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Functional outcome of semiconstrained total elbow arthroplasty.
BACKGROUND: The objective of the present study was to review the results of primary total elbow arthroplasty with use of the Coonrad-Morrey prosthesis. Two hypotheses were tested: (1) the results in patients with inflammatory arthritis would be superior to those in patients with a traumatic or posttraumatic condition, and (2) the isometric extensor torque after total elbow arthroplasty would be significantly less than that of the contralateral elbow. METHODS: Forty-seven consecutive patients (fifty-one elbows) had the operation performed by one of three surgeons between November 1, 1989, and June 30, 1996. Thirty-six surviving patients (thirty-nine elbows) were available for follow-up. The mean duration (and standard deviation) of follow-up was 50 +/- 11 months (range, twenty-four to ninety-seven months). The mean age at the time of the operation was 64 +/- 11 years (range, twenty-seven to eighty-seven years). Eighteen patients (twenty-one elbows) had inflammatory arthritis. Eighteen patients (eighteen elbows) had an acute fracture or posttraumatic condition (posttraumatic osteoarthritis in eight, an acute fracture of the humerus in seven, nonunion of the distal aspect of the humerus in two, and primary osteoarthritis in one). The patients were evaluated with use of questionnaires (the Mayo elbow performance index, the Short Form-36 [SF-36], and the Disabilities of the Arm, Shoulder and Hand [DASH] Questionnaire); clinical examination by an orthopaedic surgeon who was not involved with the pre-operative, operative, postoperative, or follow-up care; radiographs; and elbow strength-testing with an isokinetic dynamometer. RESULTS: The mean score (and standard deviation) on the Mayo elbow performance index for the group that had inflammatory arthritis (90 +/- 11 points) was significantly higher than that for the group with a traumatic or posttraumatic condition (78 +/- 18 points) at the time of the latest follow-up (p < 0.05). In both groups, the mean extensor torque of the involved elbow was significantly less than that of the contralateral elbow (p < 0.05). No significant difference between the groups was found with respect to the flexion-extension arc of motion. Ten elbows (26 percent) had ulnar nerve dysfunction (a transient deficit in six and a permanent deficit in four); nine (23 percent), an intraoperative fracture (of the humeral diaphysis in four, of the ulnar diaphysis in four, and of the olecranon in one); three (8 percent), a periprosthetic infection; three, a triceps disruption; and one (3 percent), a revision because of a fracture of the ulnar component. There were no other revisions. Of the thirty-four elbows with complete radiographic follow-up, twenty-three had no change in the bone-cement interface. Progressive radiolucency was noted around the ulnar prosthesis in eight elbows, around the humeral prosthesis in one elbow, and around both components in two elbows. CONCLUSIONS: Patients who had a total elbow arthroplasty with use of a semiconstrained Coonrad-Morrey prosthesis were generally satisfied; the mean level of patient satisfaction was 9.2 of a possible 10 points for those who had inflammatory arthritis and 8.6 points for those who had a fracture or posttraumatic condition. The rates of complications involving the ulnar nerve, intraoperative fracture, triceps disruption, deep infection, and periprosthetic radiolucency are of concern.
Aged↗
[Hinged external fixator in elbow trauma management].
OBJECTIVE: To introduce a new way of treatment for elbow stiffness and instability. METHODS: 30 cases of elbow trauma were treated with mobile hinged Orthofix elbow fixator, 26 of them were followed up. There are 15 male patients and 11 female patients. The average age is 32.6 years old. The 26 injured elbows involved 12 cases on left side and 14 cases on right side; Sixteen cases on the dominant side and 10 cases on the non-dominant side. Sixteen cases had elbow stiffness, 5 cases had acute radial head fracture and posterior dislocation of the elbow, 3 of cases had Monteggia's fracture dislocation, and 2 cases had neglected posterior dislocation of the elbow. RESULTS: The average follow up time was 6 months (3 - 12 month). The mean time of fixation with fixator was 8.5 weeks (6 - 11 weeks). The mean ROM of the 16 cases of elbow stiffness was (37.5 +/- 0.8) degrees before operation, and (96.5 +/- 0.6) degrees operation, with a significant difference (P < 0.05). The mean Mayo elbow score was (69.5 +/- 1.7) before operation, compared with (82.8 +/- 1.6) after operation, with a significant difference (< 0.05). For the other 10 cases (5 cases with acute radial head fracture and posterior dislocation of the elbow, 3 cases with Monteggia's fracture dislocation, 2 cases with neglected posterior dislocation of the elbow), the average ROM of the elbow flexion-extension was 95 degrees (65 degrees - 150 degrees ); The average range of flexion was 117 degrees; the average loss of extension was 22 degrees; the average pronation was 76 degrees (20 degrees - 90 degrees ), the average supination was 75 degrees (15 degrees - 90 degrees ). Nine of the cases achieved anatomic reduction and proved by X-ray. The mean Mayo elbow score was 84 (49 - 96). Three cases were rated excellent, 4 good, 2 fair and 1 poor. The rate of excellent and good was 70% (7/10). Nine cases had no pain or mild pain, and did not need analgesic. Eight cases returned to their former work, 5 of the cases had complications. CONCLUSIONS: The mobile hinged elbow external fixator have following advantages: (1) distraction of the articular space and enhance fracture healing; (2) allow early movement of the elbow during healing; (3) provide stable environment for the healing after arthrolysis and reconstruction. Mobile hinged elbow external fixator can achieve successful result in the treatment of elbow stiffness or unstable fracture dislocation of elbow.
