Thomas G. Harris and Ronald W. Smith
DEFINITION
Hallux rigidus is a degenerative condition of the first metatarsophalangeal (MTP) joint.
This leads to a functional limitation of motion of this joint, especially with respect to dorsiflexion.
Other terms, such as hallux limitus and dorsal bunion, have also been used to describe this condition.
Hallux rigidus affects about 3% of the adult population.5
This chapter pertains to the surgical procedure of a dorsal closing wedge osteotomy of the proximal phalanx, popularized by Moberg. Although it was initially recommended for young patients (under 18 years of age), Moberg extended the indications to include adults.8
It is usually performed in conjunction with a cheilectomy.
ANATOMY
Usually dorsiflexion is blocked by a dorsal osteophyte on the metatarsal head. In some cases there is an osteophyte or ossicle on the dorsum of the base of the proximal phalanx. Dorsiflexion is also limited by contracture of the plantar portion of the MTP joint capsule.
Articular erosion is characteristically seen on the dorsum of the articular surface of the first metatarsal head and, to a lesser extent, on the dorsum of the base of the proximal phalanx.
The medial and plantar aspect of the MTP joint is usually spared until later in the disease process (FIG 1).
PATHOGENESIS
The primary etiology of the hallux rigidus is not known.
A common cause is trauma, and hallux rigidus may occur after a fracture, sprain, or crush injury. Furthermore, it is thought that microtrauma may injure the articular cartilage over time, leading to degeneration.4
FIG 1 • Hallux rigidus: dorsiflexion of proximal phalanx produces painful impingement at the metatarsophalangeal joint.
Systemic conditions such as gout and rheumatoid arthritis can also cause degeneration of the first MTP joint, simulating the idiopathic form.
NATURAL HISTORY
Hallux rigidus is more common in adults than adolescents.
Generalized degenerative changes tend to progress with increasing age, but this has not been linked with symptoms.9
Women are affected more often than men and boys, and the condition is often bilateral.
PATIENT HISTORY AND PHYSICAL FINDINGS
Patients usually describe an insidious onset of activity-related pain at the first MTP joint.
Swelling and stiffness are common complaints.
On physical examination in the characteristic case, dorsiflexion motion is measurably limited and plantarflexion motion with force is painful. In some cases, forceful dorsiflexion is also painful, but not as painful as forceful plantarflexion.
Limitation of dorsiflexion usually leads to problems with running, walking on inclines, and wearing high-heeled shoes.
The increasing dorsal prominence can lead to problems with shoe wear.
Paresthesias may rarely occur distal to the MTP joint with the compression of the dorsal cutaneous nerves by the dorsal osteophyte and tight-fitting shoes.
Adaptive gait measures such as a supinated forefoot to unload the painful medial forefoot may lead to lateral foot pain and calluses.6
There is usually generalized enlargement of the joint due to a combination of osteophytes and soft tissue swelling.
In severe cases with full loss of cartilage and motion, there is sometimes no irritability even with forced flexion. These patients often just have pain because of the osteophytic enlargement causing impingement in the shoe. In these cases, a simple cheilectomy with limited dissection often leads to satisfactory results. These are patients often in their 70s and 80s.
Interphalangeal joint hyperextension may develop to compensate for restricted MTP joint dorsiflexion, but this is very uncommon.2
Axial loading of the great toe is usually not painful unless severe degeneration or a large osteochondral defect is present.
Passive plantarflexion of the hallux can also produce pain, as this is thought to bring the inflamed synovium and MTP capsule over the dorsal osteophyte.
IMAGING AND OTHER DIAGNOSTIC STUDIES
Three weight-bearing views (AP, lateral, and oblique) of the foot are usually sufficient.
FIG 2 • AP weight-bearing view of foot showing decreased metatarsophalangeal joint space. The surgeon must be wary not to overestimate joint space loss on the AP view alone because overhanging osteophytes may cause joint space to appear obliterated.
Weight-bearing views are important, because non–weight-bearing views often obscure the dorsal first metatarsal osteophyte. In the non–weight-bearing views, the toes are usually in passive extension, and this may obscure the dorsal osteophyte.
The AP view is important to assess the amount of medial or lateral joint narrowing.
The AP view can overestimate the amount of degenerative change as osteophytes may overlie the joint, creating the impression that the joint space is abnormally decreased. Also, a non–weight-bearing AP view can exaggerate the narrowing of the MTP joint space because of the passive extension posturing of the toes at the MTP joint.
Lateral osteophytes are common and are often early indicators of hallux rigidus. They are also notable at the base of the proximal phalanx. Occasionally, these osteophytes seen on the AP view at the MTP joint are medial.
