TENOSYNOVITIS

A common error in the management of the flexible flatfoot is failure to recognize the presence of tenosynovitis in patients who have a seronegative spondyloarthropathy. This condition is not necessarily associated with a flatfoot deformity, but if it is not treated with a tenosynovectomy, the tendon will be progressively infiltrated until rupture and deformity occur. In the older patient with tenosynovitis associated with a mild flatfoot deformity, or no flatfoot, one issue is whether or not an osteotomy of the calcaneus should be performed with the tenosynovectomy.

HOW TO MANAGE THE FAILED TENDON TRANSFER

It is important to establish why a tendon transfer procedure failed. Was the selected tendon transfer not strong enough for the specific foot deformity? Is the patient obese? Did preoperative assessment fail to detect some stiffness of the hindfoot? Is there additional deformity of the medial column? Should an osteotomy of the calcaneus have been performed, and if so, with lengthening or medial translation?

Figure 19-1 presents an example of failure of a previous flexor digitorum longus (FDL) tendon transfer. The patient was a 54-year-old active woman weighing 76 kg. The hindfoot was quite flexible, and with the heel reduced to neutral there was a fixed forefoot supination deformity of 20 degrees. No active inversion was noted, and pain was present along the medial border of the foot and ankle, in addition to sinus tarsi pain, the result of subfibular impingement. Traditionally, if the FDL has already been used in a tendon transfer, little is left to function as an invertor. The lateral side of the foot can be weakened with a peroneus brevis-to-longus transfer, which would have the added benefit of plantar-flexing the first ray. The lateral radiograph (see Figure 19-1, A) shows a break in the foot at both the talonavicular (TN) and naviculocuneiform (NC) joints. Certainly a fusion of the NC joint could be added to the procedure without loss of too much function, but this procedure would not address the weakness and lateral foot pain. The patient had already undergone a successful triple arthrodesis on the opposite foot for management of a very rigid flatfoot deformity and wanted to avoid another arthrodesis. In this patient, uncovering of the TN joint was not so extensive as to necessitate a lengthening of the lateral column, whether by osteotomy or by arthrodesis. I do not like to use a subtalar implant in the adult, and although this would be a reasonable indication, this procedure still does not address the muscle imbalance. I therefore selected the anterior tibial tendon (ATT) for transfer, modifying the original Young procedure.

Figure 19-1 A and B, A 54-year-old woman with an active lifestyle had undergone a previous tendon transfer to correct a flexible flatfoot. The hindfoot remained flexible. C, The navicular was exposed, and a thick osteoperiosteal flap elevated from the center of the navicular and retracted inferiorly. D and E, The anterior tibial tendon was then pulled below the navicular into the prepared slot (D), and sutured with an anchor into the body of the navicular (E). F and G, The postoperative radiographs show excellent restoration of the height of the arch of the foot as well as coverage of the talonavicular joint 3 years after surgery.

For this modified procedure, the navicular is exposed, and a thick osteoperiosteal flap is raised from the center of the navicular and retracted inferiorly (see Figure 19-1, C). This flap can include the remnant of the posterior tibial tendon (PTT) as well. A ridge with an overhang of approximately 5 mm is then prepared under the navicular with a curette or chisel, to function as a ledge for the transferred ATT. The retinaculum of the ATT is opened and released proximal to the ankle joint under direct vision. The ATT is then pulled below the navicular into the prepared slot (see Figure 19-1, D) and sutured either using the osteoperiosteal flap or by adding a suture anchor into the body of the navicular. If an anchor is used, fluoroscopic guidance is recommended to ensure that it is in the navicular and not protruding into the joint. The remnant of the PTT can now be cut, sacrificed, or repaired, depending on the status of the tendon (see Figure 19-1, E). In this patient, after these procedures there was slightly more forefoot supination than I would accept, and plantar flexion of the medial column was obtained with an opening wedge osteotomy of the medial cuneiform. The postoperative radiographs showed excellent restoration of the height of the arch of the foot, as well as coverage of the TN joint (see Figure 19-1, F and G).