Adolescent↗
Effect of elbow flexion contractures on the ability of people with C5 and C6 tetraplegia to lift.
BACKGROUND AND PURPOSE: It is commonly assumed that minor elbow flexion contractures prevent people with C5-C6 tetraplegia and paralysis of the triceps brachii muscles from bearing full body weight through their upper limbs. The aim of the present study was to determine the effect of simulated bilateral elbow flexion contractures on the ability of these individuals to bear weight through their upper limbs and to determine whether full passive elbow extension is truly critical for lifting body weight. METHOD: A biomechanical study was performed. Body weight lifted was measured under conditions that simulated bilateral elbow flexion contractures. Five people with motor complete C6 tetraplegia and one person with motor complete C5 tetraplegia, all with bilateral paralysis of the triceps brachii muscles, were recruited to the study. Subjects were fitted with bilateral elbow splints that restricted elbow extension but did not restrain elbow flexion nor prevent the elbow from collapsing, and were seated on an instrumented platform that measured vertical forces under the buttocks. Subjects pushed down through their hands and lifted under five different conditions, namely: with no elbow splints; with bilateral elbow splints adjusted to restrict elbow extension by 5-10 degrees; by 15-20 degrees; by 25-30 degrees and with bilateral elbow splints adjusted to allow unrestricted movement of the elbow joint. Maximal weight lifted from under the buttocks, for each condition, was expressed in relation to weight under the buttocks during unsupported sitting (that is, 'seated body weight'). RESULTS: Subjects lifted progressively less weight from under their buttocks as passive elbow restriction was progressively restricted. However, one subject lifted all his seated body weight when elbow extension was restricted by 5-10 degrees and another lifted all his seated body weight when elbow extension was restricted by 5-10 degrees and 15-20 degrees. CONCLUSIONS: Minor elbow flexion contractures will not alone prevent people with tetraplegia and paralysis of the triceps brachii muscles from lifting. Full passive elbow extension is not critical for the performance of this task.
Adult↗
The role of the coronoid process in elbow stability. A biomechanical analysis of axial loading.
BACKGROUND: The current treatment of coronoid process fractures of the ulna is based on the classification system of Regan and Morrey. We found no biomechanical studies that specifically addressed the role of the coronoid process in elbow stability. In the present investigation, the elbows of cadavera were tested before and after fracture of the coronoid process to assess the stabilizing contribution of the coronoid process under axial loading. METHODS: Six fresh-frozen cadaveric elbows were tested mechanically. All soft tissue surrounding the elbow, including the skin, was left intact. An axial load compressing the elbow joint was applied along the shaft of the forearm in the sagittal plane. A displacement of fifteen millimeters per minute was applied until a load of 100 newtons was attained. Each elbow was tested in 15, 30, 45, 60, 75, 90, 105, and 120 degrees of flexion. Next, less than 25 percent, 25 to 50 percent, or more than 50 percent of the coronoid process was fractured with an osteotome under radiographic guidance, and the testing was repeated. Each elbow served as its own control, and one elbow was used for two tests; therefore, a total of seven situations were investigated. The difference in displacements between the intact and osteotomized elbows was measured. RESULTS: There was no significant difference, at any flexion position, in posterior axial displacement between the intact elbows and the elbows in which 50 percent or less of the coronoid process was fractured (type I and type II) (p = 0.43). There were significant differences, across all flexion positions, in posterior axial displacement between the intact elbows and the elbows in which more than 50 percent of the coronoid process was fractured (type III) (p = 0.006). Specimens with a type-III fracture also showed a significant increase in displacement compared with specimens with a type-I or type-II fracture (p = 0.012). Specifically, from 60 to 105 degrees of flexion, a significant increase in posterior translation of up to 2.4 millimeters was found (p<0.05). CONCLUSIONS: In response to axial load, elbows with a fracture involving more than 50 percent of the coronoid process displace more readily than elbows with a fracture involving 50 percent or less of the coronoid process, especially when the elbow is flexed 60 degrees and beyond.
