12.3 High-Demand Sports Conditions: ACL, Meniscus, and Shoulder Instability
Key Takeaways
A pop, rapid swelling and giving way after a cutting or landing injury raise suspicion of ACL injury. Interpret Lachman, anterior drawer and pivot shift findings with the mechanism and examination.
After ACL reconstruction, graft remodeling continues as pain and motion improve. Progress running and cutting from clinical and functional milestones and the operative plan.
Early ACL rehabilitation includes restoration of motion and quadriceps activation. Closed-chain exercise and appropriately dosed open-chain exercise can both be used.
After meniscectomy, weight bearing and motion usually advance as tolerated. After repair, the tear pattern and surgical instructions determine early loading and range restrictions.
Anterior shoulder apprehension relieved by a posteriorly directed relocation force supports anterior instability. Bankart and Hill–Sachs lesions are distinct consequences of anterior dislocation.
High-Demand Sports Conditions: ACL, Meniscus, and Shoulder Instability
After an athletic knee or shoulder injury, use the mechanism and examination to distinguish the likely injured structures. Rehabilitation decisions after surgery depend on the procedure, the tissue being protected and the athlete's response to increasing load.
Anterior Cruciate Ligament (ACL) Injuries
The ACL is a primary restraint to anterior translation of the tibia relative to the femur and also contributes to rotational stability. Its anteromedial and posterolateral bundles are named for their tibial attachments. The anteromedial bundle has greater relative tension in flexion, while the posterolateral bundle contributes more near extension. Both participate in restraint.
Injury mechanism and clinical presentation
An ACL injury can follow a direct force or occur during a sudden deceleration, landing or change of direction. The knee may be relatively extended at contact and then experience combined valgus and rotational loading. The exact sequence varies. A pop, rapid swelling or giving way and inability to continue are clues, but rapid effusion also occurs with other intra-articular injuries.
Diagnostic tests
| Test | Technique and finding | Interpretation |
|---|---|---|
| Lachman | At about 20–30 degrees of flexion, stabilize the femur and translate the tibia anteriorly. Compare translation and endpoint with the other side. | Greater translation with a soft endpoint increases suspicion of ACL injury. Pain and guarding can limit assessment. |
| Anterior drawer | At about 90 degrees of flexion with the foot stabilized, draw the tibia anteriorly. | Increased anterior translation can support ACL injury. Acute guarding and the starting position can affect the result. |
| Pivot shift | With the knee near extension, apply a controlled valgus and internal rotation load while flexing the knee. A palpable shift as the lateral tibial plateau reduces is positive. | Reproduction of a rotatory shift supports functional ACL deficiency. An awake patient may guard, so a negative test cannot exclude a tear. |
For example, rapid effusion after a non-contact cutting injury plus a soft Lachman endpoint supports referral for evaluation of ACL and associated injuries. A negative pivot shift in an acutely painful knee does not override the history and other findings.
ACL Surgical Reconstruction: Graft Options and Biological Ligamentization
Reconstruction can be considered for recurrent instability or when the athlete plans to return to activities with substantial pivoting demands. The decision also considers concomitant injuries, goals and response to rehabilitation. The American Academy of Orthopaedic Surgeons recommends considering autograft over allograft, particularly in young or active patients.
| Graft | Tissue source | Rehabilitation considerations |
|---|---|---|
| Bone–patellar tendon–bone (BPTB) autograft | Central patellar tendon with patellar and tibial bone blocks. | Bone-to-bone integration within the tunnels. Monitor anterior knee symptoms and kneeling discomfort. |
| Hamstring tendon autograft | Usually semitendinosus, with or without gracilis. | Soft tissue incorporates at the bone tunnels. Assess and restore knee-flexor strength. |
| Quadriceps tendon autograft | Quadriceps tendon, with or without a patellar bone block. | Monitor quadriceps strength and recovery at the donor site. |
| Allograft | Donor tendon. | Avoids a tendon harvest from the patient. Account for higher failure risk in young or highly active patients when discussing selection. |
Graft remodeling and early rehabilitation
Ligamentization describes changes as the graft becomes incorporated and remodels. Human biopsy studies show vascular and cellular changes followed by prolonged matrix remodeling. A comfortable knee with full motion can still have a graft that is maturing. A calendar estimate or biopsy stage cannot specify the load a particular graft will tolerate.
- Early priorities: Restore knee extension toward the individual's baseline, manage pain and effusion, recover quadriceps activation and normalize gait within the surgeon's restrictions. Compare extension with the other side where appropriate. Persistent loss of extension warrants reassessment.
- Quadriceps activation: Effusion and pain can contribute to arthrogenic muscle inhibition. Use active exercise and consider neuromuscular electrical stimulation as an early adjunct when activation is limited.
- Strength progression: Both closed and open kinetic chain exercises have a role. A supported mini-squat or leg press can train functional loading. Loaded open-chain extension near terminal range can place more demand on the graft. For isolated ACL reconstruction, the Aspetar guideline allows limited-range open-chain quadriceps work from around week 4, for example 90 to 45 degrees of knee flexion, while monitoring anterior knee symptoms and following procedure-specific restrictions.
- Return to cutting: First establish a foundation of motion, load tolerance, strength and movement control. Progress from appropriate running and planned tasks toward higher-speed and reactive changes of direction when the clinical and functional criteria are met.
Meniscal Pathology: Biomechanics, Zones, and Surgical Rehabilitation
The menisci help distribute load and contribute to joint stability. Their circumferential fibers transmit compressive joint loads as hoop tension. A root or complete radial tear can disrupt that load transfer.
