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Distance measure error induced by displacement of the ulnar nerve when the elbow is flexed.

OBJECTIVES: To determine the presence of ulnar nerve displacement at the elbow when it is flexed and to determine its effect on distance measurements using the conventional measurement method for nerve conduction studies (NCSs). DESIGN: Comparing the ultrasonography-assisted distance measurement method with the conventional measurement method. SETTING: An electrodiagnostic laboratory at a university hospital. PARTICIPANTS: Seventy-eight elbows of 39 healthy volunteers. INTERVENTIONS: We used high-resolution ultrasonography in real time. Based on sonographic searching, we marked 3 points on the skin through the course of the displaced ulnar nerve when the elbow is flexed: (1) point A, 7 cm above the elbow (from the midpoint between the medial epicondyle tip and olecranon in the postcondylar groove [point M]); (2) point B, 3 cm below the elbow; and (3) point C, the point closest to the medial epicondyle tip. MAIN OUTCOME MEASURES: Distance measurements between points A, B, and C were taken. These values were compared with measurements obtained through conventional measurement methods. RESULTS: Ulnar nerve displacement occurred in 24.3% (19/78) of the elbows; approximately 20.5% (16/78) were subluxation, and 3.8% (3/78) were dislocation. In the ulnar nerve displacement group, the distance between points A and C was 5.84+/-0.33 cm (range, 5.10-6.30 cm), and the distance between points B and C in the flexed position was 3.35+/-0.19 cm (range, 3.10-3.70 cm). When the conventional distance measurement was used, the ulnar nerve conduction velocity across the elbow was overestimated by approximately 5.33+/-2.29 m/s in the ulnar nerve displacement group. CONCLUSIONS: This distance measurement error may be responsible for the decreased sensitivity found in NCSs that test for ulnar neuropathy at the elbow. If the NCS results are normal in patients who have clear symptoms of ulnar neuropathy, the possibility of ulnar nerve displacement at the elbow should be considered, and further investigation with ultrasonography would be beneficial.

Adult↗

Five- to thirteen-year follow-up of the GSB III total elbow arthroplasty.

Between 1988 and 1995, the senior author performed total elbow arthroplasty in 28 elbows (23 patients) with the GSB III prosthesis. At the most recent follow-up, 7 patients had died (9 elbows) and 1 had the implant removed because of a deep infection. The remaining 18 elbows (15 patients) were available for clinical and radiographic review at a mean period of 7.6 years (range, 5.5-11.9 years). All 15 patients were satisfied with the results of their elbow replacement, with a mean Mayo elbow performance score of 91 (range, 75-100). The mean flexion/extension and supination/pronation arcs improved by 33 degrees and 67 degrees, respectively. Radiographic follow-up demonstrated progressive loosening in only 1 patient and no progressive loosening in those with an adequate cement technique. Mild or moderate lysis of the distal humeral or proximal ulnar components was noted in 10 elbows, and severe lysis of the distal humerus was seen in 1. Of the patients, 6 (21%) had mild complications: triceps avulsions in 3, superficial wound infections in 2, and an undisplaced fracture of the distal humeral medial condyle in 1. In 4 patients (14%) complications developed requiring reoperation, including exchange of the polyethylene bushing because of wear, debridement of synovitis, resection arthroplasty for deep infection, and exploration of an ulnar nerve palsy. In 2 additional patients (7%), persistent ulnar nerve paresthesias developed postoperatively. Of the 28 elbow replacements performed with the GSB III prosthesis, only 1 required revision because of loosening at a mean follow-up of 7.6 years. The results of this series of GSB III elbow replacements in patients with rheumatoid arthritis demonstrate reasonable survivorship of this prosthesis.

Arthritis, Rheumatoid↗

Functional outcomes and general health status after ulnohumeral arthroplasty for primary degenerative arthritis of the elbow.

