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At least 19 recordsLinked to original sources
PubMedDate not supplied

The kinematic elbow axis as a parameter to evaluate total elbow replacement: A cadaver study of the iBP elbow system.

Malpositioning of prosthetic implants leads to biomechanical changes, often resulting in deteriorating functional outcome. This emphasizes the relevance of evaluating the surgical process of inserting the prostheses. This study tested to what extent the iBP elbow prosthesis and its alignment tools enabled a surgeon to reconstruct normal joint kinematics. It demonstrates the use of the kinematic elbow axis as an evaluation tool. An electromagnetic tracking device registered controlled passive elbow flexion of 10 embalmed upper extremities. The position and direction of the preoperative and postoperative kinematic elbow axes were established with the use of helical axes and compared. The postoperative position of the elbow axis differed from the preoperative axis because of limitations of the alignment tools. Suggestions for adjustment of the alignment tools are made. The direction of the imposed resection plane was correct; therefore, the direction of the postoperative elbow axis corresponded with the direction of the preoperative axis.

Arthroplasty, Replacement↗
PubMed2005

Semi-constrained total elbow arthroplasty for the treatment of rheumatoid arthritis of the elbow.

INTRODUCTION: We retrospectively reviewed the results of total elbow arthroplasty in patients with rheumatoid arthritis of the elbow followed for a minimum of two years. METHODS: Between September 1999 and March 2001, seven patients with rheumatoid arthritis of the elbow were treated with total elbow arthroplasty using the semi-constrained Coonrad-Morrey elbow replacement prostheses. One patient died 19 months after her surgery and was excluded from the study. Two patients had bilateral total elbow replacements. Eight elbows were thus available for review. The mean age of our patients at the time of surgery was 55.5 years. The indication for surgery was severe pain and stiffness in six elbows, and distal humerus fractures in two elbows. RESULTS: The mean duration of postoperative hospitalisation stay was 6.6 days. The average length of follow-up was 39.4 months. Six elbows had no pain, while two elbows had mild pain. The mean arc of flexion was 101.3 degrees. The mean Mayo elbow performance score was 93.1 points. Excellent results were achieved in six elbows, while two elbows had good outcome. There was one case of intraoperative lateral condylar fracture treated with internal fixation. One patient developed blisters postoperatively but resolved with dressings and antibiotics. CONCLUSION: Our small study revealed good to excellent short-term outcome with the use of semi-constrained total elbow arthroplasty for the treatment of rheumatoid arthritis of the elbow in Asian patients.

Aged↗
PubMed2000

Semiconstrained total elbow arthroplasty for ankylosed and stiff elbows.

BACKGROUND: Total elbow arthroplasty can be a valuable option for the treatment of ankylosed or very stiff elbows. METHODS: A semiconstrained total elbow arthroplasty was performed in thirteen patients (fourteen elbows) with a preoperative range of elbow motion of 30 degrees or less. Nine elbows were fused or ankylosed preoperatively. The mean age at the time of the surgery was fifty years (range, twenty-four to seventy-nine years). The etiology of the stiffness was trauma for eleven elbows, juvenile rheumatoid arthritis for two, and rheumatoid arthritis for one. RESULTS: After a mean duration of follow-up of sixty-three months, the result was excellent for four elbows, good for four, fair for one, and poor for five, according to the Mayo elbow performance score. The mean arc of flexion improved from 7 degrees (range, 0 to 30 degrees) preoperatively to 67 degrees (range, 10 to 115 degrees) after the surgery. The most important factor that influenced the final result was the presence of ectopic bone surrounding the elbow joint. There were seven complications. Infection developed in five elbows. Three elbows had a superficial infection, which did not compromise the final result in two and which was treated with a myocutaneous flap in one with skin necrosis, with an excellent result. Deep infection developed in two other elbows. Both had an unsatisfactory result, one after implant removal and one after several debridements and retention of the prosthesis. Two patients sustained a fracture because of a loose component, and the prosthesis was revised. Four patients who lost motion within the first month following the surgery had a manipulation under anesthesia. CONCLUSIONS: Semiconstrained total elbow arthroplasty is a useful option for patients with an ankylosed or a very stiff elbow and results in a considerable improvement of motion. Because of the nature of the underlying pathology, complications, including reoperation, are frequent, but the risk can be lessened by careful preoperative planning and surgical technique. Replacement is the preferred option in patients who are more than sixty years of age, but it is also a good choice in younger patients if there is no other viable option.

