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Closed fracture subluxation of knee joint — Clinical Guidelines

Overview

Closed fracture subluxation of the knee joint refers to a complex injury characterized by a fracture that leads to partial dislocation or subluxation of the joint surfaces. This condition often involves significant ligamentous damage, particularly affecting the collateral ligaments and cruciate ligaments, leading to instability and functional impairment. It predominantly affects individuals involved in high-impact activities or trauma, such as athletes and trauma patients. Early and accurate diagnosis and management are crucial to prevent long-term disability and secondary complications like osteoarthritis. Proper treatment and rehabilitation are essential in day-to-day practice to restore knee function and stability 1 9.

Pathophysiology

Closed fracture subluxation of the knee typically results from high-energy trauma, such as motor vehicle accidents or severe sports injuries, leading to simultaneous fracture and ligamentous disruption. The mechanical forces cause bone fragments to displace, compromising joint congruity and stability. This disruption often involves the tibial plateau or femoral condyles, frequently accompanied by tears in the medial collateral ligament (MCL), lateral collateral ligament (LCL), anterior cruciate ligament (ACL), and posterior cruciate ligament (PCL). The resultant instability can exacerbate cartilage damage and accelerate the progression towards osteoarthritis due to abnormal joint mechanics and chronic inflammation 1 9.

Epidemiology

The incidence of closed fracture subluxation of the knee is relatively low compared to isolated fractures or ligament injuries but carries significant morbidity. These injuries are more common in younger adults, particularly those engaged in high-impact sports or exposed to traumatic events. There is no substantial geographic variation noted in the literature provided, but risk factors include male gender, younger age, and participation in contact sports. Trends suggest an increasing awareness and diagnostic accuracy due to advanced imaging techniques, leading to more precise identification and management 1 3.

Clinical Presentation

Patients typically present with acute knee pain, swelling, and an inability to bear weight. Common symptoms include deformity of the knee, audible clicking or popping sounds during injury, and instability, often manifesting as a feeling of the knee "giving way." Red-flag features include severe pain disproportionate to physical findings, signs of vascular compromise (pale, cold, or numb distal limb), and inability to fully extend or flex the knee. Prompt recognition of these signs is crucial for timely intervention 1 5.

Diagnosis

The diagnostic approach involves a thorough clinical examination followed by imaging studies. Key steps include:

Clinical Examination: Assess for joint line tenderness, range of motion limitations, and ligamentous instability tests (e.g., Lachman test, pivot shift test).

Imaging Studies:

- X-rays: Initial assessment to identify fractures and joint alignment issues. - MRI: Essential for detailed evaluation of ligamentous injuries, cartilage damage, and bone contusions. - CT: Useful for complex fractures and detailed bony anatomy assessment.

Specific Criteria and Tests:

X-ray Findings: Presence of fracture lines, joint space widening, or malalignment.

MRI Findings: Ligamentous tears (e.g., ACL tear indicated by high signal intensity in the ligament on T2-weighted images), bone marrow edema, and meniscal injuries.

Arthrography: May be used to assess joint stability and subluxation more definitively.

Differential Diagnosis:

Isolated Ligament Injury: Typically lacks associated fracture findings.

Patellar Dislocation: Often presents with a history of direct trauma to the patella and localized tenderness over the patellar region.

Meniscal Tear: Usually presents with mechanical symptoms like locking or clicking without significant instability or fracture 2 9.

Management

Initial Management

Immobilization: Application of a knee brace or cast to stabilize the joint and prevent further displacement.

Pain Control: Analgesics (e.g., NSAIDs for pain and inflammation).

Reduction: Closed reduction under anesthesia if subluxation is present, followed by immobilization.

Surgical Intervention

Fracture Repair: Open reduction and internal fixation (ORIF) using plates, screws, or intramedullary nails as indicated by fracture type.

Ligament Reconstruction: Arthroscopically assisted combined ACL/PCL reconstruction using autografts (e.g., hamstring, patellar tendon) or allografts, depending on the extent of injury.

- Graft Selection: Autografts are preferred for primary repairs due to better integration and strength. - Post-op Rehabilitation: Gradual mobilization under supervision, starting with protected weight-bearing and progressing to strengthening exercises.

Postoperative Care

Physical Therapy: Initiated early to restore range of motion, strength, and functional stability.

Regular Follow-ups: Monitor healing progress, adjust rehabilitation protocols, and address complications promptly.

Contraindications:

Severe vascular compromise or open fractures requiring immediate vascular repair.

Significant comorbidities that preclude surgical intervention or prolonged rehabilitation 1 9.

Complications

Chronic Instability: Persistent knee instability leading to recurrent subluxation or dislocation.

Osteoarthritis: Accelerated joint degeneration due to altered biomechanics and cartilage damage.

