ABOS Part I Orthopedic Surgery Review: Ankle, Knee, and Foot Arthritis Management | Part 22168

Correct Answer: C

The candidate's description of the radiograph explicitly states: 'This is an AP weightbearing radiograph of a left ankle showing narrowing of the joint space and some subchondral sclerosis consistent with post-traumatic arthritis. There is evidence of a previous fibula fracture superior to the syndesmosis and varus angulation of the ankle.' This directly matches option C.

Option A is incorrect as the description does not mention a trimalleolar fracture malunion or subtalar arthritis. Option B is incorrect as medial clear space widening is not noted; rather, varus angulation is described. Option D is incorrect as avascular necrosis of the talar dome and valgus deformity are not mentioned in the description. Option E is incorrect as the findings are consistent with post-traumatic arthritis, not inflammatory arthritis, and diffuse osteopenia or erosions are not described.

Correct Answer: D

The case explicitly states: 'Primary osteoarthritis is thought to be relatively uncommon and the most common cause of ankle arthritis is probably post-traumatic arthritis. Other causes are inflammatory arthritis and septic arthritis.' Therefore, post-traumatic arthritis is the most common cause.

Option A is incorrect because primary osteoarthritis is noted as relatively uncommon. Options B and C are incorrect as inflammatory and septic arthritis are listed as 'other causes' but not the most common. Option E, avascular necrosis of the talus, is a potential cause of ankle arthritis but is not listed in the case as one of the most common etiologies.

Correct Answer: E

The case discusses several conservative measures: 'optimize the patient’s analgesia adding in NSAIDs, and suggest activity modification. He could try footwear modification with a cushioned sole and rocker-bottom shoe which may improve his symptoms as may use of an ankle brace or AFO. Similarly an injection of intra-articular steroid or viscosupplementation may be of symptomatic benefit. Physiotherapy could be an adjunctive treatment in patients with symptoms of instability or weakness but may aggravate symptoms.' Long-term oral corticosteroids are not mentioned as a conservative management strategy for ankle arthritis in this context.

Options A, B, C, and D are all explicitly mentioned as potential conservative treatments in the case.

Correct Answer: C

The case clearly categorizes surgical options into 'temporizing measures' and 'definitive treatments'. It states: 'The temporizing measures are debridement of the joint which can be performed arthroscopically or open... The other option is distraction arthroplasty.' Therefore, distraction arthroplasty is a temporizing measure.

Options A (Total ankle replacement) and B (Ankle arthrodesis) are described as 'definitive surgical options.' Options D (Supramalleolar osteotomy) and E (Subtalar fusion) are not mentioned in the case as either temporizing or definitive treatments for ankle arthritis.

Correct Answer: C

The examiner specifically asks about the 42-year-old patient wanting an ankle replacement, and the candidate responds: 'He is a young patient, in a manual job. He wouldn’t be a candidate for total ankle replacement and I would explain to him that if his symptoms have failed to be controlled by non-operative measures and he requires definitive surgical treatment then an ankle fusion would be a better option for him.' This clearly identifies his young age and high-demand occupation as the primary contraindications.

While varus angulation (Option B) is a contraindication if significant (>10 degrees), the case highlights the patient's age and activity level as the primary reasons for not being a candidate. A previous fibula fracture (Option A) and subchondral sclerosis (Option D) are findings associated with his post-traumatic arthritis but are not listed as primary contraindications for TAR in the same way age and activity level are. Option E is irrelevant to the surgical decision-making for this patient.

Correct Answer: B

The case explicitly states the ideal position for ankle fusion: 'The foot should be plantigrade with a physiological 5 of hindfoot valgus and 5 of external rotation.'

Options A, C, D, and E describe various other positions that do not match the specific recommendations provided in the case for optimal ankle fusion.

Correct Answer: B

The case states: 'The earlier designs involved a two-component design such as the Agility total ankle replacement, which required fusion of the distal tibiofibular joint. Most modern designs are three-component uncemented mobile bearing prostheses.' This directly describes option B.

Option A describes older, less common features. Option C describes earlier designs like the Agility, but not 'most modern designs.' Options D and E do not accurately reflect the description of modern TAR designs provided in the case.

