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PubMed1995

The effect of articular conformity and the size of the humeral head component on laxity and motion after glenohumeral arthroplasty. A study in cadavera.

We used a cadaveric model to examine the mechanical effects of changes in the conformity of the articular surfaces and the size of the humeral head component in glenohumeral arthroplasty. The experimental system permitted a manual clinical examination of the glenohumeral joint while sensors monitored the humeroscapular position and orientation as well as the forces and torques applied by the examiner. Four preparations were compared: an anatomical humeroscapular preparation and three glenohumeral arthroplasty preparations (one with anatomically sized components and a radius of curvature of the glenoid that was four millimeters larger than that of the humeral head, one with anatomically sized components and a radius of curvature of the glenoid that was equal to that of the humeral head, and one with a non-anatomical, large humeral head component and a radius of curvature of the glenoid that was equal to that of the humeral head). All motions, including flexion, external and internal rotation, and maximum elevation, were diminished with use of the non-anatomical, large humeral head component. Laxity of the joint on drawer and sulcus tests was not affected by the conformity of the articular surfaces but was decreased significantly by implantation of the large humeral head component. The kinematics of the glenohumeral joint were not markedly altered by reduction of the uniformity between the articular surfaces of the prosthetic components. In all preparations, obligate displacement of the humeral head associated with a passive range of motion occurred at smaller angles with the large humeral head component.

Aged↗
PubMed2001

What's new in shoulder surgery.

The purpose of this update on shoulder surgery is to discuss, in summary fashion, topics presented at selected orthopaedic meetings during the time-period of August 1999 to July 2000. Sources for this article were presentations and symposia at meetings of the American Orthopaedic Society for Sports Medicine (Specialty Day, Orlando, Florida, March 2000, and the Twenty-sixth Annual Meeting, Sun Valley, Idaho, June 2000), the Arthroscopy Association of North America (Specialty Day, Orlando, Florida, March 2000, and the Nineteenth Annual Meeting, Miami, Florida, April 2000), the American Academy of Orthopaedic Surgeons (Sixty-seventh Annual Meeting, Orlando, Florida, March 2000), the American Shoulder and Elbow Surgeons (Specialty Day, Orlando, Florida, March 2000, and the Sixteenth Annual Meeting, Philadelphia, Pennsylvania, October 1999), and the American Orthopaedic Association (113th Annual Meeting, Hot Springs, Virginia, June 2000).

Arthroscopy↗
PubMed2002

Cementation of a polyethylene liner into a metal shell. Factors related to mechanical stability.

BACKGROUND: Various clinical situations may make polyethylene liner exchange desirable in the setting of a well-fixed metal shell. Options have included a simple polyethylene liner exchange or revision of the entire acetabular shell. A recently introduced technique involves cementation of a new liner into a well-fixed metal shell. The purposes of this study were to quantify the mechanical integrity of this method of liner fixation, to evaluate the factors that may influence immediate liner fixation, and to compare this construct with a standard locking mechanism. METHODS: One modular acetabular cup design was evaluated. Variables that may contribute to the mechanical integrity of the construct were evaluated via lever-out and multiaxis dislocation testing methods. The variables included the size of the liner (undersized versus oversized), type of liner (all-polyethylene versus modular design), modification of the modular liner (unmodified versus grooved), and groove configuration (cruciform versus circumferential). Metal shells with and without screw-holes were also tested. The modular locking mechanism was used as the control. RESULTS: None of the constructs failed at the cement-metal interface. All undersized liners required significantly higher loads to failure than either the controls (p < 0.001) or the oversized liners (p < 0.001). Oversized unmodified liners failed at significantly lower loads than the controls did (p < 0.01). The creation of circumferential grooves in the oversized liners significantly improved the strength of the constructs (p < 0.01), making them comparable with the controls. No significant differences were found among the four undersized groups (p > 0.3). The standard locking construct (control) and the oversized unmodified construct failed at a force of 2000 N in the multiaxis dislocation test. No other construct failed with use of this test mode. CONCLUSIONS: Cementation of a polyethylene liner into a metal shell can be stronger than a conventional locking mechanism if the liner is undersized. Cementation of an oversized liner into a shell should be performed with caution. The long-term durability of this fixation remains unknown.

Acetabulum↗
PubMed2004

Copeland surface replacement arthroplasty of the shoulder in rheumatoid arthritis.

