Evaluation and Management of Painless Hard Lump Over Triceps After Fall
This older adult likely has a triceps tendon rupture and requires urgent imaging with plain radiographs first, followed by MRI or ultrasound to confirm the diagnosis and guide surgical planning.
Initial Clinical Assessment
The presentation of a painless hard lump with bruising over the triceps after trauma is highly suspicious for triceps tendon rupture, even in the absence of pain. Key clinical findings to assess include:
- Palpable gap in the triceps tendon (the "hard lump" may represent retracted tendon or hematoma)
- Weakness or inability to extend the elbow against resistance
- Ecchymosis (bruising) over the posterior arm/elbow
- Swelling around the posterior elbow
The absence of pain does not exclude significant injury and may reflect the patient's pain threshold or the nature of the injury.
Imaging Algorithm
Step 1: Plain Radiographs (Initial Study)
Start with plain radiographs of the elbow 1. Look specifically for:
- "Flake sign" - a small avulsion fracture fragment proximal to the olecranon tip, which is pathognomonic for triceps tendon rupture 2, 3
- Posterior and anterior fat pad elevation indicating joint effusion
- Olecranon avulsion fractures or enthesophytes
Radiographs are beneficial as the initial imaging assessment and can identify associated fractures or the characteristic flake sign that confirms triceps injury 1.
Step 2: Advanced Imaging for Soft Tissue Evaluation
If radiographs are normal or indeterminate but clinical suspicion remains high:
MRI without contrast is the gold standard 1. MRI provides:
- Superior accuracy in identifying complete versus partial tears (76% sensitivity, 50% specificity for biceps/triceps pathology)
- Assessment of which triceps heads are involved (lateral, long, or medial)
- Detection of associated ligamentous injuries, particularly medial ulnar collateral ligament damage 1, 4
Ultrasound is an acceptable alternative 1 and can identify both complete and partial triceps tears. However, it is operator-dependent and has limitations in detecting partial tears compared to MRI.
Mechanism-Specific Considerations
The mechanism of injury matters for predicting associated injuries 1:
- Fall on outstretched hand (indirect injury): Most likely causes injury to the lateral and long heads of the triceps with intact medial head. This mechanism has a high association with ligamentous injuries (odds ratio 0.13 for associated ligament damage) 4
- Direct blow to triceps: More likely to cause full-thickness rupture (odds ratio 1.75) involving all three heads
Given this patient fell and hit her arm, assess for concomitant medial ulnar collateral ligament injury and radial head/neck pathology 4.
Management Pathway
Acute complete triceps ruptures require surgical repair 5, 2, 6:
- Early intervention within 3 days to 2 weeks is critical for optimal outcomes 2, 6
- Primary repair restores normal extensor function after 3-4 months 6
- Delayed diagnosis leads to prolonged disability and poor outcomes 5
Partial tears may be managed conservatively with immobilization in 30-degree flexion for 4-6 weeks, but should be repaired if conservative management fails 6.
Critical Pitfalls to Avoid
- Do not dismiss the injury due to lack of pain - triceps ruptures can present with minimal pain but cause substantial disability if untreated 5
- Do not miss the flake sign on radiographs - this subtle finding confirms the diagnosis 2, 3
- Do not delay imaging - early diagnosis within days is essential for surgical planning 2
- Do not forget to assess for associated injuries - particularly medial collateral ligament damage in falls on outstretched hand 4
Immediate Action
Refer urgently to orthopedic surgery if imaging confirms triceps rupture. The patient should be immobilized in a posterior splint at 30-40 degrees of flexion pending surgical evaluation. Surgical repair should ideally occur within the first week to optimize functional recovery 2, 6.