Conservative vs. Arthroscopic Treatment for Meniscal Tears: A 5-Year Follow-up RCT Study

Meniscal injury is one of the most clinically significant sports injuries among endurance and competitive athletes, with the pathology primarily located in the knee joint. Epidemiological studies indicate that the incidence of such injuries in the active athletic population cannot be underestimated and is closely related to training load, biomechanical alignment, and individual recovery capacity. According to integrated data from the BJSM and AJSM over the past decade, overuse injuries account for approximately 60% to 70% of endurance sports injuries, with meniscal injury being a recurring representative. Research points out that there are significant differences in incidence based on gender, age, and specific sports, highlighting the importance of individualized assessment.

In Taiwan, with the flourishing of general fitness culture and the growth of marathons, cycling, and triathlon events, the number of outpatient visits for meniscal injuries has been rising year by year. Athletes in urban areas often engage in high-frequency training on hard surfaces, and combined with the premature fatigue and insufficient recovery caused by the subtropical hot and humid climate, repetitive loading of the knee joint has become a critical issue in local sports medicine. This article will provide an in-depth analysis of injury mechanisms, diagnostic assessment, treatment comparisons, progressive rehabilitation, and prevention strategies, as well as local applications in Taiwan, integrating the latest academic evidence to help readers establish a scientific understanding.

Analysis of Injury Mechanisms

The core pathological mechanism of meniscal injury can be summarized as “degenerative horizontal tearing and mechanical locking.” From a biomechanical perspective, the knee joint bears repetitive and high-peak mechanical loads during exercise. When the intensity of a single load or the cumulative load exceeds the tissue’s repair capacity, micro-injuries gradually accumulate, eventually surpassing the tissue’s tolerance threshold to form clinically visible injuries. This “load-capacity imbalance” model has become the core framework for modern sports medicine to understand overuse injuries.

A study by Sihvonen R et al. (2013) in the NEJM revealed through imaging and biomechanical analysis that an imbalance in any link of the kinetic chain will alter the force distribution of the knee joint. Insufficient proximal control (such as poor hip or trunk stability) or abnormal distal alignment (such as excessive foot pronation) can transmit mechanical forces, causing the target tissue to endure non-physiological shear and compressive stress. This concept of “misalignment linkage” emphasizes that pain in a single site is often the terminal manifestation of dysfunction in the entire kinetic chain.

At the anatomical and tissue level, Katz JN et al. (2013) in the NEJM further pointed out that repetitive loading induces the release of local inflammatory mediators, disorganization of collagen fibers, and, in the chronic phase, the co-ingrowth of blood vessels and nerves (neovascularization), which explains why chronic lesions are characterized by pain rather than typical inflammatory manifestations. Histological studies show that the essence of chronic overuse lesions is “degeneration” rather than simple “inflammation,” a shift in concept that directly impacts treatment strategies—moving from anti-inflammation to progressive loading to promote tissue remodeling.

The role of neuromuscular control cannot be ignored. Thorlund JB et al. (2015) in the BMJ confirmed through electromyography and motion analysis that injured individuals often exhibit altered muscle activation timing, increased antagonist co-contraction, and delayed proprioceptive feedback. These neuromuscular maladaptations lead to decreased dynamic stability during exercise, forming a vicious cycle of “injury—control deterioration—re-injury.” Furthermore, fatigue amplifies the aforementioned deficits: when muscles are fatigued, the ability to absorb shock decreases, and the load is forced onto passive structures (bones, ligaments, tendon attachments), accelerating the accumulation of micro-injuries.

In summary, meniscal injury is not a single-factor disease, but the result of the interaction of multiple factors: “training load, biomechanical alignment, neuromuscular control, tissue repair capacity, and psychosocial stress.” Understanding this multi-factor model is a prerequisite for subsequent precise diagnosis and effective intervention.

Diagnostic and Assessment Methods

The diagnosis of meniscal injury should be based on the triangulation of a complete medical history, systematic physical examination, and appropriate imaging evidence. History taking must clarify the timing of pain onset, its relationship with training load, aggravating and relieving factors, and previous injury history. Typical overuse injuries often present a “progressive, activity-related” pain pattern, while sudden, severe pain requires vigilance for the possibility of acute structural damage or stress fractures.

