Olecranon Tip Research Articles

The shape match of the olecranon tip for reconstruction of the coronoid process: influence of side and osteotomy angle

The integrity of the coronoid process is critical to maintaining elbow stability. Unreconstructible fractures and chronic coronoid deficiency are challenging clinical problems with no clear solution. The purposes of this study were to investigate the shape match of the ipsilateral and contralateral olecranon tips as graft options and to determine the influence of the osteotomy angle on fitment. Nineteen paired cadaveric elbow joints were investigated by 3-dimensional digital analysis of computed tomography DICOM (Digital Imaging and Communications in Medicine) data. After construction of an ulnar coordinate system, the ipsilateral and contralateral olecranon tips were digitally harvested at 10°, 20°, 30°, 40°, 50°, and 60° osteotomy angles. In an overlay analysis, we compared the shape match of the ipsilateral and contralateral grafts and the different angles. The ipsilateral grafts showed an average mismatch of 1.8 mm (standard deviation, 1.38 mm), whereas the contralateral grafts had a significantly lower (P < .001) mean mismatch of 1.3 mm (standard deviation, 0.95 mm). The 50° osteotomy plane showed the best shape match in comparison with the native coronoid-in both the ipsilateral and contralateral grafts. Evaluation of the intraclass correlation coefficient was calculated at r = 0.944, showing high repeatability of the measurements. The contralateral olecranon tip graft showed significantly better shape matching to the native coronoid than the ipsilateral olecranon graft. Specifically, the contralateral graft more closely matched the biomechanically critical anteromedial coronoid facet. Finally, both the contralateral and ipsilateral olecranon grafts had better shape matching with the native coronoid when osteotomy was performed at higher angles, specifically 50°.

A Model for Stature Prediction from Percutaneous Ulnar Length in Adult Males of Tamil Population

The objective of this study was to derive a linear regression formula for determination of stature from right and left ulnar length in males belonging to Tamil population. The subjects consisted of 112 adult Tamil males in the age group of 21 to 30 years. With the help of digital sliding caliper, length of each side ulna was measured between tip of olecranon process and tip of styloid process and for stature, using the stadiometer, the subject was asked to stand barefooted in anatomical position and distance from heel to vertex measured. The data thus collected was statistically analyzed with SPSS software (version 23) and a population specific regression equation for stature pertaining to length of right and left ulna derived respectively and statistically compared with that of other Indian populations and found to be unique for this study population group and therefore, this will be a tool of much significance for anthropologists, forensic experts and archaeologists when dealing with mutilated forearm remains from deceased Tamil males where necessity of stature estimation for identification arises.

Optimization of Anterior Incision Placement for Distal Biceps Repair.

IntroductionDamage to the posterior interosseous nerve (PIN) is a known complication when using a cortical button during distal biceps tendon repair. Prior studies show that the trajectory of the drill through the biceps tuberosity can affect the distance from the PIN. We develop a mathematical model to predict the location of the tuberosity based on a palpable bony landmark and patient demographic factors.MethodsThe medical charts and elbow radiographs of (n = 82) adult patients were retrospectively reviewed. Using standard radiographic software, two observers measured the distance from the olecranon tip to the center of the biceps tuberosity. Multivariate regression analysis was used to build a linear model. The model was cross-validated with five arms from three distinct cadavers. A surgical wire was guided into the volar aspect of each forearm using the model, and a dissection was then performed to assess the proximity of the surgical wire to the insertion of the biceps tendon on the radial tuberosity.ResultsOlecranon-tuberosity distance (OTD) ranged from 52.3 mm to 77.2 mm (mean 66.5 mm). Univariate analyses revealed males had significantly longer OTD (mean 69.3 mm) compared to females (mean 61.2 mm, t-test, p < 0.001). Increased body mass index (BMI) weakly correlated with increased distance (Pearson’s r = 0.22, p = 0.048). Height showed strong positive correlation with increased distance (r = 0.77, p < 0.001). Multivariate regression revealed that significant predictive factors for olecranon-tuberosity distance were height (coefficient = 35.8, p < 0.001), BMI (coefficient = 0.14, p = 0.032), and male sex (coefficient = 3.17, p = 0.0039). The average error in the cadaveric validation, measured as distance from the surgical wire to the distal biceps insertion was 1.8 mm.ConclusionA highly accurate mathematical model can be used to predict the location of the biceps tuberosity in relation to the palpable tip of the olecranon, based only on height, BMI, and sex of the patient. Knowledge of this distance can guide accurate placement of the skin incision when a transverse single-incision approach is utilized for repair of the distal biceps tendon using a cortical button. Diagnostics showed the model to be less accurate near the extremes of the measurement. Since patients with a target incision point far removed from average would most benefit from such a model, we will continue by identifying and enrolling patients at the low and high ends of the range. We further hypothesize that the technique described above could be similarly applied to benefit other procedures.

