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Prevalence and inheritance of and selection for elbow arthrosis in Bernese mountain dogs and Rottweilers in Sweden and benefit: cost analysis of a screening and control program.

OBJECTIVE: To determine the prevalence and charges over time in the prevalence of elbow arthrosis in Bernese Mountain Dogs and Rottweilers, to ascertain whether prevalence or severity of elbow arthrosis was associated with sex of the dogs, age at the time of elbow joint examination, or ancestral background, to determine the effects of selective breeding, and to conduct an economic evaluation of the elbow arthrosis program operated by the Swedish Kennel Club. DESIGN: Analysis of radiographic evaluations of elbow joint conformity. ANIMALS: 4,515 dogs from 2 breeds registered by the Swedish Kennel Club. PROCEDURE: All radiographs were scrutinized by a single radiologist (LA), and elbow joint conformation was classified as normal or arthrotic, with the degree of arthrosis classified as 1, 2, or 3. RESULTS: Decreasing prevalence of elbow arthrosis corresponding to selection of breeding stock and high heritabilities was found. Sex differences were documented in both breeds, but with contradictory directions. This was interpreted as breed differences in the distribution of genes related to elbow arthrosis. Economic analyses showed that costs of screening and registration of elbow joints was less than the value of dogs estimated to have been saved from moderate and severe elbow arthrosis in both breeds. CLINICAL IMPLICATIONS: Documented effects of age suggest that all dogs should be screened at the same age, rather than screening a few dogs at an older, more revealing age. In screening and control programs based on an open registry with access to family records, decreasing prevalence of elbow arthrosis can be expected, and related to selection of breeding stock.

Age Distribution↗

The effect of coronoid fractures on elbow kinematics and stability.

BACKGROUND: Coronoid fractures often occur in the setting of more complex elbow trauma. Little is known about the influence of coronoid fracture size on elbow kinematics, particularly in the setting of concomitant ligament injuries. The purpose of this study was to determine the effect of coronoid fractures on elbow kinematics and stability in ligamentously intact and medial collateral ligament deficient elbows and to determine the effect of forearm position on elbow stability in the setting of coronoid fracture. METHODS: Eight cadaveric arms were tested during simulated active dependent elbow motion and gravity-loaded passive elbow motion. Kinematic data were collected from an electromagnetic tracking system. The protocol was performed in ligament origin repaired and medial collateral ligament deficient elbows with radial head arthroplasty. Testing was carried out with the coronoid intact, and with 10% (Type I), 50% (Type II), and 90% (Type III) removed. Varus-valgus angulation of the ulna relative to the humerus and maximum varus-valgus laxity were measured. FINDINGS: With repaired ligament origins and medial collateral ligament deficiency, there was increased varus angulation and increased maximum varus-valgus laxity following simulation of a Type II and Type III coronoid fracture. There was less kinematic change with the forearm in supination than in pronation. INTERPRETATION: Elbow kinematics are altered with increasing coronoid fracture size. Repair of Type II and Type III coronoid fractures as well as lateral ligament repair is recommended where possible. Forearm supination may be considered during rehabilitation following coronoid repair. Valgus elbow positioning should be avoided if the medial collateral ligament is not repaired.

Aged↗

Lateral tennis elbow: "Is there any science out there?".

