FRCS Mock Exam 5: Rapid Fire Challenge

Inferior glenohumeral. A humeral avulsion of the glenohumeral ligament (HAGL) lesion is a detachment of the inferior glenohumeral ligament (IGHL) off its humeral insertion. If missed, it can cause a failure of Bankart repair. The classic teaching is for repair via an open approach.

Transforming growth factors. Bone morphogenetic proteins (BMPs) are multifunctional growth factors that belong to the transforming growth factor beta (TGF-b) superfamily.

Perform a Henry’s approach and a separate carpal tunnel incision. In severe wrist trauma the median nerve may be under a lot of pressure. It is not acceptable to watch and wait as there will only be more swelling post-operatively. The wrist crease must always be crossed with an S shape but in this case two separate incisions are key to prevent injury to the palmar cutaneous branch of the median nerve which lies between the flexor carpi radialis and palmaris longus. Safe surgery on the median nerve should not be contemplated from either a very radial or very ulnar approach.

Superior placement of the glenoid component. Superior positioning of the glenoid component as well as superior tilt of the component with respect to the scapula can lead to scapular notching, with a resultant poorer outcome. Inferior tilt and proper placement of the glenoid component protects against notching.

Posteromedial tibial bowing. Fibular hemimelia is a postaxial deficiency or dysplasia in which there is aplasia or variable hypoplasia of the fibula. There are a number of associated features comprising from distal to proximal: absent lateral rays and/or tarsal bones, tarsal coalition, ball and socket ankle, valgus ankle, anteromedial tibial bowing, flattened tibial spine, absent anterior cruciate ligament (ACL), genu valgum, hypoplastic lateral femoral condyle, lateral patellar subluxation, femoral hypoplasia, coxa vara and possibly a true proximal femoral focal deficiency (PFFD). Congenital posteromedial bowing of the infantile tibia is considered ‘benign’ in that the deformity improves with growth. However, there is often a significant residual leg length discrepancy. 186

Previous formation of heterotopic ossification. Although the exact aetiology is poorly understood, if there is a history of heterotopic ossification, then it is very likely to recur at a new site of surgery. Other factors include: ankylosing spondylitis, hypertrophic osteoarthritis, and diffuse idiopathic skeletal hyperostosis, with weaker evidence for extensive soft tissue handling/stripping, or bone debris from reamings. Although patients with head injuries are found to produce extensive calcific deposits a patient would not have elective total hip replacement so soon after significant head injury. Over-expression of bone morphogenetic protein-4 BMP-4) may be implicated in the pathogenesis of heterotopic ossification.

Gram-positive coccus Gram-negative coccus Gram-positive bacillus Gram-negative bacillus Steptococcus Actinomyces Escherichia coli Coryneform Salmonella typhi Diphtheroids Klebsiella pneumoniae Helicobacter pylori

Open washout/debridement, polyethylene exchange and intravenous antibiotics. This patient presents with an early prosthetic infection. The accepted treatment is an open debridement and intravenous antibiotics. Arthroscopic washout can be effective in some situations, but intravenous antibiotics alone are not likely to be successful. Single or staged revision is acceptable treatment for an infected joint replacement, but would not be used in the first instance, and is reserved for if the initial treatment fails. 108

She has a claw hand. She has tight intrinsic muscles and her Bunnell test is positive as the intrinsic muscles are more powerful than her extrinsic extensors and flexors. The tight intrinsic muscles are treated with distal releases when fibrotic and a proximal slide when spastic. An intrinsic minus hand is one where there is a loss of function in the ulna and sometimes the median nerve (claw). The patient presents with a monkey grip.

An injury with external tibial rotation with the knee at 90
of flexion is likely to injure the posterior cruciate and lateral collateral ligaments. Neuromuscular training indeed explains the gender difference in the incidence of anterior cruciate ligament in similar sports, but it is higher in women. Furthermore, women have a greater total valgus knee loading when landing from a jump. A grade 3 posterior cruciate ligament injury does not necessarily need reconstruction. The majority of grade 1 and 2 injuries can be treated with protected weight bearing and quadriceps rehabilitation. Grade 3 injuries require immobilization in full extension for 2 to 4 weeks to protect the posterior cruciate ligament and the other posterolateral structures presumed to be damaged. Prophylactic knee bracing has not been shown to reduce anterior cruciate ligament injuries in contact sports, but has been shown to reduce medial collateral ligament injuries. 111

