What’s the difference between Bunions and Big Toe Arthritis?

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Patients often confuse bunions (Hallux Valgus) with Big Toe Arthritis (Hallux Limitus) because both conditions can cause pain and a bump or even enlargement of the big toe joint. But it’s important to understand that they are actually very different conditions.

What’s a Bunion (Hallux valgus)?

A bunion or hallux valgus is when the joint formed between the base of the first segment of the big toe (the proximal phalanx) and the far end of the first metatarsal bone of your foot falls out of alignment. Specifically, the big toe moves laterally so that its tip points toward the little toe, and the first metatarsal bone drifts outward so that its tip points toward your opposite foot.

The net result is that your first metatarsal and great toe are no longer in straight alignment but rather form a “V” with its apex at the first metatarsal head pointing toward the opposite foot. This process begins gradually and, at first, the bump at the first metatarsophalangeal joint (MTP joint) is rather subtle and usually felt to be just a minor annoyance.

Eventually (and sometimes quickly) symptoms worsen when shoes start rubbing on the bump. When that happens and pain begins, it’s wise to seek follow-up with a podiatrist. While at first the range of motion of the foot isn’t affected by a bunion, if the deformity is allowed to progress unchecked it can cause greater problems. The great toe joint can actually start to dislocate, prompting significant joint pain and degeneration that can affect forefoot function and, eventually, your gait.

What is Big Toe Arthritis?

Big Toe Arthritis (technically known as “Hallux Limitus,” “Hallux Rigidus,” or “rigidus arthritis of the great toe joint”) occurs when the joint between the first bone segment of the big toe and the first metatarsal bone begins to degenerate. This leads to the destruction of the cartilage that lines the ends of the bones, the formation of bone spurs as the bone attempts to regenerate, and decreased range of motion at the toe joint.

Progression of big toe arthritis

Big Toe Arthritis results in stiffness, progressive pain, joint swelling, and tenderness. At this point, physical therapy and conservative treatments will be of little help. When arthritis becomes severe, a joint replacement (known as arthroplasty) or a joint fusion (an arthrodesis) might be recommended.

Some people may be predisposed to arthritis of the big toe because of the biomechanical design of their toe joints. In others, osteoarthritis can become much worse as the result of an injury or from repetitive micro-trauma due to walking in high-heeled shoes or engaging in certain sports, for instance.

How to tell the difference between a Bunion and Big Toe arthritis

The symptoms of big toe arthritis are quite different than those of bunions. Big toe arthritis usually starts with joint stiffness that can be accompanied by swelling and redness. This usually progresses to a decrease in range of motion in both dorsiflexion and plantar flexion (upward and downward bending), a crunching sensation during movement, and eventually the formation of a bump along the top (or dorsal surface) of the joint.

This is very different from bunions which are characterized by a bump forming along the outer side of the toe that isn’t very painful at first. Bunions also have little, if any, limitation in joint movement and no crunching sensation.

The pain of hallux rigidus is a result of bone spurs that can restrict motion and foot function as your walking pattern changes when your body tries to offload the sore joint. Pain can also result from loose bone fragments that break off from the bone spurs and get trapped in the joint. The etiology of bunion pain, on the other hand, results from the soft tissue of the metatarsal head rubbing on the inside of the shoe.

Bunion vs normal foot
Bunion vs Healthy Foot

Weight-bearing x-rays taken while standing show clear-cut radiographic differences between bunions and MTP joint arthritis. Bunions are characterized by a V-shaped medial deformity (known as abducto valgus or a hallux valgus deformity) resulting from hypermobility of the MTP joint. This causes the first metatarsal head to point toward the opposite foot and the distal tip of the great toe to point toward the little toe of the same foot.

This contrasts with radiographs of an arthritic big toe that are characterized by joint space narrowing, bone spurs (called osteophytes) visible at the ends of the bones, and, in extreme cases, early signs of fusion at the MTP joint.

What happens when Bunions and Big Toe arthritis occur together?

Bunions and big toe arthritis can occur together in what is considered a more complex foot deformity.

Sometimes arthritis can develop in the presence of a bunion due to the prolonged abnormal position of the joint. This can occur when the bunion deformity is advanced and the MTP joint sustains repetitive trauma or a distinctive injury that sets the arthritis in motion.

Similarly, there can sometimes be a subtle bunion component to big toe arthritis because the MTP joint can degenerate in an asymmetric fashion due to bone spurs. This deformity is often corrected at the time of a joint clean-up surgery.

Bunions vs. Big Toe Arthritis: how do treatments vary?

Aggressive treatment of big toe arthritis (hallux limitus) is crucial during its early stages.

Once joint cartilage has been destroyed, there is nothing a physician or surgeon can do to create more cartilage. Research is underway seeking to replace or regrow cartilage, but we are many years from a solution.

In its early stages, hallux limitus can be controlled with conservative treatment using a custom orthotic or over the counter plantar inserts to take the pressure off the big toe and redistribute it through the rest of the foot. If that fails, a surgical procedure known as a cheilectomy involves the resection of scar tissue and painful bone spurs from the joint. This permits better range of motion and slows the progression of arthritis.

Some patients benefit from a surgical treatment known as an osteotomy that shortens the first metatarsal relative to the second metatarsal. This not only gives the first MTP joint better clinical biomechanics but also creates more joint space. If left untreated, Hallux limitus can lead to complete joint destruction necessitating a joint fusion (arthrodesis) or even a joint replacement (arthroplasty).

On the other hand, treatment for a conventional bunion can often be delayed until it becomes painful.

During their relatively asymptomatic early stages, bunions are considered a cosmetic concern and are treated by placing a silicone wedge between the first and second toe to force the first toe to line up with the first metatarsal.

With bunions, the MTP joint does not usually become damaged until the advanced stages of this condition. Nonetheless, it’s important to seek follow up with a foot ankle specialist once bunions begin to hurt to avoid permanent joint injury. But a bump in the absence of foot pain can wait.

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