Summary. Arthroscopic decompression of the lunate decreases clinical symptoms and slows progression of Kienböck's Disease. Introduction. The purpose of this study was to investigate the outcomes of patients suffering from avascular necrosis of the lunate, or Kienböck's Disease, who received arthroscopic decompression to treat the ischemic lunate. Previous studies have demonstrated an elevated intraosseus pressure in the ischemic lunate, and it has been hypothesised that ischemia in the lunate is secondary to this elevated pressure and subsequent venous congestion, as opposed to diminished arterial supply. Based on this work we have used decompression of the lunate to prevent progression of the disease. Patients and Methods. 21 patients, (22 wrists), reported to a single surgeon with a chief complaint of unremitting wrist pain and the subsequent diagnosis was Kienböck's disease, stages I, II, IIIA or IIIB. Range of motion measurement and grip strength, as well as self-reported outcome measures such as Disabilities of the Arm, Shoulder and Hand (DASH) and Modified Mayo, were obtained preoperatively and post operatively at 2, 7 and 12 months. The patients were treated operatively with arthroscopic decompression of the lunate. The lunate was approached dorsally at the interosseous lunotriquetral and the scapholunate ligament areas with an arthroscopic shaver until brisk bleeding was achieved upon deflating the tourniquet. In some cases, the core of the lunate had to be penetrated with a 45 k-wire until bleeding was obtained. Of the 22 wrists treated arthroscopically with lunate decompression, 18 had both pre-surgical and post-surgical follow-up evaluations. Results. The patients who underwent lunate arthroscopic decompression surgery demonstrated a statistically significant improvement in DASH score at 7 and 12 months postoperatively (p<0.05). The preoperative DASH score average for this cohort was 51, while post-operative DASH scores averaged 23 and 17 at 7 and 12 months, respectively. The patients also demonstrated some overall improvement in pain, functionality, range of motion, and grip strength as demonstrated by the Modified Mayo wrist score. Notably, the patients demonstrated statistically significant improvement in grip strength post-operatively at 7-months (p<0.05) and 12-months (p<0.01). In addition, there was noted to be improvement in supination and ulnar deviation measurements post-operatively at 7 months and 12 months, respectively. Conclusion. This study demonstrates the clinical outcome of arthroscopic decompression of the lunate in patients suffering from Kienböck's Disease using the patient's subjective evaluations as well as range of motion and grip strength measurements. Arthroscopic decompression of the lunate decreases clinical symptoms and slows progression of Kienböck's Disease using a less invasive surgical intervention

Introduction. Kienböck's disease is generally defined as the collapse of the lunate bone, and this may lead to early wrist osteoarthritis. Replacing the collapsed lunate with an implant has regained renewed interest with the advancing technology of additive manufacturing, enabling the design of patient-specific implants. The aims of this project are (1) to determine how accurate it is to use the contralateral lunate shape as a template for patient-specific lunate implants, and (2) to study the effects of shape variations wrist kinematics using 4D-computed tomography (CT) scanning. Methods. A 3D statistical shape model (SSM) of the lunate was built based on bilateral CT scans of 54 individuals. Using SMM, shape variations of the lunate were identified and the intra- and inter-subject shape variations were compared by performing an intraclass correlation analysis. A radiolucent motor-controlled wrist-holder was designed to guide flexion/extension and radial/ulnar deviation of ex vivo wrist specimens under 4D-CT scanning. In this pilot, three shape mode variations were tested per specimen in two specimens were. After post-processing each CT, the scapholunate angle (SLA) and capitolunate angle (CLA) were measured. Results. The shape of the lunate was not symmetrical, defined as exceeding the intra-subject variation in five different shape modes. The FE tests show a generalized increase in scapholunate and capitolunate angle when using lunate implants, and comparing variation of shape modes showed that shape mode 3 has a significant effect on the measured angles (p<0.05). Discussion. The design of patient-specific lunate implants may prove to be challenging using a ‘mirror’-design as it will lead to a degree of shape asymmetry. The pilot study, to determine the effects of those shape variations on wrist kinematics suggest that the degree of shape variation observed indeed may alter the wrist kinematics, although this needs to be further investigated in study using more specimens

We assessed carpal collapse by measuring the capitate-radius (CR) distance on standard plain radiographs. This new method required validation of diagnostic accuracy, so we compared it with the method of Nattrass et al. 1. known as revised carpal height (RCH). We studied wrist radiographs from 16 normal subjects and 11 patients with unilateral Kienböck’s disease. We found that there was a significant difference in the left/right CR index between the normal wrists and those with Kienböck’s disease (p < 0.001). The use of left/right RCH index showed no significant difference (p = 0.30). Diagnostic accuracy was shown to be higher for the CR index using ROC curves. We then assessed 40 normal wrists and found the mean CR index to be 0.999 ± 0.034, and suggest that values less than 0.92 are abnormal. The CR index can be used for diagnosis in unilateral carpal collapse, and for monitoring progress where the condition is bilateral

Repeated trauma to the radial head may be one of the causative factors in the genesis of osteochondritis dissecans of the capitellum. We measured the force, contact area and pressure across the radiocapitellar articulation of the elbow before and after radial shortening osteotomy in five fresh-frozen cadaver upper limbs with loads of 45, 90 and 135 N, respectively. Measurements were made on pressure-sensitive film placed in the radiocapitellar articulation with the forearm in the supinated, neutral and pronated positions before and after radial shortening. Radial shortening significantly reduced the mean force and contact area across the radiocapitellar articulation in all positions of the forearm.