Chapter 29: Ankle ConditionsDifferential Diagnosis of Chronic Ankle Pain Tarsal Tunnel Syndrome Sinus Tarsi SyndromePeroneal SubluxationAnkle ArthrodesisLateral Ankle InstabilityChronic Lateral Ankle Instability Chronic Medial Ankle Instability Ankle EquinusMalunion and Nonunion of the Malleoli

ANKLE CONDITIONS ANDTREATMENT

Differential Diagnosis of Chronic Ankle Pain1. Lateral:a. Peroneal tendon and nerve:i. Peroneal tendon stenosing tenosynovitisii. Peroneal dislocationiii. Peroneal neuropathy b. Sural nerve injury

2. Dorsolaterala. Sinus tarsi syndromeb. Extensor digitorum brevis (myositis, avulsion) c. Calcaneus anterior process fracture

3. Intracapsular:a. Talar posterior (lateral) process fractureb. Talar dome (osteochondral) defectsc. Intra-articular fibrous bands, hypertrophic synovitis, meniscoid bodies

4. Medial:a. Tarsal tunnel syndromeb. Posterior tibial tendon tendonitis, rupture c. Flexor hallucis longus tendonitis d. Os trigonum fracture

5. Other:a. Ligamentous injury (instability) b. Traumatic DJD of STJ or ankle

Tarsal Tunnel SyndromeThis is an entrapment or compression neuropathy of the posterior tibial nerve or one of its three branches, the medial and lateral plantar nerves and/or medial calcaneal nerve.1. Anatomy: Nerve entrapment occurs either In the porta pedis or lacinate ligamenta. The flexor retinaculum (lacinate ligament) extends from the medial malleolus to the medial process of the calcaneal tuberosity and the plantar aponeurosis. The deep fibrous septa form four compartments, and converts bony grooves into canals from anterior-medial to posterior lateral: #1 contains tibialis posterior tendon (most superficial), #2 FDL tendon, #3 posterior tibial nerve artery and vein, and #4 FHL tendon. These compartments are unyielding spaces.b. The porta pedis is a canal created by the abductor hallucis muscle belly through which the medial and lateral plantar nerves pass.c. Division of the posterior tibial nerve into its 3 terminal branches may occur proximal to the lacinate ligament, which is most common; within the

lacinate ligament, as described in most texts; or distal to the lacinate ligament, which is rare.d. The medial calcaneal nerve is entirely sensory, and innervates the medial and plantar aspect of the heel. It may arise from either the posterior tibial or lateral plantar nerve.e. The medial plantar nerve gives sensory innervation to the plantar aspect of the hallux, second and third toes, medial half of the fourth toe, and the medial half of the plantar aspect of the foot. It gives motor innervation to the abductor hallucis, flexor digitorum brevis, flexor hallucis brevis, and the first lumbricalis.f. The lateral plantar nerve gives sensory innervation to the plantar lateral half of the fourth toe, plantar aspect of the fifth toe, and plantar lateral aspect of the foot. Initially it sends motor fibers to the quadratus plantae and abductor digiti quinti before dividing in a superficial and deep branch. Superficial branch supplies motor innervation to the flexor digiti quinti brevis and the dorsal and plantar interossei of the fourth intermetatarsal space. The deep branch supplies the remaining intrinsic muscles of the foot.

2. Pathology: Compression of the nerve initially causes only sensory involvement with possibly partial involvement of motor fibers. Continuation of the irritation, ischemia, and compression may lead to secondary hyperactivity of the autonomic nervous system, (manifested by coldness and numbness) from the altered sympathetic activity. Eventual structural changes in the nerve result in the development of muscle wasting, paresis, and objective sensory loss.

