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8. Foot and Ankle MCQs

Practice Set 66 of 353

This practice set contains high-yield board review questions covering key concepts in 8. Foot and Ankle. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 1301

Topic: 8. Foot and Ankle

A 48-year-old patient presents with a post-traumatic distal tibial malunion. The AP radiograph (a) and corresponding pedobarograph (b) are shown below. Based on the findings, particularly the pedobarograph, which of the following gait characteristics is most consistent with this uncompensated deformity?

. A collapsing medial column with increased pressure under the great toe.
. A rigid, jarring heel strike with ground reaction forces concentrated on the lateral heel and fifth metatarsal.
. Excessive forefoot pronation during the swing phase.
. An internal limb rotation to shift the ground reaction vector medially.
. Increased shock absorption due to midfoot flexibility.

Correct Answer & Explanation

. A rigid, jarring heel strike with ground reaction forces concentrated on the lateral heel and fifth metatarsal.

Explanation

Correct Answer: BThe image (a) shows a distal tibial varus deformity, and the pedobarograph (b) for the left foot clearly demonstrates a severely lateralized center of pressure line, with ground reaction forces concentrated entirely on the lateral heel and fifth metatarsal. The case describes this as an 'uncompensated varus' leading to a 'lateral thrust gait' characterized by a rigid, jarring heel strike and poor propulsion at toe-off. Option A describes uncompensated valgus. Options C, D, and E are inconsistent with the described pathology and pedobarographic findings.

Question 1302

Topic: 8. Foot and Ankle

A 35-year-old male undergoes a full-length weight-bearing radiograph as part of a deformity analysis for chronic ankle pain. The measurements reveal a Lateral Distal Tibial Angle (LDTA) of 80°. The clinical image below shows a foot with a potential deformity. Based on Paley's principles, what is the primary implication of this specific LDTA measurement for the patient's ankle and hindfoot alignment?

. The distal tibia is in valgus, leading to a valgus hindfoot.
. The distal tibia is in varus, predisposing to a varus hindfoot.
. The ankle joint line is congruent, indicating no intra-articular pathology.
. There is a compensatory subtalar valgus to maintain a plantigrade foot.
. The deformity is primarily located in the proximal tibia.

Correct Answer & Explanation

. The distal tibia is in varus, predisposing to a varus hindfoot.

Explanation

Correct Answer: BThe case defines the normal range for the Lateral Distal Tibial Angle (LDTA) as 86-92°. An angle less than 86° indicates distal tibial varus. Therefore, an LDTA of 80° signifies a distal tibial varus deformity, which is a critical determinant of hindfoot alignment and predisposes the hindfoot to varus if uncompensated. Option A is incorrect as an LDTA > 92° indicates distal tibial valgus. Option C relates to the JLCA. Option D describes a compensation, not the primary implication of the LDTA itself. Option E refers to a different segment of the limb.

Question 1303

Topic: 8. Foot and Ankle

A 50-year-old male with a 20-year history of bilateral genu varum presents with progressive medial ankle pain, a flattening of his arch, and the foot deformity shown in the clinical image. He reports difficulty with prolonged standing and walking. Based on the kinetic chain principles discussed, what is the most likely underlying pathology in the foot, directly resulting from his chronic proximal deformity?

. Tarsal coalition
. Charcot arthropathy
. Posterior tibial tendon dysfunction (PTTD)
. Anterior tibial tendon rupture
. Peroneal tendonitis

Correct Answer & Explanation

. Posterior tibial tendon dysfunction (PTTD)

Explanation

Correct Answer: CThe case describes a scenario where chronic genu varum forces the subtalar joint into constant valgus compensation. This places the posterior tibial tendon under relentless eccentric load as it fights to control the eversion. Over years, this overload leads to posterior tibial tendon dysfunction (PTTD), attenuation, and a progressive, acquired flatfoot deformity, which aligns with the patient's symptoms of medial ankle pain and arch flattening. Tarsal coalition is a congenital fusion. Charcot arthropathy is typically associated with neuropathy. Anterior tibial tendon rupture would cause a different deformity (drop foot). Peroneal tendonitis is more commonly associated with a varus foot deformity.