Ulnohumeral arthroplasty (UHA) is considered a satisfactory surgical treatment option for patients with primary degenerative arthritis of the elbow. Most series have used categoric elbow scoring systems to evaluate the outcome of this procedure. The purpose of our study was to evaluate the outcome of UHA with patient-derived functional and general health status outcome instruments. We evaluated 17 patients (18 elbows) with primary degenerative arthritis of the elbow at a mean of 85 months after UHA. The mean age at the time of surgery was 42 years (range, 26 to 58 years). At the follow-up evaluation, the patients were assessed with a physical examination, outcome assessment tools, and plain radiographs. The mean elbow flexion arc improved by 16 degrees (range, -15 degrees to 60 degrees ; P = .012), and the mean forearm rotation arc (supination/pronation) improved by 35 degrees (range, -20 degrees to 90 degrees ; P < .001). Of the elbows, 11 were painless, 4 were painful with motion, and 3 were painful at rest and with motion. The mean Hospital for Special Surgery elbow score was 70 (range, 40 to 99), and the mean Mayo Elbow Performance Score was 83 (range, 50 to 100). The mean Disabilities of the Arm, Shoulder and Hand score was 9.75 (range, 0 to 43.48). The Short Form-36 scores were better than the mean age- and sex-adjusted normal values. Patient self-assessed outcomes and general health status after UHA for primary degenerative elbow arthritis appear to be better than those determined by some categoric scoring systems. Consequently, the clinical utility of UHA may be underrepresented if physician-derived categoric scoring systems are the only measures of outcome assessment.

Adult↗

Long-term results of unconstrained Roper-Tuke total elbow arthroplasty in patients with rheumatoid arthritis.

We evaluated the long-term results of 12 unconstrained Roper-Tuke total elbow replacements that were performed in 12 patients with rheumatoid arthritis from 1983 to 1989. The mean follow-up period was 9.5 years (range 8 to 13 years). We used the Ewald elbow-scoring system to chart results. This showed that the scores for the 12 elbows had improved from an average preoperative score of 39 points (range 17 to 72 points) to an average postoperative score of 80 points (range 45 to 97 points). The greatest improvements were in terms of pain relief, function, and range of motion. Eight elbows were free of pain by the end of follow-up. Average elbow flexion increased from 115 degrees before operation to 140 degrees after operation, and pronation and supination increased from 52 degrees to 61 degrees and 42 degrees to 71 degrees, respectively. Radiographs of the 12 elbows showed constant wear of the ulnar polyethylene with loosening of 2 ulnar components. Revision of the prosthesis was necessary in 2 elbows because of aseptic loosening. Complications included 1 subluxation, 1 supracondylar fracture, and 2 ulnar neuropathies. Despite some excellent clinical results with a follow-up of over 10 years, the authors no longer recommend the use of this kind of elbow prosthesis in patients with rheumatoid arthritis because of the high complication rate and the impossibility of adapting this implant in the event of bone loss. The authors propose a new classification of humeral bone loss that will allow for better planning of primary and revision total elbow arthroplasties.

Adult↗

The dynamic elbow suspension splint.

Elevation of the upper extremity after elbow surgery has rarely been advocated and can be difficult to achieve. Usually the extremity is elevated with the elbow at 90 degrees of flexion, so that swelling from the hand drains to the elbow but the elbow remains dependent. Excessive swelling causes discomfort and compromised wound healing, makes early mobilization difficult, and predisposes to joint contracture. We report on a dynamic elbow suspension splint, which is analogous to the Thomas splint used for femoral shaft fractures. The arm is held in full extension with an above-elbow plaster slab and is secured to the Thomas splint with skin traction. The splint is suspended on a Balkan frame at an angle of 60 degrees. We prefer to use the new Zimmer Thomas splint, because it is radiolucent and has self-adhesive sheep-skin supports that can be simply applied. It allows the patient to mobilize in bed and is well tolerated by patients and nursing staff. The dynamic elbow suspension splint is a useful adjunct after complex elbow surgery or trauma, because it reduces swelling and maintains the elbow in extension.

Elbow Joint↗

The effect of intraarticular anesthesia and elastic bandage on elbow proprioception.