Regarding physical examination, clinicians should perform local palpation to locate tender points, assess joint range of motion, muscle strength, and flexibility, and execute targeted provocation tests to reproduce symptoms. Dynamic assessments such as single-leg squats, jump landings, and running gait analysis can reveal dynamic alignment abnormalities (such as dynamic valgus or pelvic drop) that are difficult to detect during static examinations. Both Sihvonen R et al. (2013) in the NEJM and Beaufils P & Pujol N (2017) in Orthop Traumatol Surg Res emphasize that the diagnostic validity of a single test is limited; multiple tests must be combined with functional performance to improve diagnostic accuracy and reduce misdiagnosis rates.

The choice of imaging tools should be based on clinical questions to avoid over-examination. The following table summarizes the characteristics of common imaging and examination tools:

Imaging/Examination Tool	Primary Use	Sensitivity Profile	Clinical Notes
Plain X-ray	Exclude fractures, calcification, and bony structural abnormalities	Low for early soft tissue lesions	Preferred initial screening, low cost
Ultrasound (US)	Real-time assessment of meniscal injury, tendons, and soft tissues; can perform dynamic tests	High for superficial lesions	Depends on operator experience, can guide injections
Magnetic Resonance Imaging (MRI)	Assess soft tissue, bone marrow edema, and occult lesions	High for both bone and soft tissue	High cost, gold standard for difficult cases
Bone scan	Detect bone metabolic activity, early bone reaction	Sensitive to bone reaction, low specificity	Gradually being replaced by MRI

When interpreting images, one must keep in mind the “clinical-imaging correlation principle”: abnormal signals on images are not necessarily the source of symptoms, and tendon degeneration or cartilage changes are also common in asymptomatic populations. Katz JN et al. (2013) in the NEJM remind us that over-reliance on imaging can lead to unnecessary interventions and patient anxiety. Therefore, the ultimate goal of assessment is not merely to name the lesion, but to identify the correctable sources of load and functional deficits, and based on this, formulate an individualized treatment and rehabilitation plan. Grading systems (such as those based on symptom severity or imaging stages) are helpful for prognosis and planning the return-to-sport timeline.

Comparison of Treatment Options

Treatment for meniscal injuries should follow the stepwise principle of “conservative first, then invasive.” First-line treatment focuses on exercise therapy, supplemented by pain management and activity modification; invasive treatments are reserved for cases where conservative treatment fails or where there is clear structural damage. Recent high-quality RCTs consistently support progressive load exercise as the most effective intervention for most overuse injuries. A systematic review by Sihvonen R et al. (2013) in NEJM showed that exercise programs based on functional, progressive loading are superior to passive treatment in improving pain and function, with effects that are sustained long-term.

The table below compares the mechanisms, evidence levels, and timing of application for major treatment options:

Treatment Option	Mechanism of Action	Evidence Level	Timing of Application
Exercise Therapy (Progressive Loading)	Promote tissue adaptation, restore strength and control	High (supported by multiple RCTs)	First choice for all stages, long-term mainstay
Manual Therapy	Short-term pain relief, improve joint range of motion	Moderate	Adjunct in acute phase
Extracorporeal Shockwave Therapy (ESWT)	Mechanical transduction promotes vascular and cellular repair	Moderate	Chronic stubborn lesions
Injection Therapy (PRP/Corticosteroids)	Growth factors or anti-inflammatory	Low to moderate, highly controversial	Use with caution after conservative failure
Surgery	Repair or decompress structural lesions	Depends on lesion	Ineffective after 3–6 months of conservative treatment or structural damage

Regarding injection therapy, Thorlund JB et al. (2015) in BMJ and related meta-analyses present conflicting results: while corticosteroid injections can provide short-term pain relief, they may be detrimental to tissue healing in the medium to long term and even increase recurrence; evidence for Platelet-Rich Plasma (PRP) is highly heterogeneous, with some studies showing benefits for specific tendon pathologies, but overall efficacy still awaits confirmation from more rigorous trials. Extracorporeal Shockwave Therapy (ESWT) shows moderate evidence for chronic stubborn lesions and can be an option when conservative treatment stalls.

Surgery is only appropriate for clear structural damage (such as complete tears or unstable osteochondral lesions) or those ineffective with long-term conservative treatment. Beaufils P & Pujol N (2017) in Orthop Traumatol Surg Res pointed out that even for lesions traditionally inclined toward surgery, an increasing number of long-term follow-up studies show that structured conservative treatment can achieve functional results comparable to surgery, while avoiding surgical risks. Therefore, shared decision-making is particularly important in treatment selection, requiring comprehensive consideration of exercise needs, timeline, and personal preferences.

