The "Fight Bite" Saline Joint Loading Test: Effectiveness in Detecting Simulated Traumatic Metacarpophalangeal Arthrotomies.

Background: The saline load test is routinely used to recognize other joints' traumatic arthrotomies; however, there are currently no studies evaluating the novelty of this test for metacarpophalangeal joints (MCPJs). This study aimed to investigate the effectiveness and sensitivity of saline load testing in identifying the traumatic arthrotomies of the MCPJs using human cadavers. Methods: This was a cadaveric study of 16 hands (79 MCPJs). Traumatic arthrotomies were created using 11-blade stab-incisions, followed by blunt probing into the joint on the radial or ulnar side of the flexed MCPJs. A 3-mL syringe was used to inject intra-articular methylene-blue-dyed saline from the contralateral side. The volume at saline extravasation was recorded. Test sensitivity and factors influencing extravasation volume were assessed. Results: The mean (range) volume injected to identify arthrotomy of all MCPJs was 0.18 mL (0.1-0.4 mL). The mean volume to identify MCPJ arthrotomy of the thumb, index, long, ring, and small fingers was 0.16 mL (0.1-0.3 mL), 0.19 mL (0.1-0.3 mL), 0.21 mL (0.1-0.4 mL), 0.17 mL (0.1-0.3 mL), and 0.16 mL (0.1-0.3 mL), respectively. Cadaver age, laterality, and joint range of motion were not significantly associated with the injected volume at extravasation(P > .05, each). Injection volumes of 0.3 and 0.32 mL were required to detect arthrotomies at 95% and 99% sensitivities across all MCPJs. None of the MCPJs required > 0.4 mL to detect arthrotomy. Conclusions: Saline joint loading volumes to detect traumatic arthrotomy were similar for all MCPJs. Injection volumes of 0.32 mL is suggested for 99% sensitivity. Our findings provide the first report, to our knowledge, on intra-articular injection volumes expected to detect an arthrotomy of MCPJ. This is critical for further validation using in vivo clinical studies.

Wrist Arthrotomy Saline Load Test.

BACKGROUND: Failure to recognize a potential wrist arthrotomy may lead to missed septic arthritis and devastating sequelae. The saline load test is routinely used to recognize traumatic arthrotomies of other joints; however, there are limited data optimizing this test for the wrist. The purpose of this study was to investigate and perform saline load testing to identify traumatic arthrotomies of the wrist. METHODS: This was a cadaveric study of 15 wrists. Traumatic arthrotomies were created using a blunt trocar through the 3-4 portal. A 3-mL syringe with 0.1 mL markings was used to inject methylene blue dyed saline into the wrist through the 1-2 portal. Once extravasation was visible from the atherectomized site, the volume was recorded. RESULTS: The mean (range) volume injected to identify the arthrotomy of all wrists was 1.22 mL (range, 0.1-3.1 mL). Multivariate regression demonstrated that cadaver age, laterality, and extension range of motion were not significantly associated with the injected saline volume at extravasation (P > .05, each). Greater joint range of motion was independently associated with higher saline volume load for extravasation (odds ratio: 1.049; 95% confidence interval: 1.024-1.075; P = .003). CONCLUSIONS: We found that 2.68 and 3.02 mL of methylene blue dyed saline offered 95% and 99% sensitivity, respectively, for diagnosing traumatic wrist arthrotomy. The maximum volume of saline needed to recognize an arthrotomy was 3.1 mL. We recommend this be the minimum volume used to evaluate a traumatic wrist arthrotomy.

The Effectiveness of Saline Load Test in Detecting Simulated Traumatic Elbow Arthrotomies: A Cadaveric Investigation.

