Bone Health

A deceptive MRI appearance of the medial meniscus in a 14 year old boy: a case report Padmanabhan Subramanian , Charles A Willis-Owen and David G Houlihan-Burne Cases Journal 2009, 2:16 (full text available)
Background A 14 year old boy with a history and clinical examination suggestive of a medial meniscal tear is presented. Case presentation The MRI findings suggested a horizontal cleavage tear so arthroscopy was carried out. No intra articular pathology was found at the time of surgery. Conclusions The role of MRI in investigation of meniscal injuries in children is discussed and the limitations highlighted.

- bones forming the knee joint are femur, tibia, & patella;
- both the left and right femurs converge toward the knee and each tibia is nearly vertical, femur and tibia meet angle of some 5-12 deg;
- greater angle results in genu valgum;
- lesser angle results in genu varum;
- patello-femoral function:
- condyles:
- tibial plateau:
Roll Back and Sliding of the Knee Joint:
- Knee Rotation:
Wheeless' Textbook of Orthopaedics

Madigan Army Medical Center Referral Guidelines Diagnosis/Definition Knee pain localized to the anterior portion of the knee, either retropatellar or peripatellar. Usually a gradual, non-traumatic onset aggravated with increased activity, running, squatting, stair climbing, or prolonged sitting. Symptoms normally decrease with rest.

- a type of cyst which results from egress of fluid through a normal communication of a bursa (semimembranosus or medial gastrocnemius bursa) or may be caused by herniation of the synovial membrane through the joint capsule;
- symptoms develope most often in the bursa beneath the medial head of gastrocnemius or in the semimembranous bursa;
- later is a double bursa located between the semimembranosus tendon and the medial head of the gastrocnemius;
- Baker's cysts are usually located at or below the joint line, whereas cysts of semimembranous bursa are above the joint line;
Wheeless' Textbook of Orthopaedics

Authors - George El Rassi, MD Saint George University Hospital- Achrafieh-lebanon
J. Richard Bowen, MD Alfred I. duPont Hospital for Children Wilmington, DE 19803-3607
The goals of this chapter are to describe the etiology, diagnosis and treatment of bipartite patella. Bipartite patella results from failure of fusion of an accessory ossification center which typically appears on radiographs between 8 and 12 years of age. Diagnosis is usually made by routine radiographic examination. The majority of individuals with bipartite patella are asymptomatic and often need no treatment. The initial treatment of a symptomatic patient is non-operative treatment. Surgical intervention is indicated after failure of non-operative treatment. Outline - I. Introduction II. Historical Perspective III. Anatomic and Physciologic Considerations V. Diagnosis and Recognition History and physical examination Imaging VI. Treatment Nonoperative Operative VII. Summary X. References

- a common congenital fragmentation or synchondrosis of the patella
- occurs in approximately 1% of population but some have observed a much higher incidence;
- most remain asymptomatic, but direct trauma may disrupt the synchondroses, causing symtoms that mimic those of fracture;
- classification:
- type I: inferior pole of the patella;
- type II: lateral margin type;
- type III: superolateral type;
Wheeless' Textbook of Orthopaedics

- blood supply to skin around the knee is random (as opposed to axial)
- there are multiple small overlapping vessels that are interrupted by multiple small incisions;
- random supply is sustained by both intrinsic and extrinsic sources;
- intrinsic contributors to skin overlying knee are perforationg branches of the superior and inferior genicular systems;
- extrinsic supply: 3 sources;
- descending genicular (supreme genicular artery) branch of superficial femoral artery
- recurrent branch of anterior tibial artery;
- descending branch of the lateral femoral circumflex artery
Wheeless' Textbook of Orthopaedics

- chondromalacia describes softening & fissuring of articular hyaline cartilage;
- chondromalacia may result from an excessive load on patellofemoral joint, but disuse may be a contributing factor;
- most common in young women;
- relationship between chondrosis & subsequent arthrosis is unclear;
- contributing factors:
- weakness and tightness of quadriceps muscle;
- genu valgum;
- increased Q angle
- patella alta

Authors - George El Rassi, MD Saint George University Hospital- Achrafieh-lebanon Lebanon
J. Richard Bowen, MD Alfred I. duPont Hospital for Children Wilmington, DE 19803-3607
The purpose of this chapter is to describe the clinical manifestations, the diagnosis and the management of discoid lateral meniscus of the knee in children .A discoid meniscus is an infrequent congenital anomaly that affects mainly the lateral meniscus.