Progressive Rehabilitation Program

Rehabilitation for meniscal injuries should be centered on the principle of “progressive loading under pain monitoring.” Clinically, a 0–10 pain numerical rating scale is often used, allowing exercise where pain during and within 24 hours after exercise does not exceed 3/10, and morning stiffness does not worsen, serving as indicators for safe progression. Rehabilitation is typically divided into four stages, and advancement to the next stage requires meeting clear exit criteria (criteria-based progression) rather than relying solely on time.

The following is the staged rehabilitation framework:

Stage	Goal	Representative Interventions	Advancement Criteria
Stage 1: Pain Control and Protection	Reduce stimulation, maintain basic range of motion	Relative rest, isometric contraction, activity modification	No significant pain in daily activities
Stage 2: Restore Strength and Range of Motion	Rebuild strength, endurance, and joint control	Progressive resistance training, eccentric training, proximal strengthening	Affected side strength reaches >80% of the healthy side
Stage 3: Functional and Sport-Specific Strengthening	Restore power, bounce, and movement quality	Plyometric training, single-leg stability, running gait re-education	Good symmetry in functional tests, no pain
Stage 4: Return to Play and Injury Prevention	Gradually return to sport-specific training volume	Progressive return to running/cycling volume, load monitoring	Pass return-to-play tests, load is tolerable

Stage 1 emphasizes “relative rest” rather than complete immobility—complete inactivity accelerates muscle atrophy and tissue de-adaptation. Isometric contraction has been proven to provide immediate pain relief and maintain strength in many tendon pathologies. Stage 2 introduces progressive resistance and eccentric training to promote collagen remodeling and strengthen the tendon-muscle unit. Stage 3 adds plyometric and sport-specific movements to rebuild tissue tolerance to high-speed, high-impact loads. Stage 4 ensures a smooth return process through quantified load monitoring (such as weekly training volume changes, acute-to-chronic load ratio), avoiding recurrence due to rushing. The entire process should be individualized, and effectiveness should be tracked regularly with objective indicators (strength, jump tests, movement quality).

Prevention Training Strategies

The key to preventing meniscal injuries lies in two pillars: “managing training load” and “strengthening biomechanical resilience.” In terms of training load management, avoiding sudden increases in weekly training volume is the primary principle. Studies generally recommend that weekly training volume increases should not exceed about 10%, and the Acute-to-Chronic Workload Ratio (ACWR) can be maintained within a relatively safe range, balancing adaptation and risk control. Overtraining and insufficient recovery weaken tissue repair capacity, which is a common upstream factor for many overuse injuries.

Building biomechanical resilience requires targeting the entire kinetic chain. The following are specific, evidence-based prevention action directions:

1. Proximal Stability Strengthening: Strengthen hip abductors, hip extensors, and trunk core muscles to improve dynamic alignment and reduce compensatory loads, which is a common foundation for preventing lower limb overuse injuries.
2. Eccentric and Progressive Resistance Training: Eccentric loading has been proven to improve tendon and muscle tolerance, especially effective in preventing muscle and tendon pathologies.
3. Movement Quality Re-education: Improve running gait (such as moderately increasing cadence, avoiding excessive stride length) and cycling posture (reasonable saddle and handlebar configuration) to reduce peak load per stride.
4. Flexibility and Mobility Maintenance: Perform dynamic stretching and mobility training for tight key muscle groups to ensure smooth mechanical transmission.
5. Progressive Adaptation and Periodization: Schedule training with periodization, interspersing reduction weeks to allow tissues sufficient time for repair and supercompensation.

It is worth emphasizing that prevention programs need adherence to be effective. Integrating prevention movements into daily warm-ups or strength routines and presenting them in a simple, executable form is a practical key to improving long-term implementation rates. Coaches and athletes should cultivate a culture of “listening to body signals,” treating minor discomfort as an early warning sign for adjusting training rather than ignoring or pushing through.

