The aim of this prospective clinical trial study is to evaluate the clinical and radiological outcomes of treating non-union of the lateral malleolar ankle fractures by double compression screw fixation technique.

Fractures involving the lateral malleolar are among the most frequent injuries to the lower extremity, commonly occurring as part of ankle injuries due to twisting mechanisms, falls, or sports-related trauma . These fractures are typically treated effectively with conservative management in stable cases or operative fixation in unstable or displaced patterns. Internal fixation using plate and screw constructs remains the gold standard for displaced fractures, especially when associated with syndesmotic injury or disruption of the ankle mortise . Despite favorable outcomes, complications such as delayed union and nonunion, although relatively rare in the lateral malleolar fractures, can present significant management dilemmas. Non-union refers to the failure of a fracture to heal within an expected time frame and may be classified as hypertrophic (due to inadequate stability) ,atrophic (due to impaired biological activity), oligotrophic or septic non-union .

Risk factors contributing to non-union include inadequate fixation, poor vascularity, infection, smoking, diabetes, and patient non-compliance. When nonunion occurs at the lateral malleolar, it may result in persistent lateral ankle pain, instability, mechanical dysfunction, altered gait mechanics, and decreased quality of life .

The lateral malleolus plays a critical role in maintaining ankle stability and congruity. It serves as a lateral buttress, resisting talar shift and external rotation.

A non-united fibular fracture, especially in the distal third, can disrupt this alignment and compromise the overall biomechanics of the ankle joint . Therefore, surgical intervention is typically warranted in symptomatic non-unions to restore anatomical alignment, re-establish joint stability, and facilitate bony healing Various surgical options have been described for the treatment of lateral malleolar non-unions, including open reduction and internal fixation (ORIF) with plate constructs, bone grafting (autograft or allograft), intramedullary fixation, and, in some cases, external fixation. While plate fixation provides strong stability, it is associated with soft tissue irritation, increased surgical exposure, and potential wound complications, especially in the distal fibula where soft tissue coverage is limited .

In contrast, intramedullary or percutaneous fixation methods, such as the use of compression screws, offer a less invasive approach with reduced morbidity and satisfactory biomechanical outcomes in selected cases . The double compression screw technique provides rigid fixation with minimal hardware prominence and soft tissue disruption. By achieving interfragmentary compression along the fracture line, this method enhances stability and promotes biological healing, making it a suitable option for treating select cases of fibular non-union, particularly in non-comminuted fractures and in patients where soft tissue preservation is essential .

The purpose of this study will be to evaluate the clinical and radiological outcomes of treating non-union of the lateral malleolar fracture by double compression screw fixation technique.

Inclusion Criteria:

1. Age from 18 to 65 years.
2. Both sexes.
3. Transvers, non-united Weber type A Lateral Malleolar ankle fracture classification
4. Non-union classified as atrophic, oligotrophic, or hypertrophic
5. Radiologically confirmed non-union of distal fibular fracture (failure to unite after ≥ 6 months post-injury).
6. Adequate bone stock on radiographs/CT suitable for screw fixation.

Exclusion Criteria:

1. Active or previous osteomyelitis or local infection at the fracture site.
2. Pathological fractures.
3. Non-union with gross deformity or significant bone loss requiring complex reconstruction or bone transport