Correct Answer: C

When the examiner presses the candidate about the patient still wanting a replacement to get back to hill walking and sports, the candidate explains: 'A fusion would provide a stable pain-free ankle that would allow him to return to the majority of activities that he wishes to do. I would explain that many patients return to sports after ankle fusion. I would also explain that an ankle fusion would only sacrifice the residual movement that he has at his ankle joint and that his subtalar, midfoot and forefoot movements would still be present.' This comprehensive explanation aligns perfectly with option C.

Option A is incorrect because the case explicitly states that subtalar, midfoot, and forefoot movements are preserved, and many patients return to sports. Option B is incorrect as the case states fusion is still considered the 'gold standard' and is not outdated for all patients. Option D is incorrect as the case suggests fusion is suitable for active patients like the manual worker. Option E is incorrect; while adjacent joint arthritis is a known complication of fusion, the case does not state it's a higher risk than TAR, and the overall tone is that fusion is a better option for this patient.

Correct Answer: D

The candidate lists the following complications for ankle fusion: 'Non-union, malunion, delayed union, infection, wound-healing problems, nerve or vessel damage, DVT/PE, risk of exacerbating or developing arthritis in other joints.' Stress fracture of the ipsilateral tibia is not mentioned in this list.

Options A, B, C, and E are all explicitly listed as potential complications of ankle fusion in the case.

Correct Answer: B

The candidate's response to the question about TAR longevity is: 'The 10-year survival is approaching 85% but there are fewer data available than for knee and hip replacements. Many series are small.' This directly matches option B.

Options A, C, D, and E provide incorrect survival rates or make inaccurate comparisons regarding the availability of data for ankle replacements versus hip and knee replacements.

Correct Answer: C

The case explicitly states, and the image demonstrates, 'narrowing of joint spaces with bone-on-bone contact in the lateral compartments of both knees. There is early arthrosis affecting the medial compartments of both knees. There is moderate valgus deformity.' This directly matches option C.

Option A is incorrect because the deformity is valgus, not varus, and the primary bone-on-bone contact is in the lateral compartment, not medial.

Option B is incorrect as the primary finding is tibiofemoral arthritis with valgus deformity, not isolated patellofemoral arthrosis.

Option D is incorrect because while arthritis is present, the description specifies lateral compartment bone-on-bone contact and early medial arthrosis, not diffuse narrowing as the primary descriptor, and the image does not strongly suggest diffuse inflammatory changes over a specific compartment pattern.

Option E is incorrect because the radiographs clearly show significant arthritic changes with bone-on-bone contact, not preserved joint space, and the primary diagnosis is arthritis with deformity, not an isolated meniscal tear.

Correct Answer: D

The case specifically lists conditions commonly associated with valgus deformity of the knee with arthritis: 'inflammatory joint conditions such as rheumatoid arthritis... primary osteoarthritis, overcorrection of high tibial osteotomy (HTO), post-traumatic arthritis following lateral meniscectomy and osteonecrosis.' Post-traumatic arthritis following a medial meniscectomy would typically predispose to varus deformity and medial compartment arthritis, not valgus deformity.

Option A (Rheumatoid arthritis) is incorrect because the case explicitly states it is a common association.

Option B (Primary osteoarthritis) is incorrect because the case explicitly states it can occur in primary osteoarthritis.

Option C (Overcorrection of a high tibial osteotomy (HTO)) is incorrect because the case explicitly states it can occur due to HTO overcorrection.

Option E (Osteonecrosis of the lateral femoral condyle) is incorrect because the case explicitly states it can be a cause of valgus arthritis.

Correct Answer: C

The case states: 'Due to the posterior femoral condyle deficiency, the standard 3 posterior condylar referencing can result in internal rotation of the component. In this situation, AP axis (Whiteside line) is used to prevent malrotation in the form of internal rotation.' The Whiteside line (AP axis) is a reliable anatomical landmark that is less affected by condylar wear, making it crucial for accurate femoral rotation in valgus knees with condylar deficiency.