As orthopaedic surgeons, we are besieged by myths that guide our treatment of lateral epicondylitis, or "tennis elbow." This extends from the term used to describe the condition to the nonoperative and operative treatments as well. The term epicondylitis suggests an inflammatory cause; however, in all but 1 publication examining pathologic specimens of patients operated on for this condition, no evidence of acute or chronic inflammation is found. Numerous nonoperative modalities have been described for the treatment of lateral tennis elbow. Most are lacking in sound scientific rationale. This has led to a therapeutic nihilism with respect to the nonoperative management of this condition. An examination of the literature can only lead us to believe that most, if not all, common nonoperative therapeutic modalities used for the treatment of tennis elbow are unproven at best or costly and time-consuming at worst. Most of the published literature on the nonoperative treatment of patients with lateral tennis elbow consists of poorly designed trials. The selection criteria are nebulous, the control group is questionably designed, and the number of patients is often too low to avoid a serious loss of study power. These studies therefore have a high beta error, implying an inability to detect a difference between groups, even if one truly existed. If clinical signs and symptoms persist beyond the limit of acceptability of both patient and surgeon, then an array of surgical options are available. These range from a 10-minute office procedure (the percutaneous release of the extensor origin with the patient under local anesthetic) to an extensive joint denervation, in which all radial nerve branches ramifying to the lateral epicondyle are directly or indirectly divided. How is the surgeon to choose, given the fact that most of the published surgical studies are case series of one type of operation or another, consisting of patients operated on and evaluated by the same surgeon, who has a vested interest in his or her own patients' successful outcome? The orthopaedic surgeon therefore has very little on which to "hang his hat" when it comes to objective data to guide treatment of patients with lateral tennis elbow syndrome. In the final analysis we are guided simply by our own subjective viewpoint and clinical experience. In 1999, to have such a common clinical condition have such a paucity of peer-reviewed published data of acceptable scientific quality is disappointing. In this review article we will examine the "myths" of tennis elbow: the name, the salient features on history and physical examination, the diagnostic modalities, the pathology of the "lesion," the anatomy of the lateral elbow and extensor origin and why it has led to such confusion in differential diagnosis, the nonoperative and operative treatment of tennis elbow, and finally the various studies that have been carried out on elbow biomechanics as it relates to the pathoetiology of true "tennis elbow." It is our hope that the reader will emerge with a clearer picture of the pathoetiology of the condition and the scientific rationale (or lack thereof) of the various operative and nonoperative treatment modalities.

Acupuncture Therapy↗

Elbow arthroscopy in the pediatric and adolescent population.

PURPOSE: The purpose of this study was to show the diagnostic and therapeutic benefits of elbow arthroscopy in athletically active pediatric patients. We describe our techniques for elbow arthroscopy in young patients. TYPE OF STUDY: Case series of 47 patients. METHODS: We reviewed 49 cases of elbow arthroscopies performed in 47 pediatric and adolescent patients retrospectively over a 16-year period. Charts were reviewed to identify the age of patients at the time of surgery, side involved, hand dominance, diagnosis, complications, the primary sport involved, and the average volume of loose bodies if surgical removal was performed. Each patient was contacted after a minimum of 2 years after surgery and a modified Andrews elbow scoring system was used to rate elbow function. RESULTS: The average age of this group was 14.0 years (range, 3.5 to 17.0 years) with an average follow-up of 4.7 years. Elbow arthroscopy was performed for osteochondritis dissecans (58%), arthrofibrosis and joint contracture (20%), synovitis (10%), acute trauma (10%), and posterior olecranon impingement syndrome (5%). Based on a modified Andrews elbow scoring system, 85% of patients had good or excellent result with 90% of the children returning to sports without limitation. No patient experienced nerve injury, infection, or loss of elbow motion as a postoperative complication. CONCLUSIONS: This series shows that elbow arthroscopy has a safe and effective role in the treatment of selective elbow pathologies in the pediatric and adolescent population when performed by experienced small joint arthroscopists.

Adolescent↗

Treatment of bilateral elbow dislocation using external fixation with motion capacity: a report of 2 cases.

Bilateral elbow dislocation is a rare injury and only 11 cases are described in the literature, including 8 patients with isolated ligamentous and 3 patients with an additional osseous injury. We present 2 cases of bilateral posterior elbow dislocations treated with a bilateral hinged elbow fixator with motion capacity to allow for early physiotherapy. Both patients had a high-energy trauma with one who fell off a ladder from a 5 m height and the second from a mountain bike injury during off-road biking. All extremities were neurovascularly intact. In the operating room, severe instability was detected in all 4 elbows: after closed reduction in 3 elbows and open reduction in 1 elbow for a Mason type 4 fracture of the radial head that was internally fixed using fine threaded implants, an elbow fixator with motion capacity was applied in all 4 elbows for a period of 6 weeks. One year after surgery, the active range of motion was 0/10/140 degrees of extension and flexion on the right and 0/0/130 degrees on the left side. The second patient achieved 0/0/125 degrees and 0/10/130, respectively. Pro- and supination was full in both patients. All 4 elbows were stable and there were no radiologic signs of degenerative changes at the 1 year follow-up. Treatment of bilateral elbow dislocation using external fixation with early motion capacity allows for active physiotherapy although maintaining joint stability, thus minimizing complications normally associated with the injury. Using this method resulted in an excellent clinical outcome for both patients.