Adult↗
[GUEPAR I total elbow arthroplasty in rheumatoid arthritis: 19 implants followed an average of 67 months].
INTRODUCTION: The GUEPAR I total elbow arthroplasty is a nonconstrained implant used since 1985. Only one multicenter study has reported the mid-term results of this implant in rheumatoid arthritis. We presented a monocentric retrospective study evaluating the results of 19 GUEPAR I total elbow arthroplasty in rheumatoid arthritis with a mean follow-up of 67 months. MATERIALS AND METHODS: Between 1988 and 1996, 19 GUEPAR I total elbow arthroplasties have been performed on 16 patients (3 bilateral). There were 15 women and one man, averaged age 58 years. Radiographically, the elbow was classified as stage IIIA in 8 cases, and stage IIIB in 11 cases, according to the Mayo Clinic classification. A triceps splitting approach with tendon reflection was performed in all cases. A postoperative immobilization at 45 degrees extension was used for all patients during 21 days averaged, and active mobilization was then started. RESULTS: At 67 months averaged follow-up (range, 2 to 12 years) the Mayo Elbow score improved from 36 to 75 points. The overall results were considered as excellent for 8, good for 5, fair for 2, and poor for 4. Nine elbows were totally painfree and six had minimum pain. Postoperative arc of motion reached 36 to 126 degrees in extension-flexion and 147 degrees in rotation. Eleven out of 19 elbows had a normal functional score. Two elbows dislocated and two others had a valgus instability lower than 10 degrees. There were thirteen complications affecting 11 of the 19 elbows (68%), and six of these eleven elbows had a revision procedure (31%): 3 peroperative medial column fractures, one postoperative medial column fracture which has been fixed, two elbow dislocated with one ulnar component revision, and 3 loosed implants which has been revised. There were persistent ulnar paresthesiae in two cases with a secondary neurolysis performed in one. Finally two infections developed 6 years after the initial procedure, one superficial, and one deep, which lead to removal of the total elbow arthroplasty. DISCUSSION-CONCLUSION: The GUEPAR I total elbow arthroplasty is a nonconstrained implant indicated essentially in rheumatoid arthritis. Without intrinsic stability this implant must be contraindicated in front of bone stock deficiency, or chronic instability of the elbow. In selected cases the GUEPAR I total elbow arthroplasty offers a painfree elbow with a functional range of motion.
Adolescent↗
The Coonrad-Morrey total elbow arthroplasty in patients who have rheumatoid arthritis. A ten to fifteen-year follow-up study.
Sixty-nine patients (seventy-eight elbows) who had rheumatoid arthritis were managed with a Coonrad-Morrey total elbow arthroplasty between 1981 and 1986. At the time of the present review, forty-one patients (forty-six elbows) were alive and had been followed for at least ten years after the procedure (Group 1). The remaining twenty-eight patients (thirty-two elbows) had died or had had a revision less than ten years after the procedure or had been followed for less than ten years (Group 2). The patients in Group 1 had a younger mean age at the time of the procedure, but all other preoperative parameters were similar for both groups. At the latest follow-up evaluation, 97 per cent of the elbows (forty-five of the forty-six in Group 1 and thirty-one of the thirty-two in Group 2) were not painful or were only mildly painful. The mean arc of flexion-extension was 28 to 131 degrees; this represents an increase of 13 degrees (15 degrees in Group 1 and 7 degrees in Group 2) compared with the preoperative value. The mean arc of pronation was 68 degrees, and the mean arc of supination was 62 degrees; this represents an increase of 21 degrees. The results for seventy-four of the seventy-eight elbows (all forty-six in Group 1 and twenty-eight of the thirty-two in Group 2) were considered satisfactory by the patients. One patient thought that the status of the elbow was unchanged compared with preoperatively, and three thought that it was worse. Seventy-six of the seventy-eight elbows had long-term radiographic evaluation; the two remaining elbows were excluded because a resection arthroplasty had been performed. There were two loose ulnar components; one was associated with an infection, and the other had been causing no symptoms at the time of the patient's death. In addition, both components were radiographically loose in an elbow that had had a revision without cement after a previous total elbow arthroplasty. Five bushings (7 per cent) were completely worn, and six (8 per cent) were partially worn. Complications occurred in eleven elbows (14 per cent) and were serious, necessitating reoperation, in ten (13 per cent). Delayed complications included three avulsions of the triceps, two deep infections, two ulnar fractures, and one fracture of an ulnar component. In addition, two elbows were revised because of aseptic loosening. No patient had persistent ulnar neuritis or serious skin complications. At the latest clinical follow-up evaluation, according to the Mayo elbow performance score, forty-three of the seventy-eight elbows had an excellent result; twenty-six, a good result; seven, a fair result; and two (both in Group 2), a poor result. The rate of survival of the prosthesis was 92.4 per cent, with 86 per cent good or excellent and 14 per cent fair or poor results.