Twenty uninjured male volunteers were studied to characterize normal elbow proprioception and to investigate the effect of applying an elastic bandage to the extremity and injection of an intraarticular anesthetic. A modified Biodex dynamometer was used to study position sense and detection of motion. In part 1 of the study position sense was tested by flexing the elbow to a predetermined angle, returning to the starting position, and then asking the subject to identify that angle. In part 2 detection of motion was tested by asking the subject to disengage the apparatus by pressing a stop button when movement was detected. The testing conditions in part 1 and part 2 were repeated after the elbow was wrapped with an elastic bandage and again after an intraarticular injection of 3 cc 1% lidocaine with the bandage removed. Ten additional subjects underwent testing of both elbows to examine the effect of arm dominance. Mean position sense was within 3.3 degrees+/-1.3 degrees of the actual angle in trials without an elastic bandage or an anesthetic. A significant improvement in position sense was observed (2.2 degrees+/-1.2 degrees) after an elastic bandage was applied (P < .004). No significant difference was seen in position sense after lidocaine was injected. The mean threshold for detection of motion in trials without an elastic bandage or an anesthetic was 4.21 degrees+/-1.56 degrees. No significant differences were seen in detection of motion observed with the elastic bandage or intraarticular anesthetic. No significant differences were seen between dominant and nondominant extremities for both position sense and detection of motion. The application of an elastic bandage improved position sense, suggesting that tactile cues from cutaneous or other extraarticular receptors may play a role in elbow proprioception. Intraarticular anesthesia, however, had little effect, suggesting that intracapsular receptors play a lesser role in elbow proprioception. The determination of proprioceptive qualities for the normal elbow can aid in the understanding of elbow function and provide a basis for defining its role in elbow dysfunction.

Adult↗

Evaluation of the strength of elbow flexors in patients with neuromuscular diseases.

In planning the optimum treatment for patients with neuromuscular diseases (NMD), it is essential to know as much as possible about their functional state. Assessment of the strength of certain muscles is the most direct measure of motor deficiency. In the development of normative data needed for patients with NMD, the use of torque measurements is required. Forty-nine patients (31 men and 18 women),f rom 18 to 54 years (mean age 33 +/- 8.9 years), were included in the study. Five groups of patients, each having one of five different NMDs, were formed. We tested unilaterally the biceps brachii muscle that normally generates the highest torque. For this purpose an eletronic brace enabling isometric measurements of torque during elbow flexion was designed. The patients produced three maximum voluntary elbow flexions that lasted about 3 s and separated by a pause of about 3 s. Force development was rapid with continuous build-up and isometric. About 15 s later the patients produced the last maximum voluntary elbow flexion, keeping it as stable aspossible for a period of 30 s. Patients with mitochondrial myopathy (MM), having the shortest mean half fatigue time (4.3 s), elicited the highest mean torque in both short maximum voluntary elbow flexions (1.34 Nm) as well as in the 30 s-long maximum voluntary elbow flexions. In contrast, patients with facioscapulohumeral muscular dystrophy (MD-FSH), having the longest mean half-fatigue time (15.4 s), elicited the lowest mean torque in both the short maximum voluntary (0.29 Nm) as well as in 30 s-long maximum voluntary elbow flexions. Patients with Becker muscular dystrophy (MD-B), having a mean half-fatigue time (11.1 s) slightly shorter than the patients with MD-FSH, elicited a higher mean torque in both the short (0.82 Nm) and the 30 s-long elbow flexions. Finally, patients with limb-girdle muscular dystrophy (MD-RM) and spinal muscular atrophy type 3 (SMA3), having a similar mean half-fatigue time (6.9 s for patients with MD-RM and 7.4 s for patients with SMA3), also elicited similar torque in both short (0.45 Nm for patients with MD-RM and 0.65 Nm for patient with SMA3) and 30 s-long elbow flexions. The results of the study show that the methodology developed to quantitative measure the torque of elbow flexions in patients with NMD enables the characteristics and natural course of NMD to be more objectively documented. Accordingly, the optimum treatmentforpatients with NMD could be restored.