Adult↗

Medial elbow joint laxity in professional baseball pitchers. A bilateral comparison using stress radiography.

Injuries to the ulnar collateral ligament frequently occur in throwing athletes because of large, repetitive valgus stresses to the elbow during the cocking and acceleration phases of throwing. Identification of injury to this ligament is important in evaluating the throwing elbow. The purpose of this study was to determine whether differences in medial elbow laxity exist between the dominant and nondominant extremities in uninjured baseball pitchers. Forty uninjured professional baseball pitchers were tested bilaterally with a Telos GA-IIE stress radiography device. Joint space width between the trochlea of the humerus and the coronoid process of the ulna was measured on anteroposterior radiographs obtained with no stress applied and with a 15-daN valgus stress. Results showed significant differences between the medial joint space opening of the dominant and nondominant elbows with no stress applied. With stress, the dominant elbow opened 1.20 +/- 0.97 mm, while the nondominant elbow opened 0.88 +/- 0.55 mm. A significantly greater difference in medial joint space opening between the stressed and unstressed elbows was measured in the dominant elbow compared with the nondominant elbow (0.32 +/- 0.42 mm). This study identifies increased medial elbow laxity in the dominant arm in uninjured pitchers.

Adult↗

Pain dominates measurements of elbow function and health status.

BACKGROUND: Elbow function can be quantified with use of physician-based elbow-rating systems and health status questionnaires. Our hypothesis was that pain has a strong influence on these scores, which overwhelms the influence of objective factors such as motion. METHODS: One hundred and four patients were evaluated, at a minimum of six months (average, forty-six months) after the latest surgery for an intra-articular fracture of the elbow, with use of three physician-based evaluation instruments (Mayo Elbow Performance Index [MEPI], Broberg and Morrey rating system, and American Shoulder and Elbow Surgeons Elbow Evaluation Instrument [ASES]), an upper-extremity-specific health status questionnaire (Disabilities of the Arm, Shoulder and Hand [DASH]), and a general health status questionnaire (Short Form-36 [SF-36]). Multivariate analysis of variance and regression modeling were used to identify the factors that account for the variability in scores derived with these measures-in other words, which factors have the strongest influence on the final score. RESULTS: Pain alone accounted for 66% of the variability in the MEPI scores, 59% of the variability in the Broberg and Morrey scores, and 57% of the variability in the ASES scores. Models that included other factors accounted for only slightly more variability (73%, 79%, and 79%, respectively), and those that did not include pain accounted for only 22%, 41%, and 41% of the variability. Thirty-six percent of the variability in the DASH scores could be accounted for by pain alone, and 45% could be accounted for by pain and range of motion. Models not including pain accounted for only 17% of the variability in the DASH scores. CONCLUSIONS: Pain has a very strong influence on both physician-rated and patient-rated quantitative measures of elbow function. Consequently, these measures may be strongly influenced by the psychosocial aspects of illness that have a strong relationship with pain, and objective measures of elbow function such as mobility may be undervalued. It may be advisable to evaluate pain separately from objective measures of elbow function in physician-based elbow ratings.

Adult↗

[Complex injury of the elbow joint].

