Solve 5 Real Sports Medicine Cases: Boost Your Diagnostic Skills

Patient Presentation & History

A 24-year-old semi-professional male football (soccer) player presented to the emergency department following a high-energy, non-contact injury during a match. He describes planting his right foot to change direction rapidly when an opposing player collided with his lateral knee, forcing it into a valgus and hyperextension moment, followed by an audible "pop." He experienced immediate, excruciating pain, gross deformity of the knee, and was unable to bear weight. Paramedics reported the knee was visibly dislocated on arrival at the field, which spontaneously reduced prior to transport. He denies any prior significant knee injuries. His medical history is unremarkable, with no known allergies or comorbidities. He is a non-smoker and denies recreational drug use. His primary concern is return to elite-level sport.

Clinical Examination

Upon arrival, the patient was hemodynamically stable, although in significant pain.
* Inspection: The right knee was significantly swollen with a moderate hemarthrosis, diffuse ecchymosis, and palpable tenderness circumferentially. No obvious skin tenting or open wounds were noted, indicating a closed knee dislocation. The limb was aligned, suggesting spontaneous reduction.
* Palpation: Diffuse tenderness was elicited around the medial and lateral joint lines, the popliteal fossa, and the patellar borders.
* Range of Motion (ROM): Active ROM was severely restricted due to pain and swelling, approximately 10-40 degrees. Passive ROM revealed a soft end-feel in both flexion and extension, with gross instability.
* Ligamentous Stability Testing (performed gently due to acute injury):
* Anterior Cruciate Ligament (ACL): Lachman test revealed a grade III anterior translation with no discernible end-point. Anterior drawer test was also grossly positive.
* Posterior Cruciate Ligament (PCL): Posterior sag sign was evident, and the posterior drawer test at 90 degrees of flexion demonstrated grade III posterior translation. The quadriceps active test also showed posterior translation that reduced with quadriceps contraction but remained unstable.
* Medial Collateral Ligament (MCL): Valgus stress testing at 0 and 30 degrees of flexion demonstrated grade III laxity (opening >10mm), indicating complete rupture of the superficial and potentially deep MCL.
* Lateral Collateral Ligament (LCL) / Posterolateral Corner (PLC): Varus stress testing at 0 and 30 degrees of flexion demonstrated grade III laxity. Dial test at 30 and 90 degrees showed increased external rotation (>15 degrees compared to contralateral side), confirming a significant PLC injury, involving at least the LCL, popliteofibular ligament, and arcuate complex.
* Combined Instabilities: Gross rotational instability was present in both internal and external rotation, consistent with combined ACL, PCL, MCL, and PLC disruption, highly suggestive of a multi-ligament knee injury (MLKI), specifically a knee dislocation (KD-IV).
* Neurological Assessment:
* Peroneal Nerve: Weakness in dorsiflexion and eversion of the foot (Grade 3/5) was noted. Sensory deficit was present in the first web space. This indicated a partial peroneal nerve palsy.
* Tibial Nerve: Intact motor function (plantarflexion, inversion) and sensation.
* Vascular Assessment: Distal pulses (dorsalis pedis, posterior tibial) were present but somewhat diminished compared to the contralateral limb, prompting immediate concern. Ankle-brachial index (ABI) was measured as 0.85 on the affected side. Capillary refill was 3 seconds. The limb was cool to touch. Given the history of spontaneous reduction, immediate comprehensive vascular assessment was critical.

Imaging & Diagnostics

Following the clinical assessment, a rapid diagnostic workup was initiated.