Activities of Daily Living↗
Ipsilateral total shoulder and elbow arthroplasties in patients who have rheumatoid arthritis.
BACKGROUND: The data on seventeen patients with rheumatoid arthritis who had been managed with ipsilateral total shoulder and elbow arthroplasties were analyzed to determine whether the operative technique, the presence of total shoulder and total elbow prostheses in the same upper extremity, or complications of the arthroplasties affected the result in each joint or the overall functional outcome of the upper extremity. METHODS: Seventeen patients with rheumatoid arthritis who were managed with a total of eighteen ipsilateral total shoulder and elbow arthroplasties were evaluated. The most recent physical examination was at an average of six years and six months (range, two years and one month to fourteen years) postoperatively. Radiographs, including 40-degree oblique and axillary radiographs of the shoulder as well as anteroposterior and lateral radiographs of the elbow, were made at an average of six years and eleven months (range, two years and two months to twenty-two years and eleven months) postoperatively. The radiographs of the shoulder were examined for loosening of the glenoid component, glenohumeral subluxation, and radiolucency at the bone-cement or bone-implant interface. The functional results of the total shoulder arthroplasties were evaluated with use of the rating systems of Neer et al. and Cofield. The Mayo elbow-performance score was used to evaluate elbow function. A rating system was also developed to assess the overall function of the upper extremity, including pain and motion of both the elbow and the shoulder. With this system, the overall function of the upper extremity was rated as excellent, good, fair, or poor. RESULTS: Evaluation of the shoulders revealed substantial relief of pain and an increase in active elevation. On radiographic evaluation, eight glenoid and five humeral components were considered to be loose. There were no reoperations. According to the rating system of Neer et al., eight shoulders had a satisfactory result and eight had an unsatisfactory result with limited active abduction. Limited-goals rehabilitation was successful after one shoulder arthroplasty and unsuccessful after another. There were two type-B periprosthetic humeral fractures. There was also substantial relief of pain in the elbows as well as an increase in the extension-flexion arc; the pronation-supination arc was sufficient for tasks of daily living. There was no radiographic loosening. Two elbows had an avulsion of the triceps, and two had aseptic loosening (one of which also had a worn bushing); all four needed a reoperation. One other elbow had persistent ulnar neuritis. The average interval between the arthroplasties was two years and eight months when the shoulder was replaced first and three years and five months when the elbow was replaced first. The interval between the joint replacements and the sequence of the joint replacements were not found to influence the outcome. Function of the extremity was improved by replacement of either the shoulder or the elbow alone; however, it improved significantly only when both joints were replaced (p = 0.03). According to combined clinical outcomes scores, there were nine excellent outcomes, four good outcomes, four fair outcomes, and one poor outcome after ipsilateral total shoulder and elbow arthroplasties. CONCLUSIONS: When there is severe arthritis of both the shoulder and the elbow, consideration should be given to replacing both joints in order to obtain optimum functional and clinical outcomes. The possibility of fracture of the humeral shaft necessitates an alteration of the technique for ipsilateral total shoulder and elbow arthroplasties.
Adult↗
The optimal measurement of across elbow segment in ulnar motor conduction study.