Question 1304

Topic: 8. Foot and Ankle

A patient presents with a varus hindfoot, where the Ground Reaction Vector (GRV) passes medial to the ankle joint, creating a strong adductor moment. To minimize the exhaustive work required by the evertor muscles (primarily the peroneals) and restore biomechanical equilibrium, what compensatory mechanism will the patient most likely employ?

. Internal rotation of the entire limb
. Increased subtalar supination
. External rotation of the entire limb
. Increased ankle dorsiflexion
. Medial shift of the GRV

Correct Answer & Explanation

. External rotation of the entire limb

Explanation

Correct Answer: CThe case explicitly states: 'A varus hindfoot with no rotation has a GRV that passes medial to the ankle joint. This produces a strong adductor moment on the ankle, which must be counterbalanced by the evertor muscles (primarily the peroneals). To minimize the exhaustive work required by the evertors, the patient will subconsciously externally rotate the entire limb. This external rotation displaces the GRV laterally, closer to the ankle joint center, restoring biomechanical equilibrium.' Internal rotation (Option A) would exacerbate the adductor moment. Options B, D, and E are not the primary rotational compensation described for a varus hindfoot.

Question 1305

Topic: 8. Foot and Ankle

The image below illustrates the devastating effect of uncompensated valgus loading on the foot's architecture, where the ground reaction force pushes the talus into severe plantarflexion and adduction. Which of the following clinical findings is most characteristic of a patient experiencing this uncompensated distal tibial valgus deformity?

. Lateral ankle instability and recurrent sprains.
. A rigid cavovarus foot with high arch.
. Medial ankle pain, acquired flatfoot, and painful subfibular impingement.
. Lateral metatarsal stress fractures due to concentrated pressure.
. Increased medial longitudinal arch and forefoot supination.

Correct Answer & Explanation

. Medial ankle pain, acquired flatfoot, and painful subfibular impingement.

Explanation

Correct Answer: CThe case describes uncompensated valgus loading as causing a 'total collapse of the medial longitudinal arch' and placing immense strain on medial ankle stabilizers. Clinically, patients present with 'medial ankle pain, acquired flatfoot, and often painful subfibular impingement as the calcaneus abuts the tip of the fibula.' Option A is more typical of lateral column overload or ligamentous laxity. Option B describes a cavovarus foot, which is the opposite of a flatfoot. Option D is characteristic of uncompensated varus. Option E is inconsistent with medial column collapse.

Question 1306

Topic: 8. Foot and Ankle

A patient with a known proximal tibial varus deformity presents with severe, overt gait abnormalities, asymmetric and rapid shoe wear, and intractable plantar calluses (keratoses) under focal pressure points. The clinical image below shows a foot with a potential deformity. Which of the following is the most likely reason for these severe, unmasked symptoms, indicating a failure of the limb's natural compensatory mechanisms?

. Excessive subtalar pronation
. Compensatory forefoot abduction
. A stiff or arthritic subtalar joint
. A flexible flatfoot deformity
. Isolated ankle arthritis

Correct Answer & Explanation

. A stiff or arthritic subtalar joint

Explanation

Correct Answer: CThe case highlights that 'The system breaks down entirely when the subtalar joint is stiff or arthritic.' A stiff subtalar joint loses its ability to move into varus or valgus, and therefore cannot mask the proximal deformity. These patients then present with severe, overt gait abnormalities, asymmetric and rapid shoe wear, intractable plantar calluses, and a rigid, jarring gait. Options A and B describe compensatory mechanisms that would typically mask the deformity, not lead to overt symptoms. Option D (flexible flatfoot) implies a mobile subtalar joint, which would still allow for some compensation. Isolated ankle arthritis might cause pain but wouldn't necessarily lead to the specific pattern of uncompensated gait and calluses described for a proximal deformity.

Question 1307

Topic: 8. Foot and Ankle

A 14-year-old male presents with a progressive limp and anterior knee pain. Clinical examination reveals an apparent knee flexion deformity that prevents full extension. However, during a prone hang test, the knee achieves full extension, and the heel height matches the contralateral side. A standing lateral radiograph of the tibia shows a Posterior Proximal Tibial Angle (PPTA) of 60°, as depicted in the diagram. Based on the case, what is the most accurate diagnosis and appropriate management strategy?