3. Etiology: In the many cases no etiology can be found at the time of surgical decompression.a. Dilated posterior tibial veins: can also cause severe night discomfort.b. Trauma: Fracture, dislocation, sprain, post-traumatic edema and fibrosis. c. Systemic disease: Gouty arthritis with urate deposits, rheumatoid arthritis, diabetes mellitus, and myxedema.d. Space occupying lesions: Ganglions, neurofibromas, schwannomas, synovial cysts, etc.e. Hypertrophy of abductor hallucis muscle belly.f. Biomechanical: excessive pronation

4. Clinical Symptoms: Symptoms can be either distal to the metatarsal area, or the medial and lateral heel depending on the branch involved. a. Early:i. Intermittent burning pain, numbness and paresthesias over the medial side of the heel, the toes, and the plantar aspect of the foot. b. Late:i. A paresis that will develop into paralysis of the pedal intrinsic muscles.ii. Proximal radiations of pain may develop in the posterior calf.

NOTE* Reflexes are unaffected

iii. Pain that is proportional to the amount of activity during the day. iv. May develop some sensory loss

5. Diagnosis: Not always easy, as the signs are not always definitive a. History of paresthesiasb. History of traumac. History of systemic diseased. Hoffman-Tinel's sign: A tingling in region of the distribution of the involved nerve with light percussion, results in paresthesias distal to the site of percussion.e. Valleix Phenomena: A nerve trunk tenderness above and below the point of compression, with paresthesias proximal and distal to the point of percussion.f. Turk's test: Application of a venous tourniquet to the lower extremity will elicit positive symptoms on the affected side, by producing a venous occlusion.g. Forced eversion of the foot.h. Positive radiographic evidence of previous injury i. Positive lab studies for any specific diseasej. EMG's and nerve conduction studies are only useful for late stage disease.

6. Treatment: Conservativea. Local blocks: Posterior tibial nerve blocks with steroids b. Unna boot: can be combined with nerve blocks c. Support hose: for varicositiesd. Functional orthoses

7. Treatment: Surgical Decompression (positive EMG's and nerve conduction studies mandate surgical decompression). Involves the complete exploration of the tarsal tunnel with release of the flexor retinaculum and its fibrous bands, and resection and ligation of any dilated veins in the area.The surgical technique is as follows:a. A curvilinear incision is made posterior and inferior to the medial malleolus by 1 cm.b. The subcutaneous tissue Is Incised and the superficial- vessels are ligated

Note* EMG may show fibrillation potentials which indicate denervation of muscle. Nerve conduction studies may reveal an increased distal latency.

Note* Placement of nerve conduction study surface electrodes are as follows:1. Proximal stimulation point: distal aspect of popliteal fossa 2. Distal stimulation point: behind the medial malleolus3. Recording electrode (for conduction of the medial plantar nerve) through the abductor hallucis ms. belly.4. Recording electrode (for the lateral plantar nerve) through the abductor digiti quinti muscle belly.

as necessary.c. The neurovascular structures superior to the retinaculum are identified, preserved, and retracted (especially the medial calcaneal branch). d. The flexor retinaculum is incised and the posterior tibial nerve or its terminal branches are identified and mobilized. e. The nerve(s) is retracted with a penrose drain. f. The nerve(s) is followed proximally, incising the flexor retinaculum as you go.g. The nerve(s) is followed distally to the point where the medial and lateral plantar nerves pass through the fibrous canals superior to the abductor hallucis ms. belly.h. The abductor hallucis ms. is examined for any abnormality, and any hypertrophy is excised.i. If there are any posterior tibial vein varicosities, they should be ligated. j. The retinaculum is not reapproximated and no deep closure is done. k. The superficial fascia is reapproximated and the skin reapproximated i. Sterile compression dressing and a non-weight-bearing BK cast applied for 3 weeks.

8. Complications:a. Recurrence: due to fibrosisb. Severing the PT artery : if done then tie off and prepare patient for microvascular repair later.c. Severing a nerved. Tenosynovitise. Hematomaf. Wound dehiscence

Sinus Tarsi Syndrome1. Symptoms: A diffuse deep aching pain on the dorso-lateral aspect of the foot over the sinus tarsi. Relief of the discomfort after an injection of anesthesia deep into the sinus tarsi while maintaining superficial sensation is a diagnostic feature.