There is room for considerable error in the measurement of across-elbow conduction velocity due to the different possible positions of the elbow and the difficulty in accurately measuring distance. A standardized method should be used for clinical measurement. Many advocate a fully flexed elbow position with the arm abducted at 90 degrees. When the elbow is fully flexed, skin measurement across the bent elbow is difficult with respect to defining the path, which most accurately follows the nerve. However, studies on measurement technique for across-elbow segment have not been performed to date. We have proposed a standardized technique for the measurement of conduction velocity through the elbow segment. We assumed "ideal" across-elbow segmental conduction velocity is the mean of the forearm and arm segmental conduction velocities, and established an optimal deflection point at the elbow, which best reflects the ideal conduction velocity. The optimal deflection point was located medially two thirds distance between the epicondyle and the olecranon in an arm abducted 90 degrees, fully flexed elbow position. Our data suggests that an across-elbow segment velocity lower than 57.8 m/sec, or a difference of more than 7.7 m/sec between the across-elbow and forearm segments is to be considered abnormal. The lower limit values expressed as mean-2 S.D. for absolute across-elbow segmental conduction velocity and relative velocity difference between the across-elbow segment and forearm segments at other possible deflection points of the elbow were also calculated.
Adult↗
[Magnetic resonance of the elbow: technique optimization and definitions of normal anatomical features and their variations].
INTRODUCTION: MRI is a very accurate technique to study the elbow joint, tendon, ligament and chondral structures. In the last years elbow disorders were described by several MR investigators, while we studied MR capabilities in depicting normal elbow anatomy. This investigation might permit the correct differentiation of normal from abnormal MR patterns. MATERIAL AND METHODS: Eleven healthy volunteers (6 men and 5 women, mean age: 27.5 years) were examined. All studies were performed on a 1.5 T imager (Magnetom SP 4000) with two types of receiver: the knee coil was used in 7 volunteers examined in the prone position, with the arm above their head, the elbow extended and the forearm supine and the shoulder coil was used in 4 volunteers examined in the prone position, with the arm above their head, the elbow flexed and the forearm prone. We acquired T1-weighted SE sequences (TR/TE = 690/15 ms, FA 90 degrees, MA 256 x 512, NEX 2,20 3-mm sections with .3-mm interslice gap, FOV 20-22 cm) on the axial, coronal and sagittal planes and T2-weighted GE sequences (TR/TE = 450/10 ms, MA 256 x 256, 3 NEX, 18 4-mm sections with .4-mm interslice gap, FOV 13-18 cm) on the coronal plane. Two MR-expert radiologists studied the images and identified the main anatomical structures of the elbow and 12 smaller reference elements (2 anatomical variants, 4 ligaments, 3 nerves and 3 arteries) describing their MR appearance and pointing out the most effective planes for their representation. Finally, the image quality of the knee coil was compared with that of the shoulder coil. RESULTS: All bones were clearly depicted on the coronal and axial planes, while the semilunar groove and its anatomical variants were best seen on the sagittal plane. The joint cartilage was best depicted on the coronal plane with T2-weighted GE sequences. Collateral ligaments were best seen with the elbow extended and the forearm supine (knee coil), on coronal T1-weighted SE images, where the radial and ulnar collateral ligaments were visible in 71.4% and 85.7% of the subjects, respectively. Annular ligaments, muscles and tendons were best demonstrated on the axial plane with the elbow extended and the forearm supine (knee coil), while the triceps tendon was best recognized on the sagittal plane with the elbow flexed and the forearm prone (shoulder coil). Vessels and nerves were also best seen on the axial plane with the elbow extended and the forearm supine; in particular, the median nerve was visible in 71.4% of the subjects. DISCUSSION AND CONCLUSION: MRI is very effective in representing elbow anatomical structures. Its accuracy depends on elbow (flexed or extended) and forearm (prone or supine) position. The coronal images with the elbow extended and the forearm supine (knee coil) are the most effective to show the ligaments and the joint surfaces between the radial head and the coronoid process of ulna with the capitellum and trochlea of distal humerus, while the axial images best depicted the muscles, vessels and nerves. The coronal and axial planes, with the elbow flexed and the forearm prone (shoulder coil) are poorly effective for anatomical detailing, even though this position is more comfortable for the patient, while the sagittal plane is best suited to depict the triceps tendon. This position may be used when the elbow cannot be fully extended or when the triceps tendon is studied.
Adult↗
Effect of elbow flexion on upper extremity impact forces during a fall.