The pudendal nerve is at risk as it enters the pelvis through the greater sciatic notch. The Kocher–Langenbeck approach provides exposure to the posterior wall of and posterior column of acetabulum. It is considered by some as an extension to the posterior approach to the hip and exposes the greater sciatic notch and lesser sciatic notch. The superior gluteal artery and nerve are at risk of injury here and must be protected. The pudendal nerve is at risk, but it exits the pelvis via the greater sciatic notch and re-enters via the lesser sciatic notch.

A material that has an elastic limit that approximates its fracture point. A material that can undergo extensive plastic deformation is said to be ductile. Hardness is a surface property of a material. The amount of deflection for a given load relates to a material’s stiffness. The maximum amount of stress a material can withstand prior to failure is its ultimate tensile stress.

Abductor. There is no abductor compartment in the foot. Traditionally, nine compartments are described. The names and muscular contents are: Calcaneal – quadratus plantae Interosseus (4) – interossei Adductor – adductor hallucis Medial – flexor hallucis brevis, abductor hallucis Lateral – abductor digiti minimi, flexor digiti minimi Superficial – flexor digitorum brevis, lumbricals, flexor digitorum longus

Young age (<25 years old) at time of dislocation. The only consistent predictor of recurrence has been the age of the patient. In young patients (<25 years old), recurrence rates have ranged from 60% to 94%. Family history confers a 34% risk of recurrence, while dislocation in the contralateral shoulder is seen in 25% of recurrently unstable patients according to Hovelius et al. No difference in dominant and non-dominant extremities was noted.

Natatory ligament. This key question is a test of anatomy. Before considering surgery a thorough knowledge of local structures is important. The distortion of the normal anatomy results in displacement of the neurovascular structures, and explains the significant risk in Dupuytren’s disease surgery.

Decreased serum phosphate levels. Hypophosphatasia is an autosomal recessive disorder caused by an inborn error of the isoenzyme of alkaline phosphatase (ALP). Its features are similar to those of rickets. It is not associated with decreased serum levels of phosphate or calcium. Vitamin D and parathyroid hormone (PTH) levels are usually normal.

Brachioradialis. Many muscle groups in the upper limb have dual innervation. Brachialis (musculocutaneous and radial), flexor digitorum profundus (anterior interosseus and ulna), lumbricals (recurrent median and ulna) and pectoralis major (lateral pectoral and medial pectoral) are examples.

An ipsilateral far lateral disc herniation at L5–S1. A paracentral disc herniation at L4–L5 or a far lateral disc herniation at L5–S1 most commonly result in an L5 radiculopathy and therefore weakness of the gluteus medius, resulting in a Trendelenburg gait. A paracentral herniation at L5–S1 most commonly affects the S1 nerve root. A paracentral herniation at L3–L4 and a far lateral herniation at L4–L5 all affect the L4 root.

Ca10 (PO4)6 (OH)2. Calcium hydroxyapatite (Ca10 (PO4)6 (OH)2) forms part of the inorganic component of the bone matrix and gives it compressive strength.

Vascularized fibular graft. As long as there is no collapse of the femoral head, vascularized fibular graft has been shown to be superior to non-vascularized by reducing progression to collapse, as well as having better Harris Hip Scores.

Young woman, injured hill-running. In general, outcome following operative management of calcaneal fractures relies on the number of intra-articular fragments and the quality of articular reduction. A number of factors have been shown to be associated with a poor outcome and they include age >50, obesity, manual labourers, work insurance cases, smokers, bilateral fractures and vascular disease. In addition, men appear to do worse with surgery than women.

Posterior column and posterior hemitransverse. The Judet and Letournel classification describe 10 fracture patterns: Simple fractures posterior wall posterior column anterior wall anterior column transverse Complex/associated fracture both columns posterior wall and transverse T-shaped fracture anterior column and posterior hemitransverse posterior wall and posterior column

Nerve stimulation therapy. If symptoms are not severe and there is not significant and progressive neuropathy then non-operative management must be considered. This includes splintage, hand therapy, steroid injection and even yoga has been proven to be beneficial. Alternatively a patient could be referred for either open or endoscopic release.

