Forensic Medicine

Monday, May 25, 2015

Miscellaneous Facts in Orthopedics

·         Perkins rules
  1. Fractures of cancellous (metaphyseal) bone (e.g. those around joints) will take 6 weeks to unite.
  2. Fractures of cortical (diaphyseal) bone (e.g. shafts of long bones) will take 12 weeks to unite.
  3. Fractures of the tibia (because of poor blood supply), will take 24 weeks to unite.
  4. Time to union for children equals the age of the child in years plus one, e.g. tibial fracture in a 2-year-old child will unite in 3 weeks. Common sense needs to be applied when applying the rule to fractures of cancellous bone in older children.

·         As a rule, in children up to 8 years old, as much as 30° of angulation will heal satisfactorily without reduction. In older children, percentages are lower. In general, fractures that are in the metaphysis or growth plate remodel more completely than midshaft fractures. Rotational malalignment will not remodel.

·         Treatment of clubfoot
  1. The Ponseti method of serial casting is successful in 95% of feet, avoiding formal surgical release although percutaneous tenotomy is usually required
  2. The standard sequence is elevation of the first ray, gradual abduction to 60∞ and, finally, dorsiflexion, usually following Achilles tenotomy
  3. Tibialis anterior transfer can be used to correct dynamic supination in toddlers and older children
  4. Surgical release may need to address posterior, medial, plantar and lateral structures, and may result in a stiffer foot than one treated conservatively

·         Giant cell variant tumors
1 - aneurysmal bone cyst
2- osteoclastoma
3- chondroblastoma
4- unicameral bone cyst
5- chondromyxoid fibroma
6- non osteogenic fibroma
7- fibrous dysplasia
8- brown tumor of hyperparathyroidism .

·         The tuberculosis of hip mainly progresses through three stages .
a- stage of synovitis ( FABER - AL )
b- stage of arthritis ( FADIR - AS )
c- stage of erosion ( FADIR - TS )

·         Rupture of the tendon of the long head of the biceps produced a positive “popeye sign” where the biceps belly of the muscle becomes prominent in the mid upper arm. Weakness with supination is prominent, and forearm flexion is typically preserved.

·         Open reduction of a fracture involves the restoration of normal bone alignment under direct observation at surgery. In effect, open reduction converts a simple fracture into a compound (or open) fracture and thereby increases the risk of infection. Operative manipulation also increases trauma at the fracture site and may consequently add to the probability of infection. Hematomas at the site of fracture may be important for early healing; open reduction, which usually involves removing the clots in the field, could contribute to a delay in bone healing and to nonunion. The major advantage of open reduction is the shorter period of immobilization it allows, an advantage that often outweighs all the disadvantages previously mentioned, as in the open reduction of femoral neck fractures in the elderly. This allows these patients to get out of bed much sooner than if they were treated with several weeks of traction.

·         Denis developed a classification system for a thoracolumbar spine injury based on a three-column concept. In this system, the spine is divided into three longitudinal regions or columns: anterior, middle, and posterior. Although references to such “columns” is anatomically imprecise, the term is clinically useful in assessing the stability of the injured spine. In general, instability results when significant disruption is present in two of the three columns, regardless of the presence or absence of neurologic deficit.

·         Fracture of the atlas (Jefferson's fracture) occurs from an axial load, usually to the top of the head. The resulting forces fracture the ring of C1 and displace the fragments outward. This results in an increase in the cross-sectional area of the spinal canal at the level of injury. Neurologic injury is, therefore, unusual in this fracture. CT is the best roentgenographic study available to evaluate fractures of the atlas.

·         The best method of treating a supracondylar fracture of the humerus in a child that is unstable when the elbow is flexed to 90 degrees is percutaneous pinning. Hyperflexion of the elbow usually achieves stability but incurs the risk of occluding arterial inflow and may cause permanent neuromuscular deficit. Open reduction is not indicated unless the fracture is irreducible or associated with a vascular injury.

·         Wrist pain during attempted push-ups or diffuse swelling on the dorsum of the wrist may be caused by a variety of factors. Wrist popping on movement may be the result of carpal instability, subluxation of a tendon on extension and flexion of the wrist, or intra-articular problems such as an articular cartilage flap or a tear of the triangular fibrocartilage. Localized tenderness at the anatomic snuffbox (scaphoid) is the most consistent sign of scaphoid fracture.

·         Compression of the median nerve at the elbow by the lacertus fibrosus causes symptoms at more locations than just the flexor pollicis longus and flexor profundus at the index finger, since the entire median nerve is affected.
Compression of the median nerve at the axilla affects both motor and sensory elements diffusely.
The arcade of Frohse is a fibrous band at the origin of the supinator muscle. It can compress the posterior interosseous portion of the radial nerve but does not involve the median nerve.
The anterior interosseous portion of the median nerve can be compressed by an aberrant accessory forearm muscle (Gantzer's muscle).