Adult↗
PubMed2006

Elbow capsulectomy for posttraumatic elbow stiffness.

PURPOSE: To determine factors associated with diminished elbow function and upper-extremity-specific health status after elbow capsulectomy for posttraumatic stiffness. METHODS: Forty-six adult patients with posttraumatic elbow stiffness were evaluated an average of 48 months after open capsular excision. A second capsular excision was performed in 9 patients (29%). Stepwise multiple linear regression analysis was used to identify predictors of the American Shoulder and Elbow Surgeons Elbow Score, the Mayo Elbow Performance Index, and the Disabilities of the Arm, Shoulder, and Hand scores after all procedures. RESULTS: The average improvement in ulnohumeral motion after the index surgery for capsular release was 53 degrees . (The average flexion was 98 degrees .) The 9 patients who had subsequent repeat elbow contracture release gained an additional 24 degrees , leading to a final average flexion arc for the entire cohort of 103 degrees . Multiple linear regression identified the American Shoulder and Elbow Surgeons pain score, persistent ulnar nerve dysfunction, and duration of follow-up evaluation after the initial capsular release as independent predictors of a higher Disabilities of the Arm, Shoulder, and Hand questionnaire score; flexion arc and pain score as independent predictors of the Mayo Elbow Performance Index; and flexion arc, forearm arc, pain score, and persistent ulnar neuropathy as independent predictors of the American Shoulder and Elbow Surgeons score. CONCLUSIONS: Open elbow capsulectomy for posttraumatic elbow stiffness restores a near-100 degrees flexion arc on average. Second elbow releases provide limited additional motion in most patients. Final motion influences physician-based rating scales but not patient-specific health status (Disabilities of the Arm, Shoulder, and Hand questionnaire), which is dominated by pain and persistent ulnar neuropathy. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Adolescent↗
PubMed2005

Total elbow arthroplasty after interposition arthroplasty for elbow arthritis.

BACKGROUND: Interposition arthroplasty is an option for the treatment of arthritis of the elbow. Conversion to a total elbow arthroplasty can be considered later, when the patient reaches a suitable age. We investigated the results of conversion of an interpositional elbow arthroplasty to a semiconstrained total elbow arthroplasty in a series of patients. METHODS: The results of twelve consecutive linked semiconstrained total elbow arthroplasties in twelve patients who had had a prior interposition arthroplasty for the treatment of degenerative arthritis of the elbow were evaluated at an average of ten years postoperatively. The average age at the time of the total elbow arthroplasty was fifty years, and the average interval from the interposition arthroplasty to the total elbow arthroplasty was 9.9 years. Pain and elbow performance as measured with the Mayo Elbow Performance Score were assessed in a retrospective chart review and an evaluation of questionnaires, and postoperative radiographs were reviewed. RESULTS: At the time of the latest follow-up, postoperative pain was rated as mild or none in ten of the twelve patients, and the result was rated as subjectively satisfactory in ten patients. The average Mayo Elbow Performance Score improved from 32.1 points (range, 10 to 70 points) preoperatively to 80.4 points (range, 40 to 100 points) postoperatively (p < 0.001). According to these objective criteria, there were three excellent, six good, one fair, and two poor results. All of the elbows were stable following the arthroplasty. Radiographs demonstrated a well-fixed prosthesis in all but one patient who had extensive osteolysis at the site of the humeral component. One other patient had radiographic evidence of bushing wear. Both of these patients required revision procedures. CONCLUSIONS: Semiconstrained total elbow arthroplasty can be performed successfully in patients with a prior interposition arthroplasty. Reliable pain relief and a satisfactory result can be achieved in most patients.