BACKGROUND: Shoulder arthroplasty with a stemmed prosthesis is a recognized treatment for rheumatoid arthritis of the shoulder. The humeral component of the Copeland cementless surface replacement arthroplasty consists of a cup for surface replacement with a short central peg for primary fixation to the bone. We hypothesized that surface replacement may offer some advantages over stemmed prostheses. METHODS: Between 1986 and 1998, seventy-five shoulders underwent surface replacement arthroplasty (thirty-three hemiarthroplasties and forty-two total shoulder arthroplasties) for the treatment of rheumatoid arthritis. The results of these procedures were reviewed after an average duration of follow-up of 6.5 years. Patients were assessed with use of the Constant score, a patient satisfaction score, and radiographs. RESULTS: The average Constant score was 47.9 points (age and sex-adjusted score, 71%) in the hemiarthroplasty group and 53.4 points (age and sex-adjusted score, 76%) in the total shoulder replacement group. The mean range of active flexion improved from 50 degrees in the hemiarthroplasty group and 47 degrees in the total shoulder replacement group to 101 degrees and 104 degrees, respectively. Seventy-two of the seventy-five shoulders were considered by the patients to be much better or better at the time of the review. Of the sixty-eight humeral implants that were evaluated radiographically, fifty-six (82%) showed no lucencies, eleven (16%) showed localized lucencies of <1 mm in width, and one was definitely loose. Of the thirty-nine glenoid implants that were evaluated radiographically, nineteen (49%) showed no lucencies, nineteen showed localized lucencies of <1 mm, and one was definitely loose. No lucencies were observed adjacent to the hydroxyapatite-coated implants. Thirty-nine (57%) of the sixty-eight shoulders showed some degree of superior subluxation. Three patients required a major reoperation: two required a revision because of loosening of both components, and one patient with pain at the site of a hemiarthroplasty had a revision to a total shoulder arthroplasty to provide relief. CONCLUSIONS: The indications for this surface replacement are the same as those for the conventional stemmed prostheses, but the surface replacement has the advantage of bone preservation as well as avoidance of the potential complications associated with a long humeral stem in rheumatoid bone. This procedure is not suitable for severely damaged joints in which the humeral head is insufficient or too soft. LEVEL OF EVIDENCE: Therapeutic study, Level IV (case series [no, or historical, control group]). See Instructions to Authors for a complete description of levels of evidence.

Activities of Daily Living↗
PubMed1999

The effects of functional knee bracing on muscle function and performance.

When applied, knee braces compress the soft tissues of the thigh and leg. External compression may abnormally elevate intramuscular pressure beneath the straps of the knee brace, decrease local muscle blood flow and muscular oxygenation, and induce premature muscle fatigue. Functional knee braces may give valuable support to athletes with unstable knees. They may also be a valuable rehabilitative tool in patients following surgery for knee joint instability. However, prophylactic and functional knee braces do not improve performance and may even inhibit performance in asymptomatic athletes. Athletes and coaches should be aware of the serious adverse effects of knee bracing.

Athletic Injuries↗
PubMed2000

Removal of large fragments of the extensor process of the distal phalanx via arthrotomy in horses: 14 cases (1992-1998).

OBJECTIVE: To evaluate the outcome of horses with large fragments of the extensor process of the distal phalanx that were removed by use of arthrotomy. DESIGN: Retrospective study. ANIMALS: 14 horses with large fragments of the extensor process of the distal phalanx. PROCEDURE: Medical records for horses with large fragments of the extensor process that were removed by use of arthrotomy were reviewed. Data retrieved from medical records included signalment, use of horse, affected limb, lameness history, lameness examination findings, radiographic findings, surgical technique, and outcome. Follow-up evaluation was obtained by telephone interview. RESULTS: Most affected horses were < 5 years old and had a history of chronic lameness. Lameness grade ranged from 1/5 to 4/5. Fragments involved 20 to 45% of the dorsopalmar articular surface of the distal phalanx. Eight of 14 horses had a successful outcome. Outcome was not associated with age, duration or severity of lameness, or fragment size. CONCLUSIONS AND CLINICAL RELEVANCE: Despite involvement of a large portion of the articular surface and use of arthrotomy, joint instability and permanent soft tissue injury was not a problem in most horses. Outcome may be improved by selection of horses with lameness of < 2 years' duration and careful management after surgery. A fair prognosis may be anticipated for removal of large fragments of the extensor process via arthrotomy.

Animals↗
PubMed1999

Weight-bearing immobilization and early exercise treatment following a grade II lateral ankle sprain.

STUDY DESIGN: Case study. OBJECTIVES: To describe a protocol used in the rehabilitation of a grade II lateral ankle sprain, emphasizing brief immobilization with a removable boot, weight bearing as tolerated, and progression of early exercise. BACKGROUND: The optimum conservative treatment of severe grade II ankle sprains remains undefined. Short-term benefits of early mobilization have won favor over immobilization by casting; however, pain and ankle joint instability often linger. The timing of weight bearing as a variable that influences recovery has largely been ignored when either treatment is considered. METHODS AND MEASURES: The patient was a 17-year-old girl who had sustained a left ankle inversion sprain while playing high school basketball. The sprained ankle was placed in an immobilizer boot for 1 week, and weight bearing was encouraged. She received instructions for active exercise and for resistive exercise with elastic tubing. Volumetric and active range of motion measurements and gait observation provided indicators of rehabilitation progress. A digital inclinometer was used to measure active range of motion in the sagittal plane. Vertical ground reaction forces recorded with an instrumented treadmill documented gait symmetry. RESULTS: The patient responded well to the course of treatment, returning to full participation in basketball 2 weeks after the injury. The injured ankle had 29% (19 degrees) less active range of motion than the nonimpaired ankle at the beginning of physical therapy. The injured ankle also displaced 50 mL more water compared with the nonimpaired ankle at the start of treatment. Four weeks after beginning treatment, the sprained ankle had 4 degrees less active range of motion and displaced 5 mL more water compared with the nonimpaired ankle. As a college athlete, the patient has remained free of subjective complaints of ankle pain, instability, and swelling. CONCLUSION: Weight-bearing immobilization combined with early exercise provided safe and effective treatment for this patient, who suffered a grade II lateral ankle sprain.

