The repairs were tested by mounting the legs on a specially designed rig on a materials testing machine which allowed the leg to be cycled from 90° knee flexion to full extension. The specimens were cycled 1000 times at 0.25Hz or until the repair failed. Optical markers were attached to the leg which enabled the repair gap and knee angle to be monitored during testing (Smart Capture and Analyser Tracking system, Padua, Italy).
For all specimens regardless of repair type that completed 1000 cycles there was no significant difference in repair gap distance.
The box wire augmentation loop is key to maintaining patellar tendon repair. Krakow tendon sutures secured through patellar bone tunnels do not provide additional benefit to a simple appositional suture and box wire augmentation loop.
Ligamentous injury of the tarsometatarsal joint complex is uncommon but disabling. Injuries to individual ligaments can be visualised with MRI. The relative mechanical contribution of the three ligaments of the second TMTJ is unknown.
The second and third metatarsals and the first cuneiform were dissected from twenty pairs of cadaveric feet. In group I, seven pairs were submaximally loaded to determine stiffness with the dorsal, plantar, and Lisfranc ligaments intact. One of each pair underwent sectioning of the dorsal ligament and was then loaded to failure. In the contralateral specimen both plantar and Lisfranc ligaments were divided before retesting. In group II all 13 pairs underwent dorsal ligament excision and stiffness determination. One of each pair was randomly assigned to undergo sectioning of the plantar ligament, the other sectioning of the Lisfranc ligament, before retesting.
The Lisfranc ligament is stronger and stiffer than the plantar ligament. The dorsal ligament is weaker than the Lisfranc/plantar complex. This suggests that ligamentous injuries of the second tarsometatarsal joint may be considered stable if the Lisfranc ligament is intact – even if the other two ligaments are disrupted. If the Lis-franc ligament is injured then the complex is less stiff and may be unstable.
Type-I fractures of the lateral tibial plateau were simulated by osteotomy in 18 pairs of unembalmed cadaver tibiae. One fracture of each pair was fixed with two lag screws whereas the contralateral site was stabilised with three lag screws, or two lag screws plus an antiglide screw. The lateral plateau was displaced downwards using a servohydraulic materials testing machine and the resulting force and articular surface gap were recorded. Yield load was defined as the maximum load needed to create a 2.0 mm articular offset at the fracture line. The yield loads of the three-lag-screw (307 ± 240 N) and antiglide constructs (342 ± 249 N) were not significantly different from their two-screw control constructs (231 ± 227 and 289 ± 245 N, respectively). We concluded that adding an antiglide screw or a third lag screw did not provide any biomechanical advantage in stabilising these fractures.