Adult↗
PubMed2005

Effectiveness of prophylactic hyperextension elbow braces on limiting active and passive elbow extension prephysiological and postphysiological loading.

STUDY DESIGN: Experimental 3-factor design with repeated measures on all factors. OBJECTIVES: The purpose of this study was to determine the effectiveness of 3 prophylactic hyperextension elbow braces on limiting active and passive elbow extension before and after exercise. BACKGROUND: Prophylactic hyperextension elbow braces are used to protect the joint against excessive extension, but their effectiveness for this purpose has not been determined. METHODS AND MATERIALS: Twenty Division I intercollegiate football players (mean +/- SD age, 20.2 +/- 1.3 years; mean +/- SD height, 184.4 +/- 9.9 cm, mean +/- SD mass, 102.9 +/- 22.0 kg) completed all phases of the study. The Breg Functional Elbow Brace, PRO 470 Kendall Elbow Brace, and DonJoy Elbow Guard were tested both actively and passively before and after an isokinetic exercise session on a Biodex Multi-Joint Testing and Exercise Dynamometer. For all tests, the braces were set at a 30 degrees flexion limit angle. The exercise session consisted of 1 set of reciprocal elbow extension and flexion at an angular velocity of 360 degrees/s, totaling 1627 J of work. RESULTS: None of the braces limited elbow extension to the 30 degrees flexion limit. However, all of the braces were successful in preventing the elbow from reaching the vulnerable position of hyperextension. The Breg Functional Elbow Brace was the most effective for limiting elbow extension near its set angle, followed by the DonJoy Elbow Guard, and the PRO 470 Kendall Elbow Brace across all test conditions. CONCLUSION: The braces' effectiveness to limit motion is enhanced when limits are set higher than the desired angle of the protected motion.

Adult↗
PubMed2005

Effects of elbow flexion and forearm rotation on valgus laxity of the elbow.

BACKGROUND: Clinical evaluation of valgus elbow laxity is difficult. The optimum position of elbow flexion and forearm rotation with which to identify valgus laxity in a patient with an injury of the ulnar collateral ligament of the elbow has not been determined. The purpose of the present study was to determine the effect of forearm rotation and elbow flexion on valgus elbow laxity. METHODS: Twelve intact cadaveric upper extremities were studied with a custom elbow-testing device. Laxity was measured with the forearm in pronation, supination, and neutral rotation at 30 degrees, 50 degrees, and 70 degrees of elbow flexion with use of 2 Nm of valgus torque. Testing was conducted with the ulnar collateral ligament intact, with the joint vented, after cutting of the anterior half (six specimens) or posterior half (six specimens) of the anterior oblique ligament of the ulnar collateral ligament, and after complete sectioning of the anterior oblique ligament. Laxity was measured in degrees of valgus angulation in different positions of elbow flexion and forearm rotation. RESULTS: There were no significant differences in valgus laxity with respect to elbow flexion within each condition. Overall, for both groups of specimens (i.e., specimens in which the anterior or posterior half of the anterior oblique ligament was cut), neutral forearm rotation resulted in greater valgus laxity than pronation or supination did (p < 0.05). Transection of the anterior half of the anterior oblique ligament did not significantly increase valgus laxity; however, transection of the posterior half resulted in increased valgus laxity in some positions. Full transection of the anterior oblique ligament significantly increased valgus laxity in all positions (p < 0.05). CONCLUSIONS: The results of this in vitro cadaveric study demonstrated that forearm rotation had a significant effect on varus-valgus laxity. Laxity was always greatest in neutral forearm rotation throughout the ranges of elbow flexion and the various surgical conditions. CLINICAL RELEVANCE: The information obtained from the present study suggests that forearm rotation affects varus-valgus elbow laxity. Additional investigation is warranted to determine if forearm rotation should be considered in the evaluation and treatment of ulnar collateral ligament injuries of the elbow joint.

