September
Ligaments
are tough connective structures that connect bone to bone. The fundamental difference between ligament and tendon is that ligaments are weaker and not as stiff as tendons, due to a less regular collagen arrangement, because ligaments must withstand forces in varying directions, whereas the direction of force on a tendon is constant.
Composition Water makes up 60-80% of weight. Collagen makes up 70% of dry weight. Type I collagen makes up 90%, type III is the next most prevalent. Type III is seen in higher amounts in injured ligaments. Elastin makes up 1% of dry weight (higher in spinal ligaments). Fibroblasts are the dominant cell population.
Ultrastructure Bands of collagen fibrils in a more interwoven structure than tendons.
Insertion into bone Is either direct (femoral insertion of MCL) or indirect (tibial insertion). Direct insertions are characterized by attachment of collagen fibres at right angles to the bone, through four zones. Zone I is the ligament. Zone II is fibrocartilaginous. Zone III is mineralized fibrocartilage. Zone IV is bone. There is a tidemark between zones II and III. Indirect insertions are characterized by a superficial insertion into periosteum and a deep insertion via Sharpey’s fibres into the bone.
Factors affecting ligament properties
Estrogen decreases load to failure – may account for increased rates of ACL injury in females. Aging leads to decreases in stiffness and ultimate load. Immobilization decreases load to failure, and return to normal strength takes a much longer than the period of immobilization.
Healing Intrinsic healing responses are seen in extra-articular ligaments. Intra-articular healing isn’t seen.
Tendons
Tendons are regular connective tissue structures that connect muscle to bone. Compared with ligaments tendons deform less under applied load, which makes for more efficient load transfer. Tendons can be divided into two main categories – those that pull in a straight line and are surround by a paratenon (e.g. Achilles tendon) and those that pull around bends and are surrounded by a tendon sheath (e.g. flexor tendons). The former heal from granulation tissue from the paratenon; the latter can heal via intrinsic healing mechanisms from tenocytes (if passive motion is used) or heal via granulation tissue from the sheath (if the tendon is immobilized).
Factors affecting tendon properties
Flexor tendons are stronger and stiffer than extensor tendons in the digits. They have a higher collagen content. Exercise improves load to failure and stiffness. Fluroquinolones cause a decrease in proteoglycan production, increased oxidative stress and damage to collagen fibres and a decrease in decorin production.
September
Wound irrigation is used to decrease the number of viable bacteria in a wound and remove debris.
Volume of irrigation
The normal volume of irrigation is 6-10L in an open fracture. Increased volume improves wound cleansing to a point but the optimum volume is unknown. Anglen in his JAAOS article recommends 3L for Grade I fractures, 6L for Grade II fractures and 9L for Grade III fractures.
There is clinical data to show that in a dog contaminated soft tissue wound increasing the volume of irrigation from 0 to 1000mL in 250mL increments leads to progressively less contamination.
Pressure of irrigation
Data shows that higher pressures result in the removal of more bacteria than lower pressures. However, once pressures of 50-70psi are reached damage may be caused to the bone and soft tissues and bacteria may be disseminated.
Pulsatile lavage
There is no benefit in the use of pulsatile as opposed to continuous flow lavage.
Addition of antiseptics
The use of chlorhexidine, Betadine or hydrogen peroxide all results in increased soft tissue damage, and these agents should not be used. 0.2% chlorhexidine inadvertently used in an ACL reconstruction caused marked chondrolysis.
When hydrogen peroxide is diluted to the point where it is no longer harming the host cells it will have lost its effectiveness against bacteria.
Addition of antibiotics
These are often used. There is no strong evidence to support or discredit their use.
The possible deleterious effects are threefold:
- Financial
- Possible anaphylactic reaction
- Possible resistance
Use of soaps
Surfactants act to disrupt the hydrophobic or electrostatic adhesion of bacteria to host tissues, and allow removal rather than destruction of bacteria.
They are more effective at removing bacteria than antibiotic solutions or normal saline.
They should be used in heavily contaminated wounds.
September
Cellulitis
This is an infection of the subcutaneous tissues.
The infection is generally deeper and has more indistinct margins than erysipelas.
The infective organism is usually Group A strep. S.aureus is less common.
Clinical findings include erythema, warmth, tenderness, lymphangitis and lymphadenitis.