Topographic Analysis of 2 Alternative Donor Sites of the Ipsilateral Elbow in the Treatment of Capitellar Osteochondritis Dissecans

To find the best topographic subchondral bone match between the capitellum and 2 proposed alternative donor sites of the ipsilateral elbow for capitellar osteochondral autologous transplantation: the non-articulating part of the radial head and the lateral olecranon tip. In our retrospective database, 20 patients with an unremarkable computed tomography scan of the elbow despite clinical suspicion were identified for analysis. Included were patients aged 11 to 20years with intact osseous structures and a computed tomography slice thickness of 1.25mm or less. Three-dimensional polygon models were created using a standard predefined threshold, after which 4 articular surface lesions on the capitellum were created: central 40°, central 60°, lateral 40°, and lateral 60°. In addition, 3 donor locations on the non-articulating part of the radial head (diameter, 5mm) and the lateral olecranon tip (diameter, 3.5mm) were created. For each of 24 donor-recipient combinations, the donor graft surface was virtually placed on the recipient surface to quantify the mean distance between surfaces. The group of 20 patients consisted of 16 male and 4 female patients with a mean age of 15.9years (range, 12-18years). For a central 40° lesion, the mean distance across all 6 donor-recipient combinations ranged from 0.085 ± 0.023 to 0.118 ± 0.036mm; for a central 60° lesion, the mean distance ranged from 0.075 ± 0.018 to 0.117 ± 0.062mm; for a lateral 40° lesion, the mean distance ranged from 0.087 ± 0.030 to 0.182 ± 0.226mm; and for a lateral 60° lesion, the mean distance ranged from 0.084 ± 0.048 to 0.115 ± 0.045mm. There were no differences in topographic matching between donor-recipient combinations. The findings of this study show a less than 0.2-mm difference in the topographic subchondral bone match between 4 common lesion locations on the capitellum and 2 alternative donor sites of the ipsilateral elbow for capitellar osteochondral autologous transplantation: the non-articulating part of the radial head and the lateral olecranon tip. These findings suggest that the non-articulating part of the radial head and the lateral olecranon tip may potentially be used as a donor source when treating capitellar osteochondritis dissecans.

Biocatalysis in Organic Synthesis: The Retrosynthesis Approach

The knee or rib has been used routinely as a donor site for capitellar osteochondral autologous transplantation (osteoarticular transplantation) procedures with promising results. However, donor-site morbidity is a bitter truth that has led surgeons to pursue alternatives to the ipsilateral elbow. The non-articulating radial head and the lateral olecranon tip show acceptable topography and histology. However, size limitations require additional and clinical study.

