Eliminating pain and restricted movement

“Mobility means quality of life” – such is Dr. Andreas Metzger’s motto. The specialist in orthopedics and sports medicine, with his own practice in Nuremberg, explains the potential of foot orthoses in the conservative treatment of the foot’s most common wear condition: hallux rigidus in the metatarsophalangeal joint.

“Osteoarthritis of the metatarsophalangeal joint develops in a similar way to other synovial joints. As the Latin name hallux rigidus suggests, mobility in the metatarsophalangeal joint decreases continually or the joint can only be moved with great pain,” says Dr. Andreas Metzger. Statistically, people aged 30 to 50 are primarily affected, more women than men, “which may be based on a greater tendency to having a valgus leg axis,” Dr. Andreas Metzger assumes, who describes the causes for developing hallux rigidus as multi-factorial. “This wear is usually caused by repetitive excessive strain. If a patient suffers from a valgus leg position, valgus foot or plano-valgus foot, and this person’s heel-to-toe movement puts too much load on the inner edge of the foot when switching from standing to pushing off, then this can permanently affect the metatarsophalangeal joint. But this is not necessarily the consequence. These biomechanical impact factors combined must subject the joint to excessive strain.” Sports, such as tennis or squash, are predestined for this because the forefoot is subjected to strain from changes in direction and thus recurring load peaks. External influences can include unsuitable footwear. Being overweight can be another factor.

Special characteristic: gradual start
The development of hallux rigidus starts gradually. At the beginning, those affected often suffer from initial pain that subsides with continuing movement. Sometimes, pain after a (sporting) activity can also occur. When the condition progresses, the joint becomes stiffer, in dorsal flexion in particular. “Those who often walk barefoot or play sports that involve the forefoot more and thus carry out the heel-to-toe movement more intensively, will notice pain earlier. Other patients often only notice it when we really get the joint moving during an examination,” Dr. Metzger explains and elaborates: “We make a radiological distinction in four stages, like with the knee according to Kellgren. While we initially find narrowing of the intra-articular space only, later on, more serious signs of joint compartment wear will occur, such as osteophytic projections, until the joint space has disappeared completely.”

“Once the diagnosis has been made, that is always the question Question about clinical relevance. The top one The goal of therapy should be the patient as quickly as possible and largely pain-free to get mobile again.”

Dr. Andreas Metzger

During his examinations, the experienced sports physician is guided by the method described by Zammit, Munteanu, and Menz[1]. After recording the patient’s medical history and performing a manual examination, Dr. Metzger usually takes an X-ray to estimate the degree of the osteoarthritis. “Perceived problems don’t always correspond to the degree of severity. Some athletes are in serious pain at Grade 1 because of the extreme strain. Others don’t visit us until they’ve reached a later stage. Joint inflammation is always a key factor that causes pain.” In order to assess the inflammatory activation of the osteoarthritis more effectively, Dr. Metzger uses ultrasound. In this way, thickening of the capsule, joint contusions, or inflammatory hyperemia of the joint capsule can be detected sonographically using the Doppler function. He feels that a CT or MRI make sense when specific questions, such as more rare differential diagnoses or combined conditions, need to be clarified. When asked about potential differential diagnoses, the physician recommends checking for inflammation of the sesamoid bone underneath the toe and looking for signs of podagra (foot gout) or rheumatic causes.

[1] Zammit G.V., Munteanu S.E., Menz H.B. Development of a diagnostic rule for identifying radiographic osteoarthritis in people with first metatarsophalangeal joint pain. In: Osteoarthitis and Cartilage 19 (2011) 939–945

