Buying the Right Shoes: Anatomical Criteria and Podiatric Recommendations

What lies behind it

The human foot is a complex masterpiece of evolution. It consists of 26 bones, 33 joints, and over 100 ligaments, tendons, and muscles. With every step, this structure must cushion and stabilise several times one's own body weight. The arch of the foot is divided into a medial and lateral longitudinal arch as well as a transverse arch in the region of the metatarsal heads. These arch structures are dynamic and change shape under load.

When the foot strikes the ground, the arch flattens in a controlled manner to absorb impact energy. In doing so, the foot expands in both length and width. If this natural expansion is obstructed by footwear that is too narrow or too short, high mechanical shear forces and pressure peaks occur. A central concept in shoemaking is the so-called shoe last. The last is an artificial model of the foot, usually made of wood, plastic, or metal, around which the shoe is shaped. The shape of the last decisively determines the internal volume, the orientation of the heel counter, the toe spring, and the width of the ball of the foot.

If the last shape of a shoe does not match the individual foot shape, abnormal loading inevitably occurs. A typical example is pointed shoe design. Anatomically speaking, the forefoot is widest in the toe region, where the toes are arranged in a fan-like manner. Ready-to-wear shoes, however, often taper at precisely this point. This forces the hallux valgus axis laterally and shifts the lesser toes into a deformity. Furthermore, foot volume is subject to circadian fluctuations. Due to gravity, muscle activity, and venous return, fluid accumulates in the interstitium of the foot tissue over the course of the day. In terms of volume, a foot is significantly larger in the late afternoon than in the early morning.

Typical signs

An ill-fitting shoe leaves clear traces on the foot. The first sign of chronic overload is the development of localised hyperkeratoses. Calluses form wherever the epidermis is exposed to increased friction and continuous pressure. If this pressure is not reduced, deep, painful keratotic cones known as clavi or corns form in the centre of these calloused areas.

In the forefoot area, reduced toe space frequently leads to characteristic nail changes. When the tips of the toes strike the toe cap with every step, microscopic trauma occurs at the nail matrix. This results in subungual haematomas, vertical nail cracks, onycholysis, or thickening of the nail plate. Lateral pressure on the nail wall area also significantly promotes ingrown toenails.

In addition to skin and nail changes, structural and joint complaints frequently appear. Those affected complain of metatarsalgia, that is, pain beneath the metatarsal heads caused by a collapse of the transverse arch and impingement of plantar nerves. Hammer toes and claw toes develop at the interphalangeal joints, as the flexor tendons must work against the constriction. In the posterior section of the foot, a poor heel fit leads to blistering, bursitis at the insertion of the Achilles tendon, or overload of the plantar fascia.

It is important to distinguish these mechanically induced complaints from inflammatory conditions such as gout attacks, rheumatic changes, or vascular circulatory disorders. While mechanical pressure pain usually correlates directly with wearing specific shoes and subsides after pressure relief, inflammatory or ischaemic pain often persists during periods of rest.

Causes in everyday life

In daily practice, the same patterns of errors leading to the purchase of ill-fitting footwear recur continuously. One of the main causes is buying shoes at the wrong time of day. Anyone who tries on shoes in the morning almost inevitably selects a model that is too narrow for afternoon foot volume. Over the course of the day, the foot requires space for natural volume expansion.

Another factor is blind reliance on nominal shoe sizes. The specification of shoe size according to the Paris Point or Mondopoint system is by no means uniformly standardised across different manufacturers and continents. A size 40 shoe from one manufacturer may well correspond in internal dimensions to a size 39 model from another vendor. Buying shoes without checking the actual internal dimensions and toe clearance while standing carries a high risk.

Unsuitable upper materials also contribute to foot problems. Synthetic, inelastic materials do not give way over time and do not provide a microclimate that can wick away moisture. The accumulation of sweat softens the stratum corneum of the skin, rendering it more susceptible to friction damage and promoting mycoses. Furthermore, the appearance of many fashion shoes invites compromise. If the aesthetics are appealing, slight feelings of pressure during fitting are ignored in the mistaken assumption that the shoe will break in significantly.