The distal triceps tendon insertional anatomy—implications for surgery

BackgroundImproved knowledge of the distal triceps insertion is needed as a result of an increase in procedures involving this area, including distal triceps repair, posterior capsulectomy, and olecranon tip osteotomy for coronoid reconstruction.Materials and methodsFive pair-matched upper limbs were dissected to study the morphology and dimension of the distal triceps tendon, triceps tendon insertion, capsular insertion on the olecranon, and triceps lateral retinaculum. Muscle origins of the triceps insertions were identified proximally.ResultsThree distinct insertional areas were found in the olecranon corresponding to the posterior capsular insertion, the deep muscular portion, and the superficial tendinous portion of the triceps with areas of 1.5, 1.2, and 2.8 cm2, respectively. The deep muscular head corresponded to the medial head of the triceps and the tendinous portion corresponded to the long and lateral heads and correlated with the height of the specimen. The triceps width at insertion was 2.6 ± 0.5 cm (standard deviation), and the triceps lateral retinaculum extended the tendon laterally for 2.5 ± 0.7 cm. The tendinous portion of the triceps tendon extended proximally 15.3 ± 1.4 cm. The triceps inserted at a mean of 1.1 cm from the tip of the olecranon.ConclusionsThe distinct insertional heads of the triceps provides additional knowledge that can aid in diagnosing and treating partial triceps tears. In addition, a safe zone for capsulectomy and olecranon tip osteotomy is described that can be used to increase the safety of these procedures.

Ultrasound-guided Cubital Tunnel Injection: Description of Technique and Accuracy in a Cadaver Model

ABSTRACT Introduction: Ulnar nerve (UN) and cubital tunnel morphology is influenced by elbow positioning, potentially compromising injection accuracy and placing the nerve at risk during cubital tunnel injection. Materials and methods: Based on previous anatomical studies of the cubital tunnel, a proof of concept injection model was developed. Eighteen above-elbow cadaver specimens were positioned in 45° elbow flexion and in neutral forearm rotation. The ultrasound transducer was oriented in the transverse plane, in-line with the medial epicondyle and olecranon tip, facilitating visualization of the UN and cubital tunnel. A 25-gauge needle oriented parallel to the ulna was inserted percutaneously at the midpoint between olecranon and epicondyle. The needle was advanced under ultrasound guidance to replicate injection and was secured. Open dissection confirmed its location. Results: 18/18 needle tips were within the cubital tunnel and no needles penetrated the UN. Discussion: Ultrasound-guided cubital tunnel injection, with the elbow in 45° flexion and with neutral forearm rotation was a safe and reliable technique in this cadaveric model. Future clinical studies may evaluate the efficacy of both diagnostic and therapeutic cubital tunnel injection. Nickel BT, Richard MJ, Cotterell I, Crosmer M, Ruch DS, Leversedge FJ. Ultrasound-guided Cubital Tunnel Injection: Description of Technique and Accuracy in a Cadaver Model. The Duke Orthop J 2017;7(1):43-45.

Valgus extension overload syndrome in adolescent baseball players: clinical characteristics and surgical outcomes

Little is known about the clinical characteristics and surgical outcomes of valgus extension overload syndrome (VEOS) in adolescent athletes. We evaluated posteromedial compartment pathology, including combined lesions, and reported the surgical outcomes in adolescent baseball players. We retrospectively reviewed the medical records of 13 male adolescent baseball players (mean age, 15.4 years) who underwent arthroscopic olecranon tip resection (n = 9) or staged operations (arthroscopic olecranon tip resection, followed by medial collateral ligament reconstruction 2 weeks later; n = 4). The shape of the tip fragment was used to classify the olecranon into 2 types: type 1, dot-like fragment (n = 3); type 2, triangular-shape fragment (n = 10). Four outcome measures were analyzed: range of motion, visual analog scale (VAS) pain score, rate of return to play, and Conway scale score. At a mean follow-up of 3.3 years (range, 2-6 years), the mean VAS pain score decreased from 4.1 preoperatively to 1.1 postoperatively (P < .05). Preoperative mean extension and supination were 4.2° and 70.0°, which improved to 1° (P < .05) and 76.2° (P < .05), respectively. The overall rate of return to play was 85% (11 of 13). On the Conway scale, 8 of 13 patients (62%) were classified as excellent. Patients who underwent isolated arthroscopic surgery reported less pain postoperatively and achieved a higher grade on the Conway scale than patients who underwent staged operations. Arthroscopic resection of olecranon tip yielded favorable outcomes at a minimum of 2 years of follow-up. Patients with concomitant ulnar collateral ligament insufficiency had less optimal outcomes than those with isolated posteromedial impingement.