Occasionally, a CT scan is useful for detecting osteochondral injuries. MRI can be useful as well for detecting chondral damage (FIGS 2 AND 3).
DIFFERENTIAL DIAGNOSIS
MTP synovitis
Hallux valgus
Sesamoiditis or sesamoid fracture
FIG 3 • Lateral weight-bearing view of foot showing dorsal osteophytes of metatarsal head and proximal phalanx.
FIG 4 • Typical Morton type of extension to an orthotic. This is thought to decrease dorsiflexion at the metatarsophalangeal joint.
NONOPERATIVE MANAGEMENT
The decision to pursue nonoperative treatment depends on the patient's symptoms and the extent of the degenerative changes. Patients with mild synovitis and minimal complaints can be treated with rest and anti-inflammatory medications.
The hallux can be taped or braced to limit dorsiflexion, thus resting the joint.
There are many devices available to increase the rigidity of the medial forefoot. This limits the motion of the MTP joint, thus minimizing the dorsiflexion impingement pain.
A Morton extension is an example (FIG 4).
Steroid injections can be given in the MTP joint. This will help with pain relief but does not slow the degenerative process.
Standard shoes with a high toe box are helpful for cases of hallux rigidus. This increases the space for the dorsal osteophytes and reduces pressure on the irritable joint.
A shoe with a stiff-soled rocker bottom is also helpful and helps with gait smoothness.
These shoe-wear modifications can be effective, but patient compliance and acceptance vary from case to case.
A study by the senior author with a minimum follow-up of 14 years showed that the pain associated with hallux rigidus remained the same in 22 of 24 feet.9
SURGICAL MANAGEMENT
We routinely perform a cheilectomy with a proximal phalanx osteotomy. The osteotomy is not a stand-alone procedure but is used to augment the effect of the cheilectomy.10
If the osteotomy is to be combined with a cheilectomy, stable internal fixation is important to secure the osteotomy so that early motion of the MTP joint can be started within 1 to 2 weeks after the surgery.
Preoperative Planning
All radiographs and other imaging studies should be closely reviewed.
Special attention should be directed to the lateral radiograph. This study will show the dorsal osteophytes from the distal metatarsal head and proximal phalanx.
No specific physical examinations need to be done under anesthesia, but it is important to document the passive range of motion (both dorsiflexion and plantarflexion) before the onset of the procedure.
The surgeon should alert the patient that we are “stealing” motion from plantarflexion and giving it to dorsiflexion.
Positioning
The patient is placed supine on the operating table. A Martin-type tourniquet in applied to the supramalleolar region of the ankle.
The procedure is usually done under ankle block anesthesia.
A mini C-arm is also used during the procedure and should be available.
Antibiotics are given before the procedure.
Positioning is not as important for this procedure as for other operations (FIGS 5 AND 6).
FIG 5 • Operative photograph of foot; note dorsal prominence at metatarsophalangeal joint. Small areas of hemorrhage are from prior ankle block.
Approach
Usually a dorsomedial approach is used and the extensor hallucis longus (EHL) is retracted laterally. This will provide good access to both the medial and lateral sides of the MTP joint.
A directly medial approach to the first MTP joint can be used as well, but this approach can limit access to the lateral side of the joint.
FIG 6 • Lateral operative photograph of foot; note dorsal prominence at metatarsophalangeal joint. Small areas of hemorrhage are from prior ankle block.
TECHNIQUES
APPROACH AND CHEILECTOMY
Make a dorsomedial incision, taking care to identify and protect the dorsomedial cutaneous nerve.
Retract the EHL laterally.
Make the MTP capsulotomy in line with the skin incision; the capsule edges can be tagged with a 2-0 Vicryl suture for ease of identification later.
If they are not tagged, carefully identify the dorsal capsule during closure.
Retract the capsular edges both plantarly and dorsally.
Inspect the MTP joint closely.
Examine the joint surfaces for osteochondral defects or chondral flaps, as well as overall degeneration within the MTP joint.
Use a reciprocating saw to remove 1 to 2 mm of the medial eminence.
This is done to promote healing of the capsule to the bone.
Perform a dorsal cheilectomy of the metatarsal head, as described elsewhere. Bone is removed flush with the surface of the dorsum of the metatarsal neck.
We try to limit our resection to only the degenerated area of the metatarsal head.
It is important to gain access to and inspect the lateral side of the MTP joint.
Increase the lateral exposure as needed.
Osteophytes, which can be hard to detect on radiographs, are often evident on the lateral side of the joint. If present, these osteophytes are removed.
If present, remove osteophytes or ossicles from the proximal phalanx with a rongeur (TECH FIGS 1–4).
TECH FIG 1 • Operative photograph showing typical line of incision; note tourniquet at supramalleolar region.