Changing life circumstances also play a role. Weight gain, pregnancy, or age-related ligamentous weakness lead to a lowering of the arch of the foot. Consequently, the foot becomes wider and longer. Those who rigidly purchase the same shoe size for decades almost invariably wear shoes that are too small in later life.

When medical evaluation is necessary

Not every pressure point requires an immediate doctor's visit, but prompt specialist diagnostic evaluation is essential if certain warning signs appear. This applies in particular to individuals with existing underlying conditions such as diabetes mellitus or peripheral arterial disease. In these patients, even a minor pressure point can go unnoticed due to damaged nerve tissue and develop into a deep ulcer within a short time.

Should you notice the following symptoms on your feet, medical evaluation is required:

• Open wounds, persistent redness, warmth, or weeping skin areas in the forefoot or heel region.
• Sudden, severe pain that does not subside even after removing footwear.
• Numbness, tingling, or a complete loss of tactile sensation in the toes.
• Pronounced deformities that lead to joint stiffness or make normal walking impossible.

In such cases, the primary consideration is whether custom orthopaedic shoes, specialised therapeutic footwear, or diabetic protective shoes must be prescribed. At these stages, podiatric treatment is always conducted in close coordination with the attending diabetologist, orthopaedic specialist, or dermatologist.

What podiatric treatment can achieve

Podiatry bridges the gap between purely cosmetic foot care and medical orthopaedics or dermatology. In podiatric practice, treatment extends far beyond the removal of calluses. It begins with a thorough inspection of the foot, assessment of joint mobility, and evaluation of gait patterns. Existing footwear is systematically analysed for wear patterns, upper stability, and insole dimensions.

If painful keratoses, corns, or nail changes have already formed, these are precisely removed using sterile rotating instruments and scalpel techniques. For ingrown nails caused by lateral shoe pressure, nail brace therapy, also known as orthonyxia, is used. The gentle tension of an individually fitted wire brace initiates the nail correction process and permanently relieves the tissue. Information on the various treatment options can be found in our [/en/services] overview.

An essential component of podiatry is the fabrication of custom silicone pressure and friction protection devices, known as orthoses. These custom-fit appliances are moulded directly on the patient's foot. They offload harmful pressure from the vulnerable area to less sensitive regions. In addition, the state-recognised podiatrist provides detailed advice on the physical properties of suitable shoes. Treatment intervals depend on individual findings and, for high-risk patients, typically range between four and six weeks. In accordance with practice guidelines, the highest standards regarding hygiene and instrument reprocessing apply, which you can read about under [/en/hygiene].

If there is any ambiguity regarding prescribable podiatric treatments or if an expert assessment is required beforehand, status as a [/en/sectoral-practitioner] (sektorale Heilpraktikerin, a sectoral practitioner of podiatry) provides the legal framework to make independent diagnoses in podiatry and directly prescribe appropriate therapies.

What you can do yourself

To ensure successful shoe purchasing and keep your feet free of complaints in the long term, you should follow five fundamental rules during your next purchase. These instructions are easy to implement in specialist retail shops and consistently prevent mistaken purchases.

1. Strictly adhere to evening measurement: Plan your shoe purchase exclusively for late afternoon or evening hours. By this time, daily loading causes the foot to reach its maximum daily volume. A shoe that fits comfortably in the evening will not constrict you in the morning. During fitting, ensure you wear the exact socks you intend to combine with the shoe in daily life.

2. Check toe clearance while standing: The most important parameter for length is the toe allowance. When standing, weight bearing pushes the foot forward. In front of the longest toe, which is not the big toe in every individual, a clearance of 10 to 15 millimetres must be present during functional use. This corresponds roughly to a thumb's width. This space is essential to prevent the toes from striking the toe cap during the roll-over phase of walking.

3. Match the last shape to the foot shape: View your bare foot from above. Compare its outline with the sole of the shoe. There are Egyptian foot shapes, in which the hallux is the longest, Greek shapes with a dominant second toe, and square foot shapes. The shoe must follow the natural contour of your forefoot. If the shoe tapers towards the centre while your forefoot is wide, the model is unsuitable.

