the toe. The use of these reamers requires good circumferential exposure of the joint. The position of the toe is the most important aspect of this operation. The most commonly recommended position is that in which the toe is placed in approximately 15° of DF. However, the optimal position depends on the hallux declination angle, which has been described as 15-30°.

To check the position intraoperatively, a simulated weightbearing position is created by using a hard, flat surface on the plantar aspect of the foot, and the ankle is brought into neutral. The great toe is positioned in approximation to the surface. The degree of valgus is usually a few degrees and is somewhat dependent on the position of the second toe, allowing a small separation between the great and second toes. ^{[59, 60]} The "artificial floor technique" (AFT) was validated in a study by Strony et al. ^[61]

Techniques used to stabilize the prepared surfaces can be stabilized range from simple suturing to the use of single or multiple smooth or threaded pins, lag and cross screws, variable pitch screws, ^[62] and a variety of different plates. Precontoured plates with built-in DF and valgus simplify positioning and provide a strong and stable construct. (See the image below.) Shape-memory staples have been used as well. ^[63]  

Complications of arthrodesis include the following:

• Nonunion ^[64]
• Malunion
• Hardware failure
• Potential development of arthritis at the IP and tarsometatarsal (TMT) joints

Scar contracture and development of neuromas of the dorsomedial cutaneous nerve can be minimized using the medial exposure. Excessive DF is compensated for by IP joint flexion, resulting in painful dorsal keratosis over the IP joint, functional offloading of the hallux, and resultant metatarsalgia. On the other hand, excessive PF is compensated for by hyperextension at the IP joint and an increased load under the hallux MP and IP joints, with resultant painful calluses.

Postoperatively, the patient's foot is immobilized in a cast that extends beyond the toes or in a postoperative boot until union is seen on radiographs. Weightbearing is dependent on the security of fixation. Usually, patients who have undergone fixation augmented with plates can be allowed partial weightbearing when the wound is closed and dry at 2-3 weeks postoperatively. Full, unprotected weightbearing is allowed after union.

Arthroplasty

Excisional/interposition arthroplasty

Commonly known as the Keller technique, this procedure involves the excision of the base of the proximal phalanx. It is indicated in moderate to severe cases of hallux rigidus in individuals with low functional demands who desire the maintenance of joint motion. The original procedure involves the insertion of the medial capsule into the resected joint. It has been a popular procedure for many decades. ^{[44, 65]}

Complications are common, however, including hallux weakness, elevation, floppiness, a short hallux, and development of transfer lesions under the second MTP joint. For this reason, a number of modifications have been published. To avoid retraction of the extensor hallucis brevis (EHB), the thickened dorsal capsule is attached to the stumps of the EHB distal to the sesamoids. The surgeon should be careful not to excise too much of the base of the proximal phalanx and to excise only to the metadiaphyseal junction. Otherwise, a floppy toe may result. In addition, excessive resection further shortens the already shortened hallux.

A modified oblique cut of the proximal to spare the FHB has been described. Other modifications include the use of plantaris tendon as an interposition graft.

The procedure is usually performed via a medial incision. The capsule is exposed, the medial eminence is excised, and cheilectomy is performed. The soft tissues are released from the base of the proximal phalanx, including the capsule, the plantar plate, and FHB tendons. The EHB is tenotomized, and after the soft tissues are protected, the base of the proximal phalanx is excised with a saw or osteotome. The dorsal capsule is then mobilized and pulled into the resected joint space and sutured to the stumps of the FHB tendons. A 0.062 K-wire is placed across the IP and MTP joints for 3 weeks. Gentle ROM exercises are started once the K-wire has been removed.

Complications of MTP arthroplasty for hallux rigidus may necessitate revision or conversion to MTP arthrodesis. Preoperative risk factors for such revision or conversion within 2 years after primary arthroplasty include obesity, depression, and steroid use. ^[58]  

Silicone and PVA arthroplasty

Silicone arthroplasty was originally designed to provide motion and length. A number of groups reported good results with the use of silicone arthroplasty, including, in 1993, Cracchiolo et al, who followed up 86 double-stem silicone implants in the first MTP joint for an average of 5.8 years and reported an 84% satisfaction rate. ^[66]

Many other studies, however, found that silicone lacked the structural durability and surface characteristics needed to withstand the severe shear and tension stresses generated by the repetitive motion associated with normal ambulatory activities. In addition, the friction of silicone on bone produced in hemiarthroplasty and at the bone-silicone interface in stemmed implants produces wear and fragmentation of the silicone. This can induce severe local synovitis and osteolysis, and systemic dissemination of silicone can result in granulomatous adenopathy after MTP arthroplasty. ^{[67, 68, 69]}

The use of grommets seems to improve the long-term results secondary to decreasing wear by protecting the silicone implant. Long-term reports on newer, more anatomic implant designs and the use in implants of better-grade silicone with better wear characteristics are not available. Given current knowledge and the long-term durability of alternative treatments, the use of silicone implants for the treatment of hallux rigidus is not advised.

Chrea et al found that whereas the addition of a PVA implant to cheilectomy with Moberg osteotomy was safe and useful, the same procedure without the implant might have equivalent or better results. ^[70]  Shimozono et al reported a high failure rate with the PVA hydrogel implant in patients with hallux rigidus. ^[71]  Hoskins et al, in a study comparing synthetic cartilage implant (SCI) hemiarthroplasty with cheilectomy for hallux rigidus, found that whereas both are viable treatment options for decreasing pain, improving function, and maintaining motion, SCI hemiarthroplasty may offer superior ROM and functional outcomes. ^[72]

A number of adverse events have been associated with SCIs, including implant subsidence, fragmentation, infection, bone erosion, and foreign body reaction; because of the voluntary nature of the reporting, such events may be underreported. ^[73]

Metallic arthroplasty

Total arthroplasty and hemiarthroplasty designs also have been available for the treatment of moderate-to-severe hallux rigidus. Several implants are available, including those used for hemiarthroplasties and full arthroplasties. They are made of cobalt chromium, titanium, or both, with a polyethylene bearing surface of ultrahigh molecular weight. Initial reports providing long-term results were mixed. Multinucleated foreign giant cells associated with fine particulate metallic wear debris have been reported in failed cases of titanium hemiarthroplasty with periarticular osteolysis.

The common view has been that the general use of metal implants for the treatment of hallux rigidus is probably not indicated, given the results demonstrated with arthrodesis, and that more research would be needed to define the long-term outcome of metallic implants and to compare their use with that of interposition arthroplasty and MTP joint fusion in severe hallux rigidus.

A systematic review and meta-analysis of 33 studies by de Bot et al compared metallic hemiarthroplasty with arthrodesis of the first MTP joint for treatment of hallux rigidus. ^[74] They found that whereas both procedures yielded excellent clinical outcomes and acceptable rates of complications and revisions, arthrodesis appeared to be superior in reducing pain, and metallic hemiarthroplasty is a reasonable alternative for patients who carry out activities requiring motion in the first MTP joint.