A similar example of the same problem is shown in Figure 19-2. The patient was a 61-year-old man who had been treated with a previous calcaneus osteotomy and a transfer of the flexor hallucis longus. The hindfoot was quite flexible, and the heel was in moderate valgus. On observation of the heel from posterior, the calcaneus osteotomy did not appear to have accomplished much. The elements of surgical decision making were similar to those in the case shown in Figure 19-1, in which an arthrodesis was an option; however, maintaining flexibility seemed preferable in that very active patient. The ATT was transferred under the navicular, and the calcaneus osteotomy was repeated. It was not necessary to include an osteotomy of the medial cuneiform. An important point is that the ATT is not detached from its insertion and is levered inferiorly under a prepared osteoperiosteal flap in the edge of the navicular. The extent of bone resected in this process can be appreciated on the anteroposterior radiographic view (see Figure 19-2, C), in which the medial pole of the navicular has been removed to create the ridge under which to attach the ATT. It is important to leave no sharp edges on the ridge on the proximal navicular, because consequent damage to the ATT can lead to its rupture—a complication that has occurred in one of my own patients. When the rupture occurred, the patient noticed a sudden change in the foot at 8 weeks after surgery, and the ATT was no longer palpable dorsomedially. The rupture was repaired by reattaching the ATT to the dorsal central aspect of the navicular using a suture anchor.

Figure 19-2 A and B, A 61-year-old patient had been treated with a prior calcaneus osteotomy and a transfer of the flexor hallucis longus for correction of deformity. The hindfoot remained quite flexible, and the heel was in moderate valgus. C and D, Revision surgery was accomplished with the modified Young procedure, transferring the anterior tibial tendon under the navicular to support the medial arch of the foot.

Although errors in decision making and technique are inevitable, some of these are entirely avoidable. In the case illustrated in Figure 19-3, a 47-year-old woman was treated with a transfer of the FDL for correction of a flatfoot deformity. At 9 months after the surgery she presented with considerable pain in the anterior ankle, and on an anteroposterior radiograph of the foot, marked loss of the TN joint space was readily apparent. The diagnosis of rheumatoid arthritis was confirmed with a positive rheumatoid factor titer, and a TN arthrodesis was used for correction.

Figure 19-3 A patient who had been treated with a transfer of the flexor digitorum longus tendon for correction of a flatfoot deformity now presented with talonavicular pain. After appropriate investigation, the patient was found to have rheumatoid arthritis, which was the cause of the pain. A tendon transfer will not work no matter how flexible the foot if arthritis is present, particularly that associated with a rheumatologic process.

A simple error in technique is illustrated in Figure 19-4: In the case depicted, an opening wedge osteotomy was performed in conjunction with a transfer of the FDL tendon and a calcaneus osteotomy. The incorrect insertion of the bone wedge into the cuneiform, which fractured into the first metatarsocuneiform (MC) joint (see Figure 19-4), is evident. This technical error can be avoided by inserting a guide pin in the cuneiform from dorsal to plantar and obtaining a lateral view radiograph to ensure the correct orientation of the osteotomy. The cuneiform inclines obliquely, and the osteotomy is not perpendicular to the axis of the foot but must be oriented to the axis of the cuneiform. The osteotomy cut also must be completed with the saw and not end in the cuneiform, because use of an osteotome to complete the cut may result in fracture extending out into the MC joint, which probably happened in this case. Although arthritis did not develop in this patient over 3 years of follow-up, the potential for this complication nonetheless remains worrisome. The “hump” evident in the midfoot was the result of the incorrect axis of the osteotomy, which unfortunately caused abutment and symptoms in shoes.

Figure 19-4 A fracture of the cuneiform occurred during performance of an osteotomy on this foot. Although the alignment of the foot is good, the fracture could potentially cause painful arthritis. The responsible technical error was an incorrectly made osteotomy cut, which was not completed to the plantar surface of the cuneiform, so that when the cuneiform was distracted, it fractured into the first tarsometatarsal joint.

What is the optimal approach totreatment of the extremely flexible flatfoot? Is it always possible to avoid arthrodesis? In Figure 19-5, illustrating the case of a 44-year-old man with a unilateral flexible flatfoot, significant uncovering of the TN joint is apparent. The lateral radiographic view showed quite a lot of sag at the TN joint as well, with a fairly marked alteration in the talocalcaneal angle. In such cases, I have found that despite addition of a lateral column–lengthening procedure, instability may persist at the TN joint, increasing the likelihood of subsequent failure. Accordingly, although it is therefore always preferable to perform a tendon transfer with osteotomies, a TN arthrodesis is a good, reliable procedure and was performed in this patient with a successful result. The postoperative improvement in the talocalcaneal angle can be readily appreciated on the lateral view, even on a non–weight-bearing radiograph (see Figure 19-5, D).