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Extensor Carpi Radialis Longus (ECRL) avulsion is a rare injury which follows resisted wrist hyperflexion. Treatment of this condition with open reduction and internal fixation is not previously described in the literature, and treatment with plaster immobilisation or k-wire fixation requires a prolonged period of immobilisation. We believe that open reduction and internal fixation of these fractures with early mobilisation will result in the best possible wrist function. We describe a sign to raise the index of suspicion for this injury: a palpable bone lump on the dorsum of the hand in the presence of wrist extensor pain or weakness after wrist hyperflexion injury is a sign of wrist extensor avulsion.

The purpose of this short communication is to present an animal model that: (1) allows for controlled, quantifiable loading of muscle and tendon; and (2) can be used to evaluate the response of musculo-skeletal tissues to chronic loading. A loading apparatus was used to move the rabbit foot through any desired angular position and velocity, while continuously measuring moments about the transverse axis of the ankle. A stimulator was triggered at a pre-set location in the range of motion to produce a contraction of the triceps surae and plantaris muscles. Muscle forces measured with an Achilles tendon force transducer were found to correlate well with externally measured ankle extensor moments. The experimental setup was used to provide cyclic loads to the triceps surae and plantaris muscles and Achilles tendon of 16 rabbits for three loading sessions per week over the period of one to eleven weeks. The experimental model described here is appropriate for the systematic study of the adaptation of muscle and tendon to chronic loading because of the repeatability of the setup and the quantification of tissue loads.

Background: Flexor tendon repair failures have primarily been attributed to either core suture rupture or core suture pull out. Recent studies have suggested that knot unravelling may also cause failure of a tendon repair. The aim of this study was to investigate the causes of core suture failure in two types of common flexor tendon repairs.

Methods: Twenty four cadaver tendons were divided into three groups of eight. Each group tested a specific flexor tendon repair. The repairs tested included an Adelaide repair using 4/0 Ethibond (Ethicon), an Adelaide repair using 4/0 Fiberwire (Arthrex) and the Tsai repair with 4/0 Fiberloop (Arthrex). The repaired tendons were pull-tested to failure. The mechanism of failure, maximum tensile strength and 2 mm gap force were recorded.

Results: The predominant mode of failure was by the knot unravelling. This occurred in 50-88% of the tendon repairs. The sequence of failure was initiated with gapping at the repair site followed by failure of the epitendinous suture. Next the core suture knot unravels. Once the knot unravels, the suture thread slips out of the tendon resulting in the repair failure. Failures due to knot slippage occurred at a lower maximum tensile strength in Ethibond and Fiberloop sutures than failure due to core rupture or pull out. However, given the small number of tendons tested, this result was not significant.

Conclusions: This study has clearly demonstrated one of the main causes of flexor tendon repair failure in two common repair techniques is knot unravelling.

A 43-year-old female is presented who underwent a two-stage tendon reconstruction and developed a low ulnar nerve palsy postoperatively. Exploration found that the tendon graft was passing through Guyon’s canal and that the ulnar nerve was divided. This is a previously unreported complication. The reconstruction is discussed, the literature reviewed and a guide is given on how to identify the correct tissue plane when passing a tendon rod.

The conventional hand tendon zones and subzones do not reflect the actual lengths covered by the involved locus of the tendon during full digital and wrist motion, which warrant reappraisal of the tendon zone concept. Because of the tendon excursions many lacerations should be regarded as multiple zone injuries. Furthermore, the length-spans of glide of the distal tendon stump and of the tendon junction (i.e. the glide zones of tendon injury and repair, respectively) are mostly not of the same length because, due to pulley release and bulkiness of the tenorrhaphy, the glide zone of tendon repair is shorter than that of tendon injury. Therefore, it would be practical to notate the glide zones of the lacerated tendon by indicating the anatomic position of the distal tendon stump and tendon junction in full extension and flexion. This data can be provided separately or along with the conventional tendon zones, e.g. II (A4–C2) or II–III (A2–PA), where A, C, and PA stand for the annular, cruciform, and palmar aponeurosis pulleys, respectively. The conventional tendon zone classification could be improved with a tendon glide zone concept. Documentation of the actual excursions of the distal tendon stump and of the tenorrhaphy interface would prevent misinterpretation of the actual level of tendon injury and repair.