There is a poorer implant survivorship in patients with rheumatoid arthritis. Raising or lowering the joint line during total knee replacement can have an adverse effect on range of motion, patellar function and stability, and can lead to early revision. The accepted safe distance for altering the joint line is 8 mm. The minimum thickness of an ultra-high-molecular-weight polyethylene insert is 6–8 mm; thinner implants are associated with earlier failure due to fatigue wear. Contraindications to total knee replacement include a deficient extensor mechanism, infection, vascular deficiency and neuromuscular abnormalities affecting the muscles around the knee. Patients with rheumatoid arthritis have a lower risk of failure of total knee replacement; other good prognostic variables are age over 60 and use of a condylar prosthesis with a metal-backed tibial component. Following patellectomy, it is thought there are increasing stresses on the posterior cruciate ligament, resulting in deficiency and greater anteroposterior instability if the ligament is not substituted.

Internal rotation (IR) 30º, Flexion 30º, Abduction 30º. Shoulder arthrodesis should be performed so that the arm rests comfortably at the side without scapular winging and so that the hand can be brought easily to the mouth and perineum. 42 a. Instability of a vertebral fracture can be determined by loss of vertebral height >50%. b. There is no direct relationship between canal compromise and neurological deficit. c. Instability of injuries can be determined by further neurological deterioration under normal physiological load. d. Widening of the interpedicular distance on plain radiograph can indicate a burst fracture. e. In a thoracic burst fracture, a thoracolumbar orthosis is indicated if there is <50% loss of vertebral body height and >30% kyphosis. scoliosis are true except? a. With curves of 20–29
, 40% of patients who are Risser 0–1 are at risk of curve progression. b. With curves of 20–29
, 22% of patients who are Risser 2–4 progress. c. After skeletal maturity, a lumbar curve >35
can progress by 1–2
/year. d. A late curve progression in males is more common than in females. e. A rapid curve progression in females occurs before menarche and before Risser 1. retroperitoneal approach, all of the following statements are correct except? a. The ureter is adherent to the posterior peritoneum and falls away from the psoas through the dissection. b. The sympathetic trunk, lying longitudinally along the lateral border of the psoas, is at risk during this procedure. c. The ilioinguinal nerve emerges from the lateral border of the psoas and travels to the quadratus lumborium. d. A cold and pale right foot is a recognized post-operative examination finding. e. The genitofemoral nerve lies on the anteromedial surface of the psoas. except? a. Non-dystrophic deformities are indistinguishable from idiopathic scoliosis. 47

Revision to a constrained knee prosthesis. Medial collateral ligament deficiency in a total knee replacement may present with pain, instability or both. A knee brace may provide a temporary solution. Repair or reconstruction of the ligament is unlikely to provide the necessary valgus resistance, and the only sensible option is to revise to a constrained prosthesis. There is some debate as to whether this can be a high posted design (non-linked) or whether it has to be hinged. 112 a. Sural. b. Saphenous. c. Tibial. d. Deep peroneal. e. Superficial peroneal. the most important factor in predicting a satisfactory outcome? a. Severity of initial injury. b. The state of the articular cartilage. c. The age of the patient. d. The smoking status of the patient. e. Whether or not a compensation claim is involved. a. Absent fibula. b. Deficient knee ligaments. c. An equinovarus deformity. d. Talocalcaneal coalition. e. Proximal femoral focal deficiency. a. Oligohydramnios. b. Arthrogryposis. c. Congenital talipes equinovarus. d. Tarsal coalition. e. Developmental dysplasia of the hip. performing. The likely diagnosis is? a. Hallux valgus. b. Hallux rigidus. 119

Medial cuneiform to base of second metatarsal on plantar surface. The Lisfranc ligament is a strong oblique ligament, which arises from the plantar-lateral aspect of the medial cuneiform, passes in front of the intercuneiform ligament, and inserts into the plantar-medial aspect of the second metatarsal. In about 20% of patients, there are two separate bands of the ligament (dorsal and plantar).