• Plain Radiographs (AP, Lateral, Oblique views of the knee):
  • Initial radiographs confirmed spontaneous reduction of the tibiofemoral joint.
  • No gross fractures were immediately apparent.
  • Subtle findings included widening of the medial and lateral joint spaces, consistent with ligamentous disruption.
  • A small avulsion fracture from the fibular head (Segond-like fracture, though medial in location, indicating capsular avulsion) was noted, suggesting significant collateral ligament and posterolateral corner involvement.
  • A possible fleck avulsion off the posterior aspect of the tibia was seen, suspicious for a PCL avulsion.
• Ankle-Brachial Index (ABI) and Duplex Ultrasonography:
  • The ABI of 0.85 was concerning for vascular compromise.
  • Emergency duplex ultrasound revealed flow abnormalities in the popliteal artery, with reduced peak systolic velocity and increased resistance distal to the knee joint, suggesting partial intimal injury or spasm. There was no complete occlusion.
• CT Angiography (CTA):
  • Performed urgently due to the abnormal ABI and duplex findings.
  • CTA confirmed an intimal tear of the popliteal artery, with a mural hematoma causing approximately 30% luminal narrowing but no complete thrombosis. The distal runoff was compromised but patent. This necessitated immediate vascular surgery consultation and close observation.
• Magnetic Resonance Imaging (MRI):
  • Performed after vascular stability was confirmed and the patient's pain was controlled.
  • ACL: Complete mid-substance rupture of the ACL, consistent with observed instability.
  • PCL: Complete avulsion of the PCL from its tibial insertion, with a small bony fragment (consistent with the fleck avulsion seen on X-ray).
  • MCL: Complete rupture of the superficial MCL at its femoral origin and deep MCL avulsion from the medial meniscus, extending to the posterior oblique ligament (POL).
  • PLC: Complete rupture of the fibular collateral ligament (FCL) from its femoral origin, avulsion of the popliteus tendon from the lateral femoral condyle, and injury to the arcuate ligament complex.
  • Menisci: A complex radial tear of the posterior horn of the medial meniscus, extending into the root attachment. The lateral meniscus appeared intact.
  • Chondral: Diffuse bone bruising was noted on the lateral femoral condyle and lateral tibial plateau, consistent with the valgus-hyperextension mechanism. A small full-thickness chondral defect (Grade IV) was identified on the lateral femoral condyle, approximately 8mm in diameter.
  • Nerve: Signal changes consistent with stretch injury to the common peroneal nerve were seen, correlating with clinical findings.

Differential Diagnosis

Given the presentation, several severe knee injuries could be considered in the initial differential, though the gross instability and multi-planar laxity strongly pointed towards a knee dislocation. Distinguishing features are critical for accurate diagnosis and management planning.

Surgical Decision Making & Classification

This patient presented with a Schenck KD-IV injury (ACL, PCL, MCL, PLC) with associated vascular injury (intimal tear of the popliteal artery) and partial common peroneal nerve palsy. The decision-making process was as follows:

1. Emergent Reduction & Vascular Assessment: The initial priority was prompt reduction of the knee (already spontaneously reduced) and immediate thorough assessment of the vascular status. The ABI <0.9 and CTA findings of an intimal tear mandated continuous vascular monitoring and consultation with vascular surgery. While immediate surgery for the knee ligaments was not indicated with a stable intimal tear, a watchful waiting period was instituted under close observation for evolving ischemia. The vascular surgeons decided against immediate intervention given the partial luminal compromise and stable distal flow, opting for serial ABIs and clinical checks, ready for intervention if conditions worsened.
2. Knee Dislocation Classification:
   • Schenck Classification: This patient fits a KD-IV (rupture of both ACL and PCL, and at least one collateral ligament and/or the posterolateral corner). Given the MRI findings, it was a complete KD-IV injury involving all four major ligament complexes.
   • Associated Injuries: Crucially, this was a KD-IV MCN V (M=medial, C=collateral, N=nerve, V=vascular). The presence of a peroneal nerve palsy and popliteal artery intimal tear significantly influenced management.
3. Timing of Ligament Reconstruction:
   • Given the acute neurovascular compromise and significant swelling, immediate multi-ligament reconstruction was contraindicated.
   • Staged Approach: The consensus was for a staged approach:
     • Stage 1 (Acute - 0-3 weeks): Focus on restoring knee stability, reducing swelling, and addressing acute repairable structures. The medial-sided structures (MCL and POL) and the posterolateral corner (PLC) were deemed acutely repairable. Open repair of these structures can often be performed successfully within 3 weeks of injury. This also allowed for continued neurovascular monitoring.
     • Stage 2 (Subacute/Chronic - 6-12 weeks): ACL and PCL reconstruction. Performing these reconstructions in a delayed fashion allows for resolution of swelling, improved soft tissue healing, better definition of anatomy, and reduced risk of arthrofibrosis. Graft choice was discussed: autografts (hamstring and quadriceps) were favored for the primary reconstructions in this young athlete.
4. Meniscal and Chondral Management: The radial tear of the medial meniscus posterior horn root was a critical finding. Given the age and activity level, a repair was indicated if feasible. The chondral defect required debridement and microfracture or an osteochondral autograft transfer system (OATS) if larger and symptomatic.

