1. Introduction:
The case study is centered on a 57-year-old female patient who sustained a Neer two-part fracture with an avulsion of the greater tuberosity and a dislocation of the right humeral head. This injury occurred following a fall on icy pavement. The case presents a practical example of managing limited shoulder motion due to structural changes in the periarticular tissues, utilizing a biomechanical approach based on modern concepts of joint mechanics. The treatment plan focuses on tension applied to restricted structures, challenging traditional joint mobilization theories, such as the concave-convex rule.
2. Clinical Background and Examination:
Six weeks post-injury, the patient reported restricted motion with pain at the end-ranges of passive movements, though there was no resting pain. Key findings during the initial physical therapy evaluation were:
- Passive range of motion (PROM) for flexion and abduction was limited to 80° and 60° respectively.
- Pain was localized to the anterolateral shoulder, without radiating distally.
- A firm capsular end-feel was present during all movements.
- Isometric testing revealed no pain and moderate resistance, indicating that muscle strength was not a primary limitation.
This clinical picture indicated a mechanical limitation, likely due to structural changes in the periarticular tissues following immobilization, as hypothesized by the therapists.
3. Biomechanical Considerations in Treatment:
The traditional concave-convex theory, which suggests that the humeral head slides in the opposite direction of limb movement, was challenged by the study’s authors. Research cited in the paper suggests that joint surface movements, especially in the shoulder, may be controlled more by the tension in the joint capsule and periarticular structures rather than simple geometric constraints.
Recent studies, such as those by Poppen and Walker (1976), demonstrated that the humeral head translates minimally during movement, contradicting the concave-convex rule. Instead of focusing on restoring translatory gliding, treatment should aim at applying tensile stress to restricted tissues. For example, anterior gliding, which increases tension in the anterior capsule, is more effective in improving shoulder motion than posterior gliding.
4. Treatment Strategy:
The treatment plan developed for the patient emphasized low-load prolonged stretching techniques rather than brief, high-force mobilizations. The rationale behind this approach lies in the understanding that prolonged tension is more likely to cause permanent tissue elongation and remodeling than short-term deformations caused by high-force mobilizations. The following were key components of the treatment:
- Moist Heat and Ultrasound: Moist heat was applied for 20 minutes, followed by continuous ultrasound aimed at the anterior shoulder. This helped increase tissue compliance, preparing the shoulder for more aggressive stretching techniques.
- Pendulum Exercises: A common exercise in early-stage rehabilitation, pendulum exercises allowed the patient to generate passive movement in the shoulder without significant muscle activation, promoting gentle tissue stretching.
- Manual Therapy: Initially, low-grade anterior and inferior gliding movements were used to reduce pain and gently stretch periarticular tissues. As the patient tolerated treatment, high-grade mobilization, focusing on end-range stretching, was introduced.
- Continuous Passive Motion (CPM): CPM was used to maintain end-range stress on the restricted tissues for extended periods. The goal was to maximize the time spent in the stretched position, promoting tissue remodeling.
- Home Exercise Program: The patient was taught home exercises, including pendulum exercises, overhead wand exercises, and ice therapy post-exercise. This allowed for more frequent stretching, which is crucial for long-term improvement in range of motion.
- Splinting: At 10 weeks post-injury, when improvement slowed, a custom static end-range abduction splint was introduced. The splint allowed prolonged stretching of the restricting tissues without requiring continuous therapist supervision.
5. Outcome:
The patient was treated over a period of 25 weeks, during which passive range of motion progressively improved. By the end of treatment, the patient achieved nearly full PROM, with flexion reaching 175°, abduction 170°, and lateral rotation 80°. The patient’s functional goals, including independence in activities such as dressing, hair care, and household tasks, were met without pain or discomfort.
- At 1-year and 5-year follow-ups, the patient reported no pain and had maintained full range of motion and function, demonstrating the long-term success of the biomechanically focused treatment plan.
6. Discussion:
This case highlights the importance of understanding biomechanical principles when treating joint motion limitations. The treatment focused on applying prolonged tensile stress to restricted periarticular tissues, which aligns with modern concepts of tissue remodeling. By challenging the traditional concave-convex rule and focusing on joint capsule tension rather than translatory movements, the clinicians were able to guide the patient to a successful recovery. This approach may be beneficial for other patients with limited range of motion due to periarticular structural changes.
7. Educational Insights:
For medical students and apprentices, this case study illustrates the importance of biomechanics in clinical decision-making. Understanding the role of tissue tension, capsular mechanics, and the limitations of traditional theories is crucial in developing effective treatment plans for musculoskeletal injuries. Moreover, the case demonstrates the value of prolonged, low-load stretching techniques and home-based rehabilitation in achieving long-term functional outcomes.
8. Conclusion:
The management of this case demonstrates the effectiveness of a biomechanical approach to treating limited shoulder motion, emphasizing the need for sustained tensile stress and patient involvement through home exercise programs and splinting. By moving beyond conventional mobilization theories, such as the concave-convex rule, clinicians can achieve better outcomes in similar cases involving structural limitations in joint mobility.