Hajo Thermann and Christoph Becher
DEFINITION
Hallux rigidus, osteoarthrosis of the first metatarsophalangeal joint (MTP), was first described by Cotterill8 and Davies-Colley12 in 1887.
Pain and restriction in range of motion (ROM) in the first MTP joint are the major characteristics of hallux rigidus.41
After hallux valgus, hallux rigidus is the second most common deformity of the first MTP joint. The big toe is the location in the foot with the highest incidence of osteoarthrosis; estimates suggest that nearly 10% of the adult population is affected by hallux rigidus.18,19
The incidence of hallux rigidus is higher in women than in men.5,6
ANATOMY
The first MTP joint is a stable joint formed by the rounded head of the first metatarsal bone fitting into the concave proximal facet of the proximal phalanx.
The joint is enhanced by the plantar and collateral ligaments. The deep transverse metatarsal ligament is connected to the second ray.
The sesamoid bones are embedded in the flexor hallucis brevis tendon. They are accommodated at the underside of the first metatarsal in two longitudinally oriented grooves. In a normal relationship, the sesamoids glide distally and proximally within the grooves by a combination of active and passive forces.
The extensor hallucis longus tendon covers the dorsal side of the first MTP joint and inserts into the base of the distal phalanx.
The dorsomedial cutaneous nerve is in danger when using a dorsomedial approach to the joint. It is the most medial branch of the superficial peroneal nerve. An anatomic study has shown that the minimum distance from the medial edge of the extensor hallucis longus tendon is 6 mm.36
PATHOGENESIS
The mechanism responsible for developing hallux rigidus remains unclear.
In theory, damage to the cartilage surface of the first MTP joint, ie, osteochondral fractures or chondral defects, may lead gradually to posttraumatic arthrosis.
Alternatively, repetitive microtrauma to the first MTP joint, with eccentric overload and stresses that exceed physiologic stresses, may result in hallux rigidus, as seen in football players and ballet dancers.
The contact distribution shifts dorsally with increasing degrees of extension.1 This is consistent with the observation that chondral erosions often initially affect the dorsal aspect of the articular surface of the first metatarsal.
Various factors, in isolation or in combination, have been suggested as contributing to the development of first MTP joint arthrosis: (1) hyperextension injury (ie, turf toe injury) to the hallux; (2) metatarsus primus elevatus; (3) osteochondral lesions; (4) a long first metatarsal; or even (5) wearing inappropriate shoes.6,23,27,29,32,40,41
In 2003, Coughlin et al9 evaluated 114 patients treated operatively for hallux rigidus over a 19-year period in a single surgeon's practice for demographics, etiology, and radiographic findings associated with hallux rigidus.
The disease was not associated with metatarsus primus elevatus, first ray hypermobility, increased first metatarsal length, Achilles or gastrocnemius tendon tightness, abnormal foot posture, symptomatic hallux valgus, adolescent onset, footwear, or occupation.
Hallux rigidus was associated with hallux valgus interphalangeus, female gender, and a positive family history in bilateral cases.
In most cases the problem was bilateral, except when trauma was involved—if trauma had occurred, then the problem was unilateral.
Metatarsus adductus was more common in patients with hallux rigidus than in the general population, but no significant correlation was found.
A flat or chevron-shaped MTP joint was more common in patients with hallux rigidus.
NATURAL HISTORY
The natural history of hallux rigidus is similar to that of degenerative arthritis in any joint. Once the process has started, the articular cartilage is more susceptible to injury resulting from shear and compressive forces. The subchondral bone shares these stresses, which subsequently lead to increased subchondral bone density and formation of periarticular osteophytes. The osteophytes limit first MTP joint motion and further compromise the normal mechanics of this joint. This effect can accelerate the degenerative process.
The natural history is, at the endpoint, stiffness and constant pain. The length of time that elapses from initial symptoms to constant pain varies widely. The standard time frame over which daily or recreational sports activities become painful is about 5 to 10 years, whereas athletes (eg, tennis and basketball players) who experience constant and repetitive impacts develop constant symptoms in a shorter period of time. In most patients, stiffness is not an issue.
