The Effect of Surgical Treatments for Trapeziometacarpal Osteoarthritis on Wrist Biomechanics: A Cadaver Study.

PURPOSE: Studies have shown the effects of surgical treatments for trapeziometacarpal osteoarthritis on thumb biomechanics; however, the biomechanical effects on the wrist have not been reported. This study aimed to quantify alterations in wrist muscle forces following trapeziectomy with or without ligament reconstruction and replacement. METHODS: A validated physiological wrist simulator replicated cyclic wrist motions in cadaveric specimens by applying tensile loads to 6 muscles. Muscle forces required to move the intact wrist were compared with those required after performing trapeziectomy, suture suspension arthroplasty, prosthetic replacement, and ligament reconstruction with tendon interposition (LRTI). RESULTS: Trapeziectomy required higher abductor pollicis longus forces in flexion and higher flexor carpi radialis forces coupled with lower extensor carpi ulnaris forces in radial deviation. Of the 3 surgical reconstructions tested post-trapeziectomy, wrist muscle forces following LRTI were closest to those observed in the intact case throughout the range of all simulated motions. CONCLUSIONS: This study shows that wrist biomechanics were significantly altered following trapeziectomy, and of the reconstructions tested, LRTI most closely resembled the intact biomechanics in this cadaveric model. CLINICAL RELEVANCE: Trapeziectomy, as a standalone procedure in the treatment of trapeziometacarpal osteoarthritis, may result in the formation of a potentially unfilled trapezial gap, leading to higher wrist muscle forces. This biomechanical alteration could be associated with clinically important outcomes, such as pain and/or joint instability.

Alcohol injection for Morton's neuroma: a five-year follow-up.

BACKGROUND: Although many treatment modalities are available for Morton's neuroma (MN), studies looking at the long-term effectiveness of most forms of treatment are scarce. The injection of MN with alcohol has gained popularity over the past 10 years with widespread media coverage. Many surgeons have anecdotally questioned the long-term effectiveness of this treatment. We reviewed a cohort of patients at an average 5-year follow-up to assess the medium-term results of alcohol injection. METHODS: We used the modified Johnson score and visual analogue scales to assess 45 of the original cohort of patients with an average follow-up of 61 months (range, 33-73 months). Any complications from the procedure were also noted. RESULTS: Our results indicated that by 5 years, 16 of 45 patients had undergone surgical treatment and a further 13 patients had return of symptoms. Only 29% (13/45) remained symptom free. The visual analog scale and modified Johnson scores showed statistically significant deterioration in patients' symptoms at 5 years following alcohol injection. CONCLUSION: Injection with alcohol sclerosant for MN has been marketed as a definitive management option comparable to surgical excision. Our investigation illustrated that although short-term results are encouraging, alcohol injection does not offer permanent resolution of symptoms for most patients and can be associated with considerable morbidity. Our investigation provides the only long-term data for alcohol injection treatment of MN. LEVEL OF EVIDENCE: Level II, prospective case series.

Results of proximal medial gastrocnemius release for Achilles tendinopathy.

BACKGROUND: Most patients with Achilles tendinopathy (AT) are treated successfully with physiotherapy involving eccentric calf training. In some patients, gastrocnemius contracture persists and there are reports of improvement following gastrocnemius release. We present the first series of patients to have proximal medial gastrocnemius release (PMGR) for AT. METHOD: 16 PMGRs (12 patients) were performed at our institution over a 2-year period. Nine patients (10 PMGRs) were available for follow-up. The mean age of patients was 45 years (range, 25-63 years), with 5 female and 4 male subjects. The average follow-up period was 2.5 years (range, 1.7-3.3 years). The sample was divided into noninsertional and insertional tendinopathy, with 5 PMGRs per group. Outcome measures were visual analog scale (VAS) scores, Victorian Institute of Sport Assessment-Achilles (VISA-A) scores, American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score, and overall satisfaction. Complications and further procedures were also recorded. RESULTS: At an average of 2.5 years of follow-up, 6 out of 9 patients were highly satisfied. The noninsertional tendinopathy group enjoyed better results than the insertional group: mean VISA-A scores improved by 59% (noninsertional) versus 22% (insertional); mean AOFAS scores improved by 29% (noninsertional) versus 15% (insertional). The improvement in the noninsertional group was statistically significant (P < .05) for all 3 outcome measures. CONCLUSION: PMGR was an outpatient procedure that was well tolerated without wound healing concerns due to the proximally based incision. Patients with noninsertional tendinopathy who have failed conservative treatment can expect notable improvement, with VISA-A scores possibly normalizing after the procedure. We recommend PMGR for patients suffering recalcitrant noninsertional AT in whom gastrocnemius contracture persists despite an eccentric stretching program. LEVEL OF EVIDENCE: Level IV, case series.

The importance of abductor pollicis longus in wrist motions: A physiological wrist simulator study.

The abductor pollicis longus (APL) is one of the primary radial deviators of the wrist, owing to its insertion at the base of the first metacarpal and its large moment arm about the radioulnar deviation axis. Although it plays a vital role in surgical reconstructions of the wrist and hand, it is often neglected while simulating wrist motions in vitro. The aim of this study was to observe the effects of the absence of APL on the distribution of muscle forces during wrist motions. A validated physiological wrist simulator was used to replicate cyclic planar and complex wrist motions in cadaveric specimens by applying tensile loads to six wrist muscles - flexor carpi radialis (FCR), flexor carpi ulnaris, extensor carpi radialis longus (ECRL), extensor carpi radialis brevis, extensor carpi ulnaris (ECU) and APL. Resultant muscle forces for active wrist motions with and without actuating the APL were compared. The absence of APL resulted in higher forces in FCR and ECRL - the synergists of APL - and lower forces in ECU - the antagonist of APL. The altered distribution of wrist muscle forces observed in the absence of active APL control could significantly alter the efficacy of in vitro experiments conducted on wrist simulators, in particular when investigating those surgical reconstructions or rehabilitation of the wrist heavily reliant on the APL, such as treatments for basal thumb osteoarthritis.

The effects of wrist motion and hand orientation on muscle forces: A physiologic wrist simulator study.

Although the orientations of the hand and forearm vary for different wrist rehabilitation protocols, their effect on muscle forces has not been quantified. Physiologic simulators enable a biomechanical evaluation of the joint by recreating functional motions in cadaveric specimens. Control strategies used to actuate joints in physiologic simulators usually employ position or force feedback alone to achieve optimum load distribution across the muscles. After successful tests on a phantom limb, unique combinations of position and force feedback - hybrid control and cascade control - were used to simulate multiple cyclic wrist motions of flexion-extension, radioulnar deviation, dart thrower's motion, and circumduction using six muscles in ten cadaveric specimens. Low kinematic errors and coefficients of variation of muscle forces were observed for planar and complex wrist motions using both novel control strategies. The effect of gravity was most pronounced when the hand was in the horizontal orientation, resulting in higher extensor forces (p<0.017) and higher out-of-plane kinematic errors (p<0.007), as compared to the vertically upward or downward orientations. Muscle forces were also affected by the direction of rotation during circumduction. The peak force of flexor carpi radialis was higher in clockwise circumduction (p=0.017), while that of flexor carpi ulnaris was higher in anticlockwise circumduction (p=0.013). Thus, the physiologic wrist simulator accurately replicated cyclic planar and complex motions in cadaveric specimens. Moreover, the dependence of muscle forces on the hand orientation and the direction of circumduction could be vital in the specification of such parameters during wrist rehabilitation.