Operative Techniques in Orthopaedic Surgery (4 Volume Set) 1st Edition

500. Osteochondral Lesions of the Talus: Structural Allograft

Mark E. Easley, Samuel B. Adams, Jr., and James A. Nunley II

DEFINITION

images Large osteochondral defects of the talar dome, typically involving the talar shoulder (transition of superior dome cartilage to the medial or lateral talar cartilage), and also often associated with large-volume subchondral cysts

ANATOMY

images Sixty percent of the talus’ surface area is covered by articular cartilage.

images The talus is contained within the ankle mortise.

images Superior talar dome articulates with the tibial plafond.

images Medial dome articulates with the medial malleolus.

images Lateral dome articulates with the lateral malleolus.

images Talar blood supply

images Posterior tibial artery

images Artery of the tarsal canal

images Deltoid ligament branch

images Peroneal artery

images Artery of the tarsal sinus

images Dorsalis pedis artery

PATHOGENESIS

images The pathogenesis for osteochondral lesions of the talus (OLTs) is not fully understood.

images Theories include:

images Trauma

images Idiopathic focal avascular necrosis

NATURAL HISTORY

images In general, OLTs do not progress to diffuse ankle arthritis.

images However, large-volume OLTs may lead to subchondral collapse of a substantial portion of the talus and thus create deformity, higher contact stresses, and a greater concern for eventual ankle arthritis if left untreated.

PATIENT HISTORY AND PHYSICAL FINDINGS

images Patients may or may not report a history of trauma.

images Ankle pain, typically on the anterior aspect of the ankle, is a common complaint.

images Pain is usually experienced on the side of the ankle that corresponds with the OLT, but it may be poorly localized to the site of the OLT. In fact, sometimes medial OLTs produce lateral ankle pain and vice versa.

images Pain is rarely sharp, unless a fragment of the OLT should act as an impinging loose body in the joint.

images It is typically a deep ache, with and after activity, and is usually relieved with rest.

images Antalgic gait

images May be associated with malalignment or ankle instability

images Typically tenderness on side of ankle that corresponds with OLT, but not always

images Rarely crepitance or mechanical symptoms

images With chronic OLT, some degree of ankle stiffness anticipated

IMAGING AND OTHER DIAGNOSTIC STUDIES

images Plain radiographs

images Small OLTs may be missed.

images Large OLTs are usually identified on plain radiographs, three views of the ankle, weight-bearing.

images Radiographs are often limited in characterizing OLTs since the two-dimensional study cannot define the threedimensional OLT.

images Particularly useful in assessing lower leg, ankle, or foot malalignment, which needs to be considered in the management of OLTs

images May detect incidental OLTs (patient has radiograph for a different problem and an OLT is incidentally identified on plain radiographs)

images MRI

images Excellent screening tool when OLT or other foot–ankle pathology is suspected

images Will identify incidental OLT, but defines other potential soft tissue pathology

images Demonstrates associated marrow edema that may lead to overestimation of the OLT’s size

images CT

images Ideal for characterizing OLTs, particularly large-volume defects

images Defines OLT size without distraction of associated marrow edema

images Defines the character of the OLT and extent of its involvement in the talar dome

images Diagnostic injection

images Intra-articular

images An anesthetic versus anesthetic plus corticosteroid

images May have some therapeutic effect, even for several months

images If the source of pain is the OLT, then intra-articular injection should relieve symptoms from OLT (and any intra-articular pathology). If the pain is not relieved, then extra-articular diagnoses should be considered.

DIFFERENTIAL DIAGNOSIS

images Loose body in ankle joint

images Ankle impingement (anterior or posterior)

images Chronic ankle instability (lateral or syndesmosis)

images Ankle synovitis or adjacent tendinopathy

images Early ankle degenerative change

NONOPERATIVE MANAGEMENT

images Activity modification

images Bracing

images Physical therapy if associated ankle instability

images Nonsteroidal anti-inflammatories or COX-2 inhibitors

images Corticosteroid injection

images Viscosupplementation?