2. Etiology:a. Post traumatic:i. Inversion ankle sprain ii. Fibular fracture iii. Calcaneal fracture iv. Talar neck fracture

b. Biomechanical fault:i. Pes piano valgus (stretching of the cervical ligament) ii. Pes cavus

NOTE* Arthroscopic studies of the posterior facet showed an absence of the normal synovial recesses in front of the talocalcaneal interosseous ligament. This may indicate synovial hyperplasia, scarring, and/or synovitis

c. Systemic arthritic/metabolic: i. RAii. Goutiii. Seronegative arthropathies

3. Findings:a. Subjective:i. Diffuse pain on the lateral side of the footii. Feeling of rearfoot instability especially on uneven terrain iii. Dramatic relief of symptoms with an anesthetic block b. Objective:i. Pain reproduced with direct pressure over the sinus tarsi ii. Discomfort with forced inversion and plantarflexion iii. X-rays normaliv. Ankle joint is WNLv. STJ motion painful but not limitedvi. MTJ motion mostly pain freevii. Palpation of the intermediate dorsal cutaneous nerve and sural nerve uneventfulviii. Palpation of the anterior talofibular and calcaneofibular ligaments is uneventfulix. Elicit pain by digital pressure on both sides of the sinus tarsi simultaneouslyc. Diagnostic:i. X-raysii. Diagnostic anesthetic blockiii. Arthrography of the posterior facet of the STJ iv. Ankle stress films (to RIO ankle instability)v. 3 phase bone scan to R/O fracturevi. MRI to evaluate the soft tissues, fracture, and infectious disease or arthritic processvii. CT scan to R/O coalitions

4. Differential diagnosis:a. Entrapment neuropathy of the intermediate dorsal cutaneous nerve b. Entrapment neuropathy of the sural nerve c. Damage to the anterior talofibular ligament d. Damage to the calcaneofibular ligamente. Peroneal tenosynovitisf. DJD of the STJ (posterior or middle facet)g. Coalitionh. Talar neck fracturei. RA, gout, seronegative arthritidesj. Talar dome fracturesk. Space-occupying lesion

5. Treatment: a. Conservative:i. Injection of series of local anesthetic/steroid, once every 2 weeks x 3 times

ii. NSAID'siii. Tape immobilizationiv. BK castv. Foot orthoses (if biomechanical)vi. Physical therapyb. Surgery: Sinus Tarsi evacuation as follows:1. Transverse incision over the sinus tarsi 4 cm.ii. Resection of portions of the extensor retinaculum, a fatty plug, thecervical ligament, and a synovectomy of the adjacent middle andposterior articulations of the STJ for a total distance of 2 cm.iii. Evaluation of the STJ articulations (ATFL, CFL, and peroneals)iv. Postop: Orthopedic shoe for 2 weeks, followed by physical therapy

6. Complications:a. Entrapment neuropathies b. Avascular necrosis c. Subtalar instability

Peroneal Subluxation1. Clinical presentation:a. Post-traumatic state: Evident after acute injury or later with a history of recent antecedent trauma. The post-traumatic state represents:i. Either a subperiosteal dissection of the superior peroneal retinaculum orii. An avulsion fracture of the fibula with the adherent superior peroneal retinaculum and deep fasciab. Chronic subluxing state with an insidious progression of pain about the peroneals (not necessarily associated with trauma). This state represents:i. A stretching, redundancy, or pouching of the superior peroneal retinaculum and deep fascia permitting displacement of the peroneal tendons within an intact compartment

2. Classification of peroneal injuries (Eckert and Davis):

NOTE* if the pain persists despite appropriate care then a STJ fusion or triple arthrodesis is indicated

NOTE* The key difference between the two forms of tendon dislocation is based upon the relationship of the deep fascia and superior peroneal retinaculum to the peroneal tendons and the distal fibula

