Bunionectomy is a common orthopedic procedure performed to correct the painful misalignment of the big toe, known as a bunion or hallux valgus. The surgery often involves an osteotomy, a precise surgical cut made into the metatarsal bone to realign the joint into a corrected position. To ensure this newly aligned bone segment heals properly, surgeons stabilize the osteotomy site with internal fixation hardware. This fixation typically involves small metal screws or plates that hold the bone fragments together while they undergo the natural healing process. The hardware acts as temporary internal scaffolding, providing mechanical stability until the body creates a solid, unified bone bridge.
The Potential for Hardware Migration
Whether screws can move after a bunionectomy is yes, though it is an uncommon complication. The internal fixation hardware is designed to remain static and secure within the bone until the osteotomy site has completely fused. However, hardware failure can occur, including the screw loosening its grip, migrating from its original position, or, in rare cases, breaking. Migration refers to the screw backing out slightly or shifting its location, which compromises the stability of the surgical correction. When the hardware loses its secure hold, it can irritate surrounding soft tissues, causing new or persistent discomfort. Excessive forces or delays in bone healing can challenge its stability.
Factors That Cause Screw Loosening or Migration
One of the most frequent causes of hardware loosening is premature or excessive weight bearing before the bone fragments have adequately healed. Applying too much mechanical stress too early strains the fixation, causing the screw threads to lose their purchase within the bone. Patient non-compliance with post-operative instructions, such as failing to keep the foot elevated or not adhering to non-weight-bearing protocols, is a contributing factor.
Bone quality also plays a role in hardware stability. Insufficient bone density, such as that seen with osteoporosis, may not provide a strong enough grip for the screw threads. If the bone fragments fail to fuse together effectively (non-union or delayed healing), the screws remain under stress indefinitely. This prolonged mechanical load can eventually lead to fatigue or loosening. Additionally, a deep surgical site infection can compromise the integrity of the bone-screw interface, causing the surrounding bone tissue to break down and destabilize the fixation.
Recognizing Symptoms of Hardware Complications
Patients with hardware complications often experience distinct symptoms. A common sign is localized pain that is sharp, persistent, or begins to increase long after the initial surgical discomfort should have subsided. This may be caused by the screw irritating nearby tendons or soft tissues as it begins to migrate.
Inflammation or swelling localized directly over the surgical site that does not improve with rest and elevation is another symptom. If the screw has backed out, the patient may be able to feel the screw head as a hard bump just beneath the skin. Furthermore, some individuals report mechanical instability, a clicking sensation, or an altered gait due to the shifting hardware, which suggests the underlying bone alignment may be compromised. Any of these symptoms should be promptly reported to the operating surgeon.
Diagnosis and Treatment for Screw Movement
When hardware failure is suspected, the initial diagnostic step involves standard X-ray imaging of the foot. The X-ray allows the surgeon to visualize the screw’s position, confirm migration or loosening, and assess the degree of bone healing at the osteotomy site. Weight-bearing X-rays are sometimes necessary to see how the fixation responds to the mechanical load of standing.
If the bone has fully healed and fused but the hardware is causing irritation, the most common treatment is simple hardware removal. This minor procedure, often performed months after the initial surgery, typically offers a much faster and easier recovery than the original bunionectomy. If significant migration occurs before the bone has fully healed, or if the movement has compromised the alignment, a more involved revision surgery may be necessary. This procedure requires removing the unstable hardware, re-aligning the bone fragments, and re-fixing them with new hardware to ensure a successful long-term outcome.