Adolescent↗

Elbow complications after organ transplantation. Case reports.

Musculoskeletal abnormalities have rarely been reported after major organ transplantation. We recorded five cases of elbow complications after orthotopic liver and bilateral lung transplantation. Three patients (four elbows) developed heterotopic ossification at the elbow, leading to decreased range of motion, pain and difficulty performing self-feeding and perineal hygiene. Two patients (three elbows) had electrodiagnostic evidence of ulnar mononeuropathy at the elbow, whereas one patient had bilateral median mononeuropathies caused by compression at the level of the ligament of Struthers. Surgical resection of ectopic bone with postoperative radiation was required in two patients (two elbows), and nerve decompression was used in three patients (four elbows). Common factors noted in all patients with either heterotopic ossification or ulnar mononeuropathy at the elbow included prolonged encephalopathy and the use of wrist restraints with the presentation of symptoms occurring weeks after surgery. In the patient with bilateral median nerve entrapment, symptoms occurred immediately after surgery suggesting perioperative limb compression. Elbow complications after organ transplantation should be recognized to minimize long-term disability through preventive measures and appropriate treatment.

Adult↗

Treatment of ectopic ossification about the elbow.

The surgical treatment of elbow ectopic ossification associated with elbow stiffness has progressed significantly in the past decade. Although previous reports describe inconsistent results and high complication rates, numerous recent reports document not only good results, but also lower complication rates. The current study outlines the authors' treatment of patients with ectopic bone about the elbow. Various modalities have been used for prophylaxis against elbow ectopic ossification in the patient with elbow trauma. However, despite these prophylaxis efforts, periarticular ossification may form and result in disabling elbow stiffness. If ectopic ossification and stiffness develop, operative intervention may be indicated to restore motion. It has been long suggested that operative intervention be delayed for at least 1 year, with earlier intervention thought to predispose to recurrence. Recent reports, however, have documented good results with earlier intervention, from 3 to 6 months after injury. The evaluation of posttraumatic elbow stiffness associated with ectopic ossification is described, followed by a discussion regarding anatomic and functional classifications. Surgery is based on multiple factors including the location of ectopic ossification, the plane(s) of elbow stiffness, and the presence of associated nerve compression. A limited or extended Kocher approach may be used to release most contractures; however, other approaches may be necessary. Surgical technique is described in detail. Meticulous surgical technique is necessary to avoid complications, including triceps avulsion, recurrent elbow stiffness, and hematoma.

Contraindications↗

Muscle forces and pronation stabilize the lateral ligament deficient elbow.

The influence of muscle activity and forearm position on the stability of the lateral collateral ligament deficient elbow was investigated in vitro, using a custom testing apparatus to simulate active and passive elbow flexion. Rotation of the ulna relative to the humerus was measured before and after sectioning of the joint capsule, and the radial and lateral ulnar collateral ligaments from the lateral epicondyle. Gross instability was present after lateral collateral ligament transection during passive elbow flexion with the arm in the varus orientation. In the vertical orientation during passive elbow flexion, stability of the lateral collateral ligament deficient elbow was similar to the intact elbow with the forearm held in pronation, but not similar to the intact elbow when maintained in supination. This instability with the forearm supinated was reduced significantly when simulated active flexion was done. The stabilizing effect of muscle activity suggests physical therapy of the lateral collateral ligament deficient elbow should focus on active rather than passive mobilization, while avoiding shoulder abduction to minimize varus elbow stress. Passive mobilization should be done with the forearm maintained in pronation.

Collateral Ligaments↗

The reconstructive strategy for improving elbow function in late obstetric brachial plexus palsy.