3. Surgical technique (one type): A reduction of the deep fascial redundancy with insertion Into the fibulaa. 8 cm incision placed posterior to the palpable posterior division of the anterior border of the fibula overlying the peroneal compartment b. Incision into the superficial and deep fasciac. Periosteal incision just superior to the posterior division of the anterior border of the fibulad. 5 drill holes into the fibula from the lateral surface to the posterior surface, with the most distal drill hole just overlying the peroneal groove areae. Redundant deep fascia containing the peroneals is plicatedf. Sutures inserted (twice around) with the knots below the deep fascia g. BK weight-bearing cast applied for 6 weeks

NOTE* A Jones procedure for peroneal stabilization involves detaching a small strip of Achilles tendon proximally, and rerouting it from posterior to anterior through a drill hole in the fibula, then sutured onto itself

Arthrodesis of the Ankle1. Indications: This procedure is indicated primarily in patients with severe pain and deformity, Including: DJD, RA, talar collapse, failed ankle joint prostheses, infection of the ankle joint, drop foot, invasive tumors, and congenital deformities

2. Preoperative evaluation:a. Patients selected for ankle fusion should be those for whom it will be reasonable to expect a significant reduction in pain and deformity, and an increase in activityb. Evaluate integrity of adjacent joints (STJ and forefoot): To R/O the necessity for a secondary STJ fusion or triple arthrodesisc. Ankle joint is fused at right angle to the leg, and compensation for heel height must then come from plantarflexion at the midtarsal and tarsometatarsal jointsd. Stability at the knee joint is important in those patients undergoing a pantalar fusione. Good bone stock a necessity

3. Surgical approaches: Dictated by the exposure necessary to perform the desired techniquea. Transverse anterior approach (Charnley): Severs the extensor tendons and anterior neurovascular bundleb. Midline longitudinal anterior approach: Inadequate visualization of the posterior ankle jointc. Lateral approach via hockey-stick incision: When combined with a fibular osteotomy this approach gives good exposure of the posterior, lateral, and anterior aspects of the ankled. Medial malleolar approach: When combined with medial malleolar osteotomy gives good exposure of the anteromedial, medial, and posteromedial aspects of the ankle joint

4. Surgical technique categories:a. Articular wedging with or without graftingb. Anterior arthrodesis with inlay graftingc. Articular wedging combined with malleolar osteotomy d. Dowel or other subtotal fusionse. Compression arthrodesis

5. The requirements for a successful fusion:a. Complete removal of all the cartilage, fibrous tissue, and any other material that may prevent contact of raw bone to raw bone b. Accurate and close fitting of the fusion surfaces c. Optimal position of the ankle joint

NOTE* Procedure of choice for good visualization is the lateral hockeystick incision plus medial incision

d. Maintenance of the bone apposition in an undisturbed fashion until fusion is completed

Lateral Ankle Instability1. Plantar flexion inversion injury classification (Leach): a. 1st degree: ATFLb. 2nd degree: ATFL, CFL, and capsulec. 3rd degree: ATFL, CFL, PTFL, and capsule

2. Factors which predispose to recurrent ankle sprains:a. Tibial varumb. Ankle varumc. Calcaneal varum d. STJ varuse. Plantarflexed 1st ray f. Rigid forefoot valgusg. Uncompensated equinus h. Muscle imbalancei. Weak peronealsii. Overactive tibialis anterior and tibialis posterior i. Previous ankle sprainsj. Torsional abnormality k. Short leg syndrome

Chrenshaw AH (ed): Campbell's Operative Orthopedics, Volume 2, CV. Mosby, St.Louis, 1971, p. 1126, with permission

Chronic Lateral Ankle InstabilityMany surgical procedures have been devised to reconstruct the lateral ligaments, but because of their unique configuration, accurate anatomic reconstruction is nearly impossible.