Erysipelas
This is an infection of the superficial soft tissues characterized by a progressively enlarging, well demarcated, red, raised painful plaque.
The most common organism is group A strep (in non-diabetics). In diabetics the common organisms are group A strep, S.aureus, enterobacteriaceae and clostridia.
Diabetic patients with erysipelas may require debridement to rule out underlying necrotizing fasciitis.
Septic patients should have an X-ray to rule out gas in the soft tissues.
Necrotizing fasciitis
Often associated with diabetes. This is an aggressive, potentially lethal condition most commonly caused by Group A strep. May have multiple organisms, including clostridia and anaerobic organisms.
It may follow trauma or surgery or after a streptococcal skin infection.
Can be differentiated from cellulitis or erysipelas by its rapid progression, failure to respond to appropriate antibiotics and marked systemic features.
Treatment is with intravenous antibiotics and extensive surgical debridement.
Mortality of 9-26%.
Gas gangrene
Muscle infection that is associated with grossly contaminated wounds (particularly ones closed primarily).
Due to Clostridia perfringens or Clostridia septicum, which produce exotoxins.
Characterized by pain, swelling, a foul smelling serosanguinous discharge and gas in the soft tissues. May be accompanied by signs of septic shock.
Treatment is with antibiotics (penicillin and clindamycin), radical debridement and hyperbaric oxygen.
Tetanus
Caused by Clostridium tetani, a gram positive anaerobic rod.
Pyomyositis
This is a rare condition that is seen more frequently in the tropics. The mean age in one large review was 28 years old, and males were slightly more commonly affected.
The disease is rare because skeletal muscle is resistant to bacterial infection. For muscle to become infected, it must be damaged in some way, e.g. by trauma or by preceding viral or parasitic infection.
Pyomyositis is seen more frequently in patients with HIV or other causes of immunosuppression. An underlying disease should be sought in any patient over thirty.
The muscle most frequently involved is the quadriceps; other muscles often involved are the glutei and the iliopsoas.
The micro-organism most commonly implicated is S.aureus.
There are three described phases of this infection:
- Initial invasive phase
- Suppurative phase
- Late phase – fluctuance and systemic findings.
The diagnosis is best confirmed with MRI with gadolinium contrast. This allows differentiation between the inflammatory phase and the abscess stage. It also allows differentiation from polymyositis.
Treatment is with surgical debridement and intravenous antibiotics.
One alternative to surgical debridement is CT guided aspiration.
September
First principle to debride all non-viable tissue.
Some adjuncts such as vital staining, Doppler flow cytometry and CT may help determine the level of bone resection.
Acute limb shortening
Relaxes soft tissue but may result is redundant tissue Limited to defects <3cm
Autologous nonvascularised cancellous bone graft
Should be delayed until 6 weeks to allow healing of any flaps any marginal tissue May be posterolateral as described by Harmon with the patient prone (not applicable to the proximal tibia where the neurovascular bundle is in close proximity). May also use anterolateral or posteromedial graft if under flap. Note to overlap cortical bone by at least 1cm. Reaming of canals removes any sealing callous and helps re-establish medullay blood supply. May use up to 4cm.
Bone Transport Distraction Osteogenesis
Osteotomy made in metaphyseal region. 5 day latent period then 1mm per distraction with 2-3 days consolidation. Graft applied to docking site as well as freshening up the ends. Ring fixators best method. May alternatively shorten the limb then secondarily distract. Good if large injury to fibula but may have period of redundant tissue. Has treated defects up to 30cm in adults.
Free Vascularised Bone Transfer
Rib, fibula or iliac crest. Taken on nutrient vessel. Important to have 2cm of overlap at each end. 7cm of fibula left proximally to avoid knee of CPN injury. Union time 3-6months at 90% Fracture rate up to 25% in the first year. At 2 years adequate hypertrophy occurred. 20% donor site morbidity. Advantage of immediate fixation.
September
Definition
Chronic infection caused by Mycobacterium tuberculosis.
Epidemiology More common in Asians, immuno-compromised, homeless. 500 times more common in patients with HIV. The incidence doubled in the US between 1987 and 1991. Rates are higher in urban areas. Only around 5-10% of patients with TB have bone or joint involvement.