Background: A stab incision and blunt dissection prior to wire placement are believed to decrease the risk of injury to underlying structures during percutaneous pinning of distal radius fractures (DRF). However, only a few studies have compared stab incision and blunt dissection to direct wire placement. The aim of this cadaveric study is to analyse the structures at risk during percutaneous pinning of DRF and compare the two methods of wire placement.

Methods: A total of 10 cadavers (20 upper limbs) were divided into two groups of five each. Five 2.0 mm Kirschner (K)-wires were inserted into the distal radius under fluoroscopic control in a standard fashion to simulate percutaneous pinning of DRF. In group 1, the K-wires were inserted directly, whereas in group 2, the wires were inserted after making a stab incision and blunt dissection to reach the bone. Each cadaveric limb was then dissected carefully to measure the distance of the K-wires from the branches of the superficial radial nerve (SRN), the cephalic vein and the first dorsal compartment and to determine the structures injured (pierced or in close contact) by the K-wires.

Results: Out of the 100 K-wires placed, 18 wires were in close contact or pierced an underlying structure. These included 11 wires injuring tendons, six wires injuring branches of the SRN and one wire injuring the cephalic vein. Direct wire placement (group 1) resulted in injury to eight structures (44.4%) while stab incision and blunt dissection prior to wire placement (group 2) resulted in injury to 10 structures (55.5%). This difference was not statistically significant.

Conclusions: Percutaneous pinning of DRF is associated with a high risk of injury to the extensor tendons and branches of the SRN. This risk is not reduced by making a stab incision and blunt dissection prior to K-wire placement.

The best treatment for mallet fingers is still a matter of debate. Numerous splints with different designs to keep the distal interphalangeal (DIP) joint in extension have been described in literature. The outcomes of splint treatment are generally good with occasional reports of minor skin complications. Percutaneous Kirschner-wire pinning of the DIP joint for closed tendinous mallet finger represents a alternative treatment modality that reliably immobilises the joint and does not need much patient compliance or use of an external splint. We report a rare but devastating complication of percutaneous pinning of the DIP joint for closed tendinous mallet finger.

Level of Evidence: Level V (Therapeutic)

Background: Little is known regarding the effect timing of repair has on extensor tendon repair results. The purpose of this study is to determine if a relationship exists between the time of extensor tendon injury to extensor tendon repair and patient outcomes.

Methods: A retrospective chart review was conducted on all patients that underwent extensor tendon repair at our institution. The minimum time to final follow-up was 8 weeks. Patients were then divided into two cohorts for analysis; those that underwent repair less than 14 days after injury and those that underwent extensor tendon repair at or greater than 14 days after injury. These cohorts were further sub-grouped by zone of injury. Data analysis was then completed using a two-sample t-test assuming unequal variance and ANOVA for categorical data.

Results: A total of 137 digits were included in final data analysis, with 110 digits repaired less than 14 days from injury and 27 digits in the greater than or equal to 14 days to surgery group. For zones 1–4 injuries, 38 digits were repaired in the acute surgery group and eight digits in the delayed surgery group. There was no significant difference in final total active motion (TAM) (142.3° vs. 137.4°). Final extension was also similar between the groups (2.37° vs. 2.13°). For zones 5–8 injuries, 73 digits were repaired acutely, and 13 digits were repaired in delayed fashion. There was no significant difference in final TAM (199.4° vs. 172.7°). Final extension was also similar between the groups (6.82° vs. 5.77°).

Conclusions: We found time from extensor tendon injury to surgical repair did not affect final range of motion when comparing acute repair within 2 weeks from injury or delayed repair greater than 14 days from injury. Additionally, there was no difference in secondary outcomes, such as return to activity or surgical complications.

Level of Evidence: Level IV (Therapeutic)