The above diagram shows the relationship of the anterior talo-fibular ligament to the calcaneo-flbular ligament. This relationship is hard to recreate with any surgical procedure. This is why there is limitation of STJ range of motion following stabilization surgery

1. Etiology:a. Post-traumatic ligamentous disruption b. Osteochondral dome fractures c. Degenerative joint disease d. Peroneal subluxation e. Muscular weakness or paralysis f. Talofibular meniscoid g. Generalized ligamentous laxity h. Tibio-fibular diastasis i. Non-union of previous fracture j. Poorly reduced/healed fracture k. Fixed calcaneal varus l. Tibial varumm. Rigid plantarflexed 1st ray

2. Anatomy of the lateral ankle:a. The peroneal muscles terminate in tendons proximal to the ankle joint and a common synovial sheath surrounds the peroneals at this point above the ankle and contains them in a fibro-osseous tunnel b. Posterolaterally, they are contained by the superior peroneal retinaculum and medially by the lateral ankle joint ligamentsc. At the level of the ankle joint the peroneus brevis lies anterior and deep against the fibular groove, with the peroneus longus posterior d. As the peroneus brevis tendon passes distally, below the tip of the fibula, it turns anterior, plantar, and lateral, crossing the CFL superficially e. As the peroneus longus passes distally it runs plantar and anteriorly, then passes in an inferior tunnel formed by the inferior peroneal retinaculum at the level of the peroneal tubercle of the calcaneus. The peroneus brevis tendon lies in a similar tunnel superior to the tubercle on the calcaneusf. The ATFL is intracapsularg. The CFL, PTFL, and fibulotalocalcaneal (not always present) are extracapsular

3. Clinical and radiographic evaluation:a. Common complaints: persistent instability, pain, edema, weakness, and associated insecurity on uneven surfacesb. Radiology: Talar tilt and anterior draw test (need comparison views of the contralateral ankle), arthrography, tenography, and MRI

4. Surgical Procedures: Stabilization procedures depend upon the patient's needsa. Delayed primary repair: Suturing of the ATFL/CFL with a non-absorbable suture (0 or 2-0), with NWB BK casting for 6 weeks b. Delayed secondary repairs (utilizing fascial grafts): Are categorized according to the number of

NOTE* Due to the angular relationships of the ATFL and the ankle, inversion of the ankle is primarily resisted by the ATFL when the ankle is plantarflexed, and by the CFL when the ankle is dorsiflexed

NOTE* Controversy exists over the interpretation of inversion stress views. The anterior draw test is most useful in assessing the ATFL integrity (0-5 mm of anterior displacement is normal, 8-10 mm consistent with a single ligament rupture, 10-1.5 mm consistent with a double ligament rupture, and greater than 15 mm anterior displacement is consistent with a triple ligamentous rupture).These two tests are complementary.They should be done under common peroneal and sural nerve block. A Telos® stress device is used for more of a constant/gradually appliedforce.

ligaments rupturedi. Single ligament rupture: Watson-Jones*: This uses the peroneus brevis, which passes through the fibula from posterior to anterior, through the neck of the talus from plantar to dorsal, back through the fibula, from anterior to posterior, and sutured back onto itself. Lee Procedure (modified Watson-Jones)*: This uses the peroneus brevis tendon, which is then passed through the fibula, from posterior to anterior, and then sutured back onto itself. Evans*: This utilizes the peroneus brevis through an oblique hole through the fibula sutured back onto. the belly of the peroneus brevis. Storren Nilsonne Pouzet Haig Castaing and Meunier Dockery and Suppan

ii. Double ligament rupture: Elmslie*: Originally described as using the fascia lata and passed through a drill hole in the lower aspect of the fibula, through the calcaneus, back through the same drill hole, and tied onto itself, after passing through the neck of the talus. Chrisman and Snook*: This uses the split peroneus brevis, which is passed through the fibula from anterior to posterior through a flap in the calcaneus, and is then sutured back to the peroneus brevis tendon. Stroren Hambly Winfield Gschwend-Francillon

iii. Triple ligament rupture: Spotoff Rosendahl and Jansen

NOTE* A Split Peroneus Brevis Lateral Ankle Stabilization Procedure was developed at Doctor's Hospital, which has proven to have minimal morbidity and to be dependable, especially for the athletic individual The surgical procedure is as follows:a. Patient lying in the lateral position with thigh tourniquetb. Single incision beginning approx. 10-12 cm proximal to the lateral malleolus, extending distally just posterior to the fibular malleolusc. A subperiosteal channel is created from the neck of the talus to the base of the 5th metatarsal, and a wire loop is placed within the channel to facilitate passage of the tendon laterd. The peroneal retinaculum is incised just posterior to the fibula, peroneals retracted posteriorly, CFL exposed, and a 4 mm hole is made from the anterior edge of the fibula, angled slightly inferiorly (bone plug is saved)