- serial diagnostic exam should take into consideration static deformities of the lower extremities, gait, ROM, tenderness, and knee stability;
- in the child w/ a painful knee, it is essential to closely examine the hip as hip pathology can refer pain to the hip;
Wheeless' Textbook of Orthopaedics

Physical Exam Radiographs ACL Anteromedial Instability Anterolateral Rotatory Instability Arcuate Ligament Complex Arthrofibrosis Arthroscopy of the Knee Arthrodesis Articular Cartilage Baker's Cyst Bipartite Patella Blood Supply Blount's Disease Bursitis Capsule Chondral Injuries of the Knee Chondromalacia Diff Dx Discoid Meniscus Dislocations of the Knee Extensor Mechanism Injuries of the Knee Flexion Contracture Genu Varum Hemarthrosis High Tibial Osteotomy Intercondylar Eminence Fracture Jumper's Knee Kinematics of the Knee Joint Lachman Exam Lateral Anatomy Lateral Collateral Ligament Lateral Retinacular Release Ligaments of Humphrey and Wrisberg Medial Collateral Ligament Medial Compartment of the Knee Medial Synovial Plica Meniscii Meniscal Repair Menisco-Femoral Ligaments MRI-Knee Oblique Popliteal Ligament Osgood Schlatter Lesion Osteoarthritis Osteochondral Defects Osteochondritis Dissecans Osteonecrosis of the Knee Osteotomy, Tibial Osteotomy, Distal Femoral Patella bipartite patella chondromalacia patella patella alta patella infera prepatellar bursitis subluxation patellar tendon injury Physical Exam Pivot Shift Popliteal Cysts Posterior Oblique Ligament Posterior Cruciate Ligament Postero-lateral Instability Puncture of the Knee Joint Q angle of the Knee Radiograhpic Evaluation of the Knee Running Injuries Rupture of the Quadriceps Septic Knee Sindig-Larsen-Johanssen disease Subluxation of the Patella Surgical Approach Approach for TKR Posterior Approach Synovium Synovial Plica Total Knee Arthroplasty Tibial Tubercle Frx Tibial-Fibular Dislocation Unicondylar Replacement Valgus Stress Testing Varus Stress Testing
Wheeless' Textbook of Orthopaedics

- tripled layered arrangement on the lateral aspect of knee;
- posterolateral part of capsule is divided into two laminae that encompass LCL, fabellofibullar, & arcuate ligaments;
Wheeless' Textbook of Orthopaedics

Notes on the layers and ligamentous anatomy of the medial aspect of the knee.
Wheeless' Textbook of Orthopaedics

- most common form of plica;
- located over the medial femoral condyle;
- vulnerable to direct trauma when the knee is flexed;
- repeated trauma or irritation may lead to inflammation and fibrosis of the plica;
- fibrotic plica has decreased elasticity which causes it to impinge on either the patella or the femoral condyle;
Wheeless' Textbook of Orthopaedics

Nicolas Aigner , Roland Meizer , Gert Petje , Elisabeth Meizer , Ashraf Abdelkafy and Franz Landsiedl BMC Musculoskeletal Disorders 2008, 9:45 Abstract & link to free full text
Background Intra-articular shift (migration) of bone marrow edema syndrome (BMES) is a very rare disease. Only a few cases have been reported thus far. The condition may cause the clinician to suspect an aggressive disease.
Results MR imaging showed complete restitution in 6 cases and a small residual edema in one case. A final control MR could not be obtained for one patient, who had no pain. A further patient had an avascular necrosis of the contralateral hip after 16 months. Improvement on MR imaging was correlated with the clinical outcome in all cases. All patients became asymptomatic after a mean period of 9 months (6-11). Interpretation: Intra-articular shifting BMES is a very rare condition. As the disease is self-limiting, conservative therapy may be recommended.