What is Hallux Valgus ?
Patients can present initially in several ways; therefore, evaluation of the history is extremely important. A patient may present with a nonacute onset of deep or sharp pain in the first metatarsophalangeal joint during ambulation, with exacerbation during particular activities. This presentation indicates degeneration of the intra-articular cartilage.
The patient may also describe aching pain in the metatarsal head secondary to shoe irritation that is relieved when the shoes are removed. This presentation is indicative of superficial bump pain. Often, both forms of pain are progressive and have been present for many years. The frequency or duration of pain may recently have begun to increase, and activity may exacerbate the pain. Patients may even describe a recent notable increase in the size of the deformity or medial bump.
Questions on limitation of physical or daily living activities are valuable for understanding the severity of the patient's pain. It is also important to ascertain what, if anything, relieves the pain and which treatments (eg, surgery) have been attempted previously. Occasionally, trauma or inflammatory arthritis is an associated finding.
Another possible presentation is burning pain or tingling in the dorsal aspect of the bunion, which indicates entrapment neuritis of the medial dorsal cutaneous nerve. The patient may also describe symptoms caused by the deformity, such as a painful overlapping second digit, interdigital keratosis, or ulceration to the medial metatarsal head, without complaint of the bunion deformity itself.
The physical examination includes an assessment of the vascular, dermatologic, neurologic, and musculoskeletal systems.
The musculoskeletal assessment can be divided into 2 components: determination of the etiology and evaluation of the resultant pathology (or presenting deformity). Understanding both components is essential in determining the most satisfying and successful treatment plan, whether conservative or surgical.
The workup is tailored to the patient's history. If neurologic complaints, systemic arthritis, or collagen vascular disease are mentioned, they should be addressed further in detail. If none of these are present, the focus then turns to the biomechanical examination, which includes assessment of the following measures, any or all of which can contribute to hallux valgus:
- Hip internal/external rotation
- Genu valgum/varum
- Tibial torsion
- Ankle joint dorsiflexion
- Subtalar joint range of motion (ROM)
- Midtarsal joint ROM
- Neutral calcaneal stance position
- Resting calcaneal stance position
- Forefoot/rearfoot varus or valgus
Assessment of resultant pathology can be divided into weightbearing and non–weightbearing evaluations, as both yield important information for determining the appropriate treatment protocol (see image below).
Non–weight-bearing foot. Note the medial prominence, contracture of extensor hallucis longus, and callus on the second digit.
With the patient in a non–weightbearing position, examine the following:
- Hallux position: The position of the hallux in the transverse plane should be assessed relative to the second digit. The hallux can be overriding, underriding, abutting, or without contact. Lateral deviation of the hallux may result from subluxation of the metatarsophalangeal joint or structural changes to the hallux. The hallux may be rotated in the frontal plane, as noted by valgus or varus rotation of the toenail. Thus, hallux abductus indicates transverse plane deformity, while hallux abductovalgus indicates deviations in the transverse and frontal plane.
- Medial prominence: Most medial prominences are located dorsomedial and appear to be more severe in a metatarsal adductus foot type. Erythema or bursa indicates shoe pressure and irritation.
- First metatarsophalangeal joint ROM: The first aspect to assess is maximum available motion. Normal dorsiflexion is 65-75° with plantarflexion less than 15°. The next aspect is quality of joint ROM and whether pain, crepitation, or both are present; such findings indicate intra-articular cartilage degeneration. Pain without crepitation suggests synovitis. The axis of motion is the last variable to assess. The joint is considered track-bound if the hallux drifts laterally after being placed in a neutral position during ROM exercises. Degree of lateral drift indicates severity of lateral soft-tissue contracture.
First ray ROM: The first ray should be evaluated in 2 ways. The first is determination of the ROM and resting position. Normal ROM is 10 mm total, with 5 mm dorsiflexion and 5 mm plantarflexion (see image below). Resting position should be neutral compared with the second metatarsal head. The second evaluation is determination of mobility in the transverse plane. In the normal foot there is little to no motion available. However, in the presence of hallux valgus motion may be detectable.Non–weight-bearing foot with range of motion being assessed of the first ray, which is currently in neutral (neither plantarflexed or dorsiflexed) position.
- Plantar keratosis: Keratosis at the hallux interphalangeal joint (IPJ) indicates excessive pronation at push off. If present underneath the first metatarsophalangeal joint (MPJ), this indicates excessive pressure secondary to equinus, rigidly plantarflexed first metatarsal, prominent sesamoid, rigid forefoot valgus, or cavus foot type. Keratosis underneath the second metatarsal head can indicate short first metatarsal or long second metatarsal, dorsiflexed first metatarsal with resultant transfer lesion, retrograde plantarflexion of the second digit from hammertoe deformity, or hypermobility of the first metatarsal.
- Pain location: The entire first metatarsophalangeal joint complex should be palpated for pain during passive and active ROM, including but not limited to the dorsal, plantar, and/or medial metatarsal head, sesamoid, crista, proper digital nerves, and extensor hallucis longus tendon.
- Contracture of the extensor hallucis longus: This condition is present only in long-standing lateral subluxations of the first metatarsophalangeal joint or neuromuscular disease.
- Associated deformities: Second digit hammertoes and flexible or rigid flatfoot are commonly noted. Instability of the second digit may allow a more rapid progression of hallux valgus, as the second digit is unable to act as an adequate lateral buttress.
Often, the pathology or severity of deformity is not as apparent when the patient is not bearing weight as it is when the patient is bearing weight. Therefore, weightbearing examination is an important part of the physical evaluation. In the weightbearing examination, assess the following aspects:
- Positional increase of hallux abduction in the transverse and frontal planes.
- Increase in medial prominence.
- Increase in extensor hallucis longus tendon contracture.
- First metatarsophalangeal joint dorsiflexion, characterized as decrease, increase, or no change.
- Hallux purchase, noted as good, fair, poor, or absent. (This should be normal preoperatively and serves as a baseline for postoperative examination.)
- Metatarsus adductus. (The greater the adductus, the greater the deformity appears.)