High-velocity trauma now often results in complex injuries to the upper extremity, and especially the elbow joint. These can lead to both an enormous reduction in the range of motion of the shoulder, elbow and wrist joints, in severe cases with complete loss of upper extremity function. A complex injury is defined as a fracture and/or dislocation of the elbow in association with (1) a serial injury of the upper extremity, (2) a severe soft tissue trauma, or (3) concomitant injury to vessels or nerves. Serial fractures, in particular can lead to enormous problems with treatment and are often associated with special complications. A standardized operative approach therefore seems essential. An analysis of our patient populations was made to compare the frequency of different injury types, develop specific treatment regimens, and document the clinical course. We made a retrospective analysis of patients admitted to our facility between 1981 and 1992, with particular reference to cause of accident, severity of injury (ISS), type of fracture of the upper extremity (according to the AO classification), extent of soft tissue trauma and whether closed or open, and the concomitant injuries (vascular, compartment and nerve lesions). Type and sequence of therapy and any complications were noted, and the clinical course up to consolidation was recorded. The functional result (i.e., ROM, neurology) was observed at primary discharge and 12 weeks, 6 months and 2 years later. In the time period mentioned 224 complex injuries of the elbow region were noted. Often MVAs were the cause of the complex trauma (39% car/30% motorcycle). The average injury severity was scored as 32 (ISS) in these, mostly polytraumatized, patients (68%). The most frequent fracture combination at the elbow region was combined with C2/C3 fractures of the distal humerus (57%) and proximal ulna (43%). A very commonly seen complex injury was the Monteggia equivalent, with fracture dislocation of the proximal ulna. Most (82%) of the injuries at the elbow region were open, and open lesions were similarly frequently seen at the forearm shaft. The most frequent concomitant injuries was were to the nerves (63.5%) and the plexus. A compartment syndrome developed in 23.8%. This complication was frequently seen in multiple trauma patients after primary resuscitation (extensive volume therapy) and in serial fractures with more than three associated lesions. In 67% of these complex injuries a definitive operation was performed as primary treatment (in the first 24 h after injury). Debridement of open fractures and fasciotomy in compartment syndrome of the forearm are standard techniques in the initial care. In serial fractures all concomitant (humerus, forearm, wrist, etc.) fractures were operated on primarily. This primary treatment included ORIF of humeral and forearm fractures in 76%. In patients with multiple injuries (ISS > 30) primary treatment was not possible in 37%, and in these cases transfixation of the elbow joint was performed. Other indications for transfixation were severe comminution of the elbow joint, impossibility of achieving complete stability after ORIF, extensive soft tissue injuries, with healing dependent on short-term immobilization, and finally status following extensive ligamentous reconstruction. The most frequent permanent disturbance was a persisting nerve lesion in our patients. A significantly reduced range of motion (30% deficit flexion/extension) was mostly seen at the elbow (17%), most frequently associated with serial fractures (> 3 associated injuries) and with severe semicircular soft tissue trauma. The most severe injury in combined trauma of the upper extremity is a serial fracture in the elbow region. Such fractures are often associated with vascular and nerve lesions. Even with primary fracture stabilization and early soft tissue management these often end with significant functional deficits.(ABSTRACT TRUNCATED)

Elbow Joint↗

Cold elbow syndrome: spurious slowing of ulnar nerve conduction velocity.

Low temperature decreases nerve conduction velocity (NCV). The across-elbow segment of the ulnar nerve is superficial and may be particularly susceptible to decreased temperature. We evaluated patients without clinical ulnar neuropathy at the elbow (UNE) but with isolated slowing of the across-elbow ulnar NCV (normal group), and patients with clinical and electrodiagnostic findings of UNE (UNE group). All subjects had ulnar motor nerve studies completed before and after warming. The mean across-elbow NCV was 43.4 m/s and 48.6 m/s (P < 0.0001) in the normal group, and 37.4 m/s and 37.7 m/s (P = 0.90) in the UNE group, before and after warming, respectively. There was no change in the forearm segment NCV in either group. Seventeen of 32 subjects in the normal group had completely normal studies after warming. No patients with UNE developed normal across-elbow NCV with warming. Low temperature slows across-elbow ulnar NCV in normal subjects without impact on the forearm segment. Warming of the elbow improves across-elbow ulnar NCV in normals, but does not reverse the abnormalities in patients with UNE. Elbow warming should become a routine part of ulnar nerve conduction studies, especially when there is isolated conduction slowing in the across-elbow segment.

Cold Temperature↗

[Endoprosthetic joint replacement of the contracted elbow joint].

