Comparison of Sinus Tarsi Implants

1 The HyProCure™ Sinus Tarsi Implant is self-seating/positioning whereas the other implants are not. Complications ensue due to this. Other sinus tarsi implants instructions want the lateral portion of the implant to be about 1 cm from the lateral wall of the calcaneus. The problem with this is that the implant will sit in the middle part of the sinus tarsi. The sinus tarsi is made up of the deeper canalis portion and the outer sinus portion. Since the other implants are smaller in length they will only minimal enter the canalis portion. The lateral (outer) wall of the talus will hit against the outer portion of the implant causing micro-motion that can further lead to pistoning or displacement of the implant. This will cause pain and the implant will then need to be removed. If the other implants are seated too deep into the sinus tarsi, then there will be under-correction. This happens because the lateral process of the talus will still obliterate the sinus tarsi. If the implant is too superficial then it isn’t locked into the canalis portion of the sinus tarsi. The lateral process of the talus will hit up against the implant up to 20,000 times a day and may eventually come lose or piston, leading to pain and failure of the implant.

 

2 The design of the HyProCure^™ Sinus Tarsi Implant has three different distinct sections.

 

A. The inner/medial portion is threaded; the purpose of this is to lock the implant into the canalis portion of the sinus tarsi. The threads will purchase into the interosseous ligament that helps to reduce backing out of the implant.

 

B. The middle section is tapered; this is very important since this is the part that comes in contact with the lateral aspect of the talus and blocks the implant from going any deeper. It takes the guesswork out of the procedure. With other implants it becomes a game of "Is it in too far or not far enough?" then intra-op films need to be taken to visualize the location of the implant.

 

C. The outer larger diameter is smooth and is what actually leads to the prevention of the obliteration (partial/full) of the sinus tarsi. It is very important that this part of the implant has no threads since the lateral process of the talus will come in contact with the implant. Other implants have threads that are very sharp and may lead to damage to this portion of the talus and the sulcus on the calcaneus.

 

D. This implant does have a canula for a guide-wire but it is not necessary. Other implants require the use of a guide wire to make sure that the implant is actually being inserted into the correct location. The HyProCure™ Sinus Tarsi Implant can only be inserted into the sinus tarsi. It would be very difficult to insert it into any other location.

 

E. The overall length of the HyProCure™ Sinus Tarsi Implant is longer than the other implants. This is very important because it fills in the sinus better to give better correction with less of a chance for it to back out.

 

F. There is actually a much large range of sizes of the HyProCure™ Sinus Tarsi Implants as compared to the other implant. More correction is achieved with better results for the patient.

 

 

3 The instrumentation of the system is very different from the rest. The sizing of the implant has been simplified. At the end of the trial sizer is the shape of the HyProCure™ Sinus Tarsi Implant without the threads. The sizer is quite simply inserted into the sinus tarsi until it won’t go in any more and the forefoot is loaded and the rearfoot is inspected for it’s eversion. If there is greater than three (3) degrees of eversion than the next larger size is inserted until the desired 1-3 degrees. With the other implant systems, a trial implant is inserted into the sinus tarsi with it’s thread causing trauma to the internal structures, the foot is loaded again, the trial implant must then be removed and the next one inserted. Again, I want to emphasize that this is very traumatic to those tissues and very time consuming. When the desired implant is determined and inserted into the sinus tarsi there is usually under-correction. The reason for this is due to trauma from the previous sizing of the implant.

 

4 The technique for inserting the HyProCure™ Sinus Tarsi Implant involves one lateral incision, while another implant system calls for a second medial incision. This leads to needles trauma to the inner ankle and other potential complications.

 

 

5 Other implant systems also has dilators or probes to stretch out the interosseous ligament. The surgeon is instructed to push this into the sinus tarsi until there is tenting on the medial side of the ankle. As mentioned above this punctures the deltoid ligament and can potentially lead to complications post-operatively.

 

6 The post-op course is different, we allow the patients to weight-bear to tolerance without a cast. We also recommend the use of a sneaker as soon as possible and for the patient not to wear a surgical type shoe. The reason for this is the surgical shoe will make the patient walk "flat-footed" and there is no room to compensate for the pain in area of the surgery. By allowing them to walk with a sneaker, they will be able to turn their foot slightly inward to take off some of the pressure from the surgical area. .