Etiology
Musculoskeletal disease is usually secondary to primary disease in the lungs or GIT.
Pathology
The disease affects joints more commonly than bones. Spinal involvement is most common. The hip is next most commonly affected. The primary complex is the site of initial infection plus its draining lymph nodes – often the lung, or the gut. TB is able to survive for years in the draining nodes. Secondary systemic spread occurs if there is low resistance to the primary complex, resulting in miliary TB. The bony lesions are tertiary or reactivated lesions. The characteristic appearance is of a central area of caseous necrosis surrounded by multinucleated giant cells (epithelioid cells) and lymphocytes. If the synovium is involved it becomes thick and oedematous and gives rise to a marked effusion. A pannus of granulation tissue may spread across the joint and destroy the cartilage. Increased vascularity leads to localized osteoporosis.
Clinical features
The onset is usually insidious. There may be a history of exposure to TB or prior infection. The patient may present with pain, swelling and muscle wasting, or with constitutional features such as fever and weight loss. The affected joint may be markedly swollen Spinal pathology may present with an acute kyphosis (gibbus) or a cold abscess pointing in the groin.
Radiology
The initial findings are rarefaction, followed by bone destruction and joint narrowing. There is a marked absence of sclerosis and periosteal reaction. The growth plate is not a barrier to infection. Caseous material may calcify late, which is characteristic of the infection. MRI scans typically show large intra-articular effusions, and gross thickening of the synovial membrane.
Investigations
Positive Mantoux test if the patient isn’t anergic. Synovial biopsy and culture will be positive in up to 80%. The WCC and ESR are mildly raised; if the ESR is greater than 50 this suggests a pyogenic infection.
Differential diagnosis
Rheumatoid arthritis Brucellosis – found in patients who drink unpasteurized milk, causes chronic granulomatous infection, treated with tetracycline.
Management
Rest
Chemotherapy
The standard drugs are rifampicin and isoniazid, used for 9 months. Pyrazinamide is used for the first 2 months. Ethambutol may be added but is associated with retrobulbar neuritis. Streptomycin is rarely used because of problems with nephro and ototoxicity. Surgery may be required to drain pus, remove necrotic bone, correct deformity or perform an arthrodesis.
Preantibiotic natural history of tuberculosis The average time spent in hospital prior to antibiotics was incredible: Knee 2 years
Hip 3 years
Spine 5 years
It was not considered safe to operate on patients with TB until the ESR had fallen, because if operated on prior to this there was a significant risk of causing miliary TB which was often fatal. The mainstays of treatment were bed rest for the patient, splintage for the limb and good food and fresh air.
Unusual presentations of tuberculosis
Tuberculous dactylitis (aka spina ventosa)
Occurs in the short tubular bones of the hands and feet. Most common in children (particularly under 5). Usually multiple lesions, of consecutive rather than simultaneous onset. On XR typical appearance is diffuse soft tissue swelling, bone expansion, thinning of the cortex. Associated joint disease is very rare. Spina ventosa means: spina- thornlike and ventosa- inflated with air Saw XR presented by Dr Chapman at RNSH July 99.
Mycobacterium marinum
This causes chronic skin infections, and is sustained after a skin breach often in swimming pools or while fishing. This atypical mycobacterium needs to be cultured at 30 degrees celcius.
September
Definition This is a specific type of cold injury that occurs as a progression towards actual freezing of all tissues.
Epidemiology
In North America, the typical patient is characterized as an alcohol abusing male, dressed inappropriately for the conditions, and often with a psychiatric illness.
Etiology and pathology Two main causes of damage:
1. Exposure to extreme cold leads to formation of ice crystals within the tissues.
2. Vascular damage due to vasoconstriction followed by intravascular thrombosis.
In children premature physeal closure may develop.
Classification (Mills) :
Superficial – injury only to skin
Deep – injury to deeper tissues.
Treatment
In the initial phase of frostbite (less than 24 hours post injury) the treatment is rapid rewarming of the entire body, and when at hospital rapid warming of the extremity with a circulating water bath at 40 degrees celcius for 15-30 minutes. This is very painful and analgesics will be required. The next phase of treatment is to perform a three phase bone scan, and if there is no digital blood flow, use TPA. If TPA is used, the patient is then heparinized and then converted to warfarin. The patient should also receive NSAIDs to counteract the local thromboxane A2. Some also use topical aloe vera for this purpose.