Surgical Technique / Intervention

The surgical intervention was performed in two stages.

Stage 1: Acute MCL/POL and PLC Repair (Day 7 Post-Injury)

Patient Positioning: Supine on a standard operating table, affected limb prepped and draped free to allow for full range of motion. A high thigh tourniquet was used. A lateral post was applied to the thigh to facilitate valgus stress and access to the medial compartment.

Arthroscopy (Diagnostic and Meniscal Repair):
1. Standard anteromedial and anterolateral portals were established.
2. Diagnostic arthroscopy confirmed the extent of ACL and PCL ruptures (not addressed in this stage).
3. The radial tear of the posterior horn medial meniscus root was identified. An all-inside technique using sutures (e.g., Fast-Fix or similar device) was used to repair the root tear, followed by compression sutures across the radial component. The integrity of the repair was checked.
4. The chondral defect on the lateral femoral condyle was debrided to stable margins. Due to its size (8mm) and location, and patient's athletic demands, a decision was made for a single-plug OATS procedure to be performed in conjunction with the cruciate reconstructions in Stage 2, allowing for a single graft harvest site. Microfracture was deferred.

Medial Repair (MCL/POL):
1. A longitudinal incision was made over the medial aspect of the knee, centered over the MCL.
2. Dissection was carried down to the superficial MCL. The superficial MCL was found avulsed from its femoral origin. A strong primary repair was performed using non-absorbable sutures (#2 FiberWire), reattaching the ligament to its anatomical footprint on the medial epicondyle using bone anchors.
3. The deep MCL and posterior oblique ligament (POL) were also found to be avulsed and were meticulously repaired using direct sutures.
4. The integrity of the repair was assessed by applying valgus stress under direct visualization, confirming stable medial-sided structures.

Posterolateral Corner (PLC) Repair:
1. A curvilinear incision was made over the lateral aspect of the knee, extending from the distal femur to the proximal fibula head.
2. Dissection was carefully performed to protect the common peroneal nerve, which was identified and retracted.
3. The fibular collateral ligament (FCL) was found avulsed from its femoral origin. The popliteus tendon was avulsed from its femoral attachment. The arcuate complex was also significantly disrupted.
4. A direct repair of the FCL was performed using bone anchors at its femoral origin. The popliteus tendon was also repaired to its femoral footprint using suture anchors. The arcuate complex was then repaired using strong non-absorbable sutures.
5. Varus stress testing and external rotation stress (Dial Test) were performed, confirming restoration of posterolateral stability.
6. Wound closure was performed in layers.

Stage 2: ACL and PCL Reconstruction with OATS (8 weeks Post-Injury)

Patient Positioning: Supine, affected limb prepped and draped free. High thigh tourniquet. A lateral post was used to facilitate valgus and varus stress.

Graft Harvest:
1. ACL Graft: A quadriceps tendon autograft (central one-third, with bone block) was harvested through a small incision just proximal to the patella. This offers a robust graft with good biomechanical properties.
2. PCL Graft: A contralateral hamstring tendon autograft (semitendinosus and gracilis) was harvested. Alternatively, an ipsilateral hamstring could be used if sufficient tissue was available, or an allograft could be considered, but autograft was preferred for this elite athlete.
3. OATS Graft: A single osteochondral plug was harvested from a less weight-bearing portion of the ipsilateral intercondylar notch or superior patella facet for the OATS procedure.

Arthroscopic ACL Reconstruction:
1. Standard anteromedial and anterolateral portals.
2. The ACL femoral tunnel was reamed via the anteromedial portal, aiming for an anatomical footprint.
3. The tibial tunnel was created via a transtibial approach, targeting the anatomical footprint.
4. The quadriceps tendon graft was passed through the tunnels.
5. Femoral fixation was achieved with a cortical suspension device (e.g., Endobutton).
6. Tibial fixation was achieved with a bioabsorbable interference screw.
7. The graft was tensioned at 30 degrees of flexion with an anterior drawer force.

