Role of the posterior deep deltoid ligament in ankle fracture stability: A biomechanical cadaver study

BACKGROUND The deltoid ligament is a key component of ankle fracture stability.Clinical tests to assess deltoid ligament injury have low specificity.In supination externalrotation(SER)type-IV ankle fractures,there is either a medial malleolus fracture or deltoid ligament injury.These injuries are often considered unstable,requiring surgical stabilisation.We look to identify the anatomical basis for this instability.This study investigates the anatomical basis for such instability by re-creating SER type ankle fractures in a standardised cadaveric study model,investigating the anatomical basis for such instability.AIM To investigate the anatomical basis for fracture instability in SER type ankle fractures.METHODS Four matched pairs of cadaveric limbs were tested for stability both when axially loaded and under external rotation stress.Four matched pairs of cadaveric limbs(8 specimens)were tested for stability when axially loaded to 750 N with a custom rig.Specimens were tested through increasing stages of SER injury in a stepwise fashion before restoring the lateral side with open reduction and internal fixation(ORIF).Clinical photographs and radiographs were recorded at each step.We defined instability in accordance with well accepted radiological parameters:>4 mm medial clear space opening on a mortise-view radiograph or>7 degrees of talar tilt.RESULTS All specimens with an intact posterior deep deltoid ligament were stable.Once the posterior deep deltoid ligament was sectioned there was instability in all specimens.Stabilisation of the lateral side prevented talar shift,but not talar tilt.CONCLUSION If the posterior deep deltoid ligament is intact then SER fractures can be managed without surgery.If the posterior deep deltoid is incompetent,ORIF and cautious rehabilitation is recommended because the talus can still tilt in the mortise.

Anatomic location of the first dorsal extensor compartment for surgical De-Quervain’s tenosynovitis release:A cadaveric study

BACKGROUND De-Quervain’s tenosynovitis is a disorder arising from the compression and irritation of the first dorsal extensor compartment of the wrist.Patients who fail conservative treatment modalities are candidates for surgical release.However,risks with surgery include damage to the superficial radial nerve and an incomplete release due to inadequate dissection.Currently,there is a paucity of literature demonstrating the exact anatomic location of the first dorsal extensor compartment in reference to surface anatomy.Thus,this cadaveric study was performed to determine the exact location of the first extensor compartment and to devise a reliable surgical incision to prevent complications.AIM To describe the location of the first dorsal compartment in relation to bony surface landmarks to create replicable surgical incisions.METHODS Six cadaveric forearms,including four left and two right forearm specimens were dissected.Dissections were performed by a single fellowship trained upper extremity orthopaedic surgeon.Distance of the first dorsal compartment from landmarks such as Lister’s tubercle,the wrist crease,and the radial styloid were calculated.Other variables studied included the presence of the superficial radial nerve overlying the first dorsal compartment,additional compartment subsheaths,number of abductor pollicis longus(APL)tendon slips,and the presence of a pseudo-retinaculum.RESULTS Distance from the radial most aspect of the wrist crease to the extensor retinaculum was 5.14 mm±0.80 mm.The distance from Lister’s tubercle to the distal aspect of the extensor retinaculum was 13.37 mm±2.94 mm.Lister’s tubercle to the start of the first dorsal compartment was 18.43 mm±2.01 mm.The radial styloid to the initial aspect of the extensor retinaculum measured 2.98 mm±0.99 mm.The retinaculum length longitudinally on average was 26.82 mm±3.34 mm.Four cadaveric forearms had separate extensor pollicis brevis compartments.The average number of APL tendon slips was three.A pseudo-retinaculum was present in four cadavers.Two cadavers had a superficial radial nerve that crossed over the first dorsal compartment and retinaculum proximally(7.03 mm and 13.36 mm).CONCLUSION An incision that measures 3 mm proximal from the radial styloid,2 cm radial from Lister’s tubercle,and 5 mm proximal from the radial wrist crease will safely place surgeons at the first dorsal compartment.

Bridge plating in the setting of radiocarpal instability:Does distal fixation to the second or third metacarpal matter?A cadaveric study

BACKGROUND Radiocarpal dislocations are rare but potentially devastating injuries.Poorer outcomes are associated with inadequate or lost reduction,such as ulnar translocation,but no consensus exists on the ideal fixation technique.Dorsal bridge plate fixation has been described for various settings in the treatment of complex distal radius fractures and can be fixed distally to the second or third metacarpal,but its application for radiocarpal dislocations has not been established.AIM To determine whether distal fixation to the second or third metacarpal matters.METHODS Using a cadaveric radiocarpal dislocation model,the effect of distal fixation was studied in two stages:(1)A pilot study that investigated the effect of distal fixation alone;and(2)a more refined study that investigated the effect of described techniques for distal and proximal fixation.Radiographs were measured in various parameters to determine the quality of the reduction achieved.RESULTS The pilot study found that focusing on distal fixation alone without changing proximal fixation results in ulnar translocation and volar subluxation when fixing distally to the second metacarpal compared with the third.The second iteration demonstrated that anatomic alignment in coronal and sagittal planes could be achieved with each technique.CONCLUSION In a cadaveric radiocarpal dislocation model,anatomic alignment can be maintained with bridge plate fixation to the second metacarpal or the third metacarpal if the described technique is followed.When considering dorsal bridge plate fixation for radiocarpal dislocations,the surgeon is encouraged to understand the nuances of different fixation techniques and how implant design features may influence proximal placement.

An anatomical comparison of two minimally invasive pelvic reconstructive surgeries using fresh female cadavers

Background During the past decade, graft materials have been widespread used in the vagina in order to correct pelvic organ prolapse. The aim of this study was to describe and compare the exact anatomical position of the puncture devices and their relations to the relevant anatomical structures in the ProliftTM and a modified pelvic reconstructive surgery with mesh. Methods Twelve fresh cadavers were allocated randomly to either the ProliftTM or the modified pelvic reconstructive surgery group. Each group had six fresh cadavers. Relevant distances between the puncture devices and anatomical structures were recorded in both minimally invasive puncture surgeries. Results The mean distances from the posterior puncture points of the obturator membrane to the posterior branch of obturator arteries were shorter （（0.60＋0.36） cm and （0.78＋0.10） cm） when compared with the distances to the anterior branch of obturator arteries （（1.53＋0.46） cm and （1.86＋0.51） cm） for the reconstruction of the anterior compartment in both surgeries （all P 〈0.05）. The distance from the puncture points of the pelvic floor through the ischiorectal fossa to the coccygeal and inferior gluteal arteries in the ProliftTM technique （（0.88＋0.10） cm） and （（1.59＋0.36） cm））were much shorter than that in the modified pelvic reconstructive surgery （（2.95＋0.09） cm） and （（3.40＋0,36） cm）） for the reconstruction of the middle and posterior compartments （all P 〈0.05）. Conclusions Compared with the ProliftTM technique, the modified pelvic reconstructive surgery with mesh would be safer not to cause great damage to the inferior gluteal arteries and the coccygeal arteries, The posterior branch of obturator arteries would be easier to be injured than the anterior branch of obturator arteries during anterior compartment reconstruction in both surgeries.