Aged↗
PubMed2006

Open elbow arthrolysis for posttraumatic elbow stiffness.

OBJECTIVES: The elbow joint is vulnerable to stiffness, especially after trauma. The aim of this study was to evaluate the results of open arthrolysis for posttraumatic elbow stiffness. DESIGN: Cohort retrospective study. PATIENTS: Eighteen consecutive patients were evaluated by an independent observer at an average of 16 months (6 to 43) after open elbow arthrolysis was performed for posttraumatic stiffness. Initial traumas were: isolated fractures (11) or dislocation (1) and complex fracture-dislocations (6). Initial treatments were: nonoperative (3), radial head resection (1), and ORIF (14). Patients presented predominantly with mixed contractures (combined extrinsic and intrinsic contractures). INTERVENTION: Open elbow arthrolysis. MAIN OUTCOME MEASUREMENTS: Elbow function and patient satisfaction were the principal outcome measures. At follow-up European Society for Shoulder and Elbow Surgery (SECEC) elbow scores were calculated. RESULTS AND CONCLUSIONS: Three patients had minor postoperative complications: 1 partial wound dehiscence, 1 subcutaneous infection, and one seroma. None of these complications influenced the final result clinically. The mean total increase in range of motion was 40 degrees (13 to 112 degrees), with a mean gain in flexion of 14 degrees (0 to 45 degrees) and 26 degrees in extension (5 to 67 degrees). No patient showed signs of elbow instability. There was no radiographic evidence of osteoarthritis progression at follow-up. We did not find any correlations between the type of stiffness, the approaches used, and the results. However, patients with the greatest preoperative stiffness had significantly better improvement of mobility (P<0.001). The best results were obtained in patients who had arthrolysis done within 1 year after the initial trauma (P=0.008). The mean SECEC scores were 88 (52 to 100) for the injured elbows, and 96 (88 to 100) for the contralateral elbows. CONCLUSION: Open elbow arthrolysis for patients with posttraumatic stiffness improves joint function and provides patient satisfaction. The best results, in terms of gain of motion and patient satisfaction, were obtained in patients with severe stiffness who had operations within the first year after initial trauma.

Adult↗
PubMed1994

[The collateral ligaments of the elbow joint: their functional anatomy with special reference to the pathology and treatment of post-traumatic stiff elbow].

Factors which cause stiff elbow were investigated both experimentally and clinically. Since a thickened and shortened medial collateral ligament is often seen in stiff elbow, then changes in the length of the medial collateral ligament (MCL) and in the length of the lateral collateral ligament (LCL) were investigated in cadaver elbow specimens, and correlated with the observed range of motion. The MCL was divided into five bundles, and the LCL into three bundles. The length changes during flexion and extension of the elbow joint were measured, and the length change pattern was found to be different from bundle to bundle. The lengths of the LCL and the anterior oblique ligament (AOL) of the MCL changed little during elbow flexion. On the other hand, the length of the posterior oblique ligament (POL) of the MCL considerably increased when the elbow joint was flexed. The more posterior the bundle was, the larger the change in length that was observed. Because the origin of the POL is far distant from the axis of motion, it was suspected that a shortening in the POL was one of the most important pathologic changes in stiff elbow. The results of the biomechanic study were applied to a subsequent clinical study. Scar formation or ectopic ossification on the medial and/or posterior parts of the elbow joint was observed in 38 of 43 cases at surgery. These pathologic regions were resected, including the scarred POL. The intra-operative findings revealed that the major restraints in stiff elbow were the medial and/or posterior parts of the elbow. The importance of the shortened POL in the clinical pathology of stiff elbow was clearly demonstrated.

Adolescent↗
PubMed1992

Diffuse idiopathic skeletal hyperostosis (DISH) of the elbow: a cause of elbow pain? A controlled study.

