6.1 Arthroscopic and Open Synovectomy/Tenosynovectomy of the Tibiotalar Joint
Indication
Synovitis of the tibiotalar joint and/or tenosynovitis with maximum Larsen Stage II destruction. Patients frequently do not have any subjective clinical symptoms.
Detection of isolated synovitis of the tibiotalar joint is often very difficult clinically, and frequently requires additional diagnostic investigation such as ultrasonography and MRI. Isolated synovitis of the tibiotalar joint can usually be addressed arthroscopically.
Open synovectomy is almost always performed if the synovitis is accompanied by tenosynovitis.
The patient must be informed of the potential for intraoperative conversion to an open procedure.
Position
Supine. Ankle in neutral position with toes pointed toward the ceiling. It is usually necessary to place a positioning roll under the ipsilateral buttock in order to compensate for external rotation of hip. A contralateral pelvic support and tilting of the table can be used to achieve a better ankle position. The ankle joint rests approximately 3 to 5 cm over the end of the table.
Mobilize under partial load for 3 weeks to allow for synovial regeneration. Radiosynoviorthesis is usually recommended 6 weeks after arthroscopic synovectomy.
Fig. 6.1 An anterolateral port is usually placed first after a stab incision. Next, an anteromedial port is placed under direct vision. The joint can be insufflated with normal saline first if the joint is difficult to localize. Distraction mechanisms are often unnecessary. Posterior approaches are generally avoided, unless the preoperative MRI scan demonstrates pronounced dorsal synovitis. The instruments usually need to be switched several times between the portals in order to perform a thorough synovectomy. 1, Anterocentral portal. 2, Accessory anterior portal. 3, Anteromedial portal. 4, Extensor hallucis longus tendon. 5, Anterior tibial tendon. 6, Extensor digitorum longus tendon. 7, Anterolateral portal. Fig. 6.2 Anteromedial portal (medial to the anterior tibial tendon). Anterolateral portal (lateral to the extensor digitorum longus tendon). If needed, the joint is first insufflated with normal saline using an injection needle.Fig. 6.3 After placement of the lateral portal, the medial portal is placed under direct vision. This is frequently more difficult due to extensive synovitis.Fig. 6.4 The entire ankle joint is examined. Synovectomy is first performed in the central portion of the joint, along the tibial crest and talus. This frequently results in a substantial improvement in visibility.Fig. 6.5 The synovectomy is completed in the medial and lateral compartment.Fig. 6.6 Completed synovectomy. The cartilage is still in relatively good condition.Fig. 6.7 Schematic drawing of the anatomy. It is important to pay attention to the exact location of the vessel and nerve structures when planning the anatomical approaches. 1, Superior extensor retinaculum. 2, Inferior extensor retinaculum. 3, Extensor hallucis longus muscle tendon. 4, Extensor digitorum longus muscle tendon. 5, Extensor hallucis brevis muscle. 6, Extensor digitorum brevis muscle. 7, Dorsalis pedis artery. 8, Greater saphenous vein. 9, Deep peroneal nerve. 10, Superficial peroneal nerve. 11, Intermediate dorsal cutaneous nerve. 12, Medial dorsal cutaneous nerve. 13, Saphenous nerve.Fig. 6.8 Following palpation, a midline incision is made at the level of the anterior tibial muscle tendon. The position of the tibiotalar joint is determined by palpation during movement, and then marked.Fig. 6.9 Flexor retinaculum. Anterior tibial muscle tendon. Dissection of the subcutaneous tissue must be undertaken carefully because the superficial peroneal nerve runs extrafascially from proximal lateral to medial distal. If there are significant inflammatory changes and major displacement, it is advisable to deliberately expose the nerve and hold it to the side. Otherwise, the nerve is vulnerable in the distal area of the incision. The extensor retinaculum is exposed and divided at the level of the anterior tibial muscle. The tibia is accessed behind the anterior tibial muscle tendon. Dissection is started as far proximal as possible, because the distance to the neurovascular bundle is greater there. Dissection is then continued distally. This allows the neurovascular bundle to be retracted laterally (see Fig. 6‑7 ). Often a synovectomy is required because the tendons are severely altered from synovitis.Fig. 6.10 Schematic drawing of the approach. 1, Extensor hallucis longus muscle. 2, Extensor digitorum longus muscle tendon. 3, Crural fascia. 4, Talocrural joint capsule. 5, Tibia. 6, Deep peroneal nerve. 7, Anterior tibial artery and vein. 8, Anterior medial malleolar and lateral malleolar artery and vein.Fig. 6.11 It is important to ensure adequate hemostasis of the numerous vessels that cross in front of the joint when it is opened. Severe synovitis frequently leads to an increased number of blood vessels. The surgical site is then held open with a large spreader. Caveat: keep retractor tension to a minimum to avoid impaired wound healing. Synovectomy is performed under distraction to allow access to all of the compartments of the rheumatic joint, particularly the posteromedial areas and the lateral compartment. The joint structures are frequently elongated due to inflammation.