Arthroscopic PCL Reconstruction:
1. Posteromedial and posterolateral portals were established for improved visualization and access to the posterior aspect of the tibia.
2. The PCL femoral tunnel was reamed anatomically from an outside-in approach.
3. For the tibial avulsion, the bony fragment and PCL stump were identified. A single tibial tunnel was created through the anteromedial tibia, aiming for the anatomical PCL insertion.
4. The hamstring graft was passed through the femoral tunnel, then across the joint to the tibial tunnel.
5. Femoral fixation was achieved with an interference screw.
6. Tibial fixation was secured with a cortical button on the anterior tibia, with the graft tensioned under posterior sag reduction at 90 degrees of flexion.

OATS Procedure:
1. The previously debrided chondral defect on the lateral femoral condyle was sized.
2. A recipient socket was prepared using a matching coring reamer.
3. The harvested osteochondral plug was precisely impacted into the recipient site, ensuring a flush articulation.

Final Assessment and Closure:
1. A thorough assessment of knee stability was performed after all reconstructions were complete. The knee demonstrated excellent stability in all planes.
2. All portals and incisions were closed in layers.
3. A hinged knee brace was applied with the knee locked in extension.

Post-Operative Protocol & Rehabilitation

Rehabilitation for a multi-ligament knee injury is protracted, aggressive, and highly individualized, typically lasting 12-18 months.

Phase 1: Protection and Early Motion (Weeks 0-6)
* Weight Bearing: Non-weight bearing for 4 weeks on the operated limb, followed by partial weight-bearing (25%) with crutches, progressing as tolerated. This is critical for MCL, PLC, and meniscal root repair healing. The OATS procedure also necessitates protected weight bearing.
* Bracing: A hinged knee brace locked in full extension for the first 2 weeks. Gradually unlocked to allow 0-90 degrees ROM by week 6. The brace is worn full-time, including sleep.
* ROM: Gentle passive ROM (CPM machine encouraged) 0-90 degrees. Avoid isolated hamstring activation for PCL (no resisted knee flexion past 70 degrees for 8-12 weeks). Avoid isolated quadriceps activation for ACL for 4-6 weeks (no open kinetic chain knee extension past 60 degrees). Gentle quadriceps sets and prone hangs for extension.
* Pain & Swelling Management: Ice, elevation, compression, NSAIDs.
* Peroneal Nerve: Continued observation, nerve gliding exercises, ankle-foot orthosis (AFO) if significant foot drop persists.

Phase 2: Progressive Strengthening and Controlled Mobility (Weeks 6-12)
* Weight Bearing: Progress to full weight-bearing with crutches discontinued.
* Bracing: Continue hinged brace, unlocking for increasing ROM (0-120 degrees by week 12).
* ROM: Achieve full passive extension and at least 130 degrees of flexion.
* Strengthening:
* Closed kinetic chain exercises (mini-squats, leg press, wall slides).
* Hip strengthening (abduction, adduction, extension).
* Core stability exercises.
* Isometric hamstring contractions in extension (protected PCL).
* Gentle open kinetic chain quadriceps (0-60 degrees) after 8 weeks.
* Proprioception: Begin balance board, single-leg stance.

Phase 3: Advanced Strengthening and Return to Activity (Months 3-6)
* Bracing: Discontinue brace for daily activities, use for higher-risk activities.
* Strengthening:
* Progressive resistance exercises for all major muscle groups.
* Initiate eccentric loading.
* Step-ups, lunges, agility drills.
* Cycling, elliptical trainer.
* Neuromuscular Control: Advanced balance and proprioception.
* Sport-Specific Drills: Begin light jogging, swimming. Avoid cutting, jumping, and contact sports.

Phase 4: Sport-Specific Training and Return to Sport (Months 6-12+)
* Functional Testing: Isokinetic strength testing, hop tests, agility tests (e.g., T-test, shuttle run).
* Sport-Specific Drills: Progressive plyometrics, cutting, pivoting, jumping. Gradually introduce controlled contact drills.
* Return to Sport Criteria:
* No pain, swelling, or instability.
* Full range of motion.
* Isokinetic strength >90% contralateral limb.
* Hop test battery >90% contralateral limb.
* Passing sport-specific functional drills.
* Psychological readiness.
* Minimum 12 months post-PCL reconstruction and OATS. For a professional athlete, this may be extended to 18 months for optimal outcome.
* Peroneal Nerve: Continual assessment. If no recovery by 6-9 months, nerve conduction studies and EMG, potentially surgical exploration.