SURGICAL MANAGEMENT

Preoperative Planning

images Indications for this surgery include:

images Large-volume OLTs not amenable to other joint-sparing procedures

images Failed arthroscopic surgery (débridement and microfracture)

images Failed open procedures (cylindrical osteochondral transfer)

images Large-volume OLTs typically are not amenable to autologous osteochondral transfer (talus or knee).

images We favor reconstruction of the large talar defect with an allograft talus. While we prefer fresh allograft tissue, we have on occasion used fresh-frozen tissue.

images Scheduling of this procedure with fresh allograft tissue is similar to organ transplantation but with a wider window for implantation after procurement.

images Multiple tissue banks have the ability to obtain fresh allograft tali.

images Once a donor talus is identified, the tissue bank performs appropriate screening.

images If the talus is deemed safe for implantation and represents a match based on radiographic size, on average 14 to 21 days of reasonable chondrocyte viability remains for the talar allograft to be used.

images While fresh structural talar allograft reconstruction for large-volume OLTs has gained a foothold as an accepted treatment among reconstructive foot and ankle surgeons, not all third-party payers cover this procedure. We do not seek an allograft talus for our patients from the tissue banks until our patient has secured insurance coverage for the procedure.

images In seeking an allograft talus that is suited for the patient, the surgeon must:

images Be sure that the talus is the correct side (right or left)

images Provide the tissue bank with the optimal size of talar graft. Tissue banks use different methods for talar sizing.

images Plain radiographic dimensions (if the defect in the diseased talus is particularly large, making measurements difficult, radiographs of the healthy, contralateral talus may be needed)

images CT scan measurements (may be more accurate, with measurements possible in three dimensions)

images The surgeon should check for associated pathology that may need to be addressed at the time of allograft talar reconstruction:

images Osteophyte removal

images Ligament reconstruction

images Corrective osteotomies

images Calcaneal

images Supramalleolar

images The surgeon determines the optimal surgical approach.

images In our hands, this depends on the amount of talus that will be reconstructed.

images A portion of the medial talar dome (usually posteromedial) typically warrants a medial malleolar osteotomy.

images A portion of the lateral talar dome (often centrolateral) typically necessitates ligament releases (anterior talofibular and calcaneofibular) with or without lateral malleolar osteotomy.

images Involvement of the majority of the medial or lateral talar dome, particularly if involving its respective talar shoulder, usually can be performed through an anterior approach without osteotomy by replacing one third to one half of the talar dome.

images Patient education

images This is a complex procedure.

images The patient must understand that the intent is to implant allograft tissue.

images There is a negligible, but real, risk of disease transmission and possible graft rejection by the host.

images There is no guarantee that the procedure will work, and a revision procedure may be required, such as arthrodesis, which will eliminate joint motion.

Positioning

images Before anesthesia and moving the patient into the operating room, the surgeon should inspect the allograft to be sure it is the correct side (right or left) and for cartilage defects that may be present directly at the site that the graft is to be harvested.

images The patient is positioned supine.

images For a lateral OLT, a bolster under the ipsilateral hip typically affords better access to the lateral talar dome.

images We routinely use a thigh tourniquet.

Approach

images As noted above, the approach depends on the size and location of the OLT.

images For medial OLTs amenable to reconstruction of only a portion of the medial talar dome: direct medial approach, similar to that for open reduction and internal fixation (ORIF) of a medial malleolar fracture, with a medial malleolar osteotomy

images For lateral OLTs amenable to reconstruction of only a portion of the lateral talar dome: lateral approach, combining typical approaches for ORIF of a fibular fracture and the extensile exposure for a modified Brostrom procedure

images For large medial or lateral OLTs, involving the majority of the medial or lateral talar shoulder: anterior approach, similar to that for ankle arthrodesis or total ankle arthroplasty; typically no malleolar osteotomy is required.

TECHNIQUES

STRUCTURAL ALLOGRAFT RECONSTRUCTION OF CONTAINED MEDIAL OSTEOCHONDRAL LESIONS OF THE TALUS

Approach and Oblique Medial Malleolar Osteotomy

images  Make a curvilinear incision over the medial malleolus, similar to that for ORIF of a medial malleolar fracture.

images  Protect the saphenous vein and accompanying saphenous nerves.

images  Anterior ankle arthrotomy (TECH FIG 1A)

images Defines anterior joint margin for safe performance of medial malleolar osteotomy

images Allows partial visualization of the OLT and allows confirmation that there is not diffuse articular cartilage degeneration

images  Open the posterior tibial tendon sheath–flexor retinaculum, directly on the posterior margin of the tibia and medial malleolus (TECH FIG 1B). Protect the posterior tibial tendon: it rests in a groove immediately posterior to the tibia and is at great risk with a medial malleolar osteotomy.