Outcomes in 22 patients with hallux rigidus representing 24 feet treated nonoperatively at an average follow-up of 14.4 years showed that the pain remained about the same in 22 feet, improved with time in 1 foot, and became worse in 1 foot. There was measurable loss of cartilage space radiographically over time in 16 of 24 feet, and in 8 of the 16 feet, the loss of cartilage space was dramatic.16
PATIENT HISTORY AND PHYSICAL FINDINGS
Hallux rigidus is associated with a positive family history of great toe problems in almost two thirds of patients.9
The standard history is a trauma at the MTP joint several years earlier, but more often we find active persons—mostly former athletes—who are performing high-impact sports such as tennis, golf, or basketball. Starting with “feeling the joint” after exercising, it becomes a progressively limiting factor that prevents them from performing their sport at their normal level.
The true etiology of hallux rigidus is often not known.
In the early stages, the patient complains of pain only on dorsiflexion of the great toe; the ROM is unaffected or only moderately restricted. In the mid-stage of hallux rigidus, the patient complains of motion-dependent pain. Dorsiflexion of the great toe is restricted. Osteophytes may occur dorsal to the first metatarsal head and may be palpable, the plantar structures become tight, plantarflexion becomes painful at the sesamoid–metatarsal joint (mostly medial), and the ROM also is restricted. A dynamic stress test in dorsiflexion (ie, pressure with the thumb on the medial or lateral sesamoid) can distinguish between sesamoid–MT head pain and MTP pain. Unfortunately, this test is not clear in the presence of ongoing stiffness and arthritic changes of the MTP joint. The late stages present with reduced to complete inhibited dorsiflexion and plantarflexion of the toe, with palpable osteophytes dorsal (medial and lateral) to the metatarsal head and especially around the entire phalangeal base.
The most striking physical manifestation of hallux rigidus noticed by patients is the bony prominence at the dorsum of the metatarsal head, which is disturbing and painful, especially in firm leather shoes.
Methods for examining the first MTP joint are as follows:
ROM, dorsiflexion, and plantarflexion are checked. In the early stages, restriction of dorsiflexion (“dorsal impingement”) is found. In later stages, restriction of plantarflexion and pain at the midrange of the motion arc (indicative of global first MTP joint degenerative joint disease) also are found.
Palpation of the first MTP joint. In later stages, palpable and painful osteophytes are present as a symptom of ongoing osteoarthritis.
Inspection for clinical changes in form or color of the first MTP joint
IMAGING AND OTHER DIAGNOSTIC STUDIES
Standard weight-bearing AP (FIGS 1 and 2) and lateral radiographs of the foot as well as weight-bearing radiographs of the metatarsals and, in cases of sesamoid pathologies, a sesamoid special radiograph, should be performed.
Coughlin and Shurnas10 proposed a classification system based on the radiographic system of Hattrup and Johnson20 that is representative of the natural history. It includes ROM, as well as radiographic and examination findings, as follows:
Grade 0: Dorsiflexion (DF) of 40 to 60 degrees (ie, 20% loss of normal motion), normal radiographic results, and no pain
FIG 1 • Hallux rigidus grade 2 on AP weight-bearing radiograph.
Grade 1: DF of 30 to 40 degrees, dorsal osteophytes, and minimal to no other joint changes
Grade 2: DF of 10 to 30 degrees, mild flattening of the MTP joint, mild to moderate joint narrowing or sclerosis, and dorsal, lateral, or medial osteophytes
Grade 3: DF of less than 10 degrees, often less than 10 degrees plantarflexion, severe radiographic changes with hypertrophied cysts or erosions or with irregular sesamoids, constant moderate to severe pain, and pain at the extremes of the ROM
Grade 4: stiff joint, radiographs showing loose bodies or osteochondritis dissecans, and pain throughout the entire ROM
Indications for MRI in MTP–sesamoid pathology include:
Severe pain in the MTP complex unrelated to radiographic results
Absence of visible joint space narrowing on radiography
Suspected osteochondral lesion in the MT head on radiography
Suspected sesamoid arthritis or necrosis on radiography
The MRI examination should include sagittal, axial, and coronal views with T1-weighted (TR 35 ms, TE 16 ms) and high-resolution gradient echo (TR 1060 ms, TE 16 ms) images (FIG 3).