5. Complications after reconstruction:a. Questions that should be asked to determine problems:i. Is there still a sense of ankle instability and repeated inversion injuries?ii. Is the primary problem chronic pain? If the problem is the former, then reconstruction is the problem.. If the problem is the latter then there might be a secondary lesionb. A varus rearfoot can contribute to reinjuring the ligament and causing a failed reconstruction over time. Also subtalar instability can cause failure (if this is the reason, the patient might. require additional surgery involving the calcaneofibular ligament)c. If pain is the patient's main complaint you must rule out a coexistent lesion such as an osteochondral fracture, tarsal coalition, ankle arthrosis, chronic tear in the peroneal tendon, or postoperative neuroma of the sural nerve

Chronic Medial Ankle InstabilityDeltoid injuries are rare and occur when the foot is forcibly everted on the leg (see chapter 25: Deltoid Injuries). If an external rotary component is also present, a concomitant fibular fracture with disruption of the T-F syndesmosis will occur. Therefore, when confronted with an unstable medial ankle check for a displaced fibular fracture or T-F diastasis 1. Anatomy:a. Superficial deltoid: Tibiocalcanealb. Deep deltoid: Anterior tibiotalar, tibionavicular, and posterior tibiotalar

2. Surgical repair:a. Delayed primary repair

e. A 6 mm hole is made in the body of the calcaneus adjacent to the insertion of the CFLf. A final subperiosteal channel is made from the posterior fibula to the hole created in the calcaneus, and a wire loop is inserted for later passage of the tendong. The peroneus brevis tendon is then split (at the start of the muscle belly), tagged with a suture and pulled distally within its tendon sheath to the base of the 5th metatarsalh. The tendon is brought through the 1st subperiosteal channel to the neck of the fibula and passed through from anterior to posterior, sutured to the anterior fibulai. The tendon is brought through its 2nd subperiosteal channel and buried into the hole created in the calcaneus

NOTE* Either dacron mesh (Dacron Cooley graft) or Marlex surgical mesh (porous film) can be used as an adjunct in the repair of the lateral ligaments

Ankle EquinusPrimary neuromuscular spasticity of the posterior muscle group needs to be approached differently than a secondary acquired contracture of the gastrocnemius. The goal of the surgery will also depend on the etiology.The resulting gains in ankle joint dorsiflexion must be weighed against the loss of a grade of muscle strength1. Patient complaints:a. Low back painb. Calcaneal apophysitis in childrenc. Heel spur syndrome in adultsd. Arch paine. Inability to stand for long periods without pain/fatigue f. Juvenile HAVg. Digital contractures

2. Anatomy:a. The gastrocnemius is a muscle spanning two joints, and forming the belly of the calf attached by two heads to the femoral condyles, the medial head being largerb. The gastrocnemius and soleus are innervated by the tibial nerve from S1 and S2c. The soleus is a broad flat muscle deep to the gastrocnemius, arising from the back of the head and the upper fourth of the posterior surface of the fibula.d. The soleus joins with the gastrocnemius to form the tendo Achilles. At the insertion, the gastrocnemius component usually comprises the lateral side of the superficial surface and a small portion of the lateral aspect of the deep or anterior surface of the tendone. Superficial to soleus are gastrocnemius and plantaris; deep are flexor digitorum longus, flexor hallucis longus, tibialis posterior, and the posterior tibial vessels and tibial nerve, all separated from soleus by the deep transverse fasciaf. The plantaris arises in close association with the lateral head of the gastrocnemius, has a small fusiform belly, that ends in a long slender tendon, which crosses obliquely between gastrocnemius and soleus and runs along the medial border of the tendo Achilles,-to be inserted with it. The plantaris limits dorsiflexion of the ankleg. The tendo Achilles is the thickest and strongest human tendon, surrounded by a paratenon (highly vascular areolar tissue which bathes the tendon in synovial fluid). The tendo Achilles attaches to the posteriorsuperior surface of the calcaneush. The anatomy of the ankle joint is a modified ginglymus joint because in full plantarflexion, the narrow posterior aspect of the trochlear surface of the talus allows the frontal plane motion of inversion and eversion to occur in the mortise (normal dorsiflexion should be 10-200, normal plantarflexion 30-500)