OBJECTIVE: The overall objectives are to develop a biomechanical model for a simulated fall with outstretched hand. DESIGN: Cross-sectional study involving young healthy volunteers in a university research laboratory setting. BACKGROUND: Little is known about the factors which influence fracture risk during a fall on outstretched hand. METHODS: A group of 11 male subjects volunteered for this investigation. A set of eight reflective markers was placed bilaterally on selected anatomic landmarks. Subjects were suspended with both elbows extended and wrists dorsiflexed, preparing to impact the ground and force plates from two different fall heights: 3 and 6 cm. Two different postures for the elbows were employed. In the elbow extension experiment, the elbows were extended at all times. In the elbow flexion experiment, the elbows were extended at impact, but then flexed immediately, as though in the initial downward phase of a push-up exercise. RESULT: Increasing the fall height significantly increased the upper extremity axial forces by 10% and 5%. No significantly different differences were found in the axial forces applied to the wrist, elbow or shoulder between the elbow flexion and elbow extension trials, but the elbow mediolateral shear force was 68% larger (P=0.002) in the extension trials. CONCLUSIONS: Performing an elbow flexion movement at impact reduces the first peak impact force value and postpones the maximum peak value. Although changing the fall arrest strategy from elbow extension to elbow flexion did not affect the peak impact force on the hand, it did require substantially greater elbow and shoulder muscle strengths. RELEVANCE: This paper yields insights into how the physical demands of arresting mild falls may relate to upper extremity muscle capacity, joint dislocation and bony fracture.
Accidental Falls↗
Radiographic study of joint destruction patterns in the rheumatoid elbow.
Knowledge of the pattern of joint destruction is important for planning the therapeutic approach to rheumatoid arthritis (RA) of the elbow. Accordingly, we carried out a large-scale radiographic study with the objective of elucidating the joint destruction pattern in rheumatoid elbows. From 2001 through 2003, we examined and took plain X-rays of both elbows of 193 RA patients (i.e., 386 elbows), consisting of 18 men and 175 women, with a mean age of 57.0 years. Radiographic images of the elbow joints were used to classify the degree of bone loss in various zones on the elbow joint surface into four grades of severity, and joint destruction was compared between the left and right elbows. In addition, correlation in the extent of bone loss between each of the zones of the same elbow and differences in the extent of bone loss were analyzed statistically. The results showed direct correlations for destruction of the elbow joint surface among the zones for the left and right elbow joints and in the same elbow joint. However, more severe destruction was observed on the radial side of the humeral trochlea, and it was surmised that destruction of the elbow joint must begin at that site and gradually spread mediolaterally. In addition, in the same elbow joint, the correlation in the degree of bone loss between the trochlea of humerus and the trochlear notch was especially strong, indicating that the bone destruction at both sites represented mirror lesions. We conclude that when performing radiographic diagnosis of the joint damage in the rheumatoid elbow, knowledge of this pattern of joint destruction will be useful for assessing whether there is joint destruction in the initial stage and for deciding the therapeutic approach.
Adult↗
Effects of elbow flexion on radial nerve motor conduction velocity.
The position of the elbow while conducting motor studies of the radial nerve is generally extended (15) or slightly flexed (10), but little is known about the effects of elbow flexion on the radial motor conduction velocity. We attempted to measure the effects of the elbow position on the radial motor conduction velocity, as well as directly measure the change in the length of the nerve at different elbow positions in the cadaver. In addition, we established normal values for the radial F-wave with the recording electrode on the extensor indicis proprius muscle. Radial motor nerve conduction was studied in 25 normal subjects to evaluate the effect of 3 different elbow positions (0 degree, 45 degrees, and 90 degrees) on motor conduction velocity (MCV) across the elbow. Direct (in situ) radial nerve measurements were performed on four cadaver specimens to compare changes in nerve length during elbow flexion. Normal values for radial F-wave latencies recording from the extensor indicis proprius muscle were also determined in 23 subjects. The radial MCV decreased significantly as the elbow flexed from 0 degree to 90 degrees. The normal range of values for radial motor nerve conduction at 0 degree of elbow flexion was 71.7 +/- 4.7 m/s, 68.9 +/- 4.9 at 45 degrees of elbow flexion, and 62.0 +/- 6.4 m/s at 90 degrees elbow flexion. Actual (in situ) radial nerve measurements were also found to decrease in length as the elbow flexed. The minimal radial F-wave latency was 19.8 +/- 3.7 milliseconds. For routine determination of motor nerve conduction velocity across the elbow, we recommend that the elbow be fully extended, as the distance measurement most accurately reflects the maximum anatomic length of the nerve. We also feel that the radial nerve F-wave latency is readily obtainable from the extensor indicis proprius muscle.
Adult↗
Hierarchical control of different elbow-wrist coordination patterns.