If blisters rupture the hand should be covered with silver sulphadiazine.
Additional treatment is to splint the foot in a plantigrade position, provide tetanus prophylaxis and antibiotics, and watch for the development of compartment syndrome which may occur with swelling after rewarming.
Amputation/debridement should be delayed as long as possible to permit maximal salvage of the digits. “Demarcation of nonviable tissue may take as long as 2-3 months and should be patiently awaited” Greens. The exception to this is escharotomy.
Late treatment for vasospasticity may involve regional sympathectomy, which can be surgical or with intravenous reserpine.
September
Microbiology
S.aureus is commonest pathogen.
If long standing can become superinfected, often with Pseudomonas.
Treatment principles in chronic osteomyelitis
1. Radical debridement
a. Of both affected bone and soft tissue
2. Antibiotic therapy
3. Wound closure – preferably with healthy vascularized muscle
a. Split skin grafts on healing granulation tissue
b. Local rotation flaps
c. Microvascular free flaps
4. Cancellous bone grafting
Lethal complications of chronic osteomyelitis
1. Amyloidosis
a. Causes death through renal failure
2. Marjolin’s ulcer
a. Squamous cell cancer in a site of chronic infection
b. This grows slowly initially and metastasizes late, because of scarring of the local lymphatics. Once it
reaches normal tissue it spreads at a normal rate.
September
Radial club hand – longitudinal failure of formation
Definition
Preaxial deformity resulting in partial or complete absence of the radius.
Epidemiology
1 in 100 000 live births. Bilateral in 50%. When unilateral the right side is affected twice as often as the left. Aetiology Most cases sporadic. Some cases related to thalidomide.
Associated abnormalities
Cardiac – Holt Oram syndrome. ASD, transmitted as an autosomal dominant. Aplastic anaemia – Fanconi’s anaemia. This has an increased risk of malignancy. Thrombocytopaenia absent radius syndrome – TAR VATER complex – vertebral anomalies, imperforate anus, tracheo-oesophageal aplasia and renal anomalies. Now VACTERALS – Vertebral, Anal atresia, Cardiac, Tracheoesophageal fistula, Renal, Absent Radius, Lower Limb (DDH, Clubfoot), Single umbilical artery.
Clinical
The forearm is short and the wrist is radially deviated. Complete or partial absence of the thumb and radial carpus, and absence of the thenar musculature is common. The scaphoid and trapezium are most frequently absent. The ulna is usually short and bowed. Averages 60% of normal length. The humerus is often short. The median nerve is thickened because it carries the sensory nerves usually found in the radial nerve, and it lies most radially, deep to the deep fascia. In 25% of cases the median nerve is duplicated, one representing the radial nerve. There is an extension contracture in around 25%.
Classification
Bayne classification:
Type 1 – short distal radius with delayed appearance of the distal radial epiphysis
Type 2 – hypoplastic radius with defective proximal and distal epiphyseal growth
Type 3 – partial absence of the distal and middle thirds of the radius
Type 4 – Complete absence. This is the most common variety.
In stages 3 and 4 the carpus may articulate with the side of the ulna.
Treatment
Investigation for other abnormalities – referral for paediatrician and ultrasound. Treatment of types 1 and mild types 2 is with stretching and serial casting. These cases may also require release of tight fascia or other structures to position the carpus over the ulna. In type 3 and 4 and severe type 2 deformities some form of centralization of the carpus is required. Centralization is performed between 6 and 12 months of age. It is only done if there is elbow movement; without elbow movement there is no point BUT Smith in Lister’s disagrees with this and says that elbow flexion occurs in a matter of weeks after centralization. Buck-Gramko advocates over reduction to place the ulna in a position akin to where the radius should lie. Centralization involves selective carpal resection, transfers and ulnar closing wedge osteotomy. Centralization should aim to preserve the distal ulnar epiphysis. Transfer of ECRL to ECU helps prevent recurrent deformity. Distraction lengthening is being performed but is associated with a high complication rate. If pollicization is required for the thumb deformity it can be performed 6 months after the centralization. Centralization produces a loss of length in the arm, but this balanced by the improvement in appearance and to a lesser extent function.