3. Muscular activity:a. The muscles of the calf are the major plantarflexors, the gastrocnemius

also extends the knee, and the soleus steadies the leg on the foot in standingb. Phasic activity of the triceps is from shortly after heel contact until justbefore toe-off, all functioning to extend the knee during a normal gaitcycle (it does this through the soleus, by slowing the forward progression of the tibia, thus allowing the femur to rotate over it, extending the knee joint)c. The soleus fires at about 15%-20% of the stance phase of gait, slightly ahead of the gastrocnemius

4. Pathomechanics:a. In normal function, with the knee fully extended and the STJ in neutral position, at least 100 of dorsiflexion of the foot to the leg are needed b. When there is pronation past perpendicular, this shortens the origin to insertion distance of the gastrocnemius (the distal aspect of the calcaneus lowers, the midtarsal joint lowers to the ground, the calcaneal inclination angle decreases) and over a period of time there is secondary adaptation, and the amount of dorsiflexion is limitedc. With a primary equinus deformity at 50%-60% of midstance, with the hip and knee extended, you cannot get 100 of dorsiflexion and, therefore, the subtalar joint and midtarsal joints pronate to give more dorsiflexion (the oblique axis of the MTJ gives more dorsiflexion than any other joint in the foot as it compensates for the equinusd. This midtarsal joint pronation will also induce the forefoot into a supinatus deformity

5. Classification:a. Uncompensated: The STJ remains supinated, therefore, the lack ofdorsiflexion at the ankle joint cannot be compensated by abnormal STJ and MTJ pronation (the CP patient)b. Fully compensated: Presents with STJ and MTJ pronation, seen as the hypermobile flatfoot, with the rearfoot maximally everted to the floor and the forefoot everted on the rearfoot (the most severe symptom complex). Creates a spinal lordosis, excessive transverse plane motion about the knee, low back pain, chondromalacia, exaggerated genu valgum, juvenile bunions, and digital contracturesc. Partially compensated: The patient has sufficient combination of ankle joint dorsiflexion and dorsiflexion about the oblique axis of the MTJ to permit heel contact during the early portion of the stance phase of gait. However, there is insufficient dorsiflexory motion to permit the leg to angulate 100 to the floor later in stance. Early heel-off is seen during gait. Generally, with a partially compensated equinus, the calcaneus will strike the floor but will evert only minimally, and then will rapidly achieve an early heel-off

6. Etiologies:a. Muscular (gastrocnemius equinus, gastrosoleus equinus)

NOTE* Tendon lengthening should not be done unless the etiology of the equinus is absolutely certain because there will be an automatic loss of 10% of its strength

ii. Congenital shortness: Toe walker for 1 st 6 monthsiii. Acquired shortness: From casts, high-heeled shoes, excessive pronationb. Osseousi. Osseous equinus: Dorsal exostosis of the talar neck from a flat top talus (can be from treatment of a clubfoot)ii. Pseudoequinus (cavus foot type)

7. Clinical findings:a. With the patient supine and the knee extended and the STJ in neutral position, the foot is dorsiflexed. If dorsiflexion is less than 100 an ankle equinus to existsb. Silverskiold test is then used to differentiate gastrocnemius equinus from the remaining types of posterior equinus: by flexing the patient's knee to a right angle and again dorsiflexing the patient's foot. If more than 100 of dorsiflexion is found a gastrocnemius equinus still exists. Thus after performing the Silverskiold test there is still limitation of ankle joint dorsiflexion, other sources of ankle joint dorsiflexion remain to be evaluated (either gastrosoleal equinus or osseous equinus).