·         While patients with carpal tunnel syndrome often complain of subjective symptoms such as numbness of the thumb, index, and long fingers, objective decreased sensibility is not usually present.
Testing with von Frey filaments produces the most sensitive results.
Decreased light touch is noted before decreased two-point discrimination.
Dryness of the skin in the median nerve distribution is evident with severe injury to the nerve but not in the routine carpal tunnel syndrome.
Although the abductor pollicis brevis and opponens pollicis are supplied by the motor branch of the median nerve, atrophy of these muscles is not seen until long-term median nerve compression has occurred. Symptomatic carpal tunnel syndrome without evidence of thenar atrophy has a greater frequency than the more severe median nerve compression, with demonstrable thenar atrophy.
Percussion over the median nerve at the wrist producing paresthesias distally in the distribution of the median nerve and paresthesias caused by wrist flexion are two of the most common signs of median nerve compression at the wrist.
Although patients with carpal tunnel syndrome intermittently complain of weak grip and dropping objects, cramping of the hand while writing and difficulty writing are not routine symptoms of this condition.

·         The blood supply to the femoral head is provided predominantly by the branches of the medial femoral circumflex artery, which take a posterior course and are confluent with the retinacular vessels. The lateral femoral circumflex artery runs anteriorly.

·         The amount of energy absorption and the degree of bony comminution is the most significant factor in predicting healing of tibial fractures. Location along the tibia and age are not thought of as significant factors in healing. The soft tissue damage may contribute to lack of vascular envelope, but the destruction of soft tissue is based on the amount of energy absorbed.

·         The blood supply of the talus is somewhat tenuous because there are no muscles or tendons associated with this bone.

·         Level of amputation: Clinical competence of the extremity with observations of skin turgor, discoloration, perfusion, sensation, and integrity is the mainstay of surgical decision making. This can be complemented by transcutaneous PO2, ankle-arm systolic pressure ratios, xenon skin clearance, serum albumin levels, and total lymphocyte count.

·         Hematogenous osteomyelitis occurs most frequently in children and involves the metaphyseal ends of long bones. The cause is thought to relate to the pattern of blood flow in the metaphysis wherein arterioles empty into numerous sinusoidal veins with sluggish blood flow favoring the lodgement of bacteria.

·         The flexor retinacular system from the metacarpophalangeal joint to the distal interphalangeal joint maintains the flexor tendons against the digit during flexion, preventing bow stringing and allowing the digital tip to flex to the distal palmar crease. Division of the A 1, A 3, or A 5 pulleys minimally compromises this function; however, division of the A 2 or A 4 pulleys can significantly limit digital excursion.
Continuous passive mobilization (CPM) causes a 16% improvement in range of digital motion compared to intermittent mobilization. The incidence of poor results is much lower (3% versus 26%) despite no postoperative ruptures or infections. Continuous passive mobilization appears to be a more effective yet safe means of improving postoperative function following flexor tendon injury.

Zone II of flexor tendon injury that carries the poorest prognosis.

·         A number of PROTEINS have been demonstrated to directly or indirectly influence bone induction.
Platelet-derived growth factor from platelets and macrophages has been shown to induce migration and mitosis of mesenchymal cells in wounds and to enhance cartilage and bone formation in adult rats.
Fibroblast growth factors is a mitogenic and angiogenic protein that favors new bone formation, particularly if neo-ascularization is required.
Transforming growth factor-b is secreted from bone cell cultures. This protein appears to be naturally released from platelets at the time of a fracture and stimulates proliferation of osteoblasts and increases their production of collagen.
Osteogenin has the ability to induce cartilage and bone formation and to play a major controlling role in the development of de novo bone in muscle and subcutaneous tissues.

·         Fracture of the radial head is more common in adults; fracture of the neck is more common in children.

·         Quadrilateral Space Syndrome: axillary nerve injury

·         Sprengel's deformity (congenital elevation of the scapula) results from the failure of normal scapular descent during fetal life, thereby resulting in an elevated, hypoplastic scapula. The affected side of the neck appears shorter and broader and may give the appearance of torticollis. A fibrocartilaginous band or omovertebral bone may bridge the space between the medial upper scapula and the spinous process of a cervical vertebra. Abduction of the ipsilateral arm is usually limited, but this limitation may not be clinically significant. Sprengel's deformity may be associated with congenital scoliosis and renal anomalies.