Children with previously untreated obstetric brachial plexus palsy frequently have abnormal elbow function because of motor recovery with aberrant reinnervation, or because of paresis or paralysis. From 1988 to 1997 (9-year period), 62 children with obstetric brachial plexus palsy with resulting elbow deformity underwent various methods of palliative reconstruction to improve elbow function. For motor recovery with aberrant reinnervation, release of aberrantly reinnervated antagonistic muscles and augmentation of paretic muscles form the basis of surgical intervention. The surgical procedures included triceps-to-biceps transfer, biceps-to-triceps transfer, brachialis-to-triceps transfer, or combined biceps- and brachialis-to-triceps transfer. Choice of procedures was individualized and randomly determined on the basis of the degree and pattern of aberrant reinnervation between elbow flexors and extensors. In patients' motor recovery with paresis or paralysis, persistently weak elbow flexion was salvaged with a functioning free muscle transplantation or Steindler's flexorplasty, or regional shoulder muscle transfer. In addition, patients with aberrant reinnervation between shoulder abductors and elbow flexors underwent anterior deltoid-to-biceps transfer with a fascia lata graft. All patients had a minimum follow-up of 2 years. Results are assessed and discussed and a reconstructive algorithm is recommended. In general, reconstruction of elbow extension should precede that of elbow flexion. Biceps-to-triceps transfer with preservation of an intact brachialis muscle, or brachialis-to-triceps transfer with preservation of an intact biceps, allows 50 percent of these patients to achieve acceptable elbow flexion and extension in a single-stage procedure.

Adolescent↗

Computerised infrared thermography and isotopic bone scanning in tennis elbow.

Thirty five cases of tennis elbow (17 unilateral, nine bilateral) were studied with infrared thermography and isotopic bone scanning. A hot focus was visualised in 16 of 17 cases of unilateral tennis elbow (94%) and in all nine cases of bilateral tennis elbow (100%) on infrared thermography, and abnormal increased epicondylar activity seen in 12 of 17 (71%) and eight of 18 (44%) cases respectively with isotopic bone scanning. Unilateral visual cooling (somatosympathetic responses) occurred in seven of 13 cases of unilateral tennis elbow (54%) with infrared thermography, and reduced perfusion in seven of 12 (58%) of similar cases with blood pool isotopic bone scanning. Computerised temperature assessments showed statistically significant side to side temperature differences when 17 active tennis elbows were compared with the opposite normal elbows for spot temperatures, proximal and distal forearm gradients. Similar temperature assessments in 18 bilateral tennis elbows compared with 17 normal elbows showed significant temperature differences for elbow spot temperatures and distal forearm gradients, but not for proximal gradients.

Adult↗

Elbow valgus stress radiography in an uninjured population.

Valgus instability of the elbow joint is a clinical diagnosis. However, many authors describe valgus stress radiographs as an aid in making this diagnosis. We studied valgus stress radiographs of 20 men (40 elbows) and 20 women (40 elbows), none with a history of elbow trauma or instability. The medial ulnohumeral distance was measured with no stress, valgus stress by gravity, and an applied valgus stress of 25 N (approximately 5 pounds). Measurements were made with the elbow positioned in extension and in 30 degrees of flexion. The increase in medial ulnohumeral gapping with either gravity or 5 pounds of stress was statistically significant at both extension and 30 degrees of flexion compared with the unstressed condition. The difference in ulnohumeral gapping between gravity stress and 5 pounds of valgus stress in extension and in 30 degrees of flexion was also significant. We found no differences with regard to hand dominance or sex. We conclude that uninjured elbows have significant medial ulnohumeral gapping on valgus stress radiography. Although this is an important tool in diagnosing valgus instability of the elbow, it may yield a false-positive assessment of valgus instability. Valgus stress radiographs comparing contralateral elbows may reduce the false-positive rate since there appears to be no significant difference in medial ulnohumeral gapping between the two elbows.

Adolescent↗

A review of the Liverpool elbow prosthesis from 1974 to 1982.