Elbow pain is a common complaint and elbow hyperostosis a frequent radiological condition. However, little is known about the association between the clinical and radiological findings. To evaluate the relationship between spinal and extraspinal hyperostotic features and the clinical relevance of elbow hyperostosis we have performed the first controlled, double-blinded study of 85 hospitalized probands, 33 with and 52 without thoracospinal hyperostosis on lateral chest X-ray. Elbow and shoulder hyperostosis were graded on bilateral standard radiographs. Elbow pain was assessed by an interviewer using a standardized questionnaire and extraskeletal causes of elbow pain were recorded. The prevalence of elbow hyperostosis was increased in cases with thoracospinal hyperostosis compared to controls (82% versus 58%, chi 2 = 5.32, P less than 0.025, n = 85, olds ratio (OR) 3.30 (95% CI 1.16-9.35)). Similarly, the prevalence of elbow hyperostosis was increased in cases with shoulder hyperostosis compared to controls (83% versus 60%, chi 2 = 4.51, P less than 0.05, n = 84, OR = 3.20 (95% CI 1.06-9.66)), emphasizing the multifocal nature of hyperostotic features. Elbow pain was only slightly more prevalent in cases with elbow hyperostosis compared to controls (21% versus 13%, chi 2 = 0.75, NS, OR = 1.84 (95% CI 0.46-7.44)). We conclude that elbow hyperostosis is a radiological finding of doubtful clinical relevance.

Aged↗
PubMed1999

Instability of the elbow treated with semiconstrained total elbow arthroplasty.

The results of nineteen semiconstrained modified Coonrad-Morrey total elbow arthroplasties performed in nineteen patients to treat instability were evaluated at an average of seventy-two months (range, twenty-five to 128 months) postoperatively. Preoperatively, all patients had either a flail elbow or gross instability of the elbow that prevented useful function of the extremity. The instability of sixteen elbows was the result of a traumatic injury or of the treatment of such an injury. The most recent result was satisfactory for sixteen elbows and unsatisfactory for three. The average overall Mayo elbow performance score increased from 44 points preoperatively to 86 points postoperatively. At the most recent follow-up examination, no elbow was unstable. The average arc of flexion was from 25 degrees (range, 0 to 60 degrees) to 128 degrees (range, 30 to 142 degrees), which represented a 58-degree increase from the preoperative average arc. Sixteen patients had little or no pain after the arthroplasty. There were four complications in four patients. Three complications (loosening of the humeral component in one patient and a fracture of the ulnar component in two) occurred postoperatively; all three were treated with a revision procedure. The other complication (a fracture of the olecranon) occurred intraoperatively and was treated with tension-band fixation; the most recent outcome was not affected. Radiographically, one patient had complete (type-V) radiolucency about the humeral component. None of the nine patients for whom true anteroposterior radiographs were available had evidence of wear of the bushings. The bone graft behind the anterior flange of the humeral prosthesis was mature in fourteen elbows, incomplete in two, and resorbed in two. One patient was excluded from this analysis because radiographs were not available. Instability of the elbow resulting in the inability to use the extremity is a challenging clinical situation. However, in patients who are more than sixty years old and in selected patients who are less than sixty years old but who have extensive loss of bone as a result of severe injury, have had multiple operations, or have rheumatoid arthritis, total elbow arthroplasty with a linked, semiconstrained prosthesis reestablishes a mobile, stable joint without premature loosening or failure of the components. In our experience, the use of customized implants, maintenance of the muscular attachments to the epicondyles, and reconstruction of the epicondyles to the implant were unnecessary.

Arthroplasty, Replacement↗
PubMedDate not supplied

The effect of elbow position on the radial pulse measured by Doppler ultrasonography after surgical treatment of supracondylar elbow fractures in children.