Medial circumflex vessels. The blood supply to the proximal femoral epiphysis is reported to change with age. Until age 4, the supply to the femoral head is derived equally from medial and lateral circumflex vessels as well as the ligamentum teres. The physis acts as a mechanical barrier with virtually no traversing metaphyseal vessels reaching the epiphysis. After age 4, supply from the ligamentum teres diminishes and the distribution of supply from the circumflex vessels changes; the lateral circumflex system supplies predominantly the metaphysis whilst the medial circumflex system becomes the predominant supply to the proximal femoral epiphysis via its posterosuperior branch. After age 10 years, supply by the ligamentum teres diminishes further and the femoral epiphysis relies upon the end arterial supply of the retinacular vessels. With the closure of the physis at skeletal maturity, anastamoses develop between the vessels of the ligamentum teres, epiphyseal and metaphyseal systems and there is less reliance on end arteries.

A hyperextension injury in a patient with a facet joint hypertrophy and thickened ligamentum flavum. Central cord syndrome is the most common incomplete spinal cord lesion. It is usually seen in patients with cervical spondylosis who sustain a hyperextension injury. The mechanism causes compression of the cord by osteophytes anteriorly and ligamentum flavum posteriorly. 65 avascular necrosis (AVN) and non-union rates are affected in this way? a. No difference between AVN and non-union rates. b. AVN higher, no change in non-union. c. No change in AVN, non-union higher. d. AVN and non-union both higher. e. AVN higher but non-union lower. posterior approach to the hip? a. Inferior gluteal. b. Superior gluteal. c. Pudendal. d. Ascending branch of lateral circumflex femoral. e. Popliteal. a. Wound infection is higher with use of drains. b. Haematoma formation is lower with use of drains. c. Wound dehiscence is more likely without the use of drains. d. Blood transfusion is more likely with the use of drains. e. Bruising is more likely with the use of drains. a. Lateral circumflex artery. b. Obturator artery. c. Medial circumflex artery. d. Descending branch of lateral circumflex artery. e. Superior gluteal artery. a. Gluteus minimus and tensor fascia lata. b. Obturator internus, superior and inferior gemelli. 71

Low (T1)/High (T2). MRI uses radiofrequency pulses on tissues in a magnetic field to generate images in different planes. Protons in compounds of hydrogen (e.g. water, fat, marrow, etc) are aligned in a magnetic field. The strength of this imaging modality is its sensitivity to changes in water distribution. T1 images are weighted towards fat and T2 images are weighted towards water. Water, cerebrospinal fluid and soft tissue tumours appear dark on T1 sequences and bright on T2 sequences. Fat, nerves and bone marrow appear bright on T1 sequences and grey (moderate) on T2 sequences.

Osteofibrous dysplasia. Most orthopaedic oncology centres would agree that there is no role for curettage and grafting in osteofibrous dysplasia. This condition often regresses by the time a child reaches 161 skeletal maturity and therefore observation is all that is required. This line of management is controversial. Osteofibrous dysplasia has been linked to progression to adamantinoma, in which case wide surgical excision is recommended.

Nail patella syndrome. This syndrome is a result of an abnormality on chromosome 9. Patients may have subluxed or dislocated radial heads and never realize they have a problem until they have an X-ray. The syndrome can include abnormalities of the patella and nail growth, generalized ligamentous laxity and bony exostoses.

Cobalt chrome, stainless steel, titanium, cortical bone, PMMA cement, UHWMPE. Material Young’s modulus (approx. values in GPa) Ceramic 350 Cobalt chrome 210 Stainless steel 190 Titanium 100 Cortical bone 20 PMMA cement UHWMPE Cancellous bone Tendon Cartilage

Less in ceramic than polyethylene cups. The Swedish Hip Registry reports that deep infections are slightly lower with ceramic components. The exact mechanism is unclear, but may be due to bacterial adhesion being poorer on the smoother surface of ceramic components.

Right L5 perineural fibrosis. Gadolinium-enhanced MRI scans are helpful post discectomy in differentiating between recurrence of disc herniation, which does not enhance with gadolinium, and perineural 61 fibrosis, which shows enhancement around the root. A schwannoma enhances with gadolinium although the root would be enlarged. Systemically the patient is well and there is no evidence of fluid collection on scanning to suggest an infective process.

