The BioPro First MPJ Hemi Implant
Understanding Painful Great Toe
Pain in the great toe, otherwise known as the first metatarsophalangeal joint, can be caused by osteoarthritis, rheumatoid arthritis, bone spurs, bunions and posttraumatic injuries.
Hallux limitus and hallux rigidus are terms used to describe the loss of motion in the first metatarsophalangeal joint with hallux rigidus being considered the end stage of hallux limitus. This is a challenging problem that can affect patients of all ages and activity levels. The majority of cases appear to be mechanically induced and are often associated with a long first metatarsal and fallen arch foot types. However, trauma such as a stubbing injury may also result in hallux limitus. Long-standing gout can be a contributing factor as well.
Osteoarthritis (OA), also known as degenerative arthritis, is the most common type of arthritis and usually develops slowly over several years. It occurs when there is a systematic loss of cushioning cartilage in the joints and the bones in the joint rub against one another; this can be very painful and reduce movement drastically in the joint. If the condition is not treated, the bones could overgrow and fuse together on their own causing a complete loss of function.
Rheumatoid Arthritis (RA) is an autoimmune disease that causes chronic inflammation of the joints. A typical joint in the body is made up of bones that move against each other and are held together by ligaments and a sheath (called a capsule) that surrounds the entire joint. The inner lining of the capsule is called the synovium. In rheumatoid arthritis, the synovium of the joint becomes inflamed and enlarged, eroding the neighboring bones, ligaments, and cartilage. The end result is damaged and painful joint surfaces.
Osteophytes, or bone spurs, are bony projections that form along joints. They are due to arthritis or damage of the joint, and they may limit joint movement and cause pain.
A bunion is an enlargement of bone or tissue around the joint at the base of the big toe. It is a condition caused by abnormal mechanics of the foot or congenital factors, such as flatfeet, abnormal bone structure, and neurological conditions. The end of the large toe, or the phalange, points toward the second toe causing the metatarsal to bump, or bow outward.
Common symptoms of osteoarthritis, rheumatoid arthritis, bone spurs, and/or a bunion are:
- Pain experienced when walking
- Joint tenderness
- Inflammation that may produce a mild warm feeling or occasional redness
- Significant stiffness of the toe
- Loss of function
Before considering surgery there are always non-operative treatments such as:
- Shoe modifications
- Cast immobilization with a reduction in activity
- Anti-inflammatory drugs
- Physical therapy
- Local injections
When non-operative solutions are no longer able to control the pain and disability, surgery becomes a reasonable option. Surgical options include:
Keller Arthroplasty – The base of the phalanx and the attached tendons are severed and approximately 1/3 to 1/2 of the phalange is removed. This decompresses the joint and allows soft tissue to in-grow. Complications may include flail toe, which is where the toe sticks up in the air, and a return of pain as there is still the potential for bone on bone contact.
Cheilectomy – Bone spurs on the top of the metatarsal head that interfere with movement are removed, thus allowing joint motion. Along with the Keller arthroplasty, a cheilectomy is simply the removal of bone without resurfacing the joint. The possibility of having bone on bone or diseased/damaged cartilage post surgery is still a concern.
Arthrodesis (Fusion) – The cartilage surfaces of the joint are removed and a device such as a screw or plate is utilized to prevent motion. The bones eventually grow together which prevents pain; however, a loss of function occurs as the joint will no longer bend. With this loss of motion, your gait, or way of walking, may change, which could affect other joints such as knees, hips, spine, etc. Additionally, shoe wear selection may be limited due to the inability to bend your toe.
Hemi-Joint Arthroplasty – The surface of the metatarsal head is reshaped and the phalange is resurfaced with a new, smooth-surfaced component. This eliminates the possibility of bone on bone contact, thereby reducing pain, while restoring motion and maintaining function of the toe. Great toe joint replacement is usually performed to treat severe arthritis conditions. Most patients with a great toe joint prosthesis are middle-aged and older, but the operation may be performed on younger patients at the discretion of the surgeon. Though motion and function should be restored, achieving the normal movement of a completely healthy joint may not be possible.
How it Works
The BioPro Implant treats the arthritic joint by resurfacing the phalanx (low force, non-weight-bearing joint side) with a smooth, durable metal implant for the metatarsal head to articulate against.
Why it Works
Many factors allow the implant to provide improved range of motion, pain-relief and long-term survivorship.[1,2,3,4,5,6,7,8,9,10,11,12,13]
Improved range of motion
During the surgical procedure, large osteophytes (bony outgrowths) are removed and the joint is smoothed out. This, along with minimal bone resection, allows for decompression of the joint and improved range of motion.
Before surgery, the joint had damaged cartilage or was bone on bone. After surgery, there is a remodeled metatarsal head articulating against a smooth metal spacer allowing for reduced pain and restored motion.
Since the implant is placed on the phalanx, it avoids the weight-bearing forces placed on the metatarsal head. Furthermore, the implants outer edge rests on hard cortical bone, preventing the implant from receding into the soft cancellous bone. The implant is manufactured from a well established biocompatible material with a durable wear surface that is proven to last over 30 years.
How big is the implant?
The implant is very similar in both thickness and diameter to a US nickel. It is 2mm thick and available in diameters from 17mm to 23mm depending on a patient’s anatomy.
A 40 year review of the BioPro First MPJ Hemi Implant was conducted and then published in 1994. The study included 279 patients ranging from 8 months to 33 years postoperative.
The patients were evaluated through questionnaires that measured pain, joint stiffness, functional disability, and overall satisfaction. They were also clinically examined for range of motion and alignment. In order to achieve “Excellent” results, the patient had to be entirely pain-free in all activities, with no functional limitation of motion and have normal alignment.
The study showed 93.1% excellent, 2.2% good, and 4.7% unsatisfactory. The study was then followed up on in 1998, in which 189 patients were added. The follow up on the 468 patients was conducted from 2 months to 38 years postoperative and showed a 97.3% implant survivorship.
Since then, several studies have been conducted on the BioPro First MPJ Hemi Implant.
BioPro vs Fusion
A recent study was published comparing long-term results (average 8.3 years) of the BioPro implant hemiarthroplasty procedure to arthrodesis (fusion). A total of 78 procedures performed from 2005 to 2011 were reviewed (31 hemiarthroplasty and 47 fusion). The data revealed that hemiarthroplasty provided better functional outcomes with considerably more satisfied patients.
The following charts highlight some key findings.
What to expect after hemiarthroplasty surgery
Most patients have a rapid recovery and have considerably less pain than they did before surgery. Partial to full weight-bearing is permitted at the discretion of the surgeon. A standard post-operative shoe may be used for the first 3 weeks. Dressings are changed for 3 weeks, with sutures usually removed at the 2 week period. Passive range of motion, such as movement of the foot upward or downward is permitted by the 2nd or 3rd post-operative week. Physical therapy and return to soft shoes is usually permitted by the 3rd to 4th post-operative week.
Note: dressing changes, return to regular shoes and types of postoperative range of motion therapies may vary based on your surgeon’s recommendations.
Possible complications after surgery include:
Infections – Any infection in your body can spread to your joint replacement. Infections may occur while you are in the hospital or after you go home. Minor infections can be treated with antibiotics, while major infections may require surgery and removal of the prosthesis.
Stiffness – In some cases, the ability to bend the toe does not return to normal after an artificial great toe joint replacement. This can be reduced with aggressive physical therapy.