. True Fixed Flexion Deformity (FFD) requiring posterior capsular release.
. Proximal tibial procurvatum causing an obligate knee flexion, best treated with a corrective osteotomy.
. Distal femoral procurvatum requiring a distal femoral extension osteotomy.
. Patellofemoral pain syndrome secondary to quadriceps weakness, managed with physical therapy and strengthening.
. Genu recurvatum requiring a posterior closing wedge osteotomy of the proximal tibia.

Correct Answer & Explanation

. Proximal tibial procurvatum causing an obligate knee flexion, best treated with a corrective osteotomy.

Explanation

Correct Answer: BThe case describes proximal tibial procurvatum as 'the classic, high-yield example' of an extra-articular bony deformity mimicking a joint contracture. It states, 'In this deformity, the proximal tibia has an anteriorly directed apex of angulation (an anterior bow). This pathologic shape decreases the normal Posterior Proximal Tibial Angle (PPTA), which should normally be approximately 81° (with a normal range of 77° to 84°).' The image shows a PPTA of 60°, which is significantly decreased. The case further explains that this 'forces the knee joint into a flexed posture simply to allow the foot to become plantigrade (flat) on the floor.' The prone hang test result (full extension) confirms that it isnota true capsular contracture. The treatment is a corrective osteotomy of the bone.Option A is incorrectbecause the prone hang test rules out a true FFD (capsular contracture). Treating this with soft-tissue releases would be a 'disastrous surgical error.'Option C is incorrect; while distal femoral procurvatum is a sagittal plane deformity, the PPTA measurement and the description of the anterior bow of the proximal tibia point to a tibial deformity.Option D is incorrect; while patellofemoral pain is a symptom, it is secondary to the underlying bony deformity and the increased quadriceps workload, not the primary diagnosis or treatment.Option E is incorrect; genu recurvatum is hyperextension, the opposite of the presented obligate flexion. A posterior closing wedge osteotomy would correct recurvatum, not procurvatum.

Question 1308

Topic: 8. Foot and Ankle

A 40-year-old patient presents with a long-standing, rigid equinus contracture of the ankle. Over the past several years, they have developed increasing knee pain and a noticeable hyperextension deformity of the knee during gait. Based on the kinetic chain principles described in the case, what is the most likely underlying cause of the knee hyperextension, and what is its long-term consequence?

. Primary genu recurvatum, leading to compensatory ankle equinus and anterior impingement.
. Compensatory knee hyperextension due to the rigid ankle equinus, causing chronic stress on the posterior capsule and cruciate ligaments, potentially leading to structural knee recurvatum.
. Proximal tibial procurvatum, forcing the knee into flexion and subsequently hyperextension.
. A Duchenne gait pattern, which causes knee hyperextension to reduce medial compartment loading.
. A true fixed flexion deformity of the knee, which is being masked by the ankle equinus.

Correct Answer & Explanation

. Compensatory knee hyperextension due to the rigid ankle equinus, causing chronic stress on the posterior capsule and cruciate ligaments, potentially leading to structural knee recurvatum.

Explanation

Correct Answer: BThe case explicitly details this exact kinetic chain compensation: 'Similarly, a rigid equinus contracture of the ankle (where the ankle is fixed in plantarflexion) forces a devastating compensation at the knee. To achieve a stable, plantigrade foot during the stance phase, a patient with a stiff equinus ankle must find motion elsewhere. Since the ankle cannot dorsiflex to allow the tibia to advance over the foot, the body's only option is to force the knee backward into hyperextension (genu recurvatum).' The long-term consequence is also described: 'Walking with this compensatory hyperextension pattern for years places immense, chronic stress on the posterior capsule, cruciate ligaments, and posterolateral corner of the knee. Over time, these soft tissues stretch and attenuate, leading to anterior impingement of the tibiofemoral joint, meniscal tears, and a structural, painful knee hyperextension deformity.'Option A is incorrect; the primary problem is the ankle equinus, leading to secondary knee recurvatum, not the other way around.Option C is incorrect; proximal tibial procurvatum causes obligate knee flexion, not hyperextension.Option D is incorrect; a Duchenne gait compensates for coronal plane varus, not ankle equinus or knee hyperextension.Option E is incorrect; a fixed flexion deformity is the opposite of hyperextension, and the ankle equinus would exacerbate the functional shortening, not mask an FFD.