Dynamic Ulnar Deviation Deformity of Wrist Due to Post Infective/Posttraumatic Contracture of Isolated Musculotendinous unit—A Report of Two Unusual Cases

Keywords Extensor carpi ulnaris.Flexor carpi ulnaris.Z PlastyIntroductionDeformities at wrist are commonly attended in an orthope-dic outpatient department. The causes in young rotatearound epiphyseal plate growth disturbances, which may becongenital as in madelung deformity or acquired afterinfection, trauma or tumor. Shortening of extensor carpiulnaris (ECU) musculotendinous unit as sequelae ofinfection or flexor carpi ulnaris (FCU) musculotendinousunit as sequelae of trauma leading to a dynamic wristdeformity has not been reported in literature yet.Case reportCase 1 A 15 years old male presented with c/o deformity(ulnar deviation) of left wrist for last 6 years. Patient wasapparently all right 6 years back when he suffered trauma todorso ulnar aspect of left upper forearm followed bydevelopment of an abscess, which was incised and drainedby a local practitioner. Patient started developing ulnardeviation at left wrist which kept on progressivelyincreasing (it has been static for last 1 year). Patient hadsome functional disability as a result of this deformity, inparticular, in picking up objects and holding glass (glassholding requires radial deviation at wrist). However thepower grip (in ulnar deviation of hand) was normal. Therewas no complaint of any numbness or weakness.On local examination a 5 cm×2 cm scar was seen ondorso-ulnar aspect of upper 1/3rd of left forearm (i.e. thesite of previous I&D) (Fig. 1a). There was fixed ulnardeviation deformity of left wrist—45° (Fig. 1b). The rangeof supination and pronation was full. Range of motion ofelbow was full and painless. Dorsiflexion and palmarflexion were 80° and 90° respectively. No radial deviationwas possible. Ulnar deviation ranged from 45° to 60° withwrist in neutral dorsi/palmar flexion. On attempt at activeulnar deviation and dorsiflexion by the patient contractionof ECU muscle belly could be felt. Ulnar lengths measuredfrom olecranon tip to ulnar styloid and radial lengths fromradial head to radial styloid were bilaterally symmetricaland hence normal.Ulnar deviation deformity at wrist manifested itselfcompletely on palmar flexion but disappeared on dorsi-flexion (60° ulnar deviation deformity on palmar flexionand no ulnar deviation deformity on dorsiflexion) (Fig. 1cand d) .ECU tendon got taut and became prominent onattempted radial deviation (Fig. 1e).This is a fixed length phenomenon suggestive ofshortened ECU. No neurovascular deficit was found. X-rays of bilateral wrist and left elbow with forearm werenormal. A provisional diagnosis of left ECU contracturewith dynamic ulnar deviation deformity of left wrist wasmade.Written informed consent was taken from the patient andhis parents for surgery and they were also informed that thiscase will be considered for publication in some scientificjournal including electronic publication on the internet.

Two cases of reconstruction of the coronoid process using the tip of the ipsilateral olecranon

Two cases of reconstruction of the coronoid process using the tip of the ipsilateral olecranon

A study to evaluate importance of length from tip of olecranon to the tip of little finger in pre-operative assessment of K-nail in fracture shaft of femur in a tertiary care hospital of Bareilly district

Background: The magnitude of incidence of femoral shaft fracture is approximately 15-20 fractures per 1,00,000 person years. Most commonly intramedullary nailing is preferred for adult femoral shaft fracture. The objective of this study was to assess the intra-medullary femoral nail length in adults by various methods in fracture shaft of femur and to access correlation between these lengths. Methods: Study was conducted on 100 adult healthy volunteers including 41 males and 59 females attending the orthopaedic O.P.D of a tertiary medical college in North India. The length from tip of olecranon to the tip of little finger and the length from tip of the greater trochanter to the upper pole of patella of the same side were measured using a measuring tape on a couch. Results: Analysis showed that the mean length from tip of olecranon to the tip of little finger and the length from tip of the greater trochanter to the upper pole of patella of the same side were 42.175 (SD, 2.0641) and 42.093 (SD, 2.0846) respectively. The mean difference between these two measurements was 0.083 (95% CI, 0.020 to 0.145). The significant correlation was found between these 2 lengths i.e. 0.987 by Pearson co-relation (95% CI, 0.977 to 0.994) (p<0.001). Age, sex and body mass index did not affect this correlation. Conclusions: The length from the tip of the olecranon to the tip of the little finger correlated with the femoral length and is more convenient to perform and can also be used when the patient has sustained bilateral fractures of femur.