4. Use the insole removal test: If the selected shoe has a removable footbed, remove it and stand on it with full body weight. If your toes or the ball of your foot project laterally beyond the sole, the shoe is definitely too tight or too narrow. The footprint must lie completely within the contour of the insole.

5. Pay attention to material and heel fit: Select uppers made of genuine leather or high-quality, breathable textiles. The heel counter must be sturdy and provide firm support to the calcaneus without causing pressure. If the heel slips out of the shoe during walking, many people tend to claw their toes to hold the shoe, which rapidly leads to painful tension in the plantar intrinsic muscles.

Common errors

In clinical practice, classic misconceptions repeatedly surface during consultations, leading to inappropriate purchases. Avoiding these pitfalls protects your feet effectively from secondary damage.

• Believing that shoes will stretch: A common misconception is assuming that a shoe that is too short or too narrow at the ball of the foot will stretch sufficiently with wear. While soft leather yields minimally in width, the length of a shoe never changes through breaking in. Never purchase shoes in the hope that they will expand.
• Trying on shoes while seated: Anyone who tries on shoes only while seated evaluates the fit without weight bearing. As soon as full body weight rests on the foot, the arch flattens and expands. The foot becomes longer and wider. Therefore, always test shoes while standing and walk around the shop for several minutes.
• Trying on only one shoe: Almost no one possesses two entirely identical feet. Typically, one foot is slightly longer or wider than the other. Always try on both shoes and base your purchase on the larger and wider foot. If necessary, a thin compensatory insole can be used for the smaller foot.
• Confusing shoe size with shoe width: Many people buy a size larger when experiencing pressure at the ball of the foot. However, this alters the entire anatomy of the shoe. The flex line of the sole no longer aligns with the metatarsophalangeal joints, making propulsion and rolling difficult. Instead, look for models offered in different width fittings.

Scientific evidence and context

For many years, medical research has confirmed the direct relationship between ill-fitting footwear and foot pathologies. A comprehensive systematic review by Buldt and Menz investigated the prevalence of ill-fitting shoes in the population [1]. The authors concluded that between 63 and 72 percent of evaluated individuals wore shoes that did not match the actual length and width dimensions of their feet. In this meta-analysis, incorrect footwear was significantly associated with foot pain, hallux valgus, hammer toes, and hyperkeratotic lesions.

The importance of fit increases particularly in older age. In their study on older adults, Brenton-Rule and colleagues demonstrated that ill-fitting footwear not only causes local tissue damage but also negatively affects postural stability and can increase fall risk [2]. Shoes that are too wide or unstable lead to gait instability, whereas shoes that are too tight distort the natural gait pattern due to pain stimuli.

In patients with metabolic diseases, the evidence is even clearer. Nixon and co-workers demonstrated that adequate shoe fitting in diabetic patients drastically reduces the risk of primary pressure ulcerations [3]. Guidelines for the management of diabetic foot syndrome therefore explicitly demand regular verification of internal shoe dimensions using sole impressions.

Studies on foot morphology by Barisch-Fritzsche and team further confirmed that discrepancies between mass-produced shoes and real foot shapes are widespread [4]. In particular, the ball angle and forefoot width of modern shoes rarely correspond to the natural volume expansion of the foot under dynamic load. This underlines the necessity of individualised advice and measurement in daily life.

Treatment in Memmingen

Professional guidance is valuable for healthy feet. FREITAG® Podologie GmbH offers comprehensive podiatric care at its practice premises at Kempterstr. 25 in Memmingen. The catchment area extends across the entire Unterallgäu, the Allgäu, and adjacent regions in Upper Swabia.

Under the direction of Helga Maria Freitag, state-recognised podiatrist and sectoral practitioner of podiatry (sektorale Heilpraktikerin für Podologie), preventive and therapeutic measures take center stage. The practice is fully accessible and modernly equipped. In addition to podiatric treatment and the custom fabrication of orthoses, a unique feature offered by the practice is access to its in-house cryotherapy chamber (Kältekammer Memmingen). Those who wish to view the facilities will find further information on the [/en/practice] page.

Should you have questions about pressure points, require professional callus removal, or wish to have your footwear analysed, you can arrange an appointment directly via [/en/contact] at any time.