2018 Flashcards
If you increase the stiffness of instruments used for spine implants how does it affect the fusion mass?
A. Increased junctional failure rates/pseudoarthrosis
B. Decreased volumetric fusion mass
C. Increased mechanical load to failure
D. Decreased …
B
2024F Consensus
Which of these patients is least likely to benefit from a Varus de-rotation Osteotomy?
A. 8 year old with Herring B
B. 7 year old with lateralized hip
C. Epiphyseal slip angle >20%
D. Performing the osteotomy during initial or fragmentation phase of disease
C
A: Herring (Lateral Pillar) B is a good indication for VDRO. Herring C do poorly regardless of treatment
B: Lateralized hip is a good indication to increased femoral head coverage with VRDO
D: Initial or fragmentation phase is when you want to perform VRDO to contain the femoral head and promote spherical head development
Regarding spinal tracts, all are true except?
A. In the lateral corticospinal tract, the cervical spine is central to the sacrum
B. Lateral corticospinal tract carries more motor than anterior corticospinal tract
C. In the dorsal columns, the cervical spine is central to the sacrum
D. Lateral and anterior corticospinal tracts are also known as the pyramidal tracts
C
Which of the following is associated with an increased risk of complications with halo treatment in paediatric patients?
A. Re-tightening the screws at an appropriate interval
B. Placing the ring 2 cm above the pinna
C. Placing the ring closer to the skull
D. Using 6 pins instead of 4
B
JAAOS 2007 – The Halo Fixator
Position:
-Most halo systems offer a range of sizes (small, medium, large). The ring should not be >1 cm away from the skin and should not contact the skin or the ears at any point.
-Using a too large ring can increase cantilever bending of the pins, which may predispose to loosening.
In addition, if the ring is too large, the pins may not reach the cranium.
-To achieve ideal halo ring position, the anterior pin trajectories must be directed toward the safe zone, approximately 1 cm above the eyebrows and just above the pinnae, and at or below the equator of the skull
-The safe zone is the 1 cm width of bone above the lateral border of the eyebrow
-More lateral pin insertion risks penetration of the thin temporal bone
-More medial positioning risks injury to the supraorbital and supratrochlear nerves
Special Considerations: Pediatrics
-A CT scan of the head should be obtained before placement of a halo ring in children.
-Avoid inserting pins in immaturely fused cranial sutures and thin cortices
-Use 10-12 pins at 2 in-lb
-Avoiding the thin bone of the temporal region and frontal sinuses.
-The threshold age at which a 4-pin versus a multiple-pin arrangement should be used has not been established
-It is imperative to regularly check the patient’s cranial nerve function, particularly the function of CN-VI
Earliest complications associated with traction, with a reported incidence of 0.07%
-This complication can result in diplopia.
-Pin site infection is more common in children
39% to 57% of the time
-Superficial infections may not be associated with pin loosening
-Can be treated with PO ABX +/- pin removal
-Skin breakdown (ie, pressure necrosis) Incidence of 2% to 11%. More frequent in the elderly and the obtunded patient
Regarding a TKA using a PCL-substituting prosthesis, which of the following is true?
A. The joint line can be changed by 12mm
B. Cutting the PCL increases flexion gap by 2-3mm
C. ROM is greater for PCL-substituting than for PCL retaining implants
D. Survivorship is greater in PCL-substituting arthroplasties
C
Consensus 2024F
You design a study to compare the wear rates of 22mm, 28mm, 32mm, and 36mm femoral head sizes to each other. What methodology comparison test should you use?
A. Chi-squared
B. T-test
C. Analysis of variance (ANOVA)
D. Linear regression analysis
C
Parametric inferential statistics
-Continuous data that is normally distributed
-Continuous data is data that can take any value. Height, weight, temperature and length are all examples of continuous data.
-Normal distribution - The mean, mode and median are all equal. The curve is symmetric at the center (i.e. around the mean, μ). Exactly half of the values are to the left of center and exactly half the values are to the right. The total area under the curve is 1.
-Normal distribution can be assumed based on the central limit theorem (n=30)
Nonparametric inferential statistics
-Continuous data that is not normally distributed (skewed)
Categorical data
-Categorical variables represent types of data which may be divided into groups. Examples of categorical variables are race, sex, age group, and educational level.