images

TECH FIG 1  A. Medial incision and anterior ankle arthrotomy. B. Opening of the posterior tibial tendon sheath. C. Predrilling of medial malleolus. Kirschner wire for trajectory of medial malleolar osteotomy has already been inserted and its position confirmed with fluoroscopy. D. Fluoroscopic image demonstrating Kirschner wire being used as a guide to direct the saw. E. The periosteum is scored perpendicular to the tibial shaft, at the level of the osteotomy. F. Medial malleolar osteotomy. Care must be taken to protect the posterior tibial tendon. G. Fluoroscopic image showing nearcomplete bone cut. H. Release of posterior tibial tendon sheath from distal medial malleolus to allow mobilization.

images  Predrill the medial malleolus across the proposed osteotomy site (TECH FIG 1C).

images We routinely use two small fragment malleolar screws and predrill with the corresponding drill.

images Obtain fluoroscopic confirmation that the drill bits are in the proper trajectory.

images Consider passing a tap as well.

images  Place a Kirschner wire obliquely to define the trajectory of the medial malleolar osteotomy (TECH FIG 1C).

images Place it slightly proximal to the desired osteotomy so it can function as a guide but not interfere with the saw (TECH FIG 1D).

images Confirm the optimal Kirschner wire trajectory with intraoperative fluoroscopy.

images Ideally, the Kirschner wire will extend to the lateral margin of the OLT, but with large-volume OLTs that may be too much and unnecessary. However, in our experience, making the osteotomy only to the axilla of the tibial plafond where it meets the medial malleolus will not allow adequate access to perform ideal recipient-site preparation.

images  Determine a plane for the osteotomy in the AP plane that is perpendicular to the longitudinal axis of the tibia. We find it helpful to score the osteotomy in the periosteum from anterior to posterior to determine this level (TECH FIG 1E).

images  Periosteal stripping is unnecessary; it may be limited to the osteotomy site.

images  With a microsagittal saw oriented correctly in both planes, the osteotomy is initiated (TECH FIG 1F).

images Use cool saline to limit the risk of heat necrosis to the bone.

images Obtain intraoperative fluoroscopy shortly after initiating the osteotomy; leave the saw blade in place to confirm proper trajectory. If incorrect, a subtle adjustment is still possible (TECH FIG 1G).

images  Continue the osteotomy with the saw to the subchondral bone and then complete the osteotomy with a chisel.

images A fluoroscopic spot view allows the surgeon to confirm that the osteotomy is appropriate and is not violating the talar cartilage.

images There may be some irregularity to the osteotomy at the posterior margin; this is typical as the osteotomy is mobilized. It may be advantageous as it allows for an interference fit during reduction of the osteotomy and perhaps greater stability.

images  Reflect the medial malleolus.

images The posterior tibial tendon sheath must be released to the distal aspect of the posterior medial malleolus to allow the malleolus to reflect adequately and to gain optimal exposure of the medial talar dome (TECH FIG 1H). Protect the deltoid ligament fibers.

Preparing the Recipient Site

images  Define the extent of the OLT (TECH FIG 2A,B).

images Clinical inspection

images Review of CT scan

images  If the talar defect appears amenable to structural allograft reconstruction, have the donor talus placed on the back table and protected in a saline-soaked sponge.

images   Excise the diseased portion of the talus (TECH FIG 2CF).

images Reciprocating and microsagittal saw (use cool saline to limit risk of heat necrosis)

images May need a small curette and rasp as well

images

TECH FIG 2  A, B. Identifying the extent of the talar shoulder lesion. C–E. Excision of the talar shoulder lesion using the microsagittal and oscillating saws. F. Talar shoulder lesion removed.

images

TECH FIG 3  A. The dimensions of the recipient site are carefully recorded and transferred to the allograft. B. Two pointed reduction clamps are used to stabilize the allograft during preparation. C. Donor allograft with newly prepared graft removed.

images  Define the dimensions of the recipient site. Use a caliper and a ruler and double-check the measurements.