English

BACKGROUNDS AND OBJECTIVES: Sixty cases of fracture both bone forearm in adults were operated and fixed using various instruments in Narayana Medical College and Hospital, Nellore. The study period was June 2009 to June 2013. The case were followed up from four months to ten months. METHODS: Most of the cases were young adult male with age ranging between 17 to 73 years. The functional outcome of different modalities of surgical treatment of diaphyseal fracture of both bone forearm in adults are interpreted. We have fixed 17 patients with Dcp, 13 patients with Lcdcp, 14patients with Semitubular plating and 16 patients with Intramedullary nailing. Most cases were operated within three days of injury. Anaesthesia and Tourniquet was used for all cases. Thompsons approach was used for proximal radial fractures and Henrys approach was used for distal radial fractures. Ulna was exposed along its posterior border. Intramedullary nailing was done along radial syloid process and distal tip of olecranon in radius and ulna respectively. Closed reduction under C-arm in intramedullary procedure and open reduction and internal fixation when plating was done. Above elbow p.o.p slab were applied for all operated case. Sutures were removed at 10 th Post-operative day. Mobilization were started after suture removal in plating cases. In Intramedullary nailing cases mobilization started after clinical and radiological union. RESULTS: By Anderson Scoring System out of 14 cases of Dcp 75 %were excellent, 25% were satisfactory. Out of 11cases of Lcdcp 72.7% were excellent, 18.2% were satisfactory, 9.1% were unsatisfactory. Out of 13cases of Semitubular plating 69.2%were excellent, 23.1% were satisfactory, 7.7% were unsatisfactory. Out of 14 cases of Intramedullary nailing with Talwakar square nails 42.9% were excellent, 21.4% were satisfactory, 21.4% were unsatisfactory, 14.3%had failure results. INTERPRETATION AND CONCLUSION: Open reduction and internal fixation can be considered as the treatment of choice if there were no contraindications for this because it is important to maintain length, opposition, axial alignment and rotation alignment if a good range of movement of forearm is to be restored. This is achieved in the present study.

Olecranon tip osteoarticular autograft transfer for irreparable coronoid process fracture: a biomechanical study.

We hypothesized that transfer of the olecranon tip for simulated type III coronoid fracture would restore posterior ulnohumeral translation to a level not different from that in the intact state. The collateral ligaments were left intact in 12 fresh-frozen cadaveric elbows, and all other soft tissues were removed. The entire coronoid process was osteotomized flush with the ventral aspect of the ulna and was reconstructed using the tip of the olecranon process. Specimens were tested with an axial load of 100N at 0.25mm/s in 15° increments from 15 to 120° of flexion. Intact, osteotomized, and reconstructed posterior ulnohumeral displacement was measured. The bony reconstruction did not obstruct range of motion of the elbow. Intact translation (mean ± SD) ranged from 0.3 ± 0.1 to 1.1 ± 0.6mm, and translation in the osteotomized state ranged from 1.3 ± 1.0 to 2.0 ± 1.0mm. Resection of the coronoid resulted in a significant increase in posterior ulnar translation compared with intact at all flexion angles (p < 0.05) except at 75°. Reconstruction decreased translation versus the osteotomized state at all flexion angles, significantly at 60 and 120°. No significant difference in translation was found between reconstructed and intact states at five of eight positions tested. In this biomechanical study of irreparable coronoid fracture, autograft olecranon tip transfer restored posterior elbow stability to a level not significantly different from the intact elbow in five of eight elbow positions tested.