Question 1309

Topic: 8. Foot and Ankle

A 28-year-old patient presents with a complex multiplanar deformity of the tibia. During preoperative planning, the surgeon is evaluating a standing lateral radiograph to assess the sagittal plane alignment of the proximal tibia. The measurement obtained for the Posterior Proximal Tibial Angle (PPTA) is 70°. Based on the normal values provided in the case, what does this measurement indicate, and what is its clinical significance?

. The PPTA is within the normal range, indicating no significant sagittal plane deformity of the proximal tibia.
. The PPTA is abnormally increased, suggesting a proximal tibial recurvatum deformity.
. The PPTA is abnormally decreased, indicating a proximal tibial procurvatum deformity, which can lead to obligate knee flexion.
. The PPTA is primarily used to assess coronal plane alignment and has no direct sagittal plane significance.
. The PPTA is a measure of intra-articular deformity, indicating joint line convergence.

Correct Answer & Explanation

. The PPTA is abnormally decreased, indicating a proximal tibial procurvatum deformity, which can lead to obligate knee flexion.

Explanation

Correct Answer: CThe table of normal angles in the case lists the 'Posterior Proximal Tibial Angle (PPTA)' with a 'Normal Value Range' of '77° to 84° (Avg 81°)' and its 'Clinical Significance' as 'Evaluates proximal tibial procurvatum/recurvatum. Crucial for sagittal slope planning.' The case further explains that in proximal tibial procurvatum, 'This pathologic shape decreases the normal Posterior Proximal Tibial Angle (PPTA)...' A PPTA of 70° is significantly lower than the normal range, indicating a procurvatum (anterior bow) deformity of the proximal tibia. This deformity 'forces the knee joint into a flexed posture simply to allow the foot to become plantigrade (flat) on the floor,' leading to 'obligate flexion.'Option A is incorrectbecause 70° is outside the normal range of 77-84°.Option B is incorrect; an increased PPTA would indicate recurvatum, while a decreased PPTA indicates procurvatum.Option D is incorrect; the PPTA is explicitly listed as a sagittal plane angle.Option E is incorrect; the Joint Line Convergence Angle (JLCA) measures intra-articular deformity or ligamentous laxity, not the PPTA.

Question 1310

Topic: 8. Foot and Ankle

A 50-year-old patient presents with a long-standing distal tibial recurvatum deformity. During gait analysis, it is noted that the patient compensates for this deformity by exhibiting excessive plantar flexion of the ankle to achieve a plantigrade foot. Based on the kinetic chain principles and consequences outlined in the case, what is the most significant long-term biomechanical impact of this compensatory mechanism on the ankle joint?

. Increased tibiotalar contact area, leading to improved load distribution and joint preservation.
. Reduced stress on the posterior capsule of the ankle, preventing equinus contracture.
. A massive reduction in tibiotalar contact area, leading to increased stress per unit area of articular cartilage and rapid mechanical degeneration.
. Enhanced function of the ankle rocker mechanisms, improving gait efficiency.
. Development of a compensatory genu recurvatum to offload the ankle joint.

Correct Answer & Explanation

. A massive reduction in tibiotalar contact area, leading to increased stress per unit area of articular cartilage and rapid mechanical degeneration.

Explanation

Correct Answer: CThe case specifically addresses this kinetic chain compensation: 'For example, a recurvatum deformity of the distal tibia is often compensated for by excessive plantar flexion of the ankle to achieve a plantigrade foot. This compensatory positioning uncovers the talar dome. Research shows that as little as 5° of recurvatum with compensatory plantar flexion reduces the tibiotalar contact area by a massive 30%. This drastic reduction in contact area results in a much smaller weight-bearing surface for the exact same amount of body load. The increased stress per unit area of articular cartilage rapidly leads to mechanical cartilage degeneration and end-stage ankle arthrosis.'Option A is incorrect; the contact area is significantlyreduced, not increased.Option B is incorrect; the compensation leads to increased stress and degeneration, not prevention of contracture.Option D is incorrect; the compensation disrupts normal ankle mechanics and leads to degeneration, not enhanced function or efficiency.Option E is incorrect; genu recurvatum is a compensation for a rigidequinusankle, not distal tibial recurvatum with compensatory plantarflexion.