Harvesting Graft from Donor Talus

images  Handle the allograft talus with bone forceps.

images  Properly orient the talus (compare to native talus) to ensure that the cuts will be congruent and in the same plane as those for the recipient site.

images  Carefully mark the dimensions for graft harvest on the allograft (TECH FIG 3A).

images Same location on the allograft talus as the recipient site on the native talus

images If you err, err to have the graft slightly too large. Be sure to account for saw blade thickness.

images  “Measure twice and cut once.”

images You have only one opportunity, so be sure the measurements and orientation of the saw blade for each cut are optimal.

images The allograft can be stabilized with two large pointed reduction clamps (TECH FIG 3B).

images  Extract the graft from the donor talus (TECH FIG 3C).

images  Reduce the immunogenic load from the graft by washing the graft’s cancellous surfaces with saline.

Implanting and Securing the Graft into the Recipient Site

images  Only once have we had a graft match perfectly on the first attempt. The graft and recipient site will almost always need to be tailored slightly to allow optimal graft fit.

images  It is unlikely that a perfect clinical and fluoroscopic match will be achieved. Attempt to achieve the best clinical match of the graft’s articular surface with the surrounding native cartilage (TECH FIG 4A).

images  If the clinical match is appropriate, then the fluoroscopic match is not important.

images There is a lot of variability in cartilage thickness and talar architecture in the human talus.

images It is difficult to get four surfaces to congruently match.

images  Graft fixation

images Ideally, the graft will have some interference fit.

images We routinely secure the graft with one or two smalldiameter solid screws (1.5 or 2.0 mm in diameter). One is typically placed from dorsal to plantar, the other from medial to lateral (if the depth of the graft will allow) (TECH FIG 4B,C).

images

images

TECH FIG 4  A–C. Fitting and securing the graft to the native talus. A. After contouring the graft (some minor discoloration from debris while manipulating graft on back table; it is easily washed away). B.Drill hole perpendicular to graft. C. Securing graft with two countersunk screws. D,E. A different patient with similar graft; excellent interference fit and secured with a single screw. D. Screw is inserted in lag fashion. E. Screw head is countersunk. F–H. Reduction of the medial malleolar osteotomy. F. Screw fixation through the predrilled holes. G. Antiglide plate. H. Final fluoroscopic evaluation of graft and reduction of medial malleolar osteotomy. Despite optimal clinical fit of the graft, rarely does the fluoroscopic appearance suggest anatomic graft match to the native talus, typically due to differing cartilage thicknesses between the donor and the host. While the screws may appear prominent, two-dimensional fluoroscopy is deceiving since the screws are countersunk below the articular surface of the graft and the talar dome is curved.

images Place the screws in lag fashion.

images Countersink the screw heads below the articular surface (TECH FIG 4D,E).

images  Using fluoroscopy, confirmn that the graft and hardware are in optimal position (TECH FIG 4FH).

images The graft will not look perfect fluoroscopically, but as long as the clinical appearance is acceptable, the outcome has a good chance to be favorable.

images The hardware may appear slightly proud fluoroscopically despite being countersunk. The talar dome is not a flat plane, and therefore the screw may seem to be protruding. Moreover, the articular cartilage is rather thick compared to such a low-profile screw head.

Medial Malleolar Osteotomy Reduction and Closure

images  Irrigate the joint.

images  Reduce the medial malleolus. Confirm the reduction through the anteromedial arthrotomy and posteriorly behind the posterior tibial tendon.

images  Place the two screws in the predrilled holes and tighten the screws.

images  While not essential for healing, we favor placing an antiglide plate over the proximal aspect of the osteotomy.

images  Using fluoroscopy, confirm reduction of the graft and medial malleolus (see Tech Fig 4).

images  Anticipate some incongruencies of the graft–native talus bony interfaces. It is difficult to achieve perfectly congruent apposition.

images  There will be a slight gap at the medial malleolar osteotomy site despite anatomic reduction of the medial malleolus. This is due to the thickness of the saw blade. However, it is not acceptable to see a step-off at the osteotomy site where it enters the tibial plafond; this must be anatomic.

images  The slight gaps at the graft and medial malleolus do not typically impair healing and should obliterate with eventual remodeling.

images  Closure

images  Posterior tibial tendon sheath and flexor retinaculum

images Anterior arthrotomy

images Subcutaneous layer

images Skin to a tensionless closure

images We routinely use a drain.