·         Clubfoot, or talipes equinovarus congenita, is distinguished pathologically by a combination of forefoot and hindfoot abnormalities (e.g., malrotation of the talus under the calcaneus and plantar flexion or equinus of the ankle). As a rule, clubfoot is a rigid deformity, whereas metatarsus is more flexible. If the ankle can be dorsiflexed to neutral or beyond, metatarsus is a much more likely diagnosis.

·         Also called "rocker bottom foot," or "Persian slipper" foot; this abnormality is due to congenital vertical talus. Lateral radiographs reveal a vertically oriented talus with dislocation of the talonavicular joint. On examination, the forefoot is markedly dorsiflexed, and the heel is rigid and points downward, giving the sole the characteristic convex or boat-shaped appearance. Serial casting and subsequent surgical reversion are the usual treatments. The syndrome most commonly associated with this deformity is trisomy 18.

·         Tarsal coalition. Fusion of various tarsal bones via fibrous or bony bridges can result in a stiff foot that inverts with difficulty. When inversion of the foot is done during an examination, tenderness occurs on the lateral aspect of the foot, and peroneal tendons become very prominent. Thus, the condition is also referred to as "peroneal spastic flat foot." Unless the condition is very severe and warrants surgery, corrective shoes are usually adequate treatment. Other possible causes of a rigid flat foot include rheumatoid arthritis, septic arthritis, posttraumatic arthritis, neuromuscular conditions, and congenital vertical talus.

·         SCFE involves progressive displacement with external rotation of the femur on the epiphyseal growth plate. The patient has intermittent or constant hip, thigh, or knee pain that has often lasted weeks to months. In 25%, the pain is bilateral. A limp, a lack of internal rotation, and a hip flexion contracture may be noted. If the patient's hip is flexed, the thigh tends to fall into external rotation. It is important to realize that any patient with knee pain may have underlying hip pathology.

·         Discitis, which is the infection and/or inflammation of the intervertebral disc, most commonly occurs in children between the ages of 4 and 10 years. The etiology is often unclear, but a bacterial cause (particularly Staphylococcus aureus) is identified by blood cultures in about 50% of cases. The diagnosis can be difficult because of varied accompanying symptoms, including generalized back pain with or without localized tenderness, refusal to stand or walk, back stiffness with loss of lumbar lordosis, abdominal pain, and unexplained low-grade fever.
As with osteomyelitis, a most helpful laboratory test is an elevated ESR. WBCs may often be normal, and early x-rays (<2-4 weeks of symptoms) may not show changes. Technetium-99 bone scans will demonstrate abnormalities early during the course of illness. Magnetic resonance imaging studies can help distinguish between discitis and vertebral osteomyelitis.
Treatment consists of 3-6 weeks of antistaphylococcal antibiotics, with variable amounts of immobilization and bracing, depending on severity of symptoms. Persistent or atypical cases may require biopsy to identify the etiology.

  • If you use the tibiofemoral angle (the angle formed by the tibia and the femur) as a guide, most children at birth are bowlegged (genu varum) up to 20°, but this tendency progressively diminishes until about 24 months, when the trend toward knock knees (genu valgum) begins. Knock knees continue to the age of 3 years (up to 15°) and then begin to diminish. At about the age of 8 years, most children are-and will remain-knock-kneed at about 7°

  • Shin splints. This term describes the pain and cramping felt in the compartments of the lower leg after strenuous exercise. It is rare in children but may be seen in teenagers who exercise (especially running on hard surfaces) after extended periods of inactivity. The pain results from muscle strain and inflammation of the musculotendinous units. Swelling and cramping occur, particularly in the flexor digitorum longus muscle, which flexes the lateral four toes and plantar-flexes the foot at the ankle joint. The muscle swelling may contribute to ischemia. Snowshoeing may be the ultimate test of the anterior tibial muscles.

  • Meniscal tears rarely occur before the age of 12 years. A discoid meniscus is a congenitally abnormal meniscus and can appear at almost any age. Meniscal tears in youths are typically associated with significant injuries that arise from a memorable event. They produce pain, swelling, and limping. There is often an associated injury to the anterior cruciate ligament.

Spondylolysis is a condition in which there is a defect in the pars interarticularis (vertebral arch) of a vertebra that is most common at L5 in children and adolescents. Spondylolisthesis is a condition (usually resulting from spondylolysis) that is characterized by forward slippage of one vertebra on the lower vertebrae. Pain is the most common presenting symptom for both conditions. The etiology is unclear, but various theories relate it to hereditary factors, congenital predisposition, trauma, posture, growth, and biomechanical factors. Treatment includes watchful waiting, limitation of activity, exercise therapy, bracing, casting, and surgery, depending on the patient's age, the magnitude of the slippage, the extent of pain, and the predicted likelihood of progression of the deformity.