IIIA tibia fracture, wound bed is clean after primary I&D, which is true regarding primary vs delayed closure:
A. More infection with primary closure
B. More infection with delayed closure
C. More wound complications with delayed closure
D. More wound complications with primary closure
B
JBJS 2014 Delayed Wound Closure Increases Deep-Infection Rate Associated with Lower-Grade Open Fractures.
- Primary closure of skin wounds after debridement of open fractures is controversial.
The purpose of the present study was to determine whether primary skin closure for grade-IIIA or lower-grade open extremity fractures is associated with a lower deep-infection rate.
- We identified 349 Gustilo-Anderson grade-I, II, or IIIA fractures treated at our level-I academic trauma center from 2003 to 2007. 87 injuries were treated with delayed primary closure, and 262 were treated with immediate closure after I&D. After application of a propensity score-matching algorithm to balance prognostic factors, 146 open fractures (73 matched pairs) were analyzed.
- Deep infection developed at the sites of 3 of the 73 fractures treated with immediate closure (infection rate, 4.1%; 95% CI, 0.86 to 11.5) compared with 13 in the matched group of 73 fractures treated with delayed primary closure (infection rate, 17.8%; 95% CI, 9.8 to 28.5) (p = 0.0001).
- Immediate closure of carefully selected wounds by experienced surgeons treating grade-I, II, and IIIA open fractures is safe and is associated with a lower infection rate compared with delayed primary closure.
Pincus D, Byrne JP, Nathens AB, Miller AN, Wolinsky PR, Wasserstein D, Ravi B, Jenkinson RJ. Delay in Flap Coverage Past 7 Days Increases Complications for Open Tibia Fractures: A Cohort Study of 140 North American Trauma Centers. J Orthop Trauma. 2019 Apr;33(4):161-168. doi: 10.1097/BOT.0000000000001434. PMID: 30893215.
- Higher rates of deep infection, osteomyelitis, pneumonia, decubitus ulcer with delayed coverage
- NO difference in lower extremity amputation, DVT/PE, death
ABCs show all of the following characteristics, except?
A. Fluid-fluid levels on MRI
B. Same age group as GCT
C. Use adjunctive treatment such as cryotherapy
D. Expect them to get better with growth
B
JAAOS 2013 – Aneurysmal Bone Cyst
- Gene rearrangements localized to t(16;17) in 36 of 52 primary ABCs (69%) in which the ubiquitin-specific protease 6 (USP-6) oncogene was placed under the regulatory influence of the highly active cadherin-11 promoter. They found no such translocations in 17 cases of secondary ABC.
- In patients with ABC, age of onset ranges from 1 to 59 years, with the greatest prevalence between ages 12 and 13 years.
– 75% of patients are < 20 yrs
– GCT: ages 30-50 years
- ABC: one of the most common malignancies of the posterior elements of the spine
- Associated with other tumors 30% of time
– Giant cell tumor
– Chondroblastoma
– Fibrous dysplasia
– Chondromyxoid fibroma
– NOF
Imaging:
- Radiolucent cystic lesion within the metaphyseal portion of the bone. The lesion is destructive and may expand into the surrounding cortical bone.
- Mass may elevate the periosteum, but it typically remains contained by a thin shell of cortex.
- ABCs are eccentric, but may also be central or subperiosteal.
- MRI with contrast typically demonstrates internal septations that may contain characteristic fluid-fluid levels, signifying layering of solid blood components within cystic areas of the lesion.
- NOT PATHONAMONIC!
Management:
Nonoperative
- Indication
– ABC with acute fracture
– Non-op management is indicated until fracture has healed.
– Once healed, treat as an ABC without fracture unless the fracture has led to spontaneous healing of the ABC
– Standard is curettage and bone grafting
– Adjuvant treatment is intended to treat microscopic disease contamination within the tumor bed to lower the incidence of local recurrence.
– Use of cryotherapy has been found to reduce the recurrence rate of ABC.
– Sclerotherapy is a noninvasive management method based on the theory that ABCs arise as a vascular malformation and would heal if the hemodynamic disturbance were controlled.
Regarding total elbow arthroplasty versus ORIF in comminuted distal humerus fracture in the elderly, which of the following is true?