images Dressings, padding, and a posterior–sugar-tong splint with the ankle in neutral position

HEMI-TALUS RECONSTRUCTION OF MEDIAL OSTEOCHONDRAL LESION OF THE TALUS

Preoperative Evaluation

images  Patient is a 40-year-old man with chronic ankle pain failing prior arthroscopic débridement and microfracture. Feels he is overloading lateral border of foot.

images  Preoperative weight-bearing radiographs suggest large medial OLT and varus malalignment with some varus talar tilt (TECH FIG 5A,B).

images  CT demonstrates large-volume medial OLT (TECH FIG 5CE).

images  Before proceeding to the operating room, confirm that the allograft talus is the one intended for this patient, is available, and has not expired.

Approach

images  Anterior approach (TECH FIG 6)

images Similar to anterior approach for ankle arthrodesis and total ankle arthroplasty

images Protect the superficial peroneal nerve.

images Divide the extensor retinaculum over the extensor hallucis longus tendon.

images Protect the deep neurovascular bundle.

images Anterior capsulotomy. Unlike ankle arthrodesis and total ankle arthroplasty, must protect ankle cartilage.

images Expose OLT with plantarflexion. Assess mediolateral dimensions and attempt to assess AP dimensions.

images

TECH FIG 5  A, B. Preoperative radiographs. A. AP and mortise ankle views suggest large medial talar dome OLT and varus alignment. B. Lateral radiograph. C–E. Preoperative CT of largevolume OLT. C. Coronal view. D. Sagittal view. E. Axial view.

images

TECH FIG 6  Anterior approach, similar to that performed for total ankle arthroplasty. Since the entire medial one third to one half of the talar dome will be restructured, a medial malleolar osteotomy is typically not necessary.

images  If the talus appears appropriate for an allograft talus, ask to have the donor talus opened and soaking in a warm saline-soaked sponge on the back table. At this point, though, this only expedites the procedure; it is not as though the talus may be returned. . .that patient now owns that talus.

Preparing the Recipient Site

images  Joint distraction, preferably with an extra-articular distraction device

images  Determine dimensions of diseased talus:

images Clinical assessment

images Review and correlate with CT.

images  Determine exact lateral sagittal border of OLT.

images  Make a vertical (sagittal) cut in the talus 1 mm lateral to the lateral extent of the OLT. The depth of this cut should be conservative until the exact superior-to-inferior dimensions of the OLT can be mapped out on the talus (TECH FIG 7A).

images   Horizontal (axial) resection in the talus (TECH FIG 7B)

images To maintain the proper axis, we routinely use a Kirschner wire placed from anterior to posterior, with its trajectory and depth confirmed on intraoperative fluoroscopy, to avoid misdirection of the axial resection.

images We use a thin oscillating saw for this cut, also with cold saline irrigation to cool the blade in an attempt to avoid heat necrosis to the bone.

images Protect the medial malleolar cartilage. Consider using a malleable ribbon retractor in the medial gutter.

images  Extract the resected bone (TECH FIG 7C,D).

images  Revisit the vertical and horizontal resections with the saw, a rasp, or both. If there is residual OLT in either or both of the prepared surfaces, then consider curetting these and bone grafting, or resecting more native talus (TECH FIG 7E).

images  Fluoroscopic evaluation sometimes affords a useful appreciation of the recipient site.

images  Determining the exact dimensions of the recipient site:

images Calipers (TECH FIG 7F)

images Ruler (TECH FIG 7G)

images We routinely sketch the dimensions on a drawing of the recipient site on a surgical glove envelope or a sterile label on the back table.

Harvesting Graft from the Donor Talus

images  Secure the allograft that has been placed on the back table with a bone-holding forceps.

images  Mark the dimensions of the recipient site talus on the donor talus. One challenge is to orient the talus properly to ensure that the two cuts will be in the optimal planes to congruently match the recipient site.

images

images

TECH FIG 7  A–D. Preparing the recipient site. A. Sagittal cut with reciprocating saw. B. Axial cut also with reciprocating saw. C. Elevating diseased portion of talus with osteotome. D. Extracting diseased portion. E.Further extraction of diseased cartilage until healthy-appearing cancellous surface is apparent. F,G. Measuring dimensions of recipient site. F. Caliper. G. Modified ruler.