The present paper focused on the role of mechanical factors arising from the multijoint structure of the musculoskeletal system and their use in the control of different patterns of cyclical elbow-wrist movements. Across five levels of cycling frequency (from 0.45 Hz up to 3.05 Hz), three movement patterns were analyzed: (1) unidirectional, including rotations at the elbow and wrist in the same direction; (2) bidirectional, with rotation at the joints in opposite directions, and (3) free-wrist pattern, which is characterized by alternating flexions and extensions at the elbow with the wrist relaxed. Angular position of both joints and electromyographic activity of biceps, triceps, the wrist flexor, and the wrist extensor were recorded. It was demonstrated that control at the elbow was principally different from control at the wrist. Elbow control in all three patterns was similar to that typically observed during single-joint movements: elbow accelerations-decelerations resulted from alternating activity of the elbow flexor and extensor and were largely independent of wrist motion at all frequency plateaus. The elbow muscles were responsible not only for the elbow movement, but also for the generation of interactive torques that played an important role in wrist control. There were two types of interactive torques exerted at the wrist: inertial torque arising from elbow motion and restraining torque arising from physical limits imposed on wrist rotation. These interactive torques were the primary source of wrist motion, whereas the main function of wrist-muscle activity was to intervene with the interactive effects and to adjust the wrist movement to comply with the required coordination pattern. The unidirectional pattern was more in agreement with interactive effects than the bidirectional pattern, thus causing their differential difficulty at moderate cycle frequencies. When cycling frequency was further increased, both the unidirectional and bidirectional movements lost their individual features and acquired features of the free-wrist pattern. The deterioration of the controlled patterns at high cycling frequencies suggests a crucial role for proprioceptive information in wrist control. These results are supportive of a hierarchical organization of control with respect to elbow-wrist coordination, during which the functions of control at the elbow and wrist are principally different: the elbow muscles generate movement of the whole linkage and the wrist muscles produce corrections of the movement necessary to fulfill the task.
Elbow Joint↗
Heat-sensitive conduction block in ulnar neuropathy at the elbow.
OBJECTIVES: To study the effects of elbow heating on conduction block (CB) and across-elbow conduction velocity (CV) in patients with ulnar neuropathy at the elbow (UNE). METHODS: We studied 15 patients with UNE, performing motor nerve conduction studies at 32 degrees C and after heating the elbow to 42 degrees C. RESULTS: At 32 degrees C, mean response amplitude and area with above-elbow (AE) stimulation were 20.4 and 16.0% lower than with below-elbow (BE) stimulation, respectively. With heating the elbow to 42 degrees C, these differences increased significantly to 28.9 and 26.9% (P=0.019 and 0.029), respectively. The mean CV reduction in the across-elbow segment relative to the forearm segment also increased from 20.5 m/s at 32 degrees C to 25.6 m/s at 42 degrees C (P=0.0010). Across-elbow CV at 32 degrees C correlated with increased CB (as measured by amplitude) with heating (r=0.53, P=0.048) and approached significance for area (r=0.48, P=0.068) Likewise, baseline CB at 32 degrees C correlated with the likelihood of increased CB for amplitude (r=0.77, P<0.001), and approached significance for area (r=0.47, P=0.079). CONCLUSIONS: Elbow heating in UNE increases the relative drop in across-elbow CV and the degree of across-elbow CB; absolute across-elbow CV and the presence of baseline CB at 32 degrees C are good predictors of this latter effect.
Adult↗
Importance of a radial head component in Sorbie unlinked total elbow arthroplasty.
The effects of a radial head component on total elbow arthroplasty kinematics and stability were evaluated using an anatomic design unlinked total elbow prosthesis. An electromagnetic tracking device recorded motion and varus and valgus displacements under various conditions in 10 cadaveric elbows. The motion patterns of the intact elbows and the Sorbie-Questor total elbow prostheses with a radial head component were similar, as both tended to have a valgus position in extension, varus at midflexion, and more valgus toward full flexion. Under conditions of simulated muscle loading, the maximum valgus and varus laxity of the elbow prosthesis was, on average, 8.6 degrees +/- 4.0 degrees greater than normal. Without the radial head component, however, significant kinematic disturbances and instabilities were seen. The varus and valgus displacements were 13.3 degrees +/- 5.5 degrees greater than the intact elbows. One total elbow arthroplasty without a radial head dislocated during testing. Increasing the muscle loading across the elbow significantly enhanced dynamic stability of the total elbow arthroplasties, especially in the extension half of elbow motion where instability is greatest. However, this dynamic enhancement of stability was seen only in those elbows in which the radial head component had been implanted. The radial head component is an important stabilizer, particularly in extension for this prosthesis, and possibly for other unlinked total elbow prostheses. Although instability of unlinked prostheses depends on the prosthetic design, the use of a radial head replacement may be an important factor in preventing such instability. Perhaps even more importantly, a radial head component balances the load distribution across the articulation, which could decrease stress on the ulnohumeral articulation and therefore possibly reduce polyethylene wear, osteolysis, and loosening.
