Thumb carpal metacarpal arthritis

Innervation patterns of thumb trapeziometacarpal joint ligaments

PURPOSE

The human thumb trapeziometacarpal (TM) joint is a unique articulation that allows stability during pinch and grip and great degrees of mobility. Because the saddle-shaped articulating surfaces of the TM joint are inherently unstable, joint congruity depends on the action of restraining ligaments and periarticular muscles. From other joints, it is known that proprioceptive and neuromuscular joint stability depend on afferent information from nerve endings within ligaments. We hypothesize that the TM joint ligaments may similarly be innervated, indicating a possible proprioceptive function of the joint.

METHODS

We harvested 5 TM joint ligaments in entirety from 10 fresh-frozen cadaver hands with no or only minor signs of osteoarthritis and suture-marked them for proximal-distal orientation. The ligaments harvested were the dorsal radial, dorsal central, posterior oblique, ulnar collateral, and anterior oblique ligaments. After paraffin-sectioning, we stained the ligaments using a triple-antibody immunofluorescent technique and analyzed them using immunofluorescence microscopy.

RESULTS

Using the triple-stain technique, mechanoreceptors could be classified as Pacinian corpuscles, Ruffini endings, or Golgi-like endings. The 3 dorsal ligaments had significantly more nerve endings than the 2 volar ligaments. Most of the nerve endings were close to the bony attachments and significantly closer (P = .010) to the metacarpal insertion of each ligament. The anterior oblique ligament had little to no innervation in any of the specimens analyzed.

DISCUSSION

The TM joint ligaments had an abundance of nerve endings in the dorsal ligaments but little to no innervation in the anterior oblique ligament. The Ruffini ending was the predominant mechanoreceptor type, with a greater density in the mobile metacarpal portion of each ligament.

CLINICAL RELEVANCE

Presence of mechanoreceptors in the dorsal TM joint ligaments infers a proprioceptive function of these ligaments in addition to their biomechanical importance in TM joint stability.

Immunofluorescent triple-staining technique to identify sensory nerve endings in human thumb ligaments

Ligament innervation purportedly plays a critical role in stability, proprioception and pathology of joints with minimal bony constraints. The human thumb carpometacarpal (CMC) joint is such a joint: with a complex saddle configuration and wide circumduction, its constraint is primarily ligamentous and it is prone to osteoarthritis. CMC reconstruction is the most commonly performed arthritis surgery in the upper extremity. Little, however, is known about CMC ligament innervation. We describe a novel triple-staining immunofluorescence technique using the markers for low-affinity neurotrophin receptor p75, the pan-neuronal marker protein gene product (PGP) 9.5 and 4',6'-diamidino-2-phenylindole (DAPI) to simultaneously detect and differentiate between specific sensory nerve endings: the Pacini corpuscles, the Ruffini endings and nerve fascicles. Five primary CMC ligaments (dorsal radial, dorsal central, posterior oblique, anterior oblique and ulnar collateral ligaments) were harvested from 10 fresh-frozen human cadaver hands. Following paraffin sectioning, each ligament was stained using a triple-stain technique and imaged with fluorescence microscopy. Multidimensional acquisition permitted simultaneous capture of images at different wavelengths. Pacini corpuscles were distinguished by their distinct p75 immunoreactive capsules, and Ruffini endings by their overlapping p75 and PGP9.5 immunoreactive dendritic nerve endings. Simultaneous use of PGP9.5, p75 and DAPI immunofluorescence to analyze innervation patterns in human ligaments provides descriptive analysis of staining patterns and receptor structure as well as clues as to the proprioceptive function of CMC ligaments and the joint as a whole. Our novel findings of CMC ligament innervation augment the study of normal and pathological joint mechanics in this joint so prone to osteoarthritis.

Implant arthroplasty of the carpometacarpal joint of the thumb

Resection arthroplasty with or without ligament reconstruction for thumb trapeziometacarpal arthritis can be complicated by thumb shortening and pinch-strength weakness. Implant arthroplasties have been developed to limit loss of thumb length, improve strength, and limit postoperative convalescence. The ideal thumb carpometacarpal implant should be strong and stable, provide full range of motion, and prevent loosening. Unfortunately, no current prosthesis accomplishes all of these goals. Until the ideal implant is developed, clinical acumen must be used to determine appropriate patients and implants.