TECH FIG 2 • Operative photograph showing the metatarsophalangeal joint widely exposed. The extensor hallucis longus tendon is retracted laterally. Note exuberant osteophytes on metatarsal head and also osteophytes overhanging from proximal phalanx.
TECH FIG 3 • Operative photograph showing metatarsophalangeal joint after cheilectomy and medial eminence resection. Soft tissue around area of future proximal phalanx osteotomy has been removed.
TECH FIG 4 • Schematic of cheilectomy and proximal phalanx osteotomy. Shaded areas will be removed. Protection of the flexor hallucis longus is paramount.
PROXIMAL PHALANX OSTEOTOMY
We now shift our attention to the proximal phalanx. For the plantar osteotomy, expose the plantar aspect of the proximal phalanx sufficiently to protect the flexor hallucis longus (FHL) tendon.
During the creation of the osteotomy, be careful to ensure you have enough lateral joint exposure to protect the EHL tendon.
Place a 0.062-inch smooth Kirschner wire transversely from medial to lateral as a guidewire.
It is placed parallel and as close to the articular surface of the proximal phalanx as possible without entering the joint.
Use a mini C-arm to verify the proper extra-articular placement of the Kirschner wire. Place the guidewire such that the osteotomy is made just distal to the guide pin.
Once the placement of the Kirschner wire has been verified, the osteotomy can begin.
To maximize the amount of dorsiflexion of the tip of the toe, make the osteotomy as close to the articular surface as feasible. However, if the proximal fragment is too small, sometimes it will fragment postoperatively.
Use an oscillating saw with a 0.5-cm blade width to make the first cut in the phalanx just distal to the surface of the Kirschner wire.
The initial cut is incomplete, leaving the plantar cortex intact.
This protects the FHL and maintains stability in the phalanx in preparation for the second cut.
Make a second, oblique cut measured 5 mm distal to the first cut.
In very mild cases of hallux rigidus, a 3–4 mm wedge is used.
Keep this cut as parallel as possible to the first cut, looking at the dorsal surface.
This width is measured with a sterile ruler.
If the two cuts are not parallel, an angular deformity (hallux valgus or varus) can ensue.
If there is significant preoperative abductus (lateral angulation), it may help the appearance of the toe to make the medial part of the wedge bigger than the lateral side.
As with the first cut, it is important not to finish the osteotomy completely.
Weaken the remaining plantar cortex with multiple 1.5-mm drill holes. The osteotomy is then completed or “greensticked” (dorsiflexion) manually (TECH FIGS 5–7).
TECH FIG 5 • Operative photograph demonstrating placement of Kirschner wire from medial to lateral to ensure extra-articular placement of osteotomy.
TECH FIG 6 • Operative photograph showing sterile ruler to measure exact dimension of osteotomy.
TECH FIG 7 • Schematic showing placement of Kirschner wire to ensure extra-articular placement of Kirschner wire.
FIXATION OF THE OSTEOTOMY AND CLOSURE
Fix the osteotomy with 28-gauge wire.
The wire is placed through 1.5-mm drill holes.
Make one drill hole at the proximal dorsomedial aspect of the basal fragment.
Start this hole just adjacent to the articular cartilage at the base of the proximal phalanx and angle it about 45 degrees toward the intramedullary cavity.
This starting point is about 4 mm from the osteotomy and helps to avoid breakage of a rather fragile tunnel.
It is helpful to pass the wire from proximal to distal; this places most of the tension on the distal side of the osteotomy when the wire is pulled through the distal segment.
Start the distal drill hole 3 to 4 mm from the osteotomy and angle it about 45 degrees to the plane of the proximal phalanx.
A wire pass instrument can be used to retrieve the 28-gauge wire passed through the proximal aspect of the osteotomy.
As an alternative, a wire passer can be fashioned from the terminal 6 inches of the 28-gauge fixation wire.
The other 28-gauge wire is modified in the following ways:
A 6-inch piece of 28-gauge wire is folded onto itself to form a small loop.
The loop is compressed with a small hemostat to fit through the 1.5-mm hole. We usually fold the wire onto itself and form a small loop with the aid of a small hemostat, or mosquito.
This loop is then passed into the distal drill hole and into the osteotomy site.
Once located within the osteotomy, usually with the assistance of a small hemostat, the created loop is expanded and made larger.
This loop is made large enough so the wire from the proximal osteotomy site can be placed through it.
Once the proximal wire is placed through the loop, the wire with the loop is pulled distally, pulling the proximal wire with it.
The assistant places dorsiflexion pressure on the plantar tip of the hallux, closing the wedge osteotomy site as the wire is tightened and twisted.
While the surgeon applies finger tension on the wire, maintaining a closed osteotomy, the wire is twisted about five revolutions.