September
Incidence 1/15 000
Etiology Sporadic, no evidence of heredity CRadial club hand – longitudinal failure of formation
Definition
Preaxial deformity resulting in partial or complete absence of the radius.
Epidemiology 1 in 100 000 live births. Bilateral in 50%. When unilateral the right side is affected twice as often as the left. Aetiology Most cases sporadic. Some cases related to thalidomide. Associated abnormalities Cardiac – Holt Oram syndrome. ASD, transmitted as an autosomal dominant. Aplastic anaemia – Fanconi’s anaemia. This has an increased risk of malignancy. Thrombocytopaenia absent radius syndrome – TAR VATER complex – vertebral anomalies, imperforate anus, tracheo-oesophageal aplasia and renal anomalies. Now VACTERALS – Vertebral, Anal atresia, Cardiac, Tracheoesophageal fistula, Renal, Absent Radius, Lower Limb (DDH, Clubfoot), Single umbilical artery. Clinical The forearm is short and the wrist is radially deviated. Complete or partial absence of the thumb and radial carpus, and absence of the thenar musculature is common. The scaphoid and trapezium are most frequently absent. The ulna is usually short and bowed. Averages 60% of normal length. The humerus is often short. The median nerve is thickened because it carries the sensory nerves usually found in the radial nerve, and it lies most radially, deep to the deep fascia. In 25% of cases the median nerve is duplicated, one representing the radial nerve.
There is an extension contracture in around 25%.
Classification Bayne classification
Type 1 – short distal radius with delayed appearance of the distal radial epiphysis
Type 2 – hypoplastic radius with defective proximal and distal epiphyseal growth
Type 3 – partial absence of the distal and middle thirds of the radius
Type 4 – Complete absence. This is the most common variety.
In stages 3 and 4 the carpus may articulate with the side of the ulna. Treatment Investigation for other abnormalities – referral for paediatrician and ultrasound.
Treatment of types 1 and mild types 2 is with stretching and serial casting. These cases may also require release of tight fascia or other structures to position the carpus over the ulna. In type 3 and 4 and severe type 2 deformities some form of centralization of the carpus is required. Centralization is performed between 6 and 12 months of age. It is only done if there is elbow movement; without elbow movement there is no point BUT Smith in Lister’s disagrees with this and says that elbow flexion occurs in a matter of weeks after centralization. Buck-Gramko advocates over reduction to place the ulna in a position akin to where the radius should lie. Centralization involves selective carpal resection, transfers and ulnar closing wedge osteotomy. Centralization should aim to preserve the distal ulnar epiphysis. Transfer of ECRL to ECU helps prevent recurrent deformity. Distraction lengthening is being performed but is associated with a high complication rate. If pollicization is required for the thumb deformity it can be performed 6 months after the centralization. Centralization produces a loss of length in the arm, but this balanced by the improvement in appearance and to a lesser extent function. aused by pressure of amniotic bands or oligohydramnios Associated Talipes equinovarus Cleft lip and palate Haemangioma Meningocele Cranial or cardiac defects Classification (Patterson)
1. Simple constriction rings
2. Rings accompanied by distal deformity, with or without lymphoedema
3. Rings accompanied by distal fusion – acrosyndactyly a. Type I Tips are joined b. Type II Tips are joined, web creep c. Type III Tips are joined. No web. Complete syndactyly associated with proximal sinus tract
4. Amputation
Examination
Assess for severe lymphoedema/swelling indicative of need for urgent release. Attempt to assess distal neurological and vascular function by examining pulses, temperature gradient, and spontaneous movement. Determine level of amputation along with function of remaining joints. Attempt to establish presence or absence of hypothenar muscles by palpation, contour and observation.
Surgery
Early release of constriction bands by circumferential Z-plasties is required only if there is gross swelling and lymphoedema. Usually amputation occurs in only one or two fingers, the remaining fingers are functional and are made more useful by ray amputation of the stumps. Partial aplasia of the thumb can be treated by distraction lengthening, phalangization (deepening of the first web), digital transfer or toe to hand transfer.
September
Definition
Stenosing tenosynovitis of the A1 pulley resulting in painful clicking and locking during attempted flexion of the digit.
Epidemiology
More common in females. The ring finger is affected most often, followed by the thumb, middle, index and little fingers.