We performed a prospective study of 20 patients with displaced extension supracondylar humerus fractures and evaluated the effect of elbow flexion, forearm supination, and forearm pronation on blood flow to the injured arm after closed reduction and Kirschner wire fixation. Ten patients had a Gartland type II fracture and 10 patients had a Gartland type III fracture. After closed reduction and percutaneous pinning, the radial pulse was examined with Doppler ultrasonography starting with the elbow in extension. The elbow was slowly flexed, and the angle of elbow flexion at which the radial pulse disappeared was determined. This angle of elbow flexion was measured with the forearm in both supination and pronation. Gartland type III fractures demonstrated less elbow flexion prior to radial pulse ablation compared to Gartland type II fractures when the forearm was placed in supination (p = 0.001) and in pronation (p = 0.005). Supination allowed > or = 5 degrees of elbow flexion prior to radial pulse ablation in six Gartland type II and four Gartland type III fractures. We concluded that after closed reduction and percutaneous Kirschner wire fixation of displaced extension supracondylar fractures, vascular safety is enhanced by extending the elbow and supinating the forearm. The ideal position of elbow immobilization depends on the amount of swelling and the presence of a radial pulse.

Child↗
PubMed2005

Genetic evaluation of elbow angles as predictors of elbow dysplasia in German shepherd dogs.

Elbow angles were measured in X-rays of both elbows to elucidate the usefulness of such data for selecting against elbow dysplasia (ED) in German shepherd dogs. These measurements record the size, proportions and alignments of the anconeal process (PA), the radius (RA), the olecranon (OL), and the ulnar trochlear notch (UL). The reference system for evaluating the information content of the measurements was the score for ED (ED-SV) as recommended by the International Elbow Working Group. Data from 2645 X-rayed dogs born from 1998 to 2001 in 1331 kennels were analysed by using residual maximum likelihood procedures to estimate heritabilities, additive genetic correlations and residual correlations. The pedigree file included 11,426 dogs and contained ancestors for up to six generations. ED-SV was significantly influenced by sex, by age within sex and by month of birth. The elbow angles were significantly influenced by the month and year of birth, X-ray positioning of the dog's forelimbs, angle of elbow flection, litter size and number of dogs X-rayed by the veterinary practitioners. The following heritability estimates were found: h2=0.18+/-0.04 for ED; h2=0.76+/-0.04 for OL; h2=0.52+/-0.05 for PA; h2=0.50+/-0.04 for UL; and h2=0.39+/-0.04 for RA. The additive genetic correlations of ED-SV with three elbow angles (OL, UL and RA) were close to zero. A higher additive genetic correlation to ED-SV was found only for PA, for which r(g)=0.31. The distributions of predicted breeding values for susceptibility to ED were not affected by regarding the elbow angles as additional traits in the multivariate prediction procedure. Measurements of elbow angles were thus shown to be unsuitable for use in selection programmes against ED in German shepherd dogs.

Animals↗
PubMed2002

Cubital tunnel syndrome associated with medial elbow Ganglia and osteoarthritis of the elbow.

BACKGROUND: Medial elbow ganglia have been reported in association with cubital tunnel syndrome. This lesion is thought to occur rarely and has not been emphasized in the literature. The purposes of the present study are to report our experience with this lesion in order to elucidate its prevalence as well as its clinical and radiographic features, to describe our operative findings, and to present the results of surgical treatment. METHODS: Four hundred and eighty-seven elbows in 472 patients were treated for cubital tunnel syndrome between 1980 and 1999. We performed a retrospective study of the thirty-eight patients who had a medial ganglion. All of the ganglia were excised, and the ulnar nerve was translocated subcutaneously. Thirty-two patients were followed for a mean of thirty-seven months. RESULTS: Medial elbow ganglion was the third most common causative factor associated with cubital tunnel syndrome, with an overall prevalence of 8%. Resting pain in the medial aspect of the elbow was reported by twenty-five of the thirty-eight patients, and a sudden onset of numbness in the ring and little fingers or of medial elbow pain without prior symptoms was reported by twenty-nine patients. The symptoms lasted two months or less in thirty-one patients. All ganglia originated from the medial aspect of the ulnohumeral joint, and radiographs of that joint showed degenerative changes in thirty-seven patients. At the time of follow-up, all measurements of sensory and motor function of the ulnar nerve had improved and no recurrence of nerve palsy was found. CONCLUSIONS: Although uncommon, medial elbow ganglia have a strong association with osteoarthritis of the elbow and can cause a relatively acute onset of cubital tunnel syndrome. A patient with cubital tunnel syndrome associated with elbow osteoarthritis who complains of medial elbow pain or severe numbness within two months after the onset of the syndrome should be strongly suspected of having a ganglion. Most ganglia are occult, and ultrasonography and magnetic resonance imaging can assist in the preoperative diagnosis. Careful excision of the ganglion performed concurrently with subcutaneous anterior transposition of the ulnar nerve can produce satisfactory results.

