Introduction
Arthritis of the trapezio metacarpal joint of the base of the thumb is a common problem. It is the most common joint in the hand to be affected by arthritis. We will look into this problem in detail including the stages of the disease the standard treatment option and the role of joint replacements.
Functional Anatomy
The trapezium articulates with the thumb metacarpal, scaphoid, trapezoid and the radial facet of the index metacarpal. A complex group of ligaments maintain the functional integrity of the trapezium in relation to its neighboring bones. The most important of these is the so called beak ligament which is the primary static stabiliser of the trapezio metacarpal joint. It is also called the palmar oblique ligament. In osteoarthritis of the trapezio metacarpal joint initial attritional changes start in this ligament and lead to eventual destabilisation of the joint.
Clinical Features
Osteoarthritis of the base of the thumb is usually primary but can be secondary due to trauma i.e. as a result of an untreated Bennett's fracture. It is more common in women (15:1). Pain and restriction of movements are the most common presenting symptoms. As a result of this problem patients also manifest a weak pinch grip.
Radiological Stages
The standard x-rays taken for this condition are a plain AP and lateral view. Based on the radiological features the clinical stages of the disease were first described by Eaton and Littler.
- Stage 1-synovitis as evidenced by increased joint space in the X-ray
- Stage 2-Joint space narrowing
- Stage 3-Sclerosis in the trapezio metacarpal joint
- Stage 4-Pan trapezial OA as evidenced by radiological changes in the scapho-trapezial-trapezoidal (STT) joint.
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In addition to the standard x-rays at Banbury we also advocate the use of the 'pinch grip' views. These are AP and lateral x-rays done with the patient asked to pinch the thumb hard against the index finger. This we have found correlates better with the level of symptoms. They also show joint subluxation more effectively. These are analogous to the weight bearing views in other joints.
Treatment Options
Conservative
These include regular analgesia, splintage and intra articular steroid injections which are usually given under image intensifier control. These are usually effective for stages 1 and 2 but for stages 3 and 4 we usually have to consider surgical management.
Surgical Options
Trapeziectomy has been the traditional surgical option for the treatment of this condition. It was first performed by WH Gervis -an orthopaedic surgeon from Queen Victoria Hospital East Grinstead in 1949. He advised simple excision of the trapezium in its entirety. He was so pleased with the results of his procedure that he himself underwent the procedure on his right hand.
In his own words he said: “At first, when operating, artery forceps would not clip, and the left hand had to be used. Winding clocks was irksome and it was a year before a clock with a strong spring could be wound with the right hand”
Problems with trapeziectomy
Although trapeziectomy gave good pain relief the patients soon started complaining of functional problems relating to the sshortening of the thumb, loss of pinch grip, persistent adduction of first metacarpal, painful scapho metacarpal conflict and carpal instability.
What next?
To counter the above problems in 1960 Froimson first introduced the concept of interposition i.e.- putting something in the space occupied by the trapezium. The various substances used included Palmaris Longus, Flexor Carpi Radialis Tendon (FCR), Cadaveric allograft fascia lata, Abductor Pollicis Longus, Achilles tendon, Silicone rubber, Gore-Tex, etc.
The current trend is to have one of the following two options using the FCR:
- FCR - Ligament Reconstruction alone where the tendon is tunnelled through the base of the metacarpal
- FCR- LRTI - Ligament Reconstruction and Tendon Interposition
Problems with trapeziectomy in its various forms
There is multitude of papers on the various forms of trapeziectomies in literature but there have been two good studies which have looked into this in detail.
- Ligament reconstruction with or without tendon interposition to treat primary thumb carpomeatcarpal OA-JBJS 2004 by Gabriele Kriegs et al from Vienna Austria
- Trapeziectomy for trapezio meatcarpal Osteoarthritis: Is Ligament Reconstruction and temporary stabilisation with a K wire Important? Journal of Hand Surgery 2009 by Tim Davis et al from Nottingham
On close scrutiny of the results of both these papers it is clear that simple trapeziectomy without any interposition produces comparable results to complex reconstructions. Although it is a good pain relieving operation there are still problems associated with reduced strength and dexterity.
Joint Replacements
To overcome the problems associated with trapeziectomy a number of joint replacements were introduced in 1970s and 1980s but these were all cemented prosthesis and did not have great results and none of them have stood the test of time.
What's new?
At the moment the concept of a joint replacement is still an attractive option. The advantages with a stemmed ball and socket joint are it preserves first column length, provides better opposition of the thumb, better thumb index digit pinch, better range of motion and improved stability in addition to excellent pain relief.
The prosthesis that is commonly used is an uncemented stem which is inserted into the metacarpal and an uncemented polyethylene cup with a metal liner which press fits in the trapezium and a modular head and neck which goes onto the stem. The stem and the neck come in various sizes and offsets.
These types of prosthesis have been used for the last five years. Medium term results are encouraging but we still need to await long term results before these can become the gold standard.
Conclusion
In conclusion base of thumb arthritis is a common problem and trapeziectomy has been the gold standard surgical treatment for many years. It has many problems associated with it. Joint replacements have been shown to be superior to trapeziectomy in the short term but we still need longer term results before we can say trapeziectomy should only be done as a salvage procedure.
References
- WH Grevis A review of excision of the trapezium for osteoarthritis of the trapezio-metacarpal joint after twenty five years JBJS 55 B No.1 56-57
- O Barbier et al Prospective functional analysis of trapeziectomy combined with intermetacarpal stabilization in trapezio metacarpal arthritis. Acta Orthop Belg, 2004 70, 410-416
- G Kriegs et al Ligament reconstruction with or without tendon interposition to treat primary thumb carpomeatcarpal OA -JBJS A 86 2004 209-218.
- Tim Davis et al Trapeziectomy for trapezio metacarpal Osteoarthritis: Is Ligament Reconstruction and temporary stabilisation with a K wire Important? Journal of Hand Surgery June 2009 34 No3 312-321
- Burton et al Surgical Management of basal joint arthritis of the thumb J hand surg 1986 11-A 324-332
- Froimson et al Tendon interposition arthroplasty of carpo metacarpal joint of the thumb Hand Clinic 1987 3 489-505
- Henk et al Long term results and loosening of de la Caffini