Question 1311

Topic: 8. Foot and Ankle

When evaluating the mechanical axis of the lower extremity on a standing 51-inch AP radiograph, a line drawn from the center of the femoral head to the center of the ankle joint passes 25 mm medial to the center of the knee. What does this finding definitively indicate?

. Mechanical valgus alignment
. Mechanical varus alignment
. Normal physiologic alignment
. Significant procurvatum deformity
. Significant recurvatum deformity

Correct Answer & Explanation

. Mechanical varus alignment

Explanation

The normal mechanical axis of the lower extremity passes just medial (typically 1-8 mm) to the center of the knee joint. A mechanical axis deviation (MAD) falling significantly medial to the knee center indicates a overall mechanical varus alignment of the limb.

Question 1312

Topic: 8. Foot and Ankle

The most common joint contracture encountered during extensive tibial lengthening using circular external fixation is:

. Knee flexion contracture
. Knee extension contracture
. Ankle equinus contracture
. Ankle dorsiflexion contracture
. Subtalar varus contracture

Correct Answer & Explanation

. Ankle equinus contracture

Explanation

Ankle equinus is the most frequent contracture observed during tibial lengthening. This occurs due to the relative tightness, fascial resistance, and multi-joint span of the gastrocnemius-soleus complex as the tibia elongates.

Question 1313

Topic: 8. Foot and Ankle

During distraction osteogenesis of the tibia using an Ilizarov frame, a patient develops an equinus contracture of the ankle. What is the most appropriate initial management for this complication?

. Immediate Achilles tendon lengthening
. Stopping or slowing distraction and beginning aggressive physical therapy and splinting
. Reversing the distraction to compress the regenerate immediately
. Botulinum toxin injection to the gastrocnemius
. Immediate surgical release of the posterior capsule

Correct Answer & Explanation

. Stopping or slowing distraction and beginning aggressive physical therapy and splinting

Explanation

Soft tissue contractures, such as equinus, are common during tibial lengthening. Initial management includes pausing or slowing the distraction rate, intensive physical therapy, and dynamic splinting, before surgical release is considered.

Question 1314

Topic: 8. Foot and Ankle

A 24-year-old female is undergoing a proximal tibial corticotomy and lengthening. Postoperatively, she complains of new-onset numbness on the dorsum of her foot and weakness in great toe extension. Which step of the procedure most likely placed the injured structure at risk?

. Placement of the proximal tibial medial half-pins.
. The proximal fibular osteotomy.
. Application of the distal tibial fine wires.
. The diaphyseal corticotomy of the tibia.
. Distraction at a rate of 0.25 mm per day.

Correct Answer & Explanation

. The proximal fibular osteotomy.

Explanation

The common peroneal nerve is at high risk of injury during the proximal fibular osteotomy, a required step for tibial lengthening. Weakness in extensor hallucis longus and dorsal foot numbness clinically confirm a peroneal nerve injury.

Question 1315

Topic: 8. Foot and Ankle

A 35-year-old male presents with chronic ankle pain and a suspected distal tibial deformity. A weight-bearing coronal radiograph is obtained, and the following measurement is performed:

Based on the image provided and Paley's principles, what is the normal range for the angle depicted, and what does a value significantly outside this range primarily indicate?

. 78-82°; Sagittal plane malalignment of the ankle joint.
. 86-92°; Frontal (coronal) plane malalignment of the ankle joint.
. 80-84°; Transverse plane rotational deformity.
. 89-95°; Compensatory subtalar joint deformity.
. 90-96°; Proximal tibial varus.

Correct Answer & Explanation

. 86-92°; Frontal (coronal) plane malalignment of the ankle joint.