·         Caffey disease, or infantile cortical hyperostosis,  is characterized by a clinical triad (fever, soft-tissue swelling, and hyperirritability) and a clinching radiographic picture of underlying cortical hyperostosis (thickening or bony expansion). Caffey's disease (or syndrome), which usually occurs before 6 months of age, is a condition of unknown etiology that consists of tender, nonsuppurative, cortical swellings of the shafts of bone, most commonly the mandible and clavicle. It remits spontaneously, but exacerbations may persist for several years. In severe cases, corticosteroids may be helpful. Infantile cortical hyperostosis is a rare condition. The presence of periosteal reaction, especially if asymmetric, should raise the suspicion of battered child syndrome.               
·         Hardcastle's Syndome; Diaphyseal Medullary Stenosis with Malignant Fibrous Histiocytoma (DMS-MFH)
AD
Radiographs show thickening of the cortex, with irregularity and loss of distinction of the endosteal surface. There may be small lucent or lytic areas within or adjacent to the cortex, which may appear to permeate a region of the bone. The metaphyseal area has striated densities that may be seen as confluent fibro-osseous bands on axial imaging. Larger seemingly lytic areas may be seen, although these may areas of normal density surrounded by more sclerotic areas. The diffuse changes seen throughout multiple long bones have the appearance of "worm-eaten wood". Fractures occur with relatively minor trauma through affected bone, and healing is slow and incomplete. Visible fracture lines persist years after surgical stabilization.
Treatment should be based on:
1) Avoidance of pathological fracture by appropriate activity modifications.
2) Internal fixation, preferably by intramedullary rodding, is best. It should be expected that the rods will stay in permanently due to the lack of complete healing.
3) Ongoing monitoring for malignant transformation.

·         de Quervain tenosynovitis: exquisite pain at the thumb with the Finkelstein maneuver (a specific maneuver in which the thumb is placed in the closed fist and the affected hand is tilted towards the little finger, into ulnar deviation)
The Finkelstein sign classically occurs in mothers of infants 6-12 months of age. Interestingly, the cause is believed to be principally endocrine and related to fluid retention in breast-feeding mothers, not solely as a result of repetitive lifting motion. De Quervain tenosynovitis has also, however, been described in fathers. This suggests that the condition can occur in the absence of postpartum endocrine changes. Repetitive trauma in manual laborers is also a common cause. The pain itself may appear either gradually or suddenly
de Quervain tenosynovitis, an inflammatory process that typically involves the first dorsal extensor components of the wrist (namely, the abductor pollicis longus [APL] and the extensor pollicis brevis [EPB]) within the narrow fibro-osseous tunnel through which they normally pass
Ultrasonography of the symptomatic tendon typically shows distention in the tendon sheath, with surrounding fluid that is hypoechoic or anechoic. An axial scan of the tendon will exhibit a so-called "double target" appearance.

·         Bizarre Parosteal Osteochondromatous Proliferation (Nora's Lesion)
Bizarre parosteal osteochondromatous proliferation (BPOP) is a rare lesion that occurs most commonly in the hands and feet, usually of adults in their 20's and 30's, average age 30 -33 years, range, 2 to 73. Males and females are equally affected. The lesion is most common in the hands followed by the feet, long bones (commonly of the upper extremity), skull, jaw, and other sites. It most commonly occurs on the proximal and middle phalanges, metacarpals, and metatarsals, and it is more rare in long tubular bones. This lesion grows rapidly and has aggressive features on imaging studies as well as confusion findings on histopathology, leading to many errors in diagnosis and potentially inappropriate treatments. The lesion is thought to be related to myositis ossificans, reactive periostitis and subungual exostosis. It was described in 1983 by Dr. Nora, and is sometimes called Nora's disease or Nora's lesion.

·         Stickler syndrome (or David-Stickler syndrome or Stickler-Wagner syndrome) is a group of genetic disorders affecting connective tissue, specifically collagen. Stickler syndrome is a subtype of collagenopathy, types II and XI. Stickler syndrome is characterized by a distinctive facial appearance, eye abnormalities, hearing loss, and joint problems.

·         Jaffee-Campanacci syndrome (JCS)
The association of multiple non-ossifying fibromas with cafe au lait skin patches has been named Jaffee-Campanacci syndrome (JCS).
This rare syndrome has a wide range of manifestations, some cases are very mild, consisting only of a few pigmented skin patches and benign non-ossifying fibroma (NOF) bone tumors The author has seen cases with multiple skin patches and multiple or solitary NOF's where no other abnormality is present. Reports in the literature focus on more severe cases which demonstrate cryptorchism, hypogonadism, ocular abnormalities, alopecia, cardiovascular abnormalities, renal abnormalities, mental retardation, and other serious problems

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