Patella baja. Total knee replacement after a proximal tibial osteotomy presents a number of technical difficulties. Studies have shown that these knee replacements are more prone to complications such as persisting pain, malalignment and infections. Any number of problems can be encountered during surgery, but the most common is patella baja, seen with both opening and closing wedge osteotomies, although more commonly in the latter. Another important consideration is the change in tibial slope as closing wedge tends to decrease the posterior tibial slope and opening wedge increases it.

Mucoid cyst. This is a common lesion that arises from the osteoarthritic DIP joint. There is usually a disruption of the joint and a cyst develops. They cause deformity of the nail because of pressure on the germinal matrix. If they are large it may be necessary to perform a local flap at excision (transposition).

None of the above. The talus is made up of a head, neck, body and posterior process. It articulates with the tibia and fibula in the ankle, and the navicular and calcaneum in the foot. It has many ligamentous attachments but no muscle attachments. There is a groove posteriorly in which the flexor hallucis longus tendon runs. It is important to be aware of the blood supply of the talus; the primary source is the artery of the tarsal canal (derived from the posterior tibial artery); additional supply is from the superior neck vessels (derived from the anterior tibial artery) and the artery of the sinus tarsi (derived form the dorsalis pedis).

Homeobox genes. Limb buds are formed from mesoderm covered with surface ectoderm. The upper limb bud appears at 4 weeks post-fertilization and the lower limb bud appears two days later. Two areas form within the mesoderm – the lateral mesoderm which forms bone, cartilage and connective tissues and the somite which forms the muscular elements. Homeobox (Hox) genes via fibroblast growth factors (FGFs) influence development of the apical ectodermal ridge (AER), which is responsible for proximal to distal growth. Hox gene abnormalities therefore lead to proximal/distal losses. The AER is a transient region of activity from which the digits develop. Separation of the digits occurs at around 50 days. Apoptosis under the influence of BMPs allows digits to separate and prevents webbing whereas noggins block apoptosis thereby preserving the webbing of the digits. The Sonic hedgehog genes control the zone of proliferating activity (ZPA) in the mesoderm that is responsible for radial to ulnar growth and differentiation, i.e. the little (fifth) finger from the thumb.

anterior column of the elevated acetabulum (mnemonic: OOPWAC – Obturator Oblique Posterior Wall Anterior Column), but not the sacroiliac joint so well; and Iliac oblique, where the pelvis on that side is rotated so that the iliac wing is parallel to the X-ray cassette and the obturator foramen now lies perpendicular to the film, showing the anterior wall and posterior column.

Quadrigia effect. Though this was a bony avulsion it must be thought of like any other FDP tendon injury. In this case because of the proximal migration of the tendon it was probably repaired tightly with an adhesed improperly tensioned FDP. Because the adjacent remaining fingers share a common muscle belly, they cannot flex entirely (quadrigia effect).

Decreased risk of re-injury. This patient has an Achilles tendon rupture. Operative and non-operative management are both acceptable options, but the principal advantage of the former is a decreased risk of re-rupture. This benefit has to be balanced against the complications of surgery, which include wound breakdown, infection and nerve injury. Some of these risks may be reduced by performing surgery percutaneously. Pain and speed of recovery are not necessarily improved by surgery. Surgery may allow a shorter immobilization time, but this is not the principal benefit.

Sharp’s All of these lines on the anteroposterior (AP) pelvic radiograph are used to assess the degree of hip dysplasia/incongruence. Hilgenreiner’s line is made horizontally through the superior triradiate cartilage and serves as a reference for Perkin’s line and for measuring the acetabular index. Perkin’s line is perpendicular to Hilgenreiner’s at the superior edge of the ossified acetabulum. Normally, the femoral head should sit in the inferomedial quadrant at the intersection of these lines. Shenton’s line traces the lower edge of the pubis and the inferior aspect of the femoral neck. Any disruption to this line implies joint subluxation. Wiberg’s angle, known as the centre edge angle, is formed by the intersection of a line passing vertically upwards from the centre of the femoral head and a second line again passing from the centre of the head to the superior edge of the ossified acetabulum. This calculation is most reliable after age 5 due to increased ossification. A normal Wiberg’s angle is >25
. Sharps’s line is an alternative method of measuring the acetabular angle. The more common method is to use Caffey’s line drawn from the superior ossified acetabulum which forms an angle with Hilgenreiner’s line at the superior margin of the triradiate cartilage. This method measures the superior acetabular angle that should be <30
under age 2 191 and <20
after age 2. Sharp’s angle measures the inclination of the entire acetabulum. Sharp’s angle is formed by the intersection of a horizontal line at the inferior teardrop and a line passing through it that joins the superolateral and inferomedial aspects of the bony socket. It is used after 9 months when the teardrop becomes visible radiologically. Normal infants should have a value of <50
reducing to <38
in adolescence.