Open surgical release for contractures of the elbow.

Compared with arthroscopic release, open release is more commonly used for the treatment of stiff elbow. Flexion is recovered by releasing posterior tethering soft-tissue structures and by removing anterior impingement between the coronoid and/or radial head and the distal humerus. Extension is improved by releasing anterior soft-tissue tethers and by removing impingement between the olecranon tip and the olecranon fossa. Open elbow release is most commonly performed via ligament-sparing approaches. Ulnar nerve identification and transposition is recommended in the presence of nerve dysfunction or when correction of significant loss of elbow flexion is anticipated. Long-term improvement in flexion and extension can be expected with proper patient selection. Less predictable results are obtained in adolescent patients and in those with underlying traumatic brain injury.

Presentation of the vascular supply of the proximal ulna using a sequential plastination technique.

The purpose of this study was to demonstrate the peri- and intraosseous vascular supply of the proximal ulna. Eleven fresh human cadaveric elbows were sequentially plastinated beginning with arterial injection, followed by block and secondary slice plastination of the whole elbow. With this technique, we obtained completely transparent cadaveric slices in which the peri- and intraosseous vascular architecture could be studied. Proximal ulna vascularization is due to an arterial network: a superior and inferior collateral ulnar artery and the profunda brachial artery climbing to the olecranon from proximal. An anterior artery and a posterior recurrent artery climb up distally to the medial parts of the ulna and an interosseous recurrent artery is responsible for the lateral and posterolateral proximal part of the ulna. The intraosseous vascularization is due to directly penetrating branches out of the posterior recurrent ulnar artery and a vascular plexus at the olecranon tip. In addition, we saw a major distal bone penetration branch coming from the recurrent posterior artery, climbing intraosseously without junction to the proximal penetrating branches. The peri- and intraosseous vascularization of the proximal ulna was shown. A transitional zone of the intraosseous vascularization of the proximal ulna was detected.

Olecranon Tip Osteoarticular Autograft Transfer for Irreparable Coronoid Process Fractures. A Biomechanical Study

Coronoid process fractures are common in traumatic elbow injuries and can lead to significant elbow instability. With extensive fracture comminution, few options exist for reconstruction. The olecranon tip, being morphologically similar to the coronoid, may be a suitable option for reconstruction. In this study, we evaluate the morphology, suitability and biomechanics of an olecranon tip transfer procedure for type III coronoid fractures.

Vortical flow in human elbow joints: a three-dimensional computed tomography modeling study.

The human elbow joint has been regarded as a loose hinge joint, with a unique helical motion of the axis during extension-flexion. This study was designed to identify the helical axis in the ulnohumeral joint during elbow extension-flexion by tracking the midpoint between the coronoid tip and the olecranon tip of the proximal ulna in a three-dimensional (3D) computed tomography (CT) image model. The elbows of four volunteers were CT-scanned at four flexion angles (0°, 45°, 90°, and 130°) at neutral rotation with a custom-made holding device to control any motion during scanning. Three-dimensional models of each elbow were reconstructed and a 3D ulnohumeral joint at 45°, 90°, and 130° was superimposed onto a fully extended joint (0°) by rotating and translating each 3D ulnohumeral joint along the axes. The midpoints of the olecranon and coronoid tips were interpolated using cubic spline technique and the dynamic elbow motion was plotted to determine the motion of the helical axis. The means and standard deviations were subsequently calculated. The average midpoint pattern of joint motion from extension to flexion was elliptical-orbit-like when projected onto a sagittal plane and continuously translated a mean 2.14 ± 0.34 mm (range, 1.83-2.52 mm) to the lateral side during elbow extension-flexion. In 3D space, the average midpoint pattern of the ulnohumeral joint resembles a vortical flow, spinning along an imaginary axis, with an inconsistent radius from 0° to 130° flexion. The ulnohumeral joint axis both rotates and translates during elbow extension-flexion, with a vortex-flow motion occurring during flexion in 3D model analysis. This motion should be considered when performing hinged external fixation, total elbow replacement and medial collateral ligament reconstruction surgery.