Eighty elbows in 65 patients with an average age of 57 years have had two-part non-constrained Liverpool elbow arthroplasties performed since 1974. Fifty-five had rheumatoid arthritis, eight osteoarthritis or ankylosis secondary to injury, one osteochondritis dissecans and one pyknodysostosis. The average preoperative range of movement was 42 degrees to 112 degrees with 47 degrees of pronation and 42 degrees of supination. There was significant gain in the arc of movements at follow-up: 32 degrees in the extension-flexion range (average range 32 degrees to 134 degrees of flexion) and 42 degrees in forearm rotation (average pronation 69 degrees and supination 62 degrees). Before operation severe pain was the predominating symptom in 43 elbows (53.8%) but after replacement there was only moderate pain in five elbows (6.2%). The results were excellent in 42 (52.5%), good in 15 (18.7%), fair in 9 (11.3%) and unsatisfactory or poor in 14 (17.5%). Eight elbows required revision of the arthroplasty: three were post-traumatic, disorganised or osteoarthritic joints, three rheumatoid and both elbows in the patient with pyknodysostosis. Loosening of the prosthesis (particularly the humeral component) was the common factor necessitating revision. Of six rheumatoid elbows needing removal of the implant, four had deep infection, one had a dislodged humeral component as a result of injury and in one a divided olecranon had developed non-union. Rheumatoid elbows benefited more than post-traumatic arthritic elbows from the operation. (ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Muscle strength in rheumatoid elbow: quantitative measurement and comparison to Larsen's X-ray grade.

Accurate assessment of elbow function is important to determine the total ability of the arm. The purpose of this study was to clarify the relationship between isometric muscle strength of the elbows of patients with rheumatoid arthritis (RA) and Larsen's X-ray evaluation. Fifty-six elbows of 45 RA patients aged 47 to 77 years (mean age, 63 years) were tested. Muscle strength was measured with an isometric torque-cell dynamometer. Test-retest reliability of the dynamometer was proven by measuring 12 elbows of 6 healthy young men. In RA patients, elbow flexion and extension strength decreased in proportion to increases in the severity of Larsen's grades from Grade 1 to 4. However, Grade 5 elbows had greater muscle strength than those in Grade 4. Forearm pronation and supination strength also decreased in proportion to increases in the severity of Larsen's grades from Grade 1 to 5. This quantitative study made it clear that the muscle strength of RA patients' elbows almost completely correlates to X-ray finding according to the grade of Larsen's evaluation based on X-rays. With regard to muscle strength of postoperative elbows, both flexion strength and supination strength after total elbow replacement (TER) were about two times greater than before TER, and after synovectomy it was as great as those in non-operative RA patients of Grade 2.

Adult↗

Operative treatment of medical epicondylitis. Influence of concomitant ulnar neuropathy at the elbow.

We performed a retrospective review of the long-term results of operative treatment of medial epicondylitis in thirty elbows (twenty-six patients). Sixteen elbows had concomitant ulnar neuropathy. All of the patients had tenderness over the medial epicondyle. The most sensitive provocative maneuver was resisted pronation of the forearm (a positive result for twenty-eight elbows), followed by resisted flexion of the wrist (a positive result for twelve elbows). The operative findings included an inflammatory focus in seventeen elbows and focal ulnar-nerve compression in nine. Débridement of the origin of the flexor-pronator tendon mass, with decompression or transposition of the ulnar nerve when indicated, was associated with an 87 per cent rate (twenty-six elbows) of good or excellent results at an average of seven years (range, two to fifteen years) after the operation. Twenty-four of the twenty-five elbows that had no or mild associated ulnar neuropathy (type-IA or IB medial epicondylitis) had a good or excellent result, while two of the five elbows that had moderate or severe associated ulnar neuropathy (type-II medial epicondylitis) had a good or excellent result. This difference was significant (p = 0.009). Nine patients (nine elbows) needed more than six months before maximum improvement was obtained.

Arm Injuries↗

Changes in interstitial pressure and cross-sectional area of the cubital tunnel and of the ulnar nerve with flexion of the elbow. An experimental study in human cadavera.