Meniscal vascular zones and examination
The peripheral meniscus has more direct blood supply than the inner portion. The red–red, red–white and white–white labels describe progression from the vascular periphery through the transition zone toward the inner relatively avascular region. Peripheral longitudinal tears may be amenable to repair, but treatment also depends on tear pattern, tissue quality, symptoms and associated injuries.
- Joint-line tenderness: Compare tenderness along the medial and lateral joint lines and interpret it with the injury history.
- McMurray test: With the knee flexed, use controlled tibial rotation while extending the knee. External tibial rotation biases the medial meniscus and internal rotation the lateral meniscus. A painful or palpable joint-line click can support suspicion.
- Thessaly test: When safe to bear weight, the patient rotates over a slightly flexed knee with support. Joint-line pain or catching can be informative. Acute pain or instability may preclude testing.
No isolated test reliably confirms a meniscal tear in every setting. Consider a referral for a knee that remains locked or cannot regain extension after trauma.
Rehabilitation after meniscal surgery
| Procedure | Typical early approach | Progression considerations |
|---|---|---|
| Partial meniscectomy | Weight bearing and range of motion as tolerated in the absence of additional restrictions. Crutches can assist until gait normalizes. | Progress based on effusion, motion, strength and functional control. |
| Meniscal repair | Follow the repair-specific loading and range limits. A stable vertical repair may permit early full weight bearing. Complete radial and root repairs commonly require more protection, including restricted weight bearing and flexion. | Combine healing time with clinical milestones. Review the operative instructions before progressing flexion under load or pivoting. |
For example, early weight-bearing advice after an isolated meniscectomy cannot be carried over to a root repair. Obtain the actual tear pattern and operative restrictions before prescribing squats or increasing weight bearing.
Glenohumeral Shoulder Instability & Labral Pathology
The glenohumeral joint relies on the capsule, labrum and dynamic muscular control for stability. A traumatic anterior dislocation can occur when the arm is forced into abduction and external rotation. An acute unreduced dislocation requires urgent medical care and neurovascular assessment. Provocation tests belong to a later examination when safe.
Classic structural lesions
- Bankart lesion: Detachment of the anteroinferior labrum from the glenoid. A bony Bankart includes a fracture of the adjacent glenoid rim.
- Hill–Sachs lesion: An impaction defect on the posterolateral humeral head from contact with the anterior glenoid rim. Its size and interaction with glenoid bone loss can contribute to recurrent instability.
Instability examination
- Anterior apprehension test: With the shoulder abducted to about 90 degrees and the elbow flexed, slowly externally rotate to assess whether the patient feels that the shoulder may dislocate. Stop when apprehension is elicited.
- Relocation test: A controlled posterior force on the humeral head in the apprehensive position can relieve that sense of impending dislocation. Relief of apprehension is more informative for instability than relief of pain alone.
- Release or surprise test: Removing the stabilizing force can reproduce apprehension. This maneuver can provoke instability and is reserved for appropriate clinical settings. Interpret it with history and the rest of the examination.
SLAP lesions
A superior labrum anterior-to-posterior (SLAP) lesion involves the superior labrum near the long-head biceps anchor. Mechanisms include traction or compression, such as a fall on the outstretched hand, and repetitive overhead loading.
In the active compression test (O'Brien), position the arm at about 90 degrees of forward flexion with the elbow extended and slight horizontal adduction. Compare symptoms when resisting downward pressure with the arm internally rotated and when repeating with the palm up. Record whether the patient feels pain deep in the shoulder or at the acromioclavicular joint. In Biceps Load II, resisted elbow flexion is assessed with the shoulder abducted to about 120 degrees and externally rotated. Increased pain can support suspicion of superior labral pathology. An isolated result on either maneuver is insufficient to establish a SLAP tear.
Eight weeks after isolated ACL reconstruction with a bone–patellar tendon–bone graft, a soccer player has full motion and little pain and asks to start high-speed cutting. What is the best response?
Begin high-speed cutting because full motion establishes graft maturity
Use a single pain-free quadriceps extension as clearance for cutting
Continue staged rehabilitation and assess readiness for running and then cutting using healing considerations, strength, movement control and load tolerance
Obtain a routine MRI and base clearance on the graft signal alone
One basketball player had an isolated partial meniscectomy. Another had a meniscal root repair. Which principle should guide their early weight-bearing and range-of-motion plans?
Both should follow the same unrestricted loading plan when pain subsides
The meniscectomy requires longer weight-bearing restrictions than the root repair because some tissue was removed
Assign both athletes the same 90-degree flexion limit based on the location of their joint-line pain
Advance weight bearing and motion as tolerated after uncomplicated meniscectomy, and follow the root repair’s protected loading and flexion instructions
After recovery from the acute phase of a shoulder dislocation, external rotation at about 90 degrees of abduction reproduces the athlete’s fear that the shoulder will slip out. A posterior force on the humeral head relieves the apprehension. Which tests were performed?
Anterior apprehension followed by relocation
Active compression followed by Biceps Load II
Neer followed by Hawkins–Kennedy
Sulcus sign followed by Speed’s test
Four weeks after an isolated ACL reconstruction, the surgeon permits progressive quadriceps loading. Which exercise plan fits the Aspetar approach when pain and swelling are monitored?
Begin maximal resistance through the last 30 degrees of open-chain knee extension
Use appropriate closed-chain exercise and consider controlled open-chain extension from 90 to 45 degrees of knee flexion
Defer all quadriceps strengthening until the athlete can run
Use high box-drop landings as the first quadriceps strengthening exercise
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