If a bicep tendon tear is left untreated, other arm muscles can adapt to compensate for the injured tendon, usually allowing for full motion and reasonable function in many daily activities. However, a significant consequence is a permanent decrease in arm strength, particularly affecting specific movements.
Compensatory Function and Strength Loss
While the body's natural compensatory mechanisms allow other muscles in the arm to take over some of the bicep's functions, enabling a good range of motion and often adequate overall function for simple tasks, this adaptation does not fully restore original strength. The primary and most notable impact of an untreated bicep tendon tear is a 30 to 40% decrease in the strength of the injured arm. This strength reduction is most prominent when performing actions that involve twisting the forearm outwards, a movement known as supination.
Key Effects of an Untreated Bicep Tendon Tear
The table below summarizes the typical outcomes when a bicep tendon tear is not surgically repaired:
| Aspect | Outcome (Untreated) |
|---|---|
| Motion | Usually results in full range of motion |
| Overall Function | Generally reasonable for many common tasks |
| Strength Loss | A significant 30-40% decrease in strength |
| Primary Weakness | Most noticeable when twisting the forearm (supination) |
Practical Implications of Strength Reduction
The specific loss of strength in supination can make certain activities noticeably more challenging or less efficient. While general arm movement might seem unimpaired, tasks requiring a strong twisting force will be compromised.
Examples of activities that may be affected include:
- Opening jars or bottles with screw-on caps
- Using tools like screwdrivers that require twisting
- Turning doorknobs that are stiff or require significant force
- Lifting and pouring from heavy containers that necessitate forearm rotation
- Performing certain sports activities that rely on powerful forearm rotation, such as throwing or racquet sports.
In essence, while an untreated bicep tendon tear may not severely limit the arm's overall range of motion or basic function, it will consistently result in a noticeable and often frustrating reduction in specific arm strength, particularly for twisting movements.