Evaluation of transdermal steroids for trapeziometacarpal arthritis

PURPOSE

One conservative treatment for trapeziometacarpal joint arthritis is the delivery of steroids transdermally. In prior transdermal studies on the elbow and foot, there are mixed reports of success. It appears that the benefits of the treatment might be limited to short-term relief (approximately one week). It was hypothesized that transdermal steroid delivery would yield short-term improvements for trapezial-metacarpal joint arthritis, although these improvements would not persist at later follow-up (3 or 6 months).

METHODS

Eighty-four consecutive trapeziometacarpal joints in 62 patients presenting to an orthopedic hand surgeon were randomized to receive either steroid delivery by iontophoresis or phonophoresis or placebo delivery via iontophoresis or phonophoresis. The researchers and patients were blinded as to the treatment assignment. Patients were evaluated before treatment and at 3 follow-up appointments. Subjects were assessed via the Michigan Hand Outcomes Questionnaire, Short Form 12, analog pain score, and provocative and strength testing. The subjects' study group, gender, and arthritic grade were statistically analyzed versus patient-reported and physician-assessed data over the different time points. Following subject recruitment, 17 joints discontinued the study due to joint discomfort, electing for other treatments. Approximately half of the 67 subject joints opted for alternative treatment after the first or second follow-up; 34 subject joints completed all follow-up time points.

RESULTS

There was no significant predictive relationship between the independent variables and their ability to predict the 9 dependent measures of pain, strength, and well-being. There were trends for the pain to decrease over time, although the trends were not uniform between the different pain metrics and groups. The strength for both iontophoresis groups tended to increase over time, whereas the phonophoresis groups tended to decline.

CONCLUSIONS

Although there were some trends in the follow-up data, the overall lack of significant differences in the data suggests that transdermal steroid delivery might not be helpful in providing short- or long-term relief of arthritic symptoms.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic II.

Arthroscopically assisted percutaneous fixation of Bennett fractures

Arthroscopic-assisted reduction and fixation of Bennett-type fractures of the thumb metacarpal allow for the confirmation of reduction as well as the assessment of the degree of chondral damage. With use of a 1.9-mm arthroscope and a traction tower, direct visualization and reduction is possible. Traditional methods of fixation are used to secure the fracture fragment. Postoperative rehabilitation follows the usual protocol used in both open and percutaneous techniques. However, the potential to obtain and confirm a more accurate articular reduction may reduce the incidence of late arthritis of the thumb carpometacarpal articulation.

The carpometacarpal stress view radiograph in the evaluation of trapeziometacarpal joint laxity

PURPOSE

Hypermobility at the thumb carpometacarpal (CMC) joint has been proposed as an explanation for abnormal loading and subsequent development of osteoarthritis. Radiographic evaluation of this joint is difficult owing to the obliquity of the articulation. We modified a previously described technique to obtain a bilateral stress radiograph of the thumbs to measure CMC joint laxity. The purpose of this study was to present the details of this modified technique and evaluate its reproducibility in a group of volunteer subjects. We hypothesized that this technique would be reliable and reproducible.

METHODS

A posteroanterior radiograph was obtained after asking volunteer subjects to press their thumbs together using a foam hand support. Three measurements were performed: radial subluxation of the first metacarpal base, first metacarpal articular width, and the distance between the ulnar articular facet of the trapezium and the ulnar metacarpal edge (uncovered edge). Using digital calibration on a picture archiving and communication system radiology server, a radiologist, radiology resident, orthopedic surgeon, and orthopedic resident performed measurements at 2 time points. To evaluate consistency among the raters, intraclass correlation coefficients were calculated. Test-retest bivariate analyses were performed to assess intra-rater reliability.

RESULTS

A total of 69 volunteers (39 women and 30 men) were imaged. Women showed significantly greater radial subluxation compared to men (p < .01). Inter-rater reliability coefficients for radial subluxation and articular width initially and at 2 weeks showed high agreement, as did test-retest reliability coefficients. For the uncovered edge measurement, inter-rater reliability coefficients were low, with wide variation in reliability.