Local Application in Taiwan

Taiwan’s geography, climate, and racing environment have unique impacts on the occurrence and management of meniscal injuries. In terms of climate, Taiwan’s summer is characterized by high temperatures and humidity; core body temperature rises quickly during exercise, dehydration risk is high, and fatigue leads to early decline in neuromuscular control, indirectly increasing the risk of knee joint injuries. Local exercisers are advised to train in the early morning or evening, pay attention to hydration and electrolytes, and actively reduce training intensity and volume on hot days.

In terms of venues, urban exercisers often train on riverside bike lanes, PU tracks, and hard asphalt surfaces. One-way oval tracks can cause uneven unilateral loads; alternating directions is recommended. Long-term training on hard surfaces should be paired with appropriate footwear and gradually accumulated mileage. Taiwan’s mountainous terrain (such as Yangmingshan, Wuling, Northern Cross-Island Highway) provides rich uphill and downhill training opportunities, but long downhill sections impose extremely high eccentric loads on joints and tendons, requiring gradual progression and strengthened eccentric tolerance.

In terms of racing, Taiwan has a dense schedule of marathons, cycling events (such as the Taiwan Cycling Mountain King Challenge), triathlons, and trail running events. Concentrated seasons often lead athletes to compress recovery in pursuit of results. It is recommended to plan with complete periodization to connect with target events, reducing volume before races and allowing sufficient recovery after races. On the medical side, injury identification and grading capabilities at race sites should be strengthened to intervene early and avoid minor injuries dragging into chronic conditions. Overall, combining international evidence with Taiwan’s climate, terrain, and racing rhythm is necessary to develop prevention and rehabilitation programs truly suitable for local athletes.

Debunking Common Myths

Myth 1: “You must rest completely until the pain is gone.” While complete rest may temporarily alleviate symptoms, it leads to muscle atrophy and tissue deconditioning, which actually prolongs recovery and increases the recurrence rate. The correct approach is “relative rest” combined with progressive loading monitored by pain levels, allowing the tissue to receive appropriate stimulation for remodeling within a tolerable range.

Myth 2: “An abnormal imaging result means the injury is severe and must be treated.” Numerous studies have shown that asymptomatic individuals often have imaging abnormalities; imaging results do not necessarily correlate with symptoms. Treatment decisions should be based primarily on clinical symptoms and functional deficits, rather than relying solely on imaging reports.

Myth 3: “Injections or anti-inflammatory medication can provide a permanent cure.” Medications and injections are mostly for symptom management and cannot replace exercise therapy that corrects loading and strengthens tissues. Over-reliance on passive treatments often leads to recurring issues.

Myth 4: “You only need to treat the painful area.” Overuse injuries are often the terminal manifestation of dysfunction throughout the entire kinetic chain. Treating only the symptoms without correcting the upstream sources of loading and control deficits makes recurrence likely. Comprehensive assessment and holistic intervention are the fundamental solutions.

Conclusion

Meniscal injury is a classic multifactorial sports injury. Its occurrence and recovery involve complex interactions between training load, biomechanical alignment, neuromuscular control, tissue repair capacity, and psychosocial factors. The evidence reviewed in this article consistently points to a core message: exercise therapy centered on progressive loading is the safest and most effective intervention for the vast majority of overuse injuries, while passive treatments and invasive procedures should be used cautiously and sparingly.

For athletes in Taiwan, integrating international evidence with local climate, terrain, and race schedules to establish long-term habits of “load management, biomechanical strengthening, and listening to body signals” is far more critical than trying to fix things only after an injury occurs. The best treatment for sports injuries is always prevention; once injured, following a scientific, phased, and objective-indicator-based rehabilitation program, and gradually returning to sport with the assistance of professionals, is the only way to truly achieve the goal of “returning to sport without re-injury.” May every friend who loves sports enjoy the pleasure of exercise for a long time, based on a deep understanding of their own body.

References

1. Sihvonen R et al. (2013). NEJM
2. Katz JN et al. (2013). NEJM
3. Thorlund JB et al. (2015). BMJ
4. Beaufils P & Pujol N (2017). Orthop Traumatol Surg Res

Related Reading

• Grading and Rehabilitation of Hip Flexor Strains: A Study on Tissue Repair via Ultrasound Assessment
• Injury Patterns Among Taiwanese Cyclists: A Prospective Epidemiological Study of 107 Athletes
• Injury Prevention Programs for Trail Running in Taiwan: A Comparative Study of Injury Rates Before and After Intervention
• Osteoarthritis and Endurance Sports: A Scientific Clarification on Whether Running Really Damages the Knees