In a retrospective study 14 patients were reviewed 63 months after the implantation of a semi-constrained total elbow prosthesis in fourteen stiff or ankylosed elbows with a preoperative range of elbow motion of 30 degrees or less. The result, according to the Mayo Elbow Performance score, was excellent for four elbows, good for four, fair for one, and poor for five. The average arc of flexion improved from 7 to 68 degrees postoperatively with an average increase of 34 degrees in flexion, and 27 degrees in extension. There were seven complications affecting seven of the 14 elbows and four of these seven elbows underwent a revision procedure. Replacement for a stiff elbow is the least predictable, has the lowest overall rate of success and highest complication rate, than any other procedure. Nevertheless, these disadvantages must be placed in the context of alternative intervention options. The semiconstrained total elbow arthroplasty seems to be a useful option for patients older than 50 years with intrinsic stiffness involving more than 50% of the articular surface and with an ankylosed or very stiff elbow.

Adult↗

Radiography of the elbow for evaluation of patients with osteochondritis dissecans of the capitellum.

OBJECTIVE: This study was performed to determine the ability of a routine radiographic examination of the elbow to detect osteochondritis dissecans of the capitellum and associated intra-articular loose bodies. DESIGN AND PATIENTS: The study group consisted of 15 patients with osteochondritis dissecans of the capitellum confirmed by surgery or magnetic resonance imaging. Seven of the 15 patients had associated intra-articular loose bodies confirmed by surgery. All 15 patients had anteroposterior and lateral radiographs and magnetic resonance imaging of their symptomatic elbow. Nine of the 15 patients had subsequent elbow surgery. We reviewed the original interpretations of the radiographic examinations of the elbow of all 15 patients to determine whether osteochondritis dissecans of the capitellum and associated intra-articular loose bodies had been identified prospectively. We also reviewed the elbow radiographs of all 15 patients to determine whether osteochondritis dissecans of the capitellum and associated intra-articular loose bodies could be identified retrospectively. RESULTS: Osteochondritis dissecans of the capitellum was detected during the initial interpretations of the radiographic examinations of the elbow in seven of 15 patients. Osteochondritis dissecans of the capitellum was detected during retrospective review of the elbow radiographs in 10 of 15 patients. Intra-articular loose bodies were detected during the initial interpretations of the radiographic examinations of the elbow in three of seven patients. Intra-articular loose bodies were detected during retrospective review of the elbow radiographs in four of seven patients. CONCLUSIONS: A routine radiographic examination of the elbow has limited sensitivity for detecting osteochondritis dissecans of the capitellum and associated intra-articular loose bodies.

Adolescent↗

Rehabilitation of elbow trauma.

The rehabilitation of elbow trauma presents numerous challenges. Involvement of the osseous structures, compromise of the ligamentous stability, and loss of the soft tissue excursion necessary for elbow motion and function require due consideration during the treatment of elbow joint injuries. Stiffness of the elbow joint following trauma is common. This stiffness is caused by extrinsic and intrinsic factors. Contractures of the elbow joint develop as a result of contractures of the joint capsule, ligamentous structures, musculotendinous structures, intra-articular adhesions,and ectopic ossification. Early mobilization and splinting of the elbow following injury, within a safe arc of elbow motion, makes the elbow joint more compliant to the rehabilitative techniques outlined. Understanding the details of elbow anatomy, biomechanics, trauma, and surgical procedures for repairing the osseous and the ligamentous structures thus are the key factors in rehabilitating the elbow joint successfully.

Humans↗

The Steindler flexorplasty for the arthrogrypotic elbow.