Option A is incorrect because while 3 degrees of external rotation relative to the posterior condylar axis is a common goal, the posterior condylar deficiency in valgus knees makes this reference unreliable and prone to internal rotation malalignment.

Option B (Transepicondylar axis) is incorrect as it is a valid reference but the case specifically highlights the AP axis (Whiteside line) as the preferred method to address the posterior condylar deficiency issue in valgus knees.

Option D (Aligning the femoral component parallel to the tibial cut) is incorrect as this does not directly address femoral rotation relative to the femur's anatomical axes and could lead to malrotation if the tibial cut is not perfectly aligned or if there are significant soft tissue imbalances.

Option E (Relying solely on the measured resection technique from the posterior condyles) is incorrect because, as stated in the case, posterior condylar deficiency makes this method unreliable and can lead to internal rotation of the component.

Correct Answer: B

The case states: 'With regards to flexion–extension gap, the release of lateral and posterior structures results in increased extension gap requiring a thicker insert which may elevate the joint line.' This directly describes the consequence of extensive lateral and posterior soft tissue release in a valgus knee.

Option A is incorrect because releasing contracted structures would increase, not decrease, the extension gap.

Option C is incorrect because significant release of contracted structures will almost certainly alter the gap, making it unlikely to be perfectly balanced without specific intervention.

Option D is incorrect because the primary effect of releasing lateral and posterior structures is on the extension gap, not typically an isolated increase in the flexion gap that would necessitate a larger femoral component.

Option E is incorrect because releasing structures would loosen, not tighten, the knee, making a decreased flexion gap unlikely.

Correct Answer: C

The case states: 'Patients with severe valgus deformity usually require lateral retinacular release to achieve proper patella tracking.' The scenario describes persistent lateral subluxation, indicating the need to release the tight lateral structures that are pulling the patella laterally.

Option A is incorrect because while a distal femoral cut of 7 degrees can help in mild valgus, increasing it further is not the primary solution for persistent patellar subluxation after initial cuts and may lead to other issues like over-resection or instability. The case mentions 7 degrees for mild valgus to avoid release, implying that for persistent issues, a release is needed.

Option B (Medial retinacular release) is incorrect as this would worsen lateral patellar subluxation by releasing the medial restraints.

Option D (Downsizing the femoral component) is incorrect as this would primarily affect flexion gap and overall knee size, not directly address patellar tracking issues caused by tight lateral retinaculum.

Option E (Use a thicker polyethylene insert) is incorrect as this primarily addresses flexion-extension gap balancing and joint line elevation, not patellar tracking.

Correct Answer: D

The case explicitly warns: 'With correction of significant valgus deformity, one has to watch for peroneal nerve palsy in the postoperative period.' Foot drop and numbness along the dorsum of the foot are classic symptoms of peroneal nerve palsy, which can occur due to traction injury during significant valgus correction.

Option A (Femoral nerve) is incorrect. Femoral nerve injury typically presents with quadriceps weakness and sensory loss over the anterior thigh and medial leg, not foot drop.

Option B (Saphenous nerve) is incorrect. Saphenous nerve injury causes sensory loss along the medial aspect of the leg and foot, without motor deficits like foot drop.

Option C (Tibial nerve) is incorrect. Tibial nerve injury typically affects plantarflexion and sensation on the sole of the foot, not dorsiflexion or sensation on the dorsum.

Option E (Obturator nerve) is incorrect. Obturator nerve injury affects adduction of the thigh and sensation over the medial thigh, which is unrelated to foot drop.

Correct Answer: B

The case explicitly states: 'In valgus knees the lateral femoral condyle is deficient, therefore the femur is internally rotated and tibia is externally rotated.' This directly matches option B.

Option A is incorrect because the lateral femoral condyle is deficient, not the medial, and the rotational deformities are reversed.

Option C is incorrect because the lateral femoral condyle is specifically deficient, not both equally, and the rotational deformities are not both external.

Option D is incorrect because the lateral femoral condyle is deficient, not hypertrophied, and the rotational deformities are reversed.

Option E is incorrect because the lateral femoral condyle is deficient, not the medial, and the tibial rotation is external, not internal.