Adult↗
PubMedDate not supplied

Electromyographic activity in stiff and normal elbows during elbow flexion and extension.

This prospective, controlled pilot study investigated electromyographic activity in elbow muscles during active elbow flexion and extension and during prolonged elbow extension with and without resistance. Biceps brachii, brachialis, brachioradialis, and triceps activity was measured in 10 subjects with elbow motion deficits after injury and in 10 controls. Surface electromyography was recorded during active elbow flexion, extension, and passively positioned elbow extension with and without 3 lb on the distal forearm. All muscles of the stiff elbow group had greater activity compared with controls during active elbow flexion and extension. Biceps brachii of the stiff group showed antagonist activity equivalent to agonist. For all other flexors in both groups, agonist activity was greater than antagonist. During prolonged extension, biceps brachii, unweighted, showed greater activity in the stiff group than in controls. Both groups showed greater flexor activity when weighted. Across time, activity was sustained or increased in all muscles in both groups.

Adult↗
PubMed1995

Comparison of the flexed and extended elbow positions in localizing ulnar neuropathy at the elbow.

Electrophysiologic localization of ulnar neuropathy at the elbow often depends on demonstration of segmental slowing. Based on normative data obtained from 50 control subjects, we compared the utility of flexed and extended elbow positions in demonstrating focal slowing at the elbow as compared to the forearm segment in patients with ulnar neuropathy. We studied 35 patients with ulnar neuropathy with definite electrophysiologic localization to the elbow segment defined by conduction block across the elbow segment or by focal slowing demonstrated either in the flexed or extended position. Applying cutoff values from the control group, all 35 patients demonstrated focal slowing at the elbow in the flexed position, whereas only 5 of 35 (14%) patients did so in the extended position. We conclude that the flexed elbow position is more sensitive than the extended position in localizing ulnar neuropathy at the elbow and should be the preferred method when performing ulnar motor conduction studies.

Adult↗
PubMed1995

Loose-hinge total elbow arthroplasty. An experimental study of the effects of implant alignment on three-dimensional elbow kinematics.

A previous study suggested that the kinematics of a loose-hinge total elbow arthroplasty (TEA) are those of a truly semiconstrained joint. This study addresses the effects of malposition of the implant. The three-dimensional elbow kinematics during simulated active motion were studied in six cadaver specimens using an electromagnetic tracking device. In addition to simulated active elbow flexion, flexion arcs were obtained under an elbow varus or valgus moment, to calculate the structural varus-valgus laxities. The results after four different Coondrad-Morrey TEA positions of implantation were compared with those of the intact elbow. The flexion-extension amplitudes were not significantly decreased after TEA implantation, except with external rotation of the ulnar component, which resulted in a loss of extension. In the intact elbow and after TEA implantation in any position, the mean varus-valgus deviations throughout elbow flexion were in a narrower range than the structural limits imposed by the ligaments (intact elbow) or the TEA hinge design. With internal malrotation of the humeral component over 10 degrees, however, the valgus structural limit was reached and, conversely, the varus limit with external rotation over 10 degrees. The clinical improvement observed with the semiconstrained TEA is derived from the benefits of the less constrained articulation. The proximodistal changes of TEA implantation have no consequence on the kinematic pattern. Rotational malpositioning of either humeral or ulnar component should be avoided, the first because it changes the kinematic pattern toward the structural limits of the implant and, therefore, may lead to excessive stresses at the bone-cement-implant interfaces and to early loosening, and the latter because it causes loss of extension.

Biomechanical Phenomena↗