Subodh C. Deshmukh

Surgical treatment of complex distal humeral fractures: functional outcome after internal fixation using precontoured anatomic plates.

HYPOTHESIS Several studies have shown good results with internal fixation of distal humeral fractures; however, few have focused specifically on anatomic parallel plate fixation using the same implant and postoperative regimen. The purpose of this study was to determine the functional outcome after open reduction and internal fixation of these complex fractures using parallel precontoured anatomic plates. MATERIALS AND METHODS This was a retrospective single-surgeon series involving 16 patients (12 women, 4 men) treated with a double-column parallel plating technique. Clinical assessment included the Mayo Elbow Performance Score (MEPS) and Disabilities of the Arm, Shoulder and Hand Score (DASH). Mean age was 43 years (range, 20-78 years). Average follow-up was 35 months. Four fractures were AO type A and 12 were AO type C. RESULTS Union was achieved in all patients. There was no superficial or deep infection or hardware failure. Two patients required removal of plates for pain and prominence but not all screws could be completely removed. The mean flexion was 132 degrees and extension was 29 degrees . The mean DASH score was 46.1. Grip strength was 56% of the uninjured side. Mean flexion and extension force was 72% and 70%, respectively, of the uninjured elbow. The mean MEPS score was 72.3. DISCUSSION Anatomically precontoured parallel plates are effective in achieving bony union with low implant failure with acceptable functional outcomes. However, screw extraction can be difficult when the implant is removed.

Accuracy of direct magnetic resonance arthrography in the diagnosis of triangular fibrocartilage complex tears of the wrist

The aim of this study was to assess the value of direct magnetic resonance (MR) arthrography of the wrist for detecting full-thickness tears of the triangular fibrocartilage complex (TFCC). Twenty-four consecutive patients who had ulnar-sided wrist pain and clinical suspicion of TFCC tear were included in the study. All patients underwent direct MR arthrography and then wrist arthroscopy, and the results of MR arthrography were compared with the arthroscopic findings. The positive predictive value of MR arthrography in detecting TFCC full-thickness tear was 0.95, and the negative predictive value was 0.50. The sensitivity of MR arthrography in detecting a TFCC full-thickness tear was 74% (15/19), and specificity was 80% (4/5). The overall accuracy of MR arthrography in detecting a full-thickness tear of the TFCC in our study was 79% (19/24). We believe that diagnosis of tears in the TFCC by direct MR arthrography is not entirely satisfactory, although MR arthrography has a high positive predictive value for detecting TFCC tears. Negative results of MR arthrography in patients with clinical suspicion of TFCC tear should be interpreted with caution.

Biomechanical comparison of pull-out force of unicortical versus bicortical screws in proximal phalanges of the hand: a human cadaveric study.

BACKGROUND Bicortical fixation of proximal phalangeal fractures may damage underlying flexor tendons secondary to drilling and screw protrusion in the dorsal-ventral direction. The aim of this study was to measure and compare the pull-out force of unicortical screws compared to bicortical screws in human cadaveric proximal phalanges to identify optimal configuration for internal fixation. METHODS Forty proximal phalanges were harvested. Bicortical and unicortical self tapping 1.7mm screws were inserted into paired phalanges at the distal and proximal metaphysis and at the mid-diaphysis placed in the dorso-ventral direction. Pull-out force of unicortical and bicortical screws were measured and compared. FINDINGS Bicortical screw pull-out force is significantly higher than that of unicortical screws in the dorsal-ventral direction. Pull-out strength of unicortical screws at the mid-diaphysis was significantly higher than the pull-out strength of bicortical screws at the proximal metaphysis (181.8N versus 31.5N, P<0.0001). INTERPRETATION Diaphyseal fixation is stronger than metaphyseal for both unicortical and bicortical configurations. Unicortical mid-diaphyseal is stronger than bicortical proximal metaphyseal screw pull-out strength. This study provides biomechanical data that may be helpful for individualizing fracture fixation techniques at the proximal phalanx.

Patient satisfaction following carpal-tunnel decompression: a comparison of patients with and without osteoarthritis of the wrist.

The aim of this study was to assess whether surgical decompression for carpal-tunnel syndrome (CTS) in the presence of primary or secondary osteoarthritis of the wrist is associated with poorer patient satisfaction. We did a retrospective matched cohort study. Twenty-four patients who underwent surgical decompression for CTS secondary to osteoarthritis were identified by reviewing the notes and the radiographs. A control group consisted of 24 patients without osteoarthritis of the wrist who underwent carpal-tunnel decompression. The control group was matched for age, sex, side, and neuro-physiological severity of the nerve compression. In the group with osteoarthritis of the wrist, 17 (71%) patients reported their symptom relief as satisfactory, and 7 (29%) reported the results as unsatisfactory. In the control group, 23 (96%) patients reported their symptom relief as satisfactory, and 1 (4%) reported the results as unsatisfactory (P=0.0325). In conclusion, patient satisfaction following surgical decompression in patients with secondary CTS due to osteoarthritis was significantly lower compared to patients without osteoarthritis of the wrist.RésuméLe but de ce travail, à partir d’une étude rétrospective de 2 groupes appariés est de savoir si la décompression chirurgicale pour syndrome du canal carpien (SCC) en cas d’arthrose du poignet est associée à de mauvais résultats. 24 patients ayant eu cette intervention étaient identifiés sur dossiers et radiographies et comparés avec un groupe de 24 patients, sans arthrose du poignet, ayant eu la même intervention. Ce groupe de contrôle était apparié pour l’age, le sexe, le côté, et la sévérité neurologique de la compression. Dans le groupe avec arthrose 17 (71%) patients trouvent le résultat satisfaisant et les 7 autres (29%) le trouve insatisfaisant. Dans le groupe de contrôle 23 (96%) patients sont satisfaits et 1 (4%) est insatisfait (P=0.0325). En conclusion la satisfaction des patients opérés pour syndrome du canal carpien secondaire à une arthrose est nettement inférieure à celle ressentie chez les patients sans arthrose.

Using three-dimensional rapid prototyping in the design and development of orthopaedic screws in standardised pull-out tests

The majority of orthopaedic screws are designed, tested and manufactured by existing orthopaedics companies and are predominantly developed with healthy bone in mind. The timescales and costs involved in the development of a new screw design, for example, for osteoporotic bone, are high. In this study, standard wood screws were used to analyse the concept of using three-dimensional printing, or rapid prototyping, as a viable stage of development in the design of a new bone screw. Six wood screws were reverse engineered and printed in polymeric material using stereolithography. Three of the designs were also printed in Ti6Al4V using direct metal laser sintering; however, these were not of sufficient quality to test further. Both the original metal screws (metal) and polymeric rapid prototyping screws were then tested using standard pull-out tests from low-density polyurethane blocks (Sawbones). Results showed the highest pull-out strengths for screws with the longest thread length and the smallest inner diameter. Of the six screw designs tested, five showed no more than a 17% variance between the metal and rapid prototyping results. A similar pattern of results was shown between the screw designs for both the metal and rapid prototyping screws in five of the six cases. While not producing fully comparable pull-out results to orthopaedic screws, the results from this study do provide evidence of the potential usefulness and cost-effectiveness of rapid prototyping in the early stages of design and testing of orthopaedic screws.