A. TEA has improved outcome over ORIF at 1 year
B. Patient functional outcomes for TEA are better at 1 year
C. Re-operation rates for ORIF are significantly higher at 1 yr
D. It is “almost impossible” to do a quality ORIF with poor bone
B
McKee M, et al. A multicenter, prospective, randomized, controlled trial of open reduction–internal fixation versus total elbow arthroplasty for displaced intra-articular distal humeral fractures in elderly patients. Journal of Shoulder and Elbow Surgery 2009
- Prospective, randomized, controlled trial to compare functional outcomes, complications, and reoperation rates in elderly patients with displaced intra-articular, distal humeral fractures treated with open reduction-internal fixation (ORIF) or primary semiconstrained total elbow arthroplasty (TEA). n=42
Results:
- Decreased operative time in TEA group
- TEA better Mayo Elbow Performance Score at 3 and 6 months, 1 year and 2 years compared to ORIF
- ROM not significantly different
- reoperation rates not significantly different
What is true about nailing of an open tibia fracture?
A. Unreamed nails are better biomechanically and have ?stronger fixation and maintenance of alignment (something like this)
B. Thermal necrosis from reaming has no effect on (can’t remember if they said infection or if they said union)
C. Reamed nails are associated with fewer infections
D. Reaming allows for a larger nail which has improved fixation strength and maintenance of alignment
D
JAAOS 2010 – Open Tibial Shaft Fractures II: Definitive Management and Limb Salvage
- The current clinical evidence does not support the superiority of reamed or unreamed nailing in the treatment of open tibial shaft fractures
Reamed Nailing:
- Allows placement of larger diameter nails leading better fracture stability and reduced HW failure
- Deposits bone graft at fracture site
- Damages endosteal blood supply more than unreamed and when soft tissue stripped from open injury
- Thermal necrosis is a theoretical concern.
- Clinical studies have not found significantly increased infection or nonunion rates with reaming.
In plantar fasciitis - all are RFs, except?
A. Pes planus
B. Cavus foot
C. Heel spur
D. Tight Achilles
C
JAAOS Plantar Fasciitis 2008
- A pes planus or pes cavus foot deformity can increase loading of the plantar fascia.
- An Achilles muscle/tendon contracture is frequently associated with plantar fasciitis.
- It is now widely accepted that heel spurs can occur with plantar fasciitis, but they are not the cause.
All of the following are associated with idiopathic toe walking, except?
A. Decreased passive dorsiflexion
B. Increased tone in upper extremities
C. Autism
D. Learning disability
B
JAAOS 2012:
- Many patients who toe walk are able to achieve a normal amount of dorsiflexion (10° to 20°); thus, limited dorsiflexion may or may not be present on examination.
Lovell and Winter’s:
- On bench examination, the range of passive ankle plantarflexion will be normal and dorsiflexion will be limited, secondary to a variable degree of true shortening of the heel cord.
- The posterior calf muscles are typically very well developed; in fact, they may appear to be enlarged.
- However, the muscle texture will feel normal on examination and there will be no evidence of any weakness, proximal or distal, in the upper or lower extremities.
Idiopathic Toe-Walking: Prevalence and Natural History from Birth to Ten Years of Age. JBJS 2018:
- Prevalence of toe walker is 5% in children age 5 years
- Associated with neurodevelopment delay, disorder and symptom; Autism, ADHD, CP.
- Toe walking diagnosis between 5-10: By age of 10: 79% will have spontaneous resolution, 13 % still toe walker, 8% has surgery.
In pediatric patients undergoing biopsy, when should samples also be sent for anaerobes, acid-fast bacilli and fungus?
A. Should be sent in all patients
B. Osteomyelitis with associated septic arthritis
C. Osteomyelitis following a penetrating injury
C
Microbiologic culture methods for pediatric musculoskeletal infections. JBJS AM 2015
Conclusions: Anaerobic, fungal, and AFB cultures should not be routinely performed during the initial evaluation of children with hematogenous musculoskeletal infection. These cultures should be performed for children with immunocompromise, clinical suspicion of penetrating inoculation, or failed primary treatment
A 10 year old kid has blounts. He is Langenskiold V and has depression of the medial tibial plateau. Which of the following surgical options would be least helpful?
A. Distal femoral osteotomy for compensatory valgus deformity
B. Proximal tibial epiphiseolysis (?epiphysiodesis)
C. Varus correcting proximal tibial osteotomy with medial plateau elevation
D. Another proximal tibial osteotomy that sounded more like what we usually do
B
2024F consensus