Infection: Risk following surgical interventions, necessitating vigilant monitoring and prophylactic measures.

Malunion/Nonunion: Fracture healing complications requiring further surgical intervention.

Referral Triggers: Persistent pain, instability, or functional deficits beyond expected recovery timelines warrant specialist referral 3 8.

Prognosis & Follow-up

The prognosis for closed fracture subluxation of the knee varies based on the extent of injury and adherence to treatment protocols. Prognostic indicators include successful surgical repair, early mobilization, and comprehensive rehabilitation. Recommended follow-up intervals include:

Immediate Postoperative: Weekly for the first month.

3-6 Months: To assess healing and functional recovery.

Annually: For long-term monitoring of joint stability and signs of osteoarthritis.

Special Populations

Pediatrics: Growth plate injuries require careful management to avoid growth disturbances; conservative treatment may be preferred initially.

Elderly: Higher risk of complications and slower recovery; conservative management or minimally invasive surgical options may be favored.

Comorbidities: Patients with cardiovascular or metabolic conditions may require tailored rehabilitation plans to manage additional health risks 6 10.

Key Recommendations

Immediate Imaging and Surgical Consultation: Obtain X-rays and MRI promptly to assess fracture and ligamentous injuries; consult orthopedic surgery urgently 1 2.

Surgical Repair for Complex Injuries: Perform ORIF for fractures and arthroscopically assisted ligament reconstruction for significant ligamentous damage 1 9.

Comprehensive Rehabilitation: Initiate early physical therapy focusing on range of motion, strength, and functional training 1 5.

Regular Follow-up Monitoring: Schedule frequent follow-ups to monitor healing progress and address complications early 1 10.

Avoid Measured Resection in TKA: Opt for gap balancing techniques over measured resection for more accurate femoral component rotation in total knee arthroplasty 6.

Consider Rotational Stability in Prosthetic Designs: Evaluate the use of rotating hinged prostheses cautiously due to potential complications 8.

Aggressive Management of Instability: Prioritize surgical stabilization for persistent instability to prevent long-term joint damage 1 5.

Monitor for Osteoarthritis Risk: Regularly assess for signs of early osteoarthritis and intervene with joint preservation techniques if necessary 3.

Tailored Care for Special Populations: Adapt treatment plans considering age, comorbidities, and growth plate concerns 6 10.

Use Advanced Imaging for Post-treatment Evaluation: Employ MRI and CT for detailed post-treatment assessment to guide further management 2 7.

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References

1 Panish B, Lawson JJ, Elkadi S, Schaefer E, Perraut G, Argintar EH. Multiligament Knee Reconstruction With Suture Tape Augmentation: Patient-Reported Outcomes at Minimum 2-Year Follow-up. Orthopedics 2024. link 2 Heuck A, Woertler K. Posttreatment Imaging of the Knee: Cruciate Ligaments and Menisci. Seminars in musculoskeletal radiology 2022. link 3 Pareek A, Parkes CW, Bernard C, Camp CL, Saris DBF, Stuart MJ et al.. Spontaneous Osteonecrosis/Subchondral Insufficiency Fractures of the Knee: High Rates of Conversion to Surgical Treatment and Arthroplasty. The Journal of bone and joint surgery. American volume 2020. link 4 Ostermeier S, Bohnsack M, Hurschler C, Stukenborg-Colsman C. A rotating inlay decreases contact pressure on inlay post after posterior cruciate substituting total knee arthroplasty. Clinical biomechanics (Bristol, Avon) 2009. link 5 Ricchetti ET, Sennett BJ, Huffman GR. Acute and chronic management of posterolateral corner injuries of the knee. Orthopedics 2008. link 6 Dennis DA. Measured resection: an outdated technique in total knee arthroplasty. Orthopedics 2008. link 7 Steckel H, Murtha PE, Costic RS, Moody JE, Jaramaz B, Fu FH. Computer evaluation of kinematics of anterior cruciate ligament reconstructions. Clinical orthopaedics and related research 2007. link 8 Pour AE, Parvizi J, Slenker N, Purtill JJ, Sharkey PF. Rotating hinged total knee replacement: use with caution. The Journal of bone and joint surgery. American volume 2007. link 9 Fanelli GC, Orcutt DR, Edson CJ. The multiple-ligament injured knee: evaluation, treatment, and results. Arthroscopy : the journal of arthroscopic & related surgery : official publication of the Arthroscopy Association of North America and the International Arthroscopy Association 2005. link 10 Giori NJ, Giori KL, Woolson ST, Goodman SB, Lannin JV, Schurman DJ. Measurement of perioperative flexion-extension mechanics of the knee joint. The Journal of arthroplasty 2001. link

Closed fracture subluxation of knee joint