FIG 2 • Hallux rigidus grade 3 on AP weight-bearing radiograph.
FIG 3 • MRI scan showing an osteochondral lesion of the metatarsal head.
DIFFERENTIAL DIAGNOSIS
Gout
Rheumatoid arthritis
Psoriatic arthritis
Reiter's syndrome
Infectious arthritis
Sesamoid osteonecrosis
NONOPERATIVE MANAGEMENT
The primary nonoperative treatments of hallux rigidus are anti-inflammatory therapy and pain relief by orthotic devices.
Anti-inflammatory drugs (eg, diclofenac) may be used systemically and locally.
Injections in the joint should be restricted to single cases. A single shot of corticosteroids may lead to pain relief.
Cooling devices also inhibit the inflammation process.
Orthotic devices such as stiff inserts for shoes or rocker bottom soles take pressure from the MTP joint by facilitating the scrolling process. To further alleviate pressure on the joint, a shoe with a roomy toe box should be worn, and high heels should be avoided.
Physical therapy helps keep the joint mobile.
The question is whether immobilizing the joint by orthotics or stiff insoles in early arthritis is a reasonable approach, because doing so results in the functional breakdown of the MTP joint. In our practice, we prefer to keep the joint mobile by physical therapy and manual therapy and by having the patient perform exercises for dorsiflexion and plantarflexion daily (eg, aqua jogging on tiptoes).
We have found that chondroitin and glucosamine sulfate, slow-acting drugs for the treatment of osteoarthritis,21,34 have comparable success in improving the pain and symptoms of osteoarthritis.
Additional nonsteroidal anti-inflammatory drugs and icing can be applied to support progress at the beginning of the physical therapy program.
SURGICAL MANAGEMENT
The goal of surgical treatment is to achieve a pain-free joint.
Several surgical approaches have been proposed in the literature, including resection arthroplasty,7,22,23,30 interpositional arthroplasty,2,19,24 MTP replacement (implant arthroplasty),11,39 arthrodesis,18,28,32 and cheilectomy.13,18,20,25,27
After its first description by DuVries13 in 1959, cheilectomy emerged as the most popular choice for surgical intervention. Indications for performing a cheilectomy are controversial.10,14 Some authors recommend cheilectomy as a treatment for lower grades only,17,18,20,31 whereas others have reported successful results even for higher grades of the disease.14,15,27
Cheilectomy resects the dorsal obstacle, but does not address the plantar pathology, which includes tremendous shortening of the plantar capsular, as well as the short flexors and plantar osteophytes of the phalangeal base.
Cheilectomy alone without plantar release, in our opinion, cannot be successful.
A remaining cartilage lesion also may be responsible for persistent symptoms. This observation led to our idea of stimulating fibrocartilage regeneration by microfracturing the subchondral bone with a specially designed awl to open the zone of vascularization.
Steadman37 has developed a microfracture technique for the knee that creates fibrocartilage in chondral lesions.
It has been shown to be effective in comparison to untreated lesions in experimental studies in horses16 and in clinical studies of the knee33,37,38 and talus.4
Coughlin and Shurnas type 2 and 3 lesions are indications for the microfracture technique.
In type 3 lesions, the patient must be informed that the surgery has only limited success.
A contraindication for cheilectomy with microfracture is the stiff joint of types 3 and 4 osteoarthritis. In this case, in patients with a low activity level who want good range of motion, a resurfacing-type prosthesis (not a “head resection” type) is a good alternative and is being used with increasing frequency (FIG 4).
Patients with isolated, painful osteochondral lesions without degenerative joint disease may be considered in rare cases for microfracture alone (for a small, contained lesion) or for an osteochondral transplantation from the plantar medial talus (FIGS 5 AND 6).