Correct Answer: C

The case directly addresses this: 'EXAMINER : What is the theoretical advantage of a lateral approach? CANDIDATE : It is a direct approach providing easier access and preserves the neurovascular supply to the extensor mechanism.' This statement directly supports option C.

Option A is incorrect because a lateral approach would make medial compartment access more challenging, not easier.

Option B is incorrect because the case states that a medial parapatellar approach 'gives good access to the whole knee and better soft tissue cover,' implying this is an advantage of the medial approach, not the lateral.

Option D is incorrect because while component rotation is critical, the advantage of the lateral approach is not specifically tied to easier correction of femoral internal rotation compared to other approaches.

Option E is incorrect because the risk of peroneal nerve palsy is related to the degree of valgus correction and traction on the nerve, not inherently reduced by the surgical approach itself.

Correct Answer: C

The case explicitly states: 'Excessive PCL release usually requires cruciate sacrificing implants in order to balance the knee.' This is a direct consequence of losing the PCL's contribution to stability and balance.

Option A is incorrect because excessive PCL release would lead to a looser, not tighter, flexion gap, and would preclude PCL retention.

Option B is incorrect because excessive PCL release would destabilize the knee, making it unbalanced, and would not allow for PCL-retaining implants.

Option D is incorrect because while soft tissue releases can affect the extension gap, excessive PCL release specifically impacts flexion stability and necessitates a change in implant type, not just insert thickness while retaining the PCL.

Option E is incorrect because PCL release has a significant impact on knee kinematics and balance, directly influencing implant choice.

Correct Answer: C

The case specifically mentions: 'In mild valgus deformity (7–10) a distal femoral cut of 7 can improve patella tracking and avoid the need for lateral retinacular release.' This directly provides the recommended angle for mild valgus deformities to aid patellar tracking.

Option A (3 degrees) is incorrect as this is a common valgus angle for a varus knee or a neutral knee, but not specifically highlighted for improving patellar tracking in mild valgus.

Option B (5 degrees) is incorrect as the case specifies 7 degrees for this particular purpose.

Option D (9 degrees) is incorrect as while it falls within the 7-10 degree range of mild valgus, the specific recommendation for the cut is 7 degrees to improve tracking and avoid release.

Option E (0 degrees) is incorrect as a neutral cut would not address the valgus deformity or specifically aid patellar tracking in a valgus knee.

Correct Answer: C

The candidate's initial observation states, 'There is hallux valgus with the hallux over-riding the second toes.' The provided image (Figure 4.7, AP view) clearly depicts hallux valgus on the right foot, where the great toe is deviated laterally and appears to override the second toe. The case mentions the absence of the second toe on the left foot, not the right. Hallux varus is a medial deviation of the great toe, which is contrary to the image. Scars and specific surgical evidence are not definitively identifiable for the right foot from this initial clinical image alone.

Correct Answer: B

The case explicitly states the normal ranges for these angles: 'The intermetatarsal angle is normally less than 9. The hallux valgus angle should be less than 15. The distal metatarsal articular angle is normally a maximum of 15 from perpendicular to the axis of the first metatarsal.' Therefore, option B accurately reflects these normal values.

Correct Answer: C

The examiner presents a specific scenario: 'If this lady had an intermetatarsal angle of 15 on the right with a hallux valgus angle of 35 and minimal passive correction of the hallux, what surgery would you plan?' The candidate responds: 'If the first tarsometatarsal joint is normal, I would plan a scarf osteotomy combined with a lateral release and an Akin osteotomy of the proximal phalanx if necessary.' This directly matches option C. Chevron and Mitchell osteotomies are typically for less severe deformities or have disadvantages like shortening, as discussed later in the case. Arthrodesis is usually reserved for severe arthrosis or recurrent cases, especially with missing toes, and Keller is a salvage procedure.

Correct Answer: C

When asked 'Why would you choose a scarf osteotomy?', the candidate replies: 'It is a very versatile procedure with stable fixation allowing postoperative mobilization without a cast. It maintains length of the metatarsal but allows translation, angulation and depression of the metatarsal head as necessary.' This statement directly supports option C, highlighting stable fixation, early mobilization, and versatility. Options A and D are incorrect as Scarf is for moderate to severe deformities and is not necessarily 'simpler' than distal osteotomies. Option B is incorrect as Scarf maintains length or can even lengthen, unlike Mitchell. Option E is incorrect as arthrodesis is preferred for significant MTP arthritic change.

