Remediation:
A. A delayed union is defined as progression of radiographic but it lags behind what the normal healing time should be for a particular fracture.
B. Atrophic nonunions are avascular in nature. Radiographs will show no evidence of callus formation or healing.
C. The radiograph shows evidence of a hypertrophic nonunion, which is characterized by abundant callus formation due to persistent motion at the fracture site. This may be secondary to inadequate stability or patient-dependent factors (e.g., excessive or premature weight-bearing).
D. Oligotrophic nonunion is a hypervascular nonunion and is characterized by the lack of substantial callus formation.
E. A pseudarthrosis, or fibrous nonunion, is defined as nonunion that chronically develops into a jointlike appearance with a hypertrophic or atrophic callus due to gross motion.

Remediation:
A. An ulnar collateral injury in a nonthrowing athlete will usually resolve with nonoperative treatment. Rest and stretching are appropriate nonoperative treatments.
B. Prolonged immobilization is not needed for rehabilitation of an acute ulnar collateral ligament injury.
C. An acute ulnar collateral ligament injury in a nonthrowing athlete will typically resolve with nonoperative management.
D. An acute ulnar collateral ligament injury in a nonthrowing athlete will typically resolve with nonoperative management.

Remediation:
A. A rigid cervical collar is generally used for a type-I hangman's fracture, which is characterized by <3 mm of horizontal displacement without disruption of the C2-C3 intervertebral disc and the posterior longitudinal ligament (PLL).
B. In an acute type-II hangman's fracture, one should avoid obtaining flexion/extension radiographs because this may cause further fracture displacement and angulation.
C. Operative fixation is recommended for a type-II hangman's fracture with displacement >5 mm or for any type-III hangman's fracture, which is characterized by bilateral C2-C3 facet dislocation.
D. This patient has a type-II hangman's fracture, which is characterized by >3 mm of horizontal displacement with disruption of the C2-C3 intervertebral disc and the posterior longitudinal ligament (PLL). If the fracture is <5 mm (as in this case), the recommended treatment is closed reduction followed by halo vest immobilization.

Remediation:
A. Variations in design between reverse shoulder prostheses can affect the postoperative angles of attachment of the deltoid components.
B. The deltoid is not transferred. Wrapping refers to its insertion on the bone and not an attachment to the prosthesis itself.
C. While the soft-tissue envelope may wrap the deltoid in a sense, this is not what the term deltoid wrapping describes.
D. While internal rotation following reverse shoulder arthroplasty may be one of the remaining limitations, it does not describe the term deltoid wrapping.

Remediation:
A. A Salter osteotomy is a single transverse cut above the acetabulum, from just distal to the anterior superior iliac spine to the sciatic notch. The acetabulum is rotated and hinges through the pubic symphysis to improve anterolateral acetabular coverage.
B. A Salter osteotomy hinges through the public symphysis. A Pemberton and/or Dega osteotomy hinges through the triradiate cartilage.
C. A Salter osteotomy hinges through the public symphysis. Reconstructive osteotomies for pediatric hip dysplasia either hinge through either the pubic symphysis or the triradiate cartilage.
D. A Salter osteotomy hinges through the public symphysis. Reconstructive osteotomies for pediatric hip dysplasia either hinge through the pubic symphysis or the triradiate cartilage.

Remediation:
A. While PAX3 translocation products are associated with multiple malignancies, including PAX2-FOXO1 (alveolar rhabdomyosarcoma) and PAX3-MAML3 (sinonasal sarcoma), these are not known to be associated with these benign conditions.
B. Chondroblastoma and giant cell tumor of bone share many similarities, including either epiphyseal/apophyseal location predilection, potential for lung metastasis, and frequent association with secondary aneurysmal bone cysts. In addition, both are associated with alterations in histone H3.3 (H3F3A in giant cell tumor, H3F3B in chondroblastoma).
C. TP53 is a tumor suppressor gene, and mutations in TP53 are associated with numerous malignancies. In particular, Li-Fraumeni syndrome is associated with osteosarcoma and breast carcinoma, among other malignancies.
D. EXT1 and EXT2 mutations are associated with multiple hereditary exostoses, an autosomal dominant heritable condition with numerous osteochondromas.

Remediation:
A. While the flexor digitorum profundus can serve as a deforming force volarly, pull of the flexor alone will not lead to instability.
B. The terminal extensor displaces the dorsal lip fracture. The extensor is not in continuity with the volar fragment.
C. With the collateral ligament attached to the volar fragment, the deforming forces can allow subluxation of the joint, not just flexion.
D. A5 incompetence would not lead to joint instability.
E. Volar plate laxity would create a dorsally directed deformity, whereas a mallet finger sits in a flexed posture.

Remediation:
A. The accessory flexor digitorum longus has been implicated as a cause of tarsal tunnel syndrome.
B. The flexor hallucis longus has not been implicated as a cause of tarsal tunnel syndrome.
C. An accessory posterior tibial tendon has not been implicated as a cause of tarsal tunnel syndrome.
D. The peroneus quartus is located on the lateral side of the ankle and would not cause tarsal tunnel syndrome.

Remediation:
A. A 2019 meta-analysis by Wilson, et al. based on patient-reported outcome measures showed no significant difference in postoperative pain between those undergoing unicompartmental knee arthroplasty and those undergoing total knee arthroplasty.
B. Migliorini, et al. reported better functional outcomes on Knee Society function scores, longer walking distance, and improvement of joint flexion and range of motion in patients who had unicompartmental knee arthroplasty.
C. Liddle, et al. carried out a propensity score-matched cohort study in patients who were enrolled in the National Joint Registry of England and Wales. Patients who had unicompartmental knee arthroplasty were more likely to achieve excellent results and to be highly satisfied.
D. A retrospective review by Siman, et al. of patients who were ≥75 years old who underwent unicompartmental or total knee arthroplasty between 2002 and 2012 showed that patients undergoing unicompartmental knee arthroplasty demonstrated faster initial recovery when compared to total knee arthroplasty, while maintaining comparable complications and midterm survivorship.

Remediation:
A. If a patient sustains an intra-operative proximal femoral fracture, the surgeon should remove the broach or implant to identify and internally fix the fracture with at least one cerclage cable or wire.
B. Following internal fixation, the femur should be broached again. If the broach is stable, then the same primary stem may be reinserted. If the stem is unstable, then a different morphology must be chosen to gain adequate stability in this setting.
C. The fracture should be inspected, reduced, and secured with a cable or wire. Ignoring the fracture and employing toe-touch weight-bearing restrictions in the setting of a potentially unstable femoral component puts the patient at risk for complications.
D. These are the steps that should be taken if a calcar fracture is identified in the operating room.