Explanation

Correct Answer: BThe image displays the measurement of the Lateral Distal Tibial Angle (LDTA). According to the provided text, the normal value range for the LDTA in the frontal (coronal) plane is 86° to 92°, with an average of 89°. A deviation from this norm signifies a structural bone deformity in the distal tibia that affects the frontal plane alignment of the ankle joint, leading to abnormal joint contact pressures.Option A is incorrect because 78-82° is the normal range for the Anterior Distal Tibial Angle (ADTA), which assesses sagittal plane alignment. Option C is incorrect as the given range is not standard for LDTA, and this angle primarily assesses coronal plane, not transverse plane, deformity. Option D and E provide incorrect ranges and misattribute the primary indication of an abnormal LDTA.

Question 1316

Topic: 8. Foot and Ankle
A 50-year-old female with a history of recurrent ankle sprains and anterior impingement symptoms undergoes radiographic evaluation. A lateral radiograph is obtained, and the following measurement is performed: The image displays the measurement of the Anterior Distal Tibial Angle (ADTA). What is the normal average value for the ADTA, and what does a significantly decreased ADTA (e.g., <75°) typically suggest?
. 89°; Distal tibial varus.
. 80°; Distal tibial procurvatum.
. 80°; Distal tibial recurvatum.
. 86°; Ankle valgus.
. 78°; Midfoot collapse.

Correct Answer & Explanation

. 80°; Distal tibial recurvatum.

Explanation

The image illustrates the measurement of the Anterior Distal Tibial Angle (ADTA). The text states that the normal value range for ADTA in the sagittal plane is 78° to 82°, with an average of 80°. A significantly decreased ADTA (i.e., the anterior angle formed by the tibial mechanical axis and the ankle joint line is smaller than normal) indicates that the distal tibia is angled more posteriorly relative to the mechanical axis. This condition is known as distal tibial recurvatum. Distal tibial recurvatum can lead to anterior ankle impingement symptoms, consistent with the patient's history.

Question 1317

Topic: 8. Foot and Ankle

A surgeon is planning a distal tibial osteotomy for a patient with a varus ankle deformity. After meticulous radiographic analysis, the CORA is identified 5 cm proximal to the ankle joint line. The surgeon decides to perform the osteotomy precisely at this CORA and place the external fixator's hinge axis at the same level.

According to Paley's osteotomy rules, what is the expected outcome of this surgical plan?

. The correction will result in pure translation without any angular change.
. The correction will achieve pure angular realignment without inducing any secondary translation.
. The correction will require both angulation and a planned translation to achieve proper alignment.
. An undesirable secondary translation deformity will be induced, complicating the correction.
. The correction will primarily address the sagittal plane deformity, leaving the coronal plane uncorrected.

Correct Answer & Explanation

. The correction will achieve pure angular realignment without inducing any secondary translation.

Explanation

Correct Answer: BThis scenario directly applies Paley's Osteotomy Rule 1: 'When the osteotomy and the corrective hinge are both placedat the CORA, pure angular correction occurs without any unwanted translation. This is the ideal, most anatomical correction.'Option A is incorrect because the goal is angular correction, not pure translation. Option C describes Paley's Rule 2. Option D describes Paley's Rule 3. Option E is incorrect as the osteotomy is planned for a varus deformity, which is a coronal plane issue, and the rule describes the mechanical outcome of the correction, not its plane specificity.

Question 1318

Topic: 8. Foot and Ankle

A resident is reviewing a long-leg alignment film for a patient with ankle osteoarthritis and a suspected lower extremity malalignment. The attending asks about the difference between the overall mechanical axis and the tibial mechanical axis.

Which of the following statements accurately distinguishes the tibial mechanical axis from the overall mechanical axis of the lower extremity, as described in Paley's principles for ankle alignment?

. The overall mechanical axis connects the center of the femoral head to the center of the knee, while the tibial mechanical axis connects the center of the knee to the center of the ankle.
. The tibial mechanical axis connects the center of the tibial plateau to the center of the tibial plafond, whereas the overall mechanical axis connects the center of the femoral head to the center of the ankle mortise.
. The overall mechanical axis is used for sagittal plane analysis, while the tibial mechanical axis is exclusively for coronal plane assessment.
. The tibial mechanical axis is a theoretical line used only for calculating the CORA, while the overall mechanical axis is a true anatomical landmark.
. Both axes are identical in a perfectly aligned limb, but diverge only in the presence of a femoral deformity.