PURPOSE: The arthrogrypotic elbow often lacks active flexion. If active elbow flexion can be provided by muscle transfer, patient independence increases and the patient can function in a less conspicuous manner by avoiding adaptive mechanisms. The purpose of this article is to review the outcome of patients with arthrogryposis treated with the Steindler flexorplasty to obtain active elbow flexion. METHODS: Seventeen elbows in 10 patients with an average age of 7 years were treated surgically with the Steindler flexorplasty procedure. Before surgery none of the patients was able to flex actively the elbow against gravity. All of the patients had at least 70 degrees of passive elbow flexion. Upper-extremity active and passive range of motion, strength of flexion, functional outcome, and patient satisfaction were assessed at an average of 5 years after surgery (range, 2-9 years). RESULTS: After surgery all patients obtained active elbow flexion against gravity averaging 85 degrees (range, 30 degrees -120 degrees ); patients were able to lift an average of 1 kg through their entire arc of elbow flexion. At last follow-up evaluation patients lost an average of 27 degrees of elbow extension. Patients lost forearm rotation but did not lose wrist or finger range of motion. Subjectively, 9 of the 10 patients were satisfied with the outcome of the surgery and would recommend the surgery to others. CONCLUSIONS: The Steindler flexorplasty provides improved elbow flexion strength and patient function and should be considered for children with arthrogryposis.

Activities of Daily Living↗

Radial nerve excursion and strain at the elbow and wrist associated with upper-extremity motion.

PURPOSE: This study evaluated the excursion necessary to accommodate common motions of daily living and associated strain on the radial nerve. The radial nerve was evaluated at the wrist and proximal to the elbow before it bifurcated. METHODS: Five fresh-frozen transthoracic cadaver specimens (10 arms) were dissected; the radial nerve was exposed at the elbow and wrist only enough to be marked with a microsuture. Excursion was measured using a laser mounted on a caliper fixed to the bone and aligned in the direction of nerve motion. Strain was measured with a device applied to the nerve at the elbow. Nerve excursion associated with motion of the shoulder, elbow, wrist, and fingers (measured by a goniometer) was assessed at the wrist and elbow. RESULTS: An average of 4.3 mm of radial nerve excursion was required at the wrist to accommodate wrist motion from 15 degrees of radial deviation to 30 degrees of ulnar deviation and 8.8 mm was needed for elbow motion from 10 degrees to 90 degrees . The radial nerve at the elbow experienced a 28% strain associated with the same motion of flexion and extension at the elbow. When all the motions of the wrist, fingers, elbow, and shoulder were combined 9.4 mm of radial nerve excursion was required at the wrist and 14.2 mm at the elbow. CONCLUSIONS: Any factor that limits excursion at these sites could result in repetitive traction of the nerve and possibly could play a role in the pathophysiology of a mechanical neuropathy, which in the case of the radial nerve most often manifests as pain.

Body Weights and Measures↗

Outcome of revision surgery for failed primary Souter-Strathclyde total elbow prosthesis.

Total elbow arthroplasty is used for the treatment of the painful, destroyed elbow joint. With the increase in elbow replacement surgery in recent years, the number of revision surgeries will also increase. At our center, 236 primary Souter-Strathclyde total elbow prostheses have been placed. Twenty-four of these have been revised and were followed up for a mean of 74 months (range, 12-165 months). The postoperative clinical outcome after revision surgery can approximate the outcome after primary elbow replacement. Unfortunately, 8 elbows needed to be re-revised, 7 elbow prostheses loosened, and we had 1 early dislocation during follow-up. Three of the eight re-revised elbows had a third revision. Two other patients had a resection arthroplasty because of deep infection after the first revision. After 5 years, 73.8% of the revised elbow prostheses were still in situ. The lack of other satisfactory treatment options, combined with the satisfactory clinical results, justify revision surgery of elbow prostheses. The absence of intraoperative fracture during removal of the relatively small standard components and the availability of long-stemmed revision components, which facilitate fixation in the impaired bone, both support our preference for the Souter-Strathclyde prosthesis.

Adult↗

Simulated active control produces repeatable motion pathways of the elbow in an in vitro testing system.

