Introduction
Hyperextension of the first metacarpophalangeal joint (MCP-1) is frequently associated
with first carpometacarpal joint (CMC-1) osteoarthritis, especially in its more advanced
stages.[1]
[2] Failure to adequately treat the MCP-1 joint when the trapezius is resected can lead
to worsening hand function and require a reoperation.[3]
This study aims to determine if the simultaneous surgical treatment of both joints
results in adequate clinical and functional outcomes in the medium term.
Material and Methods
This is a descriptive study. Patients who underwent surgery in our Center between
January 2013 and October 2014 (minimum follow-up period of five years) with CMC-1
osteoarthritis associated with hyperextension of the MCP-1 joint have been reviewed.
Inclusion criteria comprised of a history of CMC-1 joint pain that requiring scheduled
treatment with analgesic agents, trapezial radiological damage classified as Eaton
grade IV, CMC-1 joint extension ≥40° and lack of response after six month of non-surgical
therapy (steroids infiltration, rehabilitation, occupational therapy). Cases with
infection, fracture or previous hand surgery were excluded.
All the patients were operated on at the Upper Limb Unit with the following technique:
first, the MCP-1 joint was approached and fixed with a intermedullary interlocking
screws system (XMCP, Extremity Medical, Parsippany, MJ) at a 25° angle, leaving the
phalanx in neutral position. Next, the CMC-1 joint was accessed through a modified
Burton-Pellegrini technique, with complete trapezial resection and MCP-1 stabilization
through a flexor carpi radialis (FCR) hemitendonplasty. Postsurgical immobilization
was performed with a forearm splint including the thumb; interphalangeal joint mobilization
was allowed after 3 weeks splint was removed, the use of the thumb in daily living
activities was recommended, and the patient was referred for rehabilitation. Strengthening
hand movements were allowed once MCP-1 joint consolidation was achieved ([Figures 1] and [2]).
Fig. 1 Preoperative radiograph.
Fig. 2 Postoperative radiograph (five-year follow-up).
In addition to age, gender, side and dominance, the following data were taken before
surgery and five years after the procedure: thumb interphalangeal joint (IP) range
of motion, key pinch, hand grip and Kapandji, visual analog scale (VAS) and Quick
Disability of Arm, Shoulder and Hand (DASH) scores. For statistical analysis, the
Wilcoxon test, a non-parametric test, was used to compare pre- and postoperative values.
At the radiological level, MCP-1 arthrodesis consolidation and the absence of shock
between MCP-1 and the scaphoid bones were assessed.
Results
Twenty-three patients were operated on during the study; since four of them were not
located for the five-year follow-up evaluation, 19 cases were reviewed, including
two men and 17 women, with seven right and 12 left sides, and seven dominant and 12
non-dominant hands.
Measured variables are shown in [Table 1].
Table 1
|
PREOPERATIVE VALUE (±standard deviation)
|
POSTOPERATIVE VALUE (± standard deviation)
|
P
|
|
Thumb interphalangeal range of motion
|
73.15° (±7.49)
|
53.95° (±22.94)
|
0.001
|
|
Key pinch
|
4.18 kg (±1.73)
|
4.79 kg (±1.53)
|
0.202
|
|
Hand grip
|
16.99 kg (±9.04)
|
21.92 kg (±6.21)
|
0.007
|
|
Kapandji score
|
9.17 (±1.38)
|
8.21 (±1.32)
|
0.103
|
|
Visual analog scale score
|
8.59 (±0.67)
|
1.42 (±1.8)
|
0.000
|
|
Quick DASH score
|
71.91 (±6.96)
|
20.63 (±14.83)
|
0.000
|
All cases presented MCP-1 arthrodesis consolidation without any problems related with
the osteosynthesis material. No shock between MCP-1 and the scaphoid bones was noted,
and there was always a space between such bones.