Correct Answer: C

The candidate explicitly states: 'A minority of patients will have significant stiffness of the MTP joint afterwards and there can be sensory loss if the dorsomedial sensory nerve is injured.' While DVT/PE and CRPS are general surgical risks, they are not specifically highlighted by the candidate in this discussion. Avascular necrosis is a known complication of some distal osteotomies (e.g., Chevron) but not specifically emphasized for Scarf in this context. The recurrence risk is mentioned as 'greatest in adolescent cases' and not given a specific high percentage like 50% for this patient.

Correct Answer: C

The candidate states: 'Whilst soft tissue procedures such as abductor hallucis and medial capsular release or transfer of a slip of EHL are described for flexible deformity, arthrodesis of the first MTP joint is a reliable option in the presence of significant stiffness or arthrosis.' This directly identifies MTP joint arthrodesis as the reliable option for stiff or arthritic hallux varus. Other options are either not mentioned or are inappropriate for this specific indication.

Correct Answer: C

The examiner asks: 'So you have successfully treated this lady’s right foot and she is pleased with the result. Would you go ahead and do the same on the left?' The candidate responds: 'No. The absence of the second toe predisposes to recurrence and I would propose arthrodesis of the hallux MTP joint.' The image (Figure 4.8, oblique view) shows the left foot, which, as noted in the initial clinical description, has only three lesser toes due to the prior removal of the second toe. This unique anatomical situation on the left foot, predisposing to recurrence, makes MTP joint arthrodesis the preferred and most reliable option for long-term stability.

Correct Answer: C

The candidate details the physical examination: 'I would palpate for areas of tenderness, paying particular attention to the hallux MTP joint and lesser metatarsal heads. I would assess the degree of active and passive correction possible and the range of movement of the involved joints and look for gastrocnemius tightness. I would also perform a grind test to assess pain from loading the MTP joint. Neurovascular status must also be assessed.' While 'Neurovascular status must also be assessed' is mentioned, the specific 'Measurement of ankle-brachial index (ABI)' is not explicitly stated as part of the physical examination components by the candidate. All other options are directly mentioned.

Correct Answer: C

When asked 'Why not use a simpler procedure such as a chevron or Mitchell osteotomy?', the candidate responds: 'For the degree of deformity described, combined with the lack of passive correction of the hallux, I believe the correction that could be achieved with a distal osteotomy would be inadequate. A further disadvantage of a Mitchell osteotomy is that it produces shortening of the first metatarsal, which could lead to transfer metatarsalgia.' This statement directly supports option C as a significant disadvantage of the Mitchell osteotomy.

Correct Answer: C

The candidate's initial description of the clinical photographs (Figures 4.7 and 4.8) includes: 'I can only count three lesser toes on the left foot and there is a scar in the webspace lateral to the hallux.' This observation is clearly visible in the images, particularly Figure 4.8 (oblique view of the left foot), which shows the absence of the second toe and a scar. The case later confirms that the left second toe was removed years ago. Options A, B, D, and E are either inaccurate or not explicitly stated as initial observations for the left foot.

Resecting additional distal femur increases the extension gap without affecting the flexion gap. Decreasing the AP femoral size or resecting more posterior condyle would alter the flexion gap, which is already well-balanced in this scenario.

The optimal position for ankle arthrodesis is neutral dorsiflexion, 0 to 5 degrees of valgus, and 5 to 10 degrees of external rotation. This alignment best approximates normal gait mechanics and limits compensatory stress on the midfoot and subtalar joints.

Profound peripheral neuropathy (e.g., Charcot arthropathy) is an absolute contraindication for total ankle arthroplasty due to high failure and complication rates. Mild to moderate deformity and high BMI are relative considerations, while post-traumatic OA is the most common indication.

The AAOS guidelines provide a strong recommendation against the use of intra-articular hyaluronic acid for symptomatic knee osteoarthritis, citing a lack of clinically significant efficacy over placebo. NSAIDs, weight loss, and physical therapy all have strong recommendations for use.