images  Double-check the measurements.

images You have only one chance to harvest this graft.

images “Measure twice, cut once.”

images   Make the cuts to harvest the talus (TECH FIG 8).

images Attempt to match the recipient site dimensions exactly, taking into account the thickness of the saw blade.

images If you have to err, then err on the side of harvesting a graft that is too large. Fine-tuning the graft is sometimes difficult, but it is still possible to downsize it or increase the size of the recipient site; it is not possible to augment the graft or reduce the size of the recipient site once the graft has been harvested.

images

TECH FIG 8  Harvesting graft from donor talus. A. Sagittal cut with oscillating saw. B. After completion of axial cut.

images  We routinely wash the graft’s cancellous surfaces with saline in an attempt to decrease the immunogenic load before implantation. However, we have no evidence to support this practice and perform this purely on an empiric basis.

Implanting and Securing Graft into Recipient Site

images   Place the graft in the recipient site (TECH FIG 9A,B).

images  We have never had a perfect match on the first attempt at seating the graft in the recipient site.

images  Tailoring the graft to match the recipient site is often challenging.

images In our hands this requires a slight deepening of the recipient site and a slight thinning of the graft.

images Making the corresponding sagittal and axial talar cuts congruently is the most important step in achieving an optimal fit of the graft.

images  Only once have we achieved a perfect graft match clinically and fluoroscopically.

images The human talus is quite variable and regardless of the match, some inconsistencies will be present.

images While the clinical appearance may suggest a nearperfect match, we routinely see slight incongruencies in the sagittal and axial preparations and what appears to be a slight mismatch to the native subchondral bone.

images In our experience, however, these are not clinically relevant and some degree of remodeling during graft incorporation is anticipated.

images   Fixation of the graft to the native talus (TECH FIG 9CG )

images We routinely use two solid small-diameter screws (1.5 or 2.0 mm) placed in lag fashion to secure the graft to the native talus.

images These are placed anteriorly and countersunk below the articular surface, typically anterior to the tibial plafond with the ankle in neutral position.

images While we would prefer to avoid violating the cartilage surface, to date we are not aware of any compromised outcome related to the articular defect created by placing the screws.

images Because the talus is contained within the ankle mortise, in our experience posterior screw fixation is unnecessary.

images We routinely assess graft position after screw placement fluoroscopically. Since the articular cartilage is not visible and the physiologic talar dome is not in a single plane, the countersunk screws may appear proud fluoroscopically.

Axial Realignment

images  Based on the preoperative plan and intraoperative reassessment, consider correction of axial malalignment. This improves the weight-bearing axis of the lower extremity and potentially unloads and protects the graft (eccentric load on the talus may have contributed to development of OLT). The preoperative plan dictates the amount of desired correction. As a rule, 1 mm of medial opening equals 1 degree of correction.

images  Through the same incision, perform supramalleolar osteotomy for varus malalignment.

images Medial opening wedge (TECH FIG 10)

images   Greenstick principle: leave lateral cortical hinge if possible

images   With or without fibular osteotomy, depending on degree of deformity

images Minimal periosteal stripping

images   Attempt to limit to osteotomy site

images Protect soft tissues

images Judicious osteotomy

images   Consider a slightly oblique trajectory to increase surface area.

images Careful medial opening

images   Protect lateral hinge.

images   If hinge is weak, maintain proper contact; control rotation of two fragments; consider using two plates in two planes for fixation.

images

images

TECH FIG 9  A, B. Optimizing graft position in native talus. A. After further “touch-ups” to the graft and recipient site, optimal graft position. B. Stabilizing graft to native talus (blunt retractor superiorly and bone reduction clamp for coronal compression). C–G. Graft fixation to native talus. C. Countersink used after drilling for screw to be placed in lag technique. D. First screw being inserted. E. First screw with compression and countersunk. F. Second screw being inserted. G. Both screws countersunk.

images

TECH FIG 10  Realignment medial opening supramalleolar osteotomy. A. Osteotomy being carefully opened with an osteotome while preserving the lateral cortical hinge. B. Plate fixation.

images We routinely bone graft the opening wedge osteotomy site. However, this is not recommended by all who perform these osteotomies.