Pearls & Pitfalls (Crucial for FRCS/Board Exams)

Pearls

1. Vascular Assessment is Paramount: In any suspected knee dislocation (reduced or unreduced), assume vascular injury until proven otherwise. Check ABIs meticulously. An ABI <0.9 warrants immediate CTA. Even with a normal ABI, if clinical suspicion is high (e.g., delayed presentation, high-energy mechanism, diminished pulses), consider CTA or observe with serial ABIs. A missed popliteal artery injury can lead to amputation in up to 80% of cases.
2. Neurological Assessment: Document meticulously. Peroneal nerve palsy is common (up to 40%) due to its superficial course and tethering. Prognosis for nerve recovery is variable; 30-50% may have incomplete recovery.
3. Acute Management: Reduce the knee immediately. Splint in 15-20 degrees of flexion to reduce tension on neurovascular structures.
4. Classification: Utilize the Schenck classification (KD-I to KD-V, with A, C, N, V modifiers) for comprehensive communication and prognosis.
5. Imaging: Plain X-rays rule out fractures/avulsions. MRI is essential for comprehensive soft tissue assessment (cruciates, collaterals, menisci, chondral surfaces) and surgical planning.
6. Staged Reconstruction: For multi-ligament knee injuries, a staged approach is generally preferred. Acute repair of collateral ligaments (MCL, PLC) and meniscal root tears within 3 weeks often yields better results. Cruciate reconstructions (ACL, PCL) are typically delayed to allow swelling to subside, soft tissues to heal, and to minimize arthrofibrosis risk (6-12 weeks).
7. Graft Selection: Autografts are generally preferred for active, young patients for their superior integration and lower immunological response. Hamstring, quadriceps, and patellar tendon are common choices. Allografts are an option but have concerns regarding disease transmission, slower incorporation, and potentially higher failure rates in young athletes.
8. Surgical Principles:
   • Anatomical tunnel placement and isometric graft positioning are critical.
   • Strong fixation with appropriate tensioning is essential.
   • Prioritize collateral ligament repair/reconstruction to restore static stability before embarking on cruciate reconstruction.
   • Address associated meniscal pathology (especially root tears) and chondral defects.
9. Arthrofibrosis Prevention: Early, controlled range of motion is crucial but must be balanced with graft protection. A well-structured rehab protocol is paramount.
10. Pre-Rehabilitation: Prior to delayed cruciate reconstruction, focus on reducing swelling, restoring full extension, and strengthening surrounding musculature to optimize post-operative outcomes.

Pitfalls

1. Missing Vascular Injury: The most catastrophic pitfall. Do not rely solely on palpable pulses; ABIs are mandatory. A pulsatile hematoma in the popliteal fossa is a red flag.
2. Missing Nerve Injury: Failure to document pre-operative neurological status can lead to medicolegal issues. Incomplete recovery of peroneal nerve function can have a significant impact on patient quality of life.
3. Inadequate Ligamentous Assessment: Not identifying all injured structures will lead to persistent instability and early graft failure. Thorough stress testing (even under anesthesia if necessary) and comprehensive MRI are key.
4. Premature Return to Activity: Pushing rehabilitation too quickly, especially for PCL and OATS, increases the risk of graft failure, recurrent instability, and failure of chondral integration.
5. Arthrofibrosis: Immobilization for too long or overly aggressive acute management can lead to debilitating stiffness. Conversely, insufficient protection can lead to graft failure.
6. Graft Mismatch/Inappropriate Tensioning: Incorrect tunnel placement or improper tensioning will result in suboptimal stability and kinematics.
7. Overlooking Meniscal Root Tears: These tears can lead to early degenerative changes similar to a total meniscectomy if not repaired.
8. Inadequate Post-Operative Follow-up: These complex patients require extensive, long-term follow-up to monitor progress, address complications (e.g., instability, arthritis, hardware issues), and guide return to sport.
9. Ignoring the Common Peroneal Nerve during Lateral Approaches: Meticulous dissection and identification of the common peroneal nerve is vital to prevent iatrogenic injury during posterolateral corner repair/reconstruction.
10. Poor Patient Selection/Expectation Management: Not every multi-ligament injury patient can return to elite-level sport. Realistic expectations must be set regarding recovery time, potential for residual symptoms, and long-term prognosis, particularly with neurovascular deficits.