Patellar clunk syndrome is caused by a fibrosynovial nodule forming on the superior pole of the patella, which becomes entrapped in the intercondylar box of a posterior-stabilized femoral component during knee extension. It typically presents as a painful pop or catch at 30 to 40 degrees of flexion.

A deficient anterior cruciate ligament (ACL) is traditionally viewed as a contraindication for mobile-bearing medial UKA due to altered knee kinematics and risk of early failure. The other options represent ideal criteria for a UKA.

Opening the anterior and posterior cortex equally during a medial opening wedge HTO will unintentionally increase the posterior tibial slope because the anterior tibial dimension is naturally larger. The anterior gap must generally be roughly half the size of the posterior gap to maintain the native slope.

For advanced hallux rigidus (Coughlin and Shurnas Grade 3 or 4) with diffuse joint space loss and significant motion restriction, a 1st MTP joint arthrodesis is the gold standard for reliable pain relief and durability. Cheilectomy is primarily indicated for Grade 1 and 2 disease with preserved joint space.

Severe loss of calcaneal height leads to a horizontal talus and anterior ankle impingement. A subtalar distraction arthrodesis using a structural bone block restores calcaneal height, declinates the talus, and resolves the anterior impingement.

The talonavicular joint historically has the highest rate of non-union during a triple arthrodesis, with rates cited between 5% to 10%. It is critical to adequately prepare this joint and ensure robust compression during fixation.

The talonavicular joint is the "key" to the acetabulum pedis. Biomechanical studies (like those by Astion et al.) demonstrate that isolated talonavicular fusion restricts subtalar motion to roughly 2 degrees, leaving less than 10% of native subtalar motion.

The optimal position for ankle arthrodesis is neutral dorsiflexion, 0 to 5 degrees of hindfoot valgus, and external rotation matching the contralateral limb (typically 5 to 10 degrees). This alignment provides the most efficient gait cycle and minimizes compensatory stress on the transverse tarsal and subtalar joints.

Charcot neuroarthropathy is considered an absolute contraindication to total ankle arthroplasty due to severe loss of protective sensation, progressive deformity, and unacceptably high rates of component subsidence and failure. Other absolute contraindications include active joint infection, severe avascular necrosis of the talus, and inadequate soft tissue coverage.

During a medial opening wedge HTO, opening the osteotomy gap symmetrically anteriorly and posteriorly tends to inadvertently increase the posterior tibial slope due to the triangular shape of the proximal tibia. To maintain the native slope, the anterior gap must be opened approximately half as much as the posterior gap.

The patient has Grade 3/4 hallux rigidus, characterized by severe radiographic changes and pain throughout the range of motion. The gold standard surgical treatment for end-stage hallux rigidus is a 1st MTP joint arthrodesis, which reliably relieves pain and restores weight-bearing function.

The talonavicular joint consistently demonstrates the highest nonunion rate following triple arthrodesis, with reports ranging from 5% to 37% in the literature. This is largely due to its spherical anatomy, limited vascularity, and high biomechanical demands, requiring meticulous preparation and rigid fixation.

After an ankle arthrodesis, the majority of compensatory sagittal plane motion occurs at the transverse tarsal joints (talonavicular and calcaneocuboid). While there is a reduction in overall walking speed and stride length, the midfoot significantly increases its sagittal excursion to simulate ankle rocker function.

The subtalar joint is highly susceptible to adjacent segment arthritis following isolated ankle arthrodesis due to increased stress transfer and altered hindfoot kinematics. The talonavicular joint is also at significant risk, as the hindfoot complex functions interdependently.

Midfoot arthritis pain occurs primarily during the propulsive phase of gait when bending moments across the tarsometatarsal joints are maximal. A stiff-soled shoe with a full-length steel shank and a rocker bottom limits midfoot dorsiflexion and effectively unloads the arthritic joints.

A fixed flexion contracture greater than 15 degrees is a classic contraindication for unicompartmental knee arthroplasty, as it is difficult to correct without performing extensive releases that are typically reserved for total knee arthroplasty. Other contraindications include ACL deficiency, inflammatory arthritis, and fixed varus deformity greater than 10 degrees.