The wire is cut, leaving about 5 mm of residual wire to be bent and placed against the bone.
Close the capsule with nonabsorbable suture, usually 2-0 in diameter.
Try to completely cover the osteotomy site with soft tissue. Sometimes this is not possible, given the limited amount of distal capsule and thin periosteum.
Close the skin with nylon type suture in an interrupted fashion.
Apply a soft dressing consisting of a nonadherent dressing, 4 × 4 gauze, and 4-inch Kling.
Apply a 2- or 3-inch elastic bandage over this, and the patient is placed in a hard-soled postoperative shoe (TECH FIGS 8–15).
Alternatively, 0.045-inch K-wires or mini fragment screw fixation may be used to secure the osteotomy site.
TECH FIG 8 • Operative photograph of 28-gauge wire loop going into distal aspect of osteotomy.
TECH FIG 9 • Operative photograph of 28-gauge wire going into wire loop from proximal to distal.
TECH FIG 10 • Operative photograph showing close-up of wire going into loop.
TECH FIG 11 • Operative photograph of wire tied and placed into soft tissue over osteotomy.
TECH FIG 12 • Creation of proximal and distal drill holes with 1.5-mm drill. Note that the plantar cortex is intact.
TECH FIG 13 • Dorsal pressure is used to close the osteotomy; the wire is tied; the osteotomy is closed.
TECH FIG 14 • Lateral radiograph showing healed osteotomy and area of resection from cheilectomy.
TECH FIG 15 • AP radiographs displaying healed osteotomy of proximal phalanx.
POSTOPERATIVE CARE
Postoperatively, patients are placed in a hard-soled shoe for 6 weeks.
Weight bearing as tolerated is allowed the day after surgery when blood coagulation is complete.
Patients are initially seen 7 to 10 days after surgery. The patient is instructed to massage the operative site to desensitize the wound beginning 1 week postoperatively.
Passive dorsiflexion exercises of the MTP joint are begun 2 weeks after surgery.
Plantarflexion-type exercises are not started until 4 weeks postoperatively to avoid early tension on the wire fixation of the osteotomy site.
Less emphasis is placed on plantarflexion unless the resting posture of the hallux is above ground.
OUTCOMES
The use of a dorsal closing wedge osteotomy increases the space at the dorsal MTP joint. In effect, the osteotomy draws the dorsal aspect of the phalanx away from the dorsal aspect of the first metatarsal head. The osteotomy may reduce the joint compression force on the dorsum of the first MTP joint during the toe-off phase of gait.
In one long-term study, eight women who had 10 toes treated for hallux rigidus by dorsal wedge osteotomy of the proximal phalanx were reviewed after an average follow-up of 22 years (no cheilectomies were done in this study).1Five toes were symptom-free, four others did not restrict walking, and only one had required metatarsophalangeal fusion. The authors concluded that dorsal wedge osteotomy afforded longlasting benefits for hallux rigidus.
COMPLICATIONS
Intra-articular osteotomy
FHL injury and laceration
Angular deformity after surgery
Fragmentation of the proximal fragment of the proximal phalanx
Nonunion3
Malunion, including rotational malunion1
Failure to improve
EHL injury and laceration
REFERENCES
· Citron N, Neil M. Dorsal wedge osteotomy of the proximal phalanx for hallux rigidus: long-term results. J Bone Joint Surg Br 1987; 69B:835–837.
· Feldman R, Hutter J, Lapow L, et al. Cheilectomy and hallux rigidus. J Foot Surg 1983;22:170–174.
· Frey CC, Jahss MJ, Kummer FJ. The Akin procedure: an analysis of results. Foot Ankle Int 1991;12:1–6.
· Giannestras NJ. Foot Disorders: Medical and Surgical Management, 2nd ed. Philadelphia: Lea & Febiger, 1973:400.
· Gould N, Schneider W, Ashikaga T. Epidemiological survey of foot problems in the continental United States: 1978–1979. Foot Ankle Int 1980;1:8–10.
· Mann RA, Clanton TO. Hallux rigidus: treatment by cheilectomy. J Bone Joint Surg Am 1988;70A:400–406.
· McMaster MJ. The pathogenesis of hallux rigidus. J Bone Joint Surg Br 1978;60B:82–87.
· Moberg E. A simple procedure for hallux rigidus. Clin Orthop Relat Res 1979;142:55–56.
· Smith RW, Katchis SD, Ayson LC. Outcomes in hallux rigidus patients treated nonoperatively: a long-term follow-up study. Foot Ankle Int 2001;22:462–470.
· Thomas PJ, Smith RW. Proximal phalanx osteotomy for the surgical treatment of hallux rigidus. Foot Ankle Int 1999;20:3–12.