Aged↗
Total elbow arthroplasty with use of a nonconstrained humeral component inserted without cement in patients who have rheumatoid arthritis.
BACKGROUND: Most total elbow prostheses that are currently in use require cement for fixation of each component. We developed a new (type-5) prosthesis that does not need cement for fixation. METHODS: The humeral component is made of cobalt-chromium alloy, and its stem is porous-coated with a plasma spray of titanium alloy. There are two options for the ulnar component: an all-polyethylene type and a metal-backed type with a porous-coated stem. Forty-three elbows in thirty-seven patients who had rheumatoid arthritis were treated with total elbow replacement arthroplasty with use of the type-5 prosthesis. The humeral component was implanted without cement in all elbows, whereas the ulnar component was implanted without cement in eleven elbows and was fixed with cement in the remaining thirty-two. The elbows were followed for an average of three years and ten months (range, two years and six months to five years and six months). RESULTS: The clinical results were assessed according to a modification of the Mayo Clinic Performance Index. At the time of the latest follow-up, the overall result was excellent for six elbows, good for thirty-one, and fair for six. All elbows had been rated as poor before the operation. There was almost complete relief of pain in twenty-nine elbows and mild or occasional pain in the remaining fourteen. Flexion increased markedly, from an average of 104 degrees preoperatively to an average of 133 degrees postoperatively; this difference was highly significant (p < 0.001, Student t test). In contrast, extension (flexion contracture) worsened slightly, from an average of 38 degrees preoperatively to an average of 42 degrees postoperatively; this difference was significant (p < 0.05). There was one postoperative dislocation of the elbow, and ectopic bone formed in another, with recurrence of ankylosis. Both elbows had a reoperation, and a good result eventually was obtained. There were no instances of postoperative infection or neuropathy of the ulnar nerve. Radiographically, there were no radiolucent lines at the bone-metal interface of any of the humeral or ulnar stems that had been implanted without cement, suggesting solid fixation by osseointegration. CONCLUSIONS: The results of total elbow arthroplasty with use of this prosthesis appear promising. There was a high rate of relief of pain as well as of restoration of adequate function in patients in whom the elbow was severely affected by rheumatoid arthritis.
Adult↗
Arthroscopic synovectomy of the elbow in rheumatoid arthritis.
BACKGROUND: The purpose of this study was to investigate the results of arthroscopic synovectomy for the treatment of elbows affected by rheumatoid arthritis. METHODS: Arthroscopic synovectomy was performed on twenty-nine elbows (twenty-seven patients) between 1984 and 1996. Twenty-one elbows (twenty patients), followed for a minimum of forty-two months, were evaluated clinically with use of the Mayo elbow performance score and radiographic findings. The mean duration of follow-up was ninety-seven months. With use of the system of Larsen et al., we classified all elbows into three groups--Grades 1 and 2, Grade 3, and Grade 4--according to the preoperative radiographic findings. These groups were then compared. RESULTS: The mean Mayo elbow performance score improved from 48.3 points preoperatively to 77.5 points (an excellent result in two elbows, a good result in thirteen, a fair result in six, and a poor result in none) at two years after the operation and 69.8 points (an excellent result in two elbows, a good result in seven, a fair result in seven, and a poor result in five) at the final follow-up evaluation. The mean score for pain improved from 9.3 points preoperatively to 31.4 points at two years after the operation and 27.9 points at the final follow-up evaluation. Clinically apparent synovitis recurred in five of the twenty-one elbows, and two of the five required total elbow arthroplasty. Among the three groups, only elbows with Larsen Grade-1 or 2 arthritis had a favorable long-term result with regard to total function. The postoperative results were unsatisfactory for Larsen Grade-4 elbows. CONCLUSIONS: Arthroscopic synovectomy in an elbow affected by rheumatoid arthritis is a reliable procedure that can alleviate pain. Our results suggest that one of the most favorable indications for arthroscopic synovectomy is a preoperative radiographic rating of Grade 1 or 2.
Adult↗