Correct Answer & Explanation

. The tibial mechanical axis connects the center of the tibial plateau to the center of the tibial plafond, whereas the overall mechanical axis connects the center of the femoral head to the center of the ankle mortise.

Explanation

Correct Answer: BThe text explicitly defines these axes: 'The mechanical axis of the lower extremity—a line drawn from the center of the femoral head to the center of the ankle mortise—is the cornerstone of alignment.' For the ankle, it further specifies: 'we narrow our focus to thetibial mechanical axis, a line connecting the center of the tibial plateau to the center of the tibial plafond.'Option A incorrectly defines both axes. Option C is incorrect; both axes are primarily used for coronal plane assessment, though sagittal plane alignment is also crucial. Option D is incorrect as both are critical for practical surgical planning. Option E is incorrect; they are distinct lines even in a perfectly aligned limb, though they may coincide or be parallel in certain segments.

Question 1319

Topic: 8. Foot and Ankle

A 40-year-old patient presents with progressive medial ankle pain and early signs of medial ankle osteoarthritis. Radiographic analysis reveals a Lateral Distal Tibial Angle (LDTA) of 82°.

Based on this finding and Paley's principles, what is the most likely underlying structural deformity and its biomechanical consequence?

. Distal tibial recurvatum, leading to increased anterior ankle joint pressure.
. Distal tibial procurvatum, leading to increased posterior ankle joint pressure.
. Distal tibial varus, leading to increased medial ankle joint pressure.
. Distal tibial valgus, leading to increased lateral ankle joint pressure.
. Subtalar joint pronation, leading to midfoot collapse.

Correct Answer & Explanation

. Distal tibial varus, leading to increased medial ankle joint pressure.

Explanation

Correct Answer: CThe normal range for the LDTA is 86° to 92° (average 89°). An LDTA of 82° is less than the normal range. A decreased LDTA indicates that the distal tibia is angled medially relative to the tibial mechanical axis, which is defined as a distal tibial varus deformity. This varus angulation shifts the weight-bearing axis medially, leading to increased pressure and accelerated cartilage degeneration in the medial compartment of the ankle joint, consistent with the patient's medial ankle pain and osteoarthritis.Options A and B relate to sagittal plane deformities (recurvatum/procurvatum) and are assessed by ADTA, not LDTA. Option D describes a valgus deformity, which would typically present with an increased LDTA and lateral ankle pain. Option E describes a foot deformity, which might be compensatory but is not the primary structural deformity indicated by an abnormal LDTA.

Question 1320

Topic: 8. Foot and Ankle
A patient presents with severe ankle pain and deformity. During the initial assessment, the orthopedic surgeon emphasizes the need for full-length standing radiographs and a comprehensive examination of the knee and hip, in addition to the ankle and foot. This approach aligns with the introductory principles of the "Total Ankle & Foot Deformity Correction: The Paley Principles Masterclass." What is the primary reason for this comprehensive evaluation?
. To identify potential unrelated pathologies that might complicate ankle surgery.
. To ensure that all joints are equally affected by the deformity, necessitating pan-joint arthrodesis.
. To understand how compensatory mechanisms in the knee, hip, and spine influence and are influenced by ankle and foot alignment.
. To determine the patient's overall bone quality for implant selection.
. To rule out systemic inflammatory conditions affecting multiple joints.

Correct Answer & Explanation

. To understand how compensatory mechanisms in the knee, hip, and spine influence and are influenced by ankle and foot alignment.

Explanation

Correct Answer: C. The introductory section of the case emphasizes: 'The evaluation and surgical management of lower extremity deformities demand more than just a local focus; they require a profound understanding of the entire kinetic chain. The ankle and foot are not isolated structures but the very foundation upon which the knee, hip, and spine depend.' It also mentions 'the critical compensatory mechanisms that can make or break a surgical outcome.' Therefore, a comprehensive evaluation is crucial to understand these interconnected biomechanical relationships. Options A, D, and E represent valid clinical considerations but are not the primary reason highlighted in the text for a comprehensive evaluation in the context of deformity correction. Option B is incorrect as the goal is not necessarily to find equal involvement or perform pan-joint arthrodesis, but to understand the interplay of deformities and compensations.

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