Prescribing foot orthoses is certainly an answer
“Once the diagnosis has been clarified, there is always the question relating to its clinical relevance. The primary objective of treatment should be getting the patient pain-free and mobile again as soon as possible,” Dr. Metzger points out. The goal therefore is to find the factors that have resulted in the excessive joint strain so they can be eliminated. In addition, pain can be counteracted with pain medication. “If the pain is severe, intra-articular injections have proven more effective than taking pain killers orally. Experience has shown that an injection (series) using the patient’s own blood plasma (Platelet Rich Plasma – PRP), potentially in combination with hyaluronic acid, can help,” Dr. Metzger reports. In any event, the foot expert will prescribe special foot orthoses in cases of hallux rigidus.[2] Their distinctive feature is what is known as the rigidus spring, reinforced material under the metatarsophalangeal joint which significantly reduces the flexibility of the shoe-foot orthosis combination. To him, it is important that the rigidus spring is far enough back so the shoe’s flexion zone is not shifted below the midfoot. This can prevent resulting inappropriate mechanical stress, in the area of the plantar fascia for example. Depending on the patient’s anatomy, Dr. Metzger recommends additional modules that should be integrated into the foot orthosis. A longitudinal arch support can ensure that the longitudinal arch does not collapse in the standing phase (known as overpronation), which would inevitably result in heel-to-toe movement via the metatarsophalangeal joint. Additional soft cushioning below the metatarsophalangeal joint can reduce strain on the sesamoid bone.

[2] Current examples of hallux rigidus foot orthoses can be found at the end of this article. 

“The deposit is the central pillar in the conservative Treatment of hallux rigidus. The better it is tailored to the patient, the more It works more effectively.”

Dr. Andreas Metzger

“Prescribing foot orthoses is very personal.We have to take into account the wearer’s typical movement patterns under dynamic conditions,” insists Dr. Metzger. Movement intensity also plays an important part. An elite athlete will deal with changed biomechanics and lever ratios caused by the foot orthoses differently than an amateur. The rigidus spring results in an extended ventral lever arm at the pivot point of the upper ankle and therefore increased tension in the Achilles tendon during the push-off phase. “We have to provide advice on preventing Achilles pain. We should also ensure that a very soft intermediate sole in the shoe, on the inside in particular, doesn’t counteract the effect of the foot orthosis. Models with pronation support are beneficial in this case. Nowadays, there are even running shoes with a convex sole. This trend is great for hallux rigidus patients,” Dr. Metzger explains, “because they make heel-to-toe movement easier in cases of a stiff metatarsophalangeal joint.” For everyday activities, he recommends to some patients that they may wish to try out a shoe with a stiffer sole than a very flexible business shoe, such as a lightweight hiking or walking boot. This can be sufficient during early stages.

Customized treatment and monitoring
“The foot orthosis is the core element of conservatively treating hallux rigidus. The better it’s adapted to the patient, the more effective it will be,” Dr. Metzger emphasizes. With comprehensive experience gathered from numerous studies, the foot specialist has made it his habit to specify the modular design of the foot orthosis on the prescription. “Of course, orthotists carrying out the work have freedom of treatment. We all have to cooperate for the sake of the patient.” A check-up at his practice two to six weeks after prescribing a product is very important to him. “I want to know how the wearer is getting on with it. Some notice an effect straight away, others still have to get used to the foot orthosis. We should support our patients and use this check-up appointment as an opportunity to expand our own experience.” In cases of hallux rigidus, Dr. Metzger categorically prescribes foot orthoses for both feet. For two reasons: usually, the side that currently does not seem affected still shows some signs of wear and the product can then prevent further degeneration. Furthermore, treating both feet prevents different heel-to-toe movements, which could otherwise lead to subsequent problems.

Slowing down the degenerative process
“Using a biomechanically correctly designed, tested foot orthosis can reduce problems so much that 70 per cent of those affected don’t require further action,” says Dr. Metzger, describing his experience with regard to the success of using foot orthoses in cases of hallux rigidus. “Of course, we can’t stop the degenerative process, but we can significantly slow it down. In the end, existing wear and strain-related, repeatedly occurring inflammatory and painful activations are the factors that decide whether further measures are required.” If foot orthoses are not sufficient, the physician initially supplements treatment with intra-articular injections. Only when the hallux rigidus has progressed so much that problems still persist after this, will Dr. Metzger consider surgery – to be joint-preserving or not, depending on the case. For this, the physician with his own practice works with a wide network of specialists to whom he will refer his patients.

Pictures: Udo Schönewald, Bauerfeind AG