Shoulder &amp; Elbow

The August 2014 Shoulder &amp; Elbow Roundup360 looks at: Myofibroblasts perhaps not implicated in post-traumatic elbow stiffness; olecranon tip biomechanically sound for coranoid reconstruction; obesity and elbow replacement don’t mix; single column plating successful for extra-articular distal humeral fractures; satisfaction not predictable in frozen shoulder; tenodesis and repair both acceptable in Grade II SLAP tears; glenoid bone grafting is effective and glenohumeral articular lesions best seen with an arthroscope.

Reconstruction of the Coronoid Process Using the Tip of the Ipsilateral Olecranon

Autograft reconstruction of the coronoid using the tip of the olecranon has been described as a treatment option for comminuted coronoid fractures or coronoid nonunions that are not repairable. The purpose of this in vitro biomechanical study of the coronoid-deficient elbow was to determine whether coronoid reconstruction using the tip of the ipsilateral olecranon would restore elbow kinematics. An elbow motion simulator was used to perform active and passive extension of six cadaveric arms in the horizontal, valgus, varus, and vertical orientations. Elbow kinematics were quantified with use of the screw displacement axis of the ulna with respect to the humerus. Testing was performed with an intact coronoid, a 40% coronoid deficiency, and a coronoid reconstruction using the tip of the ipsilateral olecranon. Creation of a 40% coronoid deficiency resulted in significant changes (range, 3.6° to 10.9°) in the angular deviations of the screw displacement axis relative to the intact state during simulated active and passive extension in the varus orientation with the forearm in pronation and in supination (p < 0.05). Reconstruction of the coronoid using the ipsilateral olecranon tip restored the angular deviations to those in the intact state (p > 0.05) with the arm in all orientations except valgus, in which there was a small but significant difference (0.4° ± 0.2°, p = 0.04) during passive motion with forearm supination. Reconstruction of the coronoid using the tip of the ipsilateral olecranon was an effective method for restoring normal kinematics over a range of elbow motion from 20° to 120° in a cadaveric model of an elbow with a 40% coronoid deficiency. This reconstruction technique may prove beneficial for patients with elbow instability due to coronoid deficiency.

Morphometric analysis of the proximal ulna using three-dimensional computed tomography and computer-aided design: varus, dorsal, and torsion angulation

The proximal ulna, particularly the course of the posterior border, has a complex three-dimensional (3D) morphology which has been highlighted recently due to its clinical relevance in relation to surgical treatments. 3D computed tomography (CT) reconstruction and computer-aided design (CAD) based software can help to visualize the complex anatomy and thus aid the investigation of the more detailed morphology of the proximal ulna. In our current study, 3D CT reconstruction images of 20 cadavers were imported into the 3D CAD program. Three morphologic angle parameters of the proximal ulna were measured including the dorsal, varus and torsion angulation. The torsion angulation was measured using the flat spot of olecranon dorsal aspect. We measured the total length of the ulna and the distance between the olecranon tip and the apex of dorsal and varus angulation. Furthermore, the thickness of olecranon was also measured for all the specimens. The results showed that the mean dorsal, varus, and torsion angulation was 4.3° (range 2.6°-5.9°), 12.1° (range 7.9°-17.6°), and 22.5° (range 16.6°-30.5°), respectively. The average length ratio of the dorsal and varus angulation apex to the total ulnar length was 26.4% (range 19.8-30.7%) and 32.7% (range 27.5-37.5%), respectively. The average of olecranon thickness at the proximal tip, mid-olecranon fossa, and at coronoid tip level was 17.8mm (range 14.1-22.8mm), 19.7mm (range 15.8-23.1mm), and 35.1mm (range 27.9-41.8mm), respectively. In conclusion, variations in the proximal ulna have to be considered when anatomically contoured dorsal plates are applied. Knowledge of the 3D morphologic anatomy of the proximal ulna would provide important information on fracture reductions, and the design of a precontoured dorsal plate or a prosthetic ulnar stem.