8. Surgical procedures: See Chapter 27, Tendon pathology: Tendon Lengthening and Tenotomya. Distal recession (Volpius and Stoffel)b. Slide lengthening (White)c. Distal recession (Strayer)d. Lengthening the apneurotic tendon of. the gastrocnemius (Baker) e. "Z" plasty (Sgarlato)f. Frontal plane "Z" plasty (McGlamry)g. Modified Baker tongue and groove (Fulp and McGlamry): For nonspastic gastrocnemius equines

Malunion and Nonunion of the MalleoliAccording to Ramsey and Hamilton, 1 mm of ankle asymmetry causes a 42% decrease in contact area between the talus and the tibia. Therefore, because stress per unit area increases as the total contact area decreases, even mild malunion of the fibula and the ensuing talar instability can result in significant disability1. Malunion of the fibula:a. Might not become symptomatic for several years, with the patient complaining of a dull ache over the anterior aspect of the ankle which worsens with use, swelling, onset of arthritis, and a limp b. Radiographic criteria used to diagnose a malunion of the lateral malleolus are similar to those used in evaluating acute ankle fracturei. Evaluation of the tibiofibular articulationii. Fibular length and rotationiii. Ankle mortise symmetryiv. Talar tiltv. Bimalleolar angle: measures the exact amount of fibular shortening(comparison of both ankles is necessary, and a 10 change in the angle

NOTE* To help evaluate osseous equinus a stress dorsiflexion lateral x-ray is used. Comparison is made with the regular lateral view and checked for 2 items:a. The excursion of the tibia over the talusb. How much motion of the tibia and talus is occurring as a unit

corresponds to a 1 mm change in fibula length).

NOTE* Three views should be used (AP), (LAT), and 15° internally rotated mortise view

c. Conservative treatment:i. AFOii. NSAIDsiii. Injectionsd. Surgical treatment: When conservative measures fail, reconstruction can be attempted. If that fails. then a fusion can always be done.i. The concurrent presence of a medial malleolar malunion makes reconstruction more difficult. A malleolar malunion has no substantial effect on stability of the ankle and only needs to be corrected if symptomatic or- with a step-off in the weight-bearing joint surface of more than 2 mm.ii. A concomitant malunion of a large posterior malleolar fragment (more than 30% of the joint) usually precludes reconstruction (posterior displacement of the talus, soft tissue scarring, and osteoporosis of the displaced piece make reduction difficult)iii. The fundamentals are that there is a shortened and externally rotated lateral malleolus, with lateral subluxation. The procedure to accomplish correction is as follows: The fibula must be freed leaving only the collateral ligaments intact An oblique or transverse osteotomy is made at the level of the malunion and an AO compression device set in the distraction mode (to increase fibular length)

A plate is fixed to the fibula The syndesmosis is held in reduction with a 4.5 mm cortical screw

2. Nonunion of the medial malleoli:a. Occurs more frequently in fractures that are treated with closed reductionb. Surgery for a nonunion should only be considered if the clinical examination, including pain, tenderness at the fracture site, correlates with the radiographic findingsc. Nonunion of the medial malleolus can occur anywhere but proximal lesions nearer the weight-bearing aspect of the tibial plafond are more likely to be symptomaticd. If a malunion is present it should be taken down and anatomically reduced with compression screws and a local cancellous bone graft from the metaphysis of the distal tibiae. If the nonunion is in anatomic alignment, it can be left in place with a troughtrough created across the nonunion site and packed by a cancellous bone

3. Nonunion of the lateral malleoli:a. Similar approach should be taken as with medial malleolar nonunions, although these are more prone to produce a malunion and instability b. A small, distal, non-united fragment (smaller than 1 cm) should be excised rather than trying to obtain osseous union. The collateral ligaments should be carefully reattached