FIG 4 • Postoperative radiograph of first MTP joint prosthesis.
FIG 5 • Osteocondral autograft transplantation from the plantar medial talus.
Preoperative Planning
Standard weight-bearing AP and lateral radiographs as well as, in some cases, MRI evaluation should be performed for grading the patient according to the Coughlin and Shurnas classification, and the cartilage damage should be assessed.
The clinical examination should include measurement of active and passive ROM and determination of power in extension and plantarflexion, along with a dynamic stress test for evaluation of sesamoid pathology.
Positioning
The patient is placed supine on the operating table.
General or local anesthesia may be used, according to the setup and the surgeon's preference.
A pneumatic tourniquet or Esmarch bandage should be used.
Approach
A 4- to 5-cm incision is made anteromedially (FIG 7), being careful to protect the dorsal nerve above the first metatarsal head.
FIG 6 • Osteochondral autograft transplantation from the plantar medial talus.
FIG 7 • Anteromedial approach.
The fatty tissue and the subcutaneous tissue are dissected, and the joint capsule is prepared.
The extensor hallucis longus tendon is retracted and the joint exposed (FIG 8).
The joint is then inspected by flexing the great toe in the plantar direction.
FIG 8 • Joint exposure from the lateral side showing the restriction in plantarflexion.
TECHNIQUES
CHEILECTOMY
After inspection of the joint, the dorsal osteophytes on the base of the proximal phalanx are removed.
Cheilectomy is performed with an oscillating saw.
The cut is performed in line with the dorsal metatarsal shaft.
The resection must not exceed about 15% to 20% of the metatarsal head (TECH FIG 1), because this leads to a jerking motion of the toe.
Osteophytes remaining on the medial and lateral facet of the joint are removed with a sharp rongeur, plantarflexing the proximal phalanx (TECH FIG 2).
The rims are smoothed with a rasp.
TECH FIG 1 • Cheilectomy
TECH FIG 2 • Resection of remaining osteophytes.
EXTENSIVE PLANTAR RELEASE
Release of the plantar structures is very important for improving the ROM.
Because of the inhibition of dorsiflexion in the first MTP joint, contracture of the plantar structures (joint capsule, short toe flexors) has taken place.
The joint capsule and the short flexors with the sesamoid bones are released subperiosteally using a McGlamry elevator (TECH FIGS 3 AND 4).
The phalangeal attachment of the plantar capsule and the insertion of the short flexor muscles are released (TECH FIG 5).
This maneuver must be performed cautiously so as not to detach the tendons from their insertion.
TECH FIG 3 • Plantar release using a McGlamry elevator.
The joint is inspected again for plantar osteophytes of the phalangeal base and unstable cartilage parts, which will be resected.
Further resection to the metatarsal head must be avoided to prevent joint instability.
The rims are smoothed again with a rasp.
Osteophytes at the proximal sesamoid site must be resected, because this also is a source for plantar pain and restricted dorsiflexion. (TECH FIG 6)
TECH FIG 4 • Plantar release using a McGlamry elevator.
TECH FIG 5 • Release of the distal capsule and short flexors using a scalpel.
TECH FIG 6 • Plantarflexion after plantar release and resection of osteophytes.
MICROFRACTURE
The remaining cartilage lesions at the first MTP joint or the proximal phalanx must be débrided of all remaining unstable cartilage and fibrous tissue.
The calcified cartilage layer must be completely removed.
Using an awl, the microfractures are placed approximately 1 to 2 mm apart and about 2 to 4 mm deep (TECH FIG 7).
TECH FIG 7 • Microfracturing of the metatarsal head.
WOUND CLOSURE
The joint capsule is closed with interrupted absorbable sutures, and a 0.8-mm drain is placed between the capsule and the continuous subcutaneous suture.
The skin is sutured intracutaneously.
Infiltration of the skin with bupivacaine and morphine decreases pain and need for pain killers after surgery.
A small splint, which fixes the joint in dorsiflexion, is important to stretch the released shortened plantar structures (TECH FIG 8).
