What are the differences in healing approaches for bone vs tendon injuries?

Bone vs Tendon Healing: Key Differences in Treatment Approaches

Critical Distinction in Pathophysiology

Bone and tendon injuries require fundamentally different healing approaches because bone heals through inflammatory-mediated regeneration while most chronic tendon injuries are degenerative conditions (tendinosis), not inflammatory processes, requiring load-based rehabilitation rather than anti-inflammatory treatment. 1

Bone Healing Characteristics

• Bone healing occurs through a predictable inflammatory cascade leading to callus formation and remodeling
• Immobilization is often beneficial during initial healing phases to maintain fracture alignment
• Healing typically follows a defined timeline with radiographic evidence of union

Tendon Healing Characteristics

• Most symptomatic tendon problems seen in primary care are chronic degenerative conditions (tendinosis), not acute inflammatory injuries (tendinitis), representing failed healing responses rather than active inflammation 1
• Tendon injuries involve collagen degeneration and failed chronic healing responses associated with both overloaded and unloaded states 2
• Complete immobilization is contraindicated as it leads to muscle atrophy, deconditioning, and impaired healing 3

Treatment Algorithm Differences

For Acute Tendon Ruptures (e.g., Achilles)

Both surgical and nonsurgical treatment are viable options for acute tendon ruptures, with the choice depending on patient factors rather than clear outcome superiority. 1

Surgical approach:

• Open, limited open, or percutaneous techniques are all acceptable options 1
• Early mobilization (before 2 weeks postoperatively) combined with active rehabilitation produces good functional outcomes 4
• Surgical repair shows significantly fewer reruptures compared to conservative treatment 1
• Minor complications are more common with surgery due to the surgical intervention itself 1

Conservative approach:

• Nonsurgical treatment is a reasonable option for acute ruptures 1
• Recent evidence suggests non-inferiority of conservative treatment compared to surgery for clinical outcomes 5
• Functional bracing evidence is inconclusive, preventing firm recommendations 1
• Reserve for patients with high surgical morbidity/mortality risk 4

For Chronic Tendinopathy (Degenerative Tendon Conditions)

The cornerstone of chronic tendinopathy treatment is eccentric strengthening exercises combined with relative rest, not anti-inflammatory medications, because these are degenerative rather than inflammatory conditions. 1, 6, 3

First-line conservative management (80% recovery rate within 3-6 months): 1, 3

• Relative rest: Reduce pain-provoking activities while maintaining activities that don't exacerbate symptoms 3
• Eccentric strengthening exercises: Highly effective and may reverse degenerative changes 6, 3, 2
• Cryotherapy: Apply melting ice water through wet towel for 10-minute periods for acute pain relief 6, 3
• Topical NSAIDs: Preferred over oral NSAIDs for fewer systemic side effects 6, 3

Advanced interventions if conservative fails:

• Deep transverse friction massage may reduce pain 6
• Combining eccentric loading with low-energy shock wave therapy produces higher success rates than either alone 2
• High-volume injection (saline, corticosteroids, or anesthetics) can reduce pain and improve function in Achilles or patellar tendinopathy 2
• Surgery reserved only for failures after 3-6 months of consistent conservative treatment 6, 3

Critical Pitfalls to Avoid

Misdiagnosing chronic tendinopathy as "tendinitis" (inflammatory) rather than "tendinosis" (degenerative) leads to inappropriate treatment focus on anti-inflammatory agents instead of load-based rehabilitation. 1, 6, 3

Key caveats:

• Corticosteroid injections provide acute pain relief but may inhibit healing, reduce tendon strength, and don't alter long-term outcomes—use cautiously 3
• Complete immobilization of tendons causes harm through atrophy and deconditioning 3
• Platelet-rich plasma, autologous blood, polidocanol, and corticosteroid injections lack strong clinical evidence despite widespread use 2
• Failure to address underlying biomechanical issues or technique problems (especially in athletes) leads to recurrence 6

Timeline Expectations

Tendon healing:

• 80% of patients with overuse tendinopathies recover within 3-6 months with conservative management 1, 6
• Post-surgical tendon repair: complete mobility by week 6, return to work/sports by weeks 8-10 4

Bone healing:

• Follows more predictable timelines based on fracture location and type
• Radiographic union typically precedes full functional recovery