Fractional Lengthening of Forearm Flexor Tendons: A Cadaveric Biomechanical Analysis.

PURPOSE: Multiple procedures have been described for wrist and finger flexion contractures and spasticity. Fractional lengthening of forearm flexor tendons involves making parallel transverse tenotomies at the musculotendinous junction to elongate the muscle. Currently, there is limited literature to define the biomechanical consequences of this lengthening technique. METHODS: Forty-eight flexor tendons were harvested from eight paired upper limbs including flexor carpi radialis, flexor carpi ulnaris, flexor pollicis longus, and flexor digitorum superficialis tendons. Each tendon that was lengthened was paired with the contralateral tendon as a control. A pair of transverse tenotomies were completed for the fractional lengthening. The first tenotomy was performed at the musculotendinous junction where the tendon narrowed to 75% of its maximal width. The second tenotomy was made 1 cm distal to the first. Tendon length was measured before and after fractional lengthening at a constant resting tension of 1 N. The maximum load at failure of each tendon and the mechanism of failure were each measured and compared with the contralateral side. RESULTS: After fractional lengthening, the mean increase in resting tendon length was 4 mm. When loaded to failure, the mean maximum load of fractionally lengthened tendons was 42% of the mean maximum load of intact tendons. All lengthened tendons failed at the distal tenotomy site. CONCLUSIONS: Fractional lengthening resulted in an increase of 3-6 mm (mean: 4 mm) in tendon length at resting tension. There was a significant loss in tensile strength and load to failure following fractional lengthening compared with an intact musculotendinous unit. CLINICAL RELEVANCE: The reduction in tensile strength following fractional lengthening results in loads at failure that are, in some cases, lower than the estimated forces required to perform basic tasks. Caution during the healing and rehabilitation period is warranted.

Long-term Effects of Repeated Botulinum Toxin Injection in Cosmetic Therapeutics.

BACKGROUND: Botulinum toxin (BT), a potent neurotoxin, has been used in clinical medicine since the 1970s for cosmetic and therapeutic purposes. Studies have consistently shown positive outcomes with a very limited adverse effect profile and a conventional understanding that results dissipate after 3 to 5 months. However, more recent evidence suggests that changes in muscle composition, function, and appearance persist for much longer, even years. To examine the potential implications of these findings on cosmetic use of BT injections in reduction of skin lines and wrinkles, we first needed to further our understanding of the current literature on long-term outcomes after repeated BT injections. METHODS: A comprehensive review of the literature on long-term outcomes after repeated BT injections for cosmetic indications was performed. We evaluated the study designs, and results were compared. RESULTS: A total of 22 publications met our inclusion criteria, of which 14 were clinical trials. Few studies extended outcome measurement past 6 months postinjection, and many were funded or supported by industry. However, the studies that extended follow-up saw persistent changes after BT injection, in some cases as far as 4 years postinjection. CONCLUSION: The current body of knowledge on the long-term results after repeated cosmetic BT injections is very limited, and the available literature provides insufficient evidence on how prolonged effects could alter clinical use of BT. Further clinical studies with extended follow-up periods with inclusion of both subjective and objective measured outcomes of appearance and muscle function are required to better understand the long-term impacts of repeated BT injections.

Risk factors for surgical site infection after surgical treatment of closed distal radial fractures.

We assessed operatively treated closed distal radial fractures to identify independent risk factors for surgical site infection after treatment. A retrospective review was carried out of 531 operatively treated closed distal radial fractures over a 5-year period. Multiple logistic regression was performed with infection as the dependent variable, using a stepwise regression procedure to select variables to construct the final model. In total, 19 (3.6%) fractures were complicated by postoperative surgical site infection. Uncontrolled diabetes with HbA1c >7, the presence of external fixation or external Kirschner wires, and tobacco use were significant independent predictors of infection. Age and time in the operating room were also statistically significant predictors but deemed to be not clinically meaningful.Level of evidence: IV.

Why do subcutaneous ports get stuck? A case-control study.

PURPOSE: We sought to identify clinical features associated with difficult subcutaneous port removals in children. METHODS: Ports placed between April 2014 and September 2017 at our institution were prospectively tracked for difficult removals. A case-control analysis was performed. Patients with ports that were difficult to remove (stuck; cases) were compared to biological sex and age-matched controls in a ratio of 1:3. Logistic regression determined the association between case/control status and clinical features adjusting for biological sex and age as covariates. A multivariable analysis was performed to identify independent associations. RESULTS: 57 stuck ports (28 extreme [10 endovascular intervention] and 29 moderate) and 171 controls were analyzed. Stuck ports were associated with a diagnosis of acute lymphoblastic leukemia (86% cases versus 22.2% controls; p < 0.001) and a longer placement duration (median 2.6 years [interquartile range (IQR) 2.5-2.6] versus 0.8 years [IQR 0.5-1.4]; p < 0.001). On univariate analysis, procedural and device features associated with stuck ports included subclavian access (71.9% cases versus 48.5% controls; p = 0.0126), a polyurethane versus silicone catheter (96.5% cases versus 79.9% controls; p = 0.001), and a rough catheter appearance at removal (92.6% cases versus 9.4% controls; p < 0.0001). A diagnosis of ALL and duration of line placement were associated with having a stuck port on multivariate analysis. CONCLUSION: Polyurethane central venous catheters placed for the two-year treatment of acute lymphoblastic leukemia may become difficult to remove. This constellation of factors warrants more extensive preoperative discussion of risk, endovascular backup availability, and scheduling for longer operating room time.