The purpose of this study was to determine if the repeatability and pattern of elbow kinematics are affected by changing the relative magnitudes of loads applied to muscles around the elbow in vitro. In eight cadaveric upper extremities, passive and three methods of simulated active elbow flexion were tested with the forearm maintained in both pronation and supination. Passive flexion involved moving the elbow manually through a full arc of motion. Simulated active flexion used a custom designed loading system to generate elbow motion by applying loads to various tendons via pneumatic actuators. Three different simulated active loading protocols, with loading ratios based on muscle activity and physiologic cross-sectional area, were tested. Testing was performed initially on an intact elbow, and then an unstable elbow model created by transection of the lateral collateral ligament (i.e. the radial and lateral ulnar collateral ligaments). An electromagnetic tracking device was used to measure rotation of the ulna relative to the humerus. Varus-valgus angulation and internal-external rotation were less repeatable during passive flexion than simulated active flexion, regardless of the loading ratio used, in both the intact (p<0.05) and unstable (p<0.05) elbows. Throughout the arc of flexion, the motion pathways were similar for the three simulated active motion protocols employed in this study (p>0.05). The pathways followed during passive motion were different from those generated with simulated active motion, especially in the unstable elbow with the forearm supinated (p<0.001). These results suggest that using simulated active motion rather than manual passive motion can improve the repeatability of elbow kinematics generated in the laboratory, and that a wide range of muscle loading ratios may produce similar kinematic output.

Aged↗

A transducer to measure isometric elbow moments.

OBJECTIVE: The purpose of this study was to design and implement a transducer to measure accurately the isometric elbow moments produced by individuals with tetraplegia. DESIGN: The device needed to be insensitive to off-axis moments and proximal joint motions and be capable of being used over a wide range of elbow and shoulder positions in an outpatient clinic setting. BACKGROUND: Measurement of the smaller isometric moments produced by individuals with tetraplegia is especially sensitive to the errors that can be introduced by inaccurate lever arm determination, off-axis loads, and proximal joint motions. Devices traditionally utilized for quantifying isometric strength are difficult to implement for the spinal cord injured population. METHODS: The elbow moment transducer consists of two four-bar parallelogram linkages joined by a lockable pivot. Strain gauges mounted on one beam of the parallelogram produce an output proportional to the elbow moment. RESULTS: Calibration of the device indicates that it accurately quantifies isometric elbow moments over a range that is appropriate for evaluating elbow extension strength in individuals with tetraplegia. CONCLUSIONS: A device was developed and implemented that accurately quantifies isometric elbow moments over a range that is appropriate for evaluating elbow extension strength in individuals with tetraplegia. RELEVANCE: The ability to quantitatively evaluate elbow strength in persons with tetraplegia is useful for understanding and improving the clinical outcomes of rehabilitative interventions that involve the elbow.

Calibration↗

Ulnar nerve excursion and strain at the elbow and wrist associated with upper extremity motion.

Significant excursion of the ulnar nerve is required for unimpeded upper extremity motion. This study evaluated the excursion necessary to accommodate common motions of daily living and associated strain on the ulnar nerve. The 2 most common sites of nerve entrapment, the cubital tunnel and the entrance of Guyon's canal, were studied. Five fresh-frozen, thawed transthoracic cadaver specimens (10 arms) were dissected and the nerve was exposed at the elbow and wrist only enough to be marked with a microsuture. Excursion was measured with a laser mounted on a Vernier caliper fixed to the bone and aligned in the direction of nerve motion. A Microstrain (Burlington, VT) DVRT strain device was applied to the nerve at both the elbow and wrist. Nerve excursion associated with motion of the shoulder, elbow, wrist, and fingers (measured by goniometer) was measured at the wrist and elbow. An average of 4.9 mm ulnar nerve excursion was required at the elbow to accommodate shoulder motion from 30 degrees to 110 degrees of abduction, and 5.1 mm was needed for elbow motion from 10 degrees to 90 degrees. When the wrist was moved from 60 degrees of extension to 65 degrees of flexion, 13.6 mm excursion of the ulnar nerve was required at the wrist. When all the motions of the wrist, fingers, elbow, and shoulder were combined, 21.9 mm of ulnar nerve excursion was required at the elbow and 23.2 mm at the wrist. Ulnar nerve strain of 15% or greater was experienced at the elbow with elbow flexion and at the wrist with wrist extension and radial deviation. Any factor that limits excursion at these sites could result in repetitive traction of the nerve and possibly play a role in the pathophysiology of cubital tunnel syndrome or ulnar neuropathy at Guyon's canal.

Cubital Tunnel Syndrome↗