Background The saline load test has not been well explored in the elbow. We aimed to determine 1) the saline infusion volume needed for 90%, 95%, and 99% sensitivity in detecting elbow arthrotomy; and 2) factors associated with higher volume at detection using sixteen forequarter upper extremity amputation cadavers. Methods Sixteen fresh-frozen forequarter upper extremity amputations were procured, and demographic data, including age, body mass index (BMI), and laterality, were recorded. The olecranon process, radial head, and the lateral epicondyle were palpated, and elbow arthrotomy was consistently performed at the direct lateral arthroscopic portal site. The elbow joint was loaded with saline mixed with methylene blue (concentration: 2 mg/300 mL) using an 18-gauge needle inserted just medial to the triceps tendon 2 cm superior to the olecranon. Results Mean volume for extravasation was 12.2 mL ±6.26. Volume needed for 90%, 95%, and 99% sensitivities were 21 mL, 23 mL, and 25.4 mL. Linear regression demonstrated that increasing age was associated with lower volume to extravasation (OR: 0.67; 95% CI: 0.48-0.932; p=0.037), while BMI (p=0.571) and extremity laterality (p=0.747) did not affect the volume. Conclusions The saline load test can be effective in diagnosing the violation of the elbow joint in traumatic injuries. This test should be used in conjunction with the clinical examination and radiographs before operative decisions are made. We recommend using ≥26 mL to rule out traumatic elbow arthrotomy.

Dual Nonlocked Plating as an Alternative to Locked Plating for Comminuted Distal Fibula Fractures: A Biomechanical Comparison Study.

The purpose of this cadaveric study was to compare the biomechanical properties of dual nonlocked plating and single-locked plating using matched pairs of isolated fibula specimens. Fractures were simulated in 10 matched pairs of isolated cadaveric fibulae and plated with a single lateral locking plate for right-sided specimens, or with a one-third tubular plate and a 7-hole 2.4-mm minifragment adaption plate for left-sided specimens. An external rotation torque was applied at a rate of 1°/second, and torque at 10° was measured. Each fibula specimen was evaluated using a micro computed tomography scanner, and bone mineral density was calculated as milligrams of bone per cubic centimeter of volume. Dual nonlocked plating and locked plating specimens demonstrated torque measurements that were not significantly different at 10° of external rotation (1.48 N·m and 1.92 N·m, respectively; p = .093). The stiffness of the dual nonlocked plated and locked plating constructs were not significantly different (p = .228 and p = .543, respectively). The effect of bone mineral density on maximum torque at failure was not a reliable predictor of maximum torque in either the dual nonlocked plating or locked plating specimens (R2 = 0.548 and R2 = 0.096, respectively). We found no differences in torque at 10° of external rotation or stiffness between locking plate and dual nonlocking plate fixation constructs. This study provides evidence that dual nonlocked plating likely constitutes adequate fixation in situations in which a locking plate is being considered for comminuted distal fibula fractures.

Procurement of Extended Vascularized Skin Flaps from the Donor Enables Hand Transplantation in Severe Upper Extremity Burns: An Anatomical Study.

BACKGROUND: Hand transplantation in patients with severe upper extremity burns can be associated with an increased risk of exposure of vessels, tendons, and nerves because of extensive skin and soft-tissue deficit. This study evaluated how to reliably transfer additional extended skin flaps with a standard hand allograft. METHODS: Twenty-five upper extremities were used. Sixteen were injected with latex to map the perforating branches of the brachial, superior ulnar collateral, radial, ulnar, and posterior interosseous arteries. Nine hand allografts were procured, injected with blue ink through the brachial artery to assess the perfusion of the skin flaps, and then mock transplanted. RESULTS: Sizable perforators from the brachial, superior ulnar collateral, radial, ulnar, and posterior interosseous arteries were used to augment the vascularization of the skin flaps. The average stained area of the medial arm flap was between 85.7 and 93.9 percent. The stained area of the volar forearm flap was the smallest when based on perforators within 6 cm from the wrist crease (51.22 percent). The dorsal forearm flap showed the least amount of staining (34.7 to 46.1 percent). The average time to repair tendons, nerves, and vessels was longer when a single volar forearm-arm flap was harvested (171.6 minutes). Harvest of the allograft associated with a distally based forearm flap and islanded arm flap was the fastest (181.6 ± 17.55 minutes). CONCLUSION: Extended skin flaps, based on perforators of the main axial vessels, can be reliably transplanted with a standard hand allograft based on the brachial or axillary vascular pedicle.