Discussion
Patients operated on for first carpometacarpal osteoarthritis require a detailed examination
of the hand, especially of the thumb bone. MCP-1 dorsoradial subdislocation in relation
to the trapezius can result in its flexion and adduction; as the intermetacarpal space
narrows, the MCP-1 joint hyperextends to grasp and apprehend objects. Similarly, thumb
IP joint flexion increases, leading to a zig-zag deformity.[1]
[2]
There is no superior technique for first carpometacarpal osteoarthritis treatment.[4] It is known that the surgical correction of a MCP-1 hyperextension of less than
30° simultaneously to the trapezius surgery does not result in an objective benefit,
since extension an improve with CMC-1 subdislocation correction.[2]
[5] However, it is also known that trapezius resection (associated or not with CMC-1
suspension) can worsen hyperextension MCP-1 because it decreases the height of the
thumb bone.[3] This does not happen if the trapezius is spared after CMC-1 reduction, as when a
CMC-1 prosthesis is used.[6] Hyperextension MCP-1 alone or associated with a shock between MCP-1 and the carpal
remnant is a cause of trapeziectomy revision.[7]
[8]
The MCP-1 joint must be treated concurrently to the CMC-1 joint to avoid revision
surgeries. Different combined surgical techniques have been proposed when hyperextension
exceeds 30°, including needle temporary fixation (with poor outcomes year), volar
capsulodesis, proximal and radial transfer of the extensor pollicis brevis (EPB) to
MCP-1, sesamoids fusion (leading to the loss of 8° in extension) or MCP-1 arthrodesis.[5]
[9]
Capsulodesis combined with trapezius resection results in tension loss over time.
Miller states that hyperextension goes from 19° one year after surgery to 30° 9 years
after the procedure, with thumb flexion preservation but no pain.[10] De Smet compared MCP-1 capsulodesis and arthrodesis with trapeziectomy outcomes
and reported no clinical differences, indicating that this finding was possibly due
to the small sample size.[11]
Some authors only recommend MCP-1 arthrodesis in case of recurrence or if the patient
is symptomatic;[9] others,[2] however, indicate its performance when joint extension exceeds 40° (a criterion
followed by these authors) because, although mobility is sacrificed, it provides a
stable column that is very important for hand function.[5] Different surgeries have been proposed to do so, including the use of needles with
or without cerclage, screws and plates.[5] We opted for a system with intramedullary screws at a fixed angle of 25° that allowed
early mobilization and resulted in fusion in all cases, without the problems related
to the osteosynthesis material (especially adhesions or the need to remove them) which
had already been noted in previous studies with this device.[12]
[13]
There is controversy on how to perform the osteosynthesis between the phalanx and
the metacarpal bone during MCP-1 arthrodesis to achieve a better thumb function. If
not combined with a trapezius resection, it is recommended to leave it in pronation;[8]
[14] since trapezius removal leads to metacarpal bone pronation and abduction, phalanx
stabilization in a slight supination was proposed to achieve better stability for
key pinch.[2] In our study, we decided to leave the phalanx in a neutral position because it is
the most comfortable with the system used.
Regarding measured variables, thumb IP joint range of motion and Kapandji score was
deemed suitable for the function of the hand, but decreased, possibly due to the new
position of the MCP-1 joint. There were no statistically significant changes in key
pinch, but hand grip increased significantly. Final key pinch, hand grip and Kapandji
score values are very similar to those from a previously published series with trapeziectomy
alone.[15] VAS and Quick DASH scores showed that pain and quality of life, respectively, improved
significantly, even considering that subjective factors influence treatment outcomes.[16] De Smet indicates that patients with CMC-1 osteoarthritis and MCP-1 hyperextension
have less pain after treatment of both joints.[11]
Our study had several handicaps, including the small sample size and the lack of a
control group with first carpometacarpal osteoarthritis plus hypermobility and treated
with resection arthroplasty alone.
Despite these limitations, MCP-1 arthrodesis with XMCP combined with trapezius resection,
ligament reconstruction and tendon interposition have good outcomes both for hand
function and quality of life in the medium term. This arthrodesis system results in
seamless fusion with no problem associated.