CONCLUSIONS

The modified thumb CMC stress view radiograph evaluates laxity and joint abnormalities of the trapeziometacarpal articulation. The details of the radiographic technique are straightforward, and the inter- and intra-observer reliability of radial subluxation and first metacarpal width are high. The ratio of the 2 measurements provides an accurate measure of the radiographic subluxation of the first metacarpal from the trapezium. This measurement is most specific to radial subluxation under simulated active loading, in the plane of the hand. The medial uncovered edge of trapezium measurement does not have high inter-observer reliability and varies widely, and it should not be included in laxity measurements.

Trapezium resection with suspension and interposition arthroplasty using acellular dermal allograft for thumb carpometacarpal arthritis

PURPOSE

Trapezium excision with ligament reconstruction and tendon interposition has proved to be highly effective in the treatment of thumb carpometacarpal joint arthritis. Donor-site morbidity from autograft harvest can be avoided by using an allograft. We report the outcomes after suspension and interposition arthroplasty using an acellular dermal allograft (GraftJacket; Wright Medical Technology, Inc., Arlington, TN) for thumb carpometacarpal arthritis.

METHODS

Eighty-nine patients (100 thumbs) had surgery for thumb carpometacarpal arthritis using acellular dermal allograft instead of flexor carpi radialis tendon autograft. Evaluation of the results was performed for 82 thumbs with adequate data. Each patient was followed up for a minimum of 12 months (average, 30 months). Pain levels, grip strength, key pinch strength, range of motion, and radiographic measurements were performed.

RESULTS

Between the preoperative and final follow-up measurements, patient pain levels (on a visual analog scale) were significantly reduced, from 6.2 to 0.7. Comparisons between preoperative and postoperative strength measurements showed an average 16% increase in grip strength and 19% increase in key pinch strength. No differences were found for radial abduction and palmar abduction data, respectively. Comparison with the preoperative x-rays showed the thumb metacarpal had subsided 31% of the arthroplasty space. No patient experienced a foreign body reaction or suffered an infection in our series.

CONCLUSIONS

Trapeziectomy with suspension and interposition arthroplasty using an acellular dermal allograft is highly effective for the treatment of thumb carpometacarpal arthritis. This procedure provides a safe and effective alternative to autograft for both ligament reconstruction and tendon interposition and eliminates the potential morbidity of autograft harvest.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Ligament reconstruction with tendon interposition using an acellular dermal allograft for thumb carpometacarpal arthritis

Ligament reconstruction tendon interposition arthroplasty is currently the preferred technique for carpometacarpal joint arthritis of the thumb by most surgeons. Despite its efficacy, morbidity has been associated with the harvest of the flexor carpi radialis tendon. Using an allograft as material for arthroplasty, donor site morbidity is avoided. In this report, we present our surgical technique to perform ligament reconstruction tendon interposition arthroplasty using an acellular dermal matrix allograft (GraftJacket) in patients with Eaton stages II, III, and IV symptomatic first carpometacarpal arthritis.One hundred thumbs with trapeziometacarpal osteoarthritis underwent surgical treatment using GraftJacket allograft instead of the flexor carpi radialis tendon autograft. Each patient was followed for a minimum of 12 months. The surgical procedure included trapezial excision and identification of the flexor carpi radialis. The allograft was cut to create a 15-cm strip. The ligament reconstruction was performed by passing the strip around the flexor carpi radialis tendon and suturing it to the base of the thumb metacarpal base through an intramedullary drill hole. The remaining portion of the allograft was fashioned as an interposition mass (anchovy) and interposed between the scaphoid and the base of the first metacarpal.All but 1 patient experienced significant improvement in his or her pain scale rating and grip and pinch strengths. Outcomes from this study compare very favorably with those of other series. No patients experienced a foreign body reaction or infection in this series. We believe that the use of an acellular dermal allograft for both ligament reconstruction and tendon interposition provides a safe and an effective alternative technique for the treatment of advanced first carpometacarpal arthritis.