6.2 Tibiotalar Joint Prosthesis
Indication
Larsen III–V destruction with significant clinical symptoms. Less than 15° axial deformity if possible. Severe deformities frequently require additional procedures, such as a simultaneous correction arthrodesis of the subtalar joint.
Specific disclosures for patient consent
Prosthetic loosening. Tendon rupture (also secondary). Dislocation of the liner. Medial, lateral malleolar fractures (particular risk in rheumatic patients). Infection with sequelae. Blood vessel and nerve injury.
Instruments
Prosthesis system from the manufacturer of choice. A TARIC prosthesis manufactured by Implantcast is shown here.
Position
Supine. Ankle in neutral position with toes pointed toward the ceiling. It is usually necessary to place a positioning roll under the ipsilateral buttock in order to compensate for external rotation of hip. A radiograph may be needed.
Joint dislocations are rarely due to supramalleolar causes in rheumatoid patients.
Any axial deviation or deformity of the subtalar joint must be corrected prior to balancing the talotibial joint. If the subtalar joint is intact, correction may involve a calcaneal osteotomy. Should the destruction also involve the subtalar joint, arthrodesis with correction of the axis is recommended (see Chapter 6.4). This can be performed as a one-stage or two-stage procedure.
Once these causes are ruled out, correction can typically be performed articularly.
The largest portion of the misalignment is corrected and aligned as follows:
Removal of all osteophytes.
Release of all soft tissue adhesions (extensive arthrolysis).
Bone resection with the ankle in neutral position, which may allow for partial correction of the resected bone.
Valgus
Valgus deformity is more frequent in rheumatic patients. The correction is similar to that for a knee prosthesis.
Deformity is caused by a bony defect and the medial ligament is still intact: further intervention is usually not necessary. If there are indications of lateral ligament instability, it may be necessary to perform a plication of the ligament structures or a ligament repair.
Medial ligament insufficiency: a medial ligament plication or augmentation is performed, depending upon the severity. Endoprosthetic replacement of the tibiotalar joint is not an option if there is severe instability of the medial ligament.
Varus
Varus deformities are relatively uncommon in rheumatic patients. Persistent instability following a standard approach is usually due to a deltoid ligament contracture. Medial malleolar corrective elongation osteotomy and realignment via an elevated liner are worth considering.
Postoperative aftercare
Immediate full-range mobilization. For a stable endoprosthesis, mobilization with full weight bearing in a stability shoe (VACOped, for example) for 6 weeks. Another option is mobilization in a walking cast boot.
Fig. 6.12 A midline incision is made, although a medial or lateral approach is also possible. For description of the approach, see Chapter 6.1. Removal of all osteophytes is performed first so as to obtain a good overview of the joint. It is important to release all of the adhesions. A large portion of the misalignment can be corrected by osteophyte removal and soft tissue release.Fig. 6.13 (a,b) Positioning of the external tibial alignment guide. Fixation is performed with 2.5-mm pins. The overall approach is very dependent upon the implant. In addition, 0° and 50° resection guide blocks are available for the tibial joint osteotomy. The size of the tibial cutting guide is determined preoperatively. The orientation is verified and the resection is performed approximately 4 mm lower than the deepest portion of the tibial joint surface. A bone pin is inserted to protect the medial malleolus (arrow). The malleoli are at particular risk in rheumatoid patients. The cut must only be directed posteriorly in order to protect the malleoli; the saw should not be allowed to move medially or laterally. The alignment block is aligned with the ankle in the neutral position and toes pointed toward the ceiling. Small imbalances of the ligament apparatus can be corrected by using the tibial and talar osteotomy planes to balance the joint.Fig. 6.14 Spacers are used to check joint stability. The tibial platform and spacer are left in place and the talus resection block, which determines size of the polyethylene insert (here 5 mm), is attached to the spacer plate. The talus is resected at the lower edge of the talus resection block. Realignment is carried out in the neutral position with toes pointed toward the ceiling; it may be possible to balance the ligament apparatus over the cut bone surfaces.Fig. 6.15 The size of the talar implant is determined. The talar reaming guide is then fastened and the talus surface is prepared. The first talus cut resects the talar dome. An extensive posterior arthrolysis is performed. Resection of the posterior capsule improves posterior extension. A bone or Hintermann distractor is inserted to facilitate the operative procedure.Fig. 6.16 A winged osteotome is used to prepare the talus for the component insertion guide.Fig. 6.17 A trial implant is placed and the liner size is determined. Forceful manipulation: the surgeon forcefully performs posterior extension. The remainder of the capsule is disrupted. On rare occasions, an Achille tendon lengthening is necessary. The lengthening is performed by making three stab incisions on alternating sides approximately 2–3 cm apart. The knife is turned in the middle of the tendon and then guided to the side, thus partially dividing the tendon. Finally, another forceful manipulation is performed. Intraoperative radiographic imaging is necessary to evaluate the position of the implant. The position of the talar dome is assessed in relation to the tibial axis. Fig. 6.18 The talus and tibia are prepared. The anchoring site for the medial pin that protects the medial malleolus is easily recognizable.Fig. 6.19 Implanted prosthesis.
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