TECH FIG 8 • Splint in 40 degrees dorsiflexion.
POSTOPERATIVE CARE
After surgery a gauze-and-tape compression dressing is applied to the wound, and the hallux is fixed in 30 to 40 degrees dorsiflexion with a plantar cast for 2 days to support plantar release and to improve immediate ROM after surgery.
A second-generation cephalosporin is prescribed for 5 days. Dexamethasone is given for 4 days, according to this schedule: day 1, 4 mg; day 2, 8 mg; day 3, 4 mg; and day 4, 2 mg.
This regimen provides protection from infection, and the dexamethasone provides significant reduction of pain and swelling, which helps to restore range of motion.
It also prevents excessive scar formation, which may result in recurrent loss of motion.
The first dressing change, with removal of the drain, occurs on the second postoperative day.
In our practice, from the second day, patients wear a postsurgical shoe with full weight bearing for 2 weeks to reduce loading and its accompanying pain and swelling. This allows the patient to become pain-free more quickly and makes it possible to regain dorsiflexion earlier (FIG 9).
The shoe permits good mobility and excellent conditions for decreased swelling and improved wound healing.
“Aggressive” treatment of pain and swelling is crucial for the success of the surgical procedure, because regaining and stabilizing the intraoperatively attained ROM is the postsurgical goal.
Passive and active ROM exercises are started from the second day if wound conditions and pain permit.
After removal of skin sutures, aggressive stretching is necessary to maintain ROM.
At this point, the patient should walk without the postsurgical shoe, focusing on a normal gait.
The rehabilitation program also includes isometric and proprioceptive training.
Cooling, nonsteroidal anti-inflammatory drugs and physical therapy with joint distraction support the daily self-guided dorsiflexion exercises.
At 3 to 4 months, the maximum ROM usually has been achieved. The patient must be aware that there is only a limited time frame for achieving good motion.
FIG 9 • This shoe reduces load to the forefoot.
OUTCOMES
In a prospective study, 36 patients (26 women and 10 men) with 37 cases of hallux rigidus were operated by the senior author (HT) using the described technique.
Patients were examined and interviewed preoperatively as well as 1 year (mean 12m; 28 cases) and 2 years (mean 23m; 22 cases) postoperatively and rated using the American Orthopaedic Foot and Ankle Society (AOFAS) Hallux Metatarsophalangeal-Interphalangeal Score31 and by a visual analog scale (VAS, not scaled 10 cm, where 0 is very poor and 10 is excellent).
The average age of the 36 patients at the time of surgery was 50 years (range 31 to 64 years).
Preoperative radiographs following Hattrup and Johnson's classification revealed 25 cases of grade 2 and 12 of grade 3. No patient was classified as grade 1.
Two patients, both grade 3, refused the follow-up examination.
According to the AOFAS score, the results revealed a significant improvement: from 43 points preoperatively to an average of 78 points (range 35–100 points) after both 1 and 2 years postoperatively.
The average outcome on the VAS after 2 years was 7.1 for pain (preoperatively: 2.2; after 1 year: 7.0); 7.1 for function (preoperatively: 2.8; after 1 year: 6.7); and 7.4 for satisfaction (preoperatively: 1.1; after 1 year: 6.6).
Clinical examination showed an average improvement in ROM of 22 degrees.3
Patients classified as grade 3 were found to have significantly poorer results on average than grade 2.
Retrospectively, several of our patients would have been classified as grade 4 and, we now believe, should not have been considered for cheilectomy. We believe grade 3 is an indication if microfracturing and plantar release are added for treatment and the joint was not stiff before surgery.
COMPLICATIONS
In patients with coexisting hallux valgus deformity, correction of the axis with a soft tissue release is essential for a successful result. However, the obligatory immobilization of the osteotomy reduces the options for postoperative management, and results sometimes are less successful in regaining ROM.
If too much metatarsal head is resected with the cheilectomy, first MTP joint instability may ensue.
Rough detachment of the short flexors may result in weak plantarflexion.
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