There is currently no commercially available and clinically successful treatment for scapholunate interosseous ligament rupture, the latter leading to the development of hand-wrist osteoarthritis. We have created a novel biodegradable implant which fixed the dissociated scaphoid and lunate bones and encourages regeneration of the ruptured native ligament. To determine if scaphoid and lunate kinematics in cadaveric specimens were maintained during robotic manipulation, when comparing the native wrist with intact ligament and when the implant was installed.

Ten cadaveric experiments were performed with identical conditions, except for implant geometry that was personalised to the anatomy of each cadaveric specimen. Each cadaveric arm was mounted upright in a six degrees of freedom robot using k-wires drilled through the radius, ulna, and metacarpals. Infrared markers were attached to scaphoid, lunate, radius, and 3rd metacarpal. Cadaveric specimens were robotically manipulated through flexion-extension and ulnar-radial deviation by ±40° and ±30°, respectively.

The cadaveric scaphoid and lunate kinematics were examined with 1) intact native ligament, 2) severed ligament, 3) and installed implant.

Digital wrist models were generated from computed tomography scans and included implant geometry, orientation, and location. Motion data were filtered and aligned relative to neutral wrist in the digital models of each specimen using anatomical landmarks. Implant insertion points in the scaphoid and lunate over time were then calculated using digital models, marker data, and inverse kinematics. Root mean squared distance was compared between severed and implant configurations, relative to intact.

Preliminary data from five cadaveric specimens indicate that the implant reduced distance between scaphoid and lunate compared to severed configuration for all but three trials.

Preliminary results indicate our novel implant reduced scapho-lunate gap caused by ligament transection. Future analysis will reveal if the implant can achieve wrist kinematics similar to the native intact wrist.

Total ankle arthroplasty is used as a treatment for end stage arthritis of the ankle.

Surgical techniques highlight risk of injury to anterior neurovascular structures. No literature highlights injury risk to the posterior neurovascular structures in ankle replacement surgery. Current literature consists of cadaveric study in relation posterior ankle arthroscopy.

A retrospective review was done of ankle MRI's, performed by the senior author in his practice. Studies were included in the study where there was no pathology of the posterior ankle present. Axial, coronal and sagital T1 weighted films were reviewed and measurements of the posterior neurovascular structures and tendons were made in relation to the posterior tibia and medial malleolus in relation to planned tibial and talar cutting planes.

A total of seventy-eight MRI's were included in the study (ages ranged from 22 to 78 years). There were 40 females and 38 males. At the level of the tibial cut the tibial nerve and artery were between two to six millimeters from the posterior surface of the tibia. The flexor hallucis longus (FHL) is located in the midline between the medial malleolus and fibula, closely related to the posterior tibial surface. The flexor digitorum longus (FDL) tendon is located in the posterior medial corner of the ankle. There is a window approx ten millimeters wide between where the neurovascular structures lie between the FDL and FHL tendons. At the level of the talus cut the tibial nerve and artery were between five to 11 mm from the posterior body of the talus.

A similar window is present at this level where the neurovascular structures lie between the FDL and FHL tendons.

The neurovascular structures of the ankle are potentially at risk during the tibial and talar bone resection. They are most at risk with the transverse cut of the tibia. This may be decreased by preventing direct pressure over these structures during bone resection.

Clinical screening aims to identify and treat infants with neonatal hip instability in order to reduce the risk of subsequent hip displacement but risks failures of diagnosis and treatment (abduction splinting) and potential iatrogenic effects. The Hip Trial aims to assess the clinical effectiveness of ultrasound (US) imaging compared to clinical assessment alone to guide the further management of infants with clinical hip instability.

Infants with clinical hip instability confirmed by a second senior doctor were recruited from 33 UK centres and randomised to standardised US hip examination at age 2–8 weeks [US group: n=314] or clinical assessment alone [no ultrasound (NU) group: n=315. ] Primary outcomes by two years were hip X-ray appearances, operative treatment, abduction, splinting and walking. Analysis was ‘intention to treat’.

Key prognostic factors were similar between the randomised groups. Protocol compliance was high (90% US; 92% NU). X-ray information was available for 91% by 12–14 months and 85% by two years. Fewer children in the US group had abduction splinting in the first two years (RR 0. 78; 95% CI 0. 65–0. 94; p=0. 01). Operative treatment was required by 21 US (6. 7%) and 25 NU (7. 9%) infants (RR 0. 84; 95% CI 0. 48–1. 47. ) By two years, subluxation, dislocation, acetabular dysplasia or avascular necrosis were identified on X-ray on one or both hips of 21 US and 21 NU children (RR 1. 00; 95% CI 0. 56 – 1. 80. ) One US and 4 NU children were not walking by two years (RR 0. 25; exact 95% CI 0. 03–2. 53; p=0. 37)

The use of US imaging in infants with screen-detected clinical hip instability allows abduction splinting rates to be reduced, and is not associated with an increase in abnormal hip development or higher rates of operative treatment by two years of age.