The AAOS strongly recommends weight loss, physical therapy, and oral NSAIDs for the symptomatic treatment of knee osteoarthritis. High-quality evidence has consistently demonstrated a lack of efficacy for oral glucosamine/chondroitin, lateral wedge insoles, and intra-articular hyaluronic acid in the routine management of primary knee OA.

The optimal position for subtalar arthrodesis is approximately 5 degrees of valgus. Fusing the subtalar joint in varus locks the transverse tarsal (Chopart) joints, resulting in a rigid midfoot and significant difficulty adapting to uneven terrain.

For a young, active patient with isolated lateral compartment knee osteoarthritis and a significant valgus deformity, the deformity typically originates in the distal femur. A distal femoral osteotomy (such as a medial closing wedge) is the procedure of choice, as correcting large valgus deformities via the tibia creates an unacceptable, non-physiologic joint line obliquity.

An isolated talonavicular arthrodesis virtually eliminates subtalar joint motion, reducing it to approximately 2 degrees. The talonavicular, subtalar, and calcaneocuboid joints function as a tightly coupled, interdependent complex; therefore, locking the TN joint severely restricts motion in the entire hindfoot.

The optimal position for ankle arthrodesis is neutral dorsiflexion (0 degrees), 5 degrees of hindfoot valgus, and external rotation equal to the contralateral side (typically 5 to 10 degrees). This position minimizes adjacent joint stress and normalizes gait.

Active infection, Charcot neuropathy, severe talar avascular necrosis, and inadequate soft tissue coverage are absolute contraindications to total ankle arthroplasty (TAA). Concomitant hindfoot arthritis is generally considered a relative indication for TAA to preserve remaining joint motion.

The optimal position for an ankle arthrodesis is neutral dorsiflexion (0 degrees), 0 to 5 degrees of valgus, and 5 to 10 degrees of external rotation to match the contralateral side. Plantarflexion causes a genu recurvatum thrust, while varus positioning leads to painful lateral border overload.

First MTP joint arthrodesis is the gold standard for advanced (Grade 3 and 4) hallux rigidus, providing reliable, long-lasting pain relief and functional improvement. Cheilectomy is primarily indicated for Grade 1 and 2 disease characterized by predominantly dorsal osteophytes and impingement.

Contraindications for unicompartmental knee arthroplasty include inflammatory arthritis, ACL deficiency, fixed varus deformity greater than 10 degrees, and flexion contracture greater than 15 degrees. A non-correctable varus deformity of 15 degrees makes him a poor candidate for UKA and better suited for a TKA.

A stiff-soled shoe with a rocker bottom effectively limits stress and motion through the arthritic midfoot joints during the toe-off phase of gait. This modification is highly successful for the conservative management of midfoot arthritis.

Following an ankle arthrodesis, the subtalar joint is subjected to significantly increased biomechanical stress to compensate for the loss of tibiotalar motion. This leads to a high incidence of adjacent segment osteoarthritis over time, most prominently in the subtalar joint.

Total knee arthroplasty is the definitive management of choice for advanced tricompartmental knee osteoarthritis in older patients who have exhausted conservative therapies. Osteotomies and unicompartmental replacements are strictly contraindicated in the setting of widespread tricompartmental disease.

A distraction bone block subtalar arthrodesis is indicated for post-traumatic subtalar arthritis accompanied by loss of calcaneal height and resultant subfibular impingement. This procedure restores talocalcaneal height, decompresses the fibula, and fuses the painful arthritic joint.

The standard anterior approach to the ankle utilizes the internervous interval between the EHL and EDL. The deep peroneal nerve and the anterior tibial artery lie directly beneath the extensor retinaculum in this space and are at high risk during exposure and retractor placement.

Uncorrected patellar maltracking, instability, or significant malalignment are contraindications to isolated patellofemoral arthroplasty due to the high risk of early implant failure. The underlying biomechanical tracking issues must be addressed concurrently, or a total knee arthroplasty should be considered if the malalignment is uncorrectable.