Etiology
Idiopathic Secondary to RA, gout, diabetes. May occur in association with Dupuytren’s disease, de Quervain’s tenosynovitis, HT. Dupuytren’s disease may present as a trigger finger, with progressive contracture following release of the pulley.
Differential Diagnosis
Dupuytrens disease MCP joint OA or loose bodies Swan neck deformity (pseudo triggering) Because lateral bands sublux towards the midline and therefore with initiation of flexion have to slide over prominence of metacarpal head
Pathophysiology
In adults, the pattern can be nodular or diffuse. The distinction is important, because nodular patterns respond best to corticosteroid injections whereas diffuse patterns need operative treatment. The A1 pulley has two layers. The external layer is a vascular layer; the internal gliding layer, in contact with the tendon, is made up of ordered collagen. The cells in this inner layer are of two types: spindle shaped fibroblasts and ovoid cells. In diseased A1 pulleys the gliding layer hypertrophies and the ovoid cells increase in number and undergo metaplasia to become chondrocytes. The superficialis tendon also undergoes fibrocartilaginous metaplasia. The damage to the tendon may be due to the considerable angulation of the flexor tendons as they pass under the A1 pulley. Diagnosis The triggering may not be initially painful; the patient may experience a mild click in the finger or be unable to fully extend the finger. With time the clicking or locking may become painful and this pain may extend up the arm. Mild triggering may occur only in the morning; as the disease becomes more severe the triggering may occur throughout the day. The nature of the pathology should be established by palpation – is the swelling nodular or diffuse? If flexion is impossible the examiner should feel to ensure that there is a tendon and get XR to rule out joint pathology.
Treatment
Based on length of symptoms (less than or more than 6 months) and whether disease is nodular or diffuse. If less than 6 months and nodular, reasonable to attempt corticosteroid injection. If more than 6 months and nodular, percutaneous release. If diffuse, open release.
Splinting
Splinting (either in 0 degrees or 15 degrees MCPJ flexion) can be trialled but the splint is cumbersome and compliance is often poor. (looks like a ring over the prox phalanx with a paddle extending proximally to prevent MCP flexion)
Corticosteroid injection
Can be via palmar or midlateral approaches. The midlateral approach can be used first. The palmar approach is preferred in later injections. Up to three injections are reasonable. The preferred material to inject is betamethasone acetate because it is water soluble, doesn’t precipitate in the tendons and doesn’t cause fat necrosis. 1mL is injected.
Percutaneous release
The points for introducing the needle are in the line of the rays and 1/3 from the distal palmar crease and 2/3 from the proximal digital crease. The technique is probably best not used in the thumb because the sensory nerves are so close to the field.
Local anaesthetic is introduced. Saldana JAAOS 2001 advises corticosteroid should be mixed with the LA because this decreases the rate of pain post release, which can be a problem for up to 3-6 months. A 20g needle is introduced and run up and down the pulley. There have been no recorded problems with division of the neurovascular structures but incomplete release can be a problem.
Open release
The main thing here is to avoid damaging the neurovascular bundles. The incision can be longitudinal, transverse or diagonal, and the neurovascular bundles need to be swept away from the surface of the sheath. Complications of open release include digital nerve transection, A2 pulley injury with bowstringing, painful scars, recurrent symptoms, stiffness and sympathetic dystrophy.
Open treatment in rheumatoid patients.
The A1 pulley should never be incised in RA patients as this will increase the ulnar moment causing ulnar drift. Instead, a meticulous synovectomy is done; if there is still triggering an FDS slip is excised. The ulnar slip is preferable. Triggering usually occurs because of synovitis and triggering at the decussation.
Triggering of the thumb
The thumb has 3 pulleys, 2 annular over the MCP and IP joints and 1 oblique in between that runs from proximal ulna to distalradial. Therefore when incising the proximal annular pulley you should incise it on the radial side to try and preserve the oblique pulley so that bowstringing doesn’t occur
Specific complications from surgical treatment
Damage to the neurovasc bundles Tendon injury Incomplete release Bowstringing from excessive release Unveiling of a PIP joint fixed flexion contracture (the patient doesn’t notice in pre-op because try not to fully extend fingers, but notice it post op and blame you. So in longstanding cases document PIP ROM preoperation)