Closure

images  Perform thorough irrigation.

images  Close the capsule.

images  Release the tourniquet.

images  Reapproximate the extensor retinaculum while protecting the deep neurovascular bundle, extensor tendons, and the superficial peroneal nerve.

images  We routinely use a drain for 24 hours.

images  Perform subcutaneous closure and tensionless skin reapproximation.

images  Dressings, adequate padding, and posterior–sugar-tong splint with the ankle in neutral or even a slightly dorsiflexed position

images

POSTOPERATIVE CARE

images We routinely observe these patients overnight for pain control.

images Follow-up is done in about 10 to 14 days.

images Provided the wound and osteotomy (if one was performed) are stable, the patient is transferred into a touch-down weightbearing cam boot. If not, a touch-down weight-bearing short-leg cast is continued until the wound and osteotomy are stable.

images Intermittent minimal, gentle ankle range of motion (ROM) encouraged, three or four times a day. If financially feasible, we arrange for an ankle continuous passive motion device.

images

FIG 1  Two-and-a-half-year follow-up. A. AP radiograph. B. Lateral radiograph. C. Clinical correlation.

images

FIG 2  Dorsiflexion. A. Radiograph (although the joint appears to narrow anteriorly, this phenomenon has not changed in 2 years and the patient experiences no pain or impingement). B. Clinical appearance.

images Touch-down weight bearing is maintained for 10 to 12 weeks, with progressively increasing ankle ROM exercise.

images We routinely obtain simulated weight-bearing radiographs at 6 weeks and 10 weeks, and again at 14 to 16 weeks, depending on the progression of healing. If there was a concern about fixation of the graft or osteotomy, then radiographs are also obtained at the first postoperative visit (FIGS 13).

OUTCOMES

images Gross et al2 reported on nine patients who underwent fresh osteochondral allograft transplantation. At a mean follow-up of 11 years, six grafts remained in situ. The three failed allografts demonstrated radiographic and intraoperative evidence of fragmentation or resorption, and these patients went on to ankle fusion. Standardized outcomes measures for comparison were not used in that study.

images Raikin3 recently reported on 15 patients who underwent bulk fresh osteochondral allografting for large-volume cystic lesions of the talus. The mean volume of the cystic lesions was 6059 mm3. At a mean follow-up of 4.5 years, the mean AOFAS ankle–hindfoot score was 83 points. Only two grafts failed and went on to have an ankle arthrodesis. Some form of graft collapse, graft resorption, or joint space narrowing was seen in all patients.

images A retrospective review by Adams et al1 showed significant improvement in pain and the Lower Extremity Functional Score (LEFS) at a mean follow-up of 48 months in eight patients who underwent osteochondral allograft transplantation of the talus. The mean postoperative AOFAS ankle– hindfoot score was 84 points. Three grafts were found to have graft-host lucencies in one plane on plain radiography. These patients were doing well and no further imaging was obtained. One patient continued to be symptomatic and was thought to have a nonunion of the graft due to circumferential lucency. Second-look arthroscopy demonstrated partial graft cartilage delamination but a stable graft. The patient did not wish to have any further treatment.

COMPLICATIONS

images Infection

images Wound complications

images Particularly for anterior approach (as is performed for total ankle replacement)

images Deep retraction only, avoiding direct tension on wound margins, reduces this risk.

images Failure of graft incorporation

images With large structural grafts, graft failure and development of degenerative change

images Articular cartilage delamination or fissuring of the graft

images Malleolar osteotomy nonunion

images Persistent pain despite radiographic suggestion of graft incorporation

images Disease transmission, although with the current screening practices of tissue banks, this risk is negligible

images

FIG 3  Plantarflexion. A. Radiograph. B. Clinical correlation.

REFERENCES

1.     Adams SB Jr., Viens NA, Easley ME, et al. Osteochondral lesions of the talar shoulder treated with fresh osteochondral allograft transplantation. American Orthopaedic Foot and Ankle Society (AOFAS) Annual Summer Meeting, July 7–10, 2010.

2.     Gross AE, Agnidis Z, Hutchison CR. Osteochondral defects of the talus treated with fresh osteochondral allograft transplantation. Foot Ankle Int 2001;22:385–391.

3.     Raikin SM. Fresh osteochondral allografts for large-volume cystic osteochondral defects of the talus. J Bone Joint Surg Am 2009;91A: 2818–2826.



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