Patients over 80 years should not have a unicompartmental knee replacement. The contraindications to unicompartmental knee replacement include anterior cruciate deficiency, inflammatory arthropathy, fixed varus deformity and medial or lateral subluxation. Patellofemoral arthritis is not always considered an absolute contraindication. Although often carried out in younger patients, if the indications are correct, a unicompartmental knee replacement can be carried out at any age. There is continued debate about unicompartmental versus total knee replacement and it is the subject of on-going trials. However, there is evidence to support better subjective results in unicompartmental; this may be due to a better ‘feel’, owing to the fact that both cruciate ligaments are retained. Simultaneous anterior cruciate ligament reconstruction and unicompartmental knee has been described. 110

Enchondral ossification. Primary healing (also known as Haversian remodelling) is a direct healing process at the cortex requiring anatomical reduction and rigid stability. Secondary bone healing involves responses in the periosteum and external soft tissues. There are two types; enchondral healing which occurs with non-rigid fixation (such as fracture braces, external fixation, bridge plating, intramedullary nailing); and intramembranous healing which occurs with semi-rigid fixation (such as locked plating in a non-absolute stability construct).

Scaphoid extension. In rheumatoid arthritis the inflammation of the synovium sets off a sequence of events that start with correctable deformity and eventually lead to fixed deformity and destruction of the joints. The synovitis at the DRUJ leads to capsular stretching with ECU subluxation and stretching of the dorsal structures. There is erosion of the radio-scapho-capitate ligament with flexion of the scaphoid. The carpus supinates as it moves in an ulna direction. Rather than the ulna becoming prominent it is the carpus that slips away from it.

It is responsible for bone formation in distraction osteogenesis. Intramembranous ossification describes ossification which occurs without a cartilage model, in comparison to enchondral ossification. Examples of this process include embryonic flat bone formation (e.g. skull, maxilla, mandible, pelvis, clavicle, subperiosteal surface of long bone), distraction osteogenesis bone formation, blastema bone (occurs in children with amputations) and fracture healing with rigid fixation (compression plate). Hurler’s syndrome is a mucopolysaccharidoses (lysosomal storage disease) and intramembranous ossification in not affected. Cleidocranial dysplasia, however, does involve defective intramembranous ossification.

In a thoracic cord injury, the return of the bulbocavernosus reflex signals the termination of spinal shock. The AO classification of spinal fractures is: Type A – compression and burst injuries Type B – flexion-distraction injuries Type C – fracture-dislocation When testing myotomes, finger abduction is under the control of the T1 nerve root: C5 – shoulder abduction/elbow flexion C6 – wrist extension/supination C7 – elbow extension/wrist flexion/pronation C8 – finger flexion T1 – finger abduction A Chance fracture is a flexion-distraction injury, which involves two or three columns (anterior may be preserved).

Closed reduction in theatre, with reassessment of the vascularity. This is a common scenario, and does not always imply a significant arterial injury. It is not appropriate to perform reduction in the emergency department. Instead, a closed reduction, with or without percutaneous K-wiring, should be performed and the vascularity reassessed. Urgent brachial angiography would delay treatment, and primary vascular exploration should not be performed. There is debate as to how urgent reduction should be performed in this scenario; a cold pulseless hand requires urgent treatment.

It is the 10 cm perforator from the posterior tibial artery, medially which is usually the largest and most reliable for distally based fascio-cutaneous flaps. Current management of open fractures has evolved and the involvement of specialist centres is recommended. All wounds do not require immediate exploration. Indications for urgent surgery include gross contamination of the wound, compartment syndrome, a devascularized limb and a multiply injured patient. Otherwise initial surgery (bony and soft tissue) should be performed by senior plastic and orthopaedic surgeons working together on scheduled trauma operating lists within normal working hours and within 24 hours of the injury (unless there is marine, agricultural or sewage contamination).