Our medical instincts tell us that when a joint is severely arthritic, two surfaces need to be replaced.  In some respects, it is a leap of faith to accept the concept that we can be successful by addressing only one surface.  Having traveled the path from simple joint arthroplasty to silicone implants, then on to joint fusion and metallic total joint implants, I have now embraced the hemi arthroplasty resurfacing prosthesis for advanced Hallux Limitus.  The procedure is simple and the results are consistently good.  The reliability of the procedure is enhanced by a strong understanding of Functional Hallux Limitus.  (See Dr. Lieberman's excellent PRESENT lecture on Hallux Limitus).  

Hemi arthroplasty resurfacing prosthesis' allow for adjunct procedures on the first metatarsal, such as chielectomy, plantar grade osteotomies and enclavement procedures.  Understanding when these procedures are indicated is of critical importance to successful outcomes.  I urge you to visit   https://www.bioproimplants.com/extremities_lower.asp.  To some extent, my approach, outlined here, is different than the one described on the website.  It is my belief that each surgeon must find a comfortable approach to the correction of this deformity.

The Bio Pro Great Toe Hemi Implant is low profile and allows for minimal bone resection.  It is manufactured from cobalt chrome and is also available in titanium for patients with a metal sensitivity. 

I use a dorsal approach to the joint.  In almost every instance a chielectomy is performed.  Marginal osteophytes are then resected from the dorsal, medial, and lateral aspects of the joint.  Cartilaginous defects in the first metatarsal are addressed via subchondral drilling.  I then load the first ray and determine if there is unimpinged motion.  On occasion I will perform an oblique osteotomy in the metaphyseal region of the first metatarsal if I have determined that it is necessary.  The goal here is to increase the internal cubic content of the joint and address the elevated position of the first ray. 

From here on in, I follow the technique described by Townly and Taranow .  �The articular surface of the phalanx is resected in a common flat plane with an oscillating saw, removing only sufficient bone to avoid prosthetic overspacing and excessive joint tension and to accommodate the thickness of the articulating plate of the implant.   The plane of the resection should be parallel to the plane of the concavity of the phalangeal articular surface."

The sizer guide template helps to select the appropriately sized implant.  The implant should not extend beyond the cortical margin.  It should be sufficiently large to rest on the cortical shelf.  The template has a central hole which can be used as a punch guide. 

Each of the trial size implants has pin type stem which fits into the hole created by the sizer guide template.  The trial implant is fitted into the joint space.  Proper fit is insured.  The toe should glide through a full, unimpinged, range of motion with the first ray loaded.  If the joint space is too tight, this may result in limited joint motion.  It may be necessary to remove additional bone from the proximal phalanx. 

A custom bone tamp (broach) is used to create a transverse canal in the proximal phalanx.  This matches the stem of the actual implant perfectly.  The properly sized implant is then inserted and completely seated.  Impaction is accomplished utilizing an Impactor which is included in the toe kit.  The toe is then once again taken through ranges of motion to insure proper fit. 

My patients use a surgical shoe for 12 days.  They will make a transition to a walking sneaker and are encouraged to begin gentle range of motion exercises.