The purpose of this study was to determine the relationship between the ulnar nerve and the cubital tunnel during flexion of the elbow with use of magnetic resonance imaging and measurements of intraneural and extraneural interstitial pressure. Twenty specimens from human cadavera were studied with the elbow in positions of incremental flexion. With use of magnetic resonance imaging, cross-sectional images were made at each of three anatomical regions of the cubital tunnel: the medial epicondyle, deep to the cubital tunnel aponeurosis, and deep to the flexor carpi ulnaris muscle. The cross-sectional areas of the cubital tunnel and the ulnar nerve were calculated and compared for different positions of elbow flexion. Interstitial pressures were measured with use of ultrasonographic imaging to allow a minimally invasive method of placement of the pressure catheter, both within the cubital tunnel and four centimeters proximal to it, at 10-degree increments from 0 to 130 degrees of elbow flexion. As the elbow was moved from full extension to 135 degrees of flexion, the mean cross-sectional area of the three regions of the cubital tunnel decreased by 30, 39, and 41 per cent and the mean area of the ulnar nerve decreased by 33, 50, and 34 per cent. These changes were significant in all three regions of the cubital tunnel (p < 0.05). The greatest changes occurred in the region beneath the aponeurosis of the cubital tunnel with the elbow at 135 degrees of flexion. The mean intraneural pressure within the cubital tunnel was significantly higher than the mean extraneural pressure when the elbow was flexed 90, 100, 110, and 130 degrees (p < 0.05). With the elbow flexed 130 degrees, the mean intraneural pressure was 45 per cent higher than the mean extraneural pressure (p < 0.001). Similarly, with the elbow flexed 120 degrees or more, the mean intraneural pressure four centimeters proximal to the cubital tunnel was significantly higher than the mean extraneural pressure (p < 0.01). Relative to their lowest values, intraneural pressure increased at smaller angles of flexion than did extraneural pressure, both within the cubital tunnel and proximal to it. With the numbers available, we could not detect any significant difference in intraneural pressure measured, either at the level of the cubital tunnel or four centimeters proximal to it, after release of the aponeurotic roof of the cubital tunnel.

Aged↗

Contribution of monoblock and bipolar radial head prostheses to valgus stability of the elbow.

BACKGROUND: The purpose of this study was to evaluate the stabilizing effect of radial head replacement in cadaver elbows with a deficient medial collateral ligament. METHODS: Passive elbow flexion with the forearm in neutral rotation and in 80 degrees of pronation and supination was performed under valgus and varus loads (1) in intact elbows, (2) after a surgical approach (lateral epicondylar osteotomy of the distal part of the humerus), (3) after release of the anterior bundle of the medial collateral ligament, (4) after release of the anterior bundle of the medial collateral ligament and resection of the radial head, and (5) after subsequent replacement of the radial head with each of three different types of radial head prostheses (a Wright monoblock titanium implant, a KPS bipolar Vitallium [cobalt-chromium]-polyethylene implant, and a Judet bipolar Vitallium-polyethylene-Vitallium implant) in the same cadaver elbow. Total valgus elbow laxity was quantified with use of an electromagnetic tracking device. RESULTS: The mean valgus laxity changed significantly (p < 0.001) as a factor of constraint alteration. The greatest laxity was observed after release of the medial collateral ligament together with resection of the radial head (11.1 degrees +/- 5.6 degrees). Less laxity was seen following release of the medial collateral ligament alone (6.8 degrees +/- 3.4 degrees), and the least laxity was seen in the intact state (3.4 degrees +/- 1.6 degrees). Forearm rotation had a significant effect (p = 0.003) on valgus laxity throughout the range of flexion. The laxity was always greater in pronation than it was in neutral rotation or in supination. The mean valgus laxity values for the elbows with a deficient medial collateral ligament and an implant were significantly greater than those for the medial collateral ligament-deficient elbows before radial head resection (p < 0.05). The implants all performed similarly except in neutral forearm rotation, in which the elbow laxity associated with the Judet implant was significantly greater than that associated with the other two implants. CONCLUSIONS AND CLINICAL RELEVANCE: This study showed that a bipolar radial head prosthesis can be as effective as a solid monoblock prosthesis in restoring valgus stability in a medial collateral ligament-deficient elbow. However, none of the prostheses functioned as well as the native radial head, suggesting that open reduction and internal fixation to restore radial head anatomy is preferable to replacement when possible.

Aged↗