Adolescent↗
PubMed2003

Reliability of classifications derived from Cyriax's resisted testing in subjects with painful shoulders and knees.

STUDY DESIGN: Intrarater and interrater reliability. OBJECTIVES: Examine intrarater and interrater reliability of the resisted-testing component of Cyriax's selective tension testing for patients with painful shoulders and knees. BACKGROUND: Clinicians make diagnostic and intervention decisions about lesions in contractile tissues based on resisted testing. Diagnostic and intervention decisions require reliable data gathering, especially when more than 1 physical therapist manages a patient. No studies have examined agreement of the results of the resisted tests used in selective tension testing, either within or between physical therapists, in subjects having pathology. METHODS AND MEASURES: Subjects with pain in 1 knee (18 male, 22 female; mean age +/- SD = 31.8 +/- 9.5 years) or shoulder (21 male, 25 female; mean age +/- SD = 34.3 +/- 12.9 years) were examined twice. Referring diagnoses included ligament injuries, overuse syndromes, joint instability, and postsurgical symptoms, with some subjects seeking initial diagnosis. Two physical therapists used standardized positions to evaluate 2 knee motions or 6 shoulder and elbow motions. Evaluators applied maximal isometric manual resistance and rated the contraction as strong or weak while subjects identified the presence or absence of pain during the contraction. Evaluators did not interview the subjects and were masked to previous test results. Analyses included percentage of agreement, kappa coefficients, confidence intervals, and maximum kappa coefficients. RESULTS: Intrarater kappa coefficients ranged from 0.44 to 0.82 and interrater coefficients ranged from 0.00 to 0.46. The small number of subjects who were classified as weak affected the kappa coefficients. In the intrarater condition, evaluators averaged 91% of maximum kappa for the knee and 66.5% for the shoulder. In the interrater condition, they averaged 60.4% of the maximum kappa for both the knee and the shoulder. CONCLUSIONS: Based on 2 physical therapist evaluators with previous education in the selective tension system and an additional 6 hours of formal training on the methods, intrarater reliability of resisted tests was generally acceptable for the knee but not for the shoulder. Interrater reliability of these tests, however, was generally not acceptable. Results were limited by subjects who were younger and had mostly chronic conditions that were mildly to moderately severe and by the small subject samples in the analyses. Reliability might be improved by more intensive training of the evaluators and by standardizing the magnitude of the applied resistance and stabilization of the subjects.

Adult↗
PubMed1984

Lunate implant arthroplasty. Evaluation of 19 patients.

The results of lunate implant arthroplasty are unpredictable and many untoward postoperative problems are encountered. A retrospective review of 19 patients operated on for lunatomalacia (Kienböck's disease) by Silastic (HP) implant arthroplasty suggests that prevention of postoperative scapholunate dissociation seems to be the key to successful results. Knowledge of the predominant role played by the palmar ulnolunate and radiolunate ligaments is important to the understanding of this mechanism. The intrinsic stability accomplished by the geometry of the carpal bones requires adequate ligamentous support. This restraint, however, may be weakened by pre-existing absence of certain palmar fibres, by the disease process or by the surgery. In the present study three operative methods have been assessed: dorsal approach and implant stem fixation; dorsal approach, removal of implant stem and Kirschner-wire fixation; volar approach, removal of implant stem, no internal fixation but palmar capsuloligamentous reinforcement. Consistently good results have been obtained using the latter technique. It seems as if most of the usual postoperative problems of lunate implant arthroplasty can be avoided by this method which warrants continued trial.

Adult↗
PubMed1988

Capsulotomy of the distal radio ulnar joint.

In 18 patients, of whom the majority had sequelae after fractures to the distal radius, a capsulotomy of the distal radio ulnar joint was performed. Their main complaints were painful restricted forearm rotation combined with reduced grip strength. All patients were examined at least one year after surgery. 15 had improved forearm rotation and reduced pain while 14 had improved grip strength. It is concluded that capsulotomy of the distal radio ulnar joint might be effective treatment in cases of restricted painful forearm rotation after injuries to the distal radio ulnar joint.

Adolescent↗
PubMed1993

Kinematic and stability of the Norway elbow. A cadaveric study.

We investigated the effect of simulated muscle loading and the contribution of the radial head to stability of the Norway elbow in 6 cadavers using an electromagnetic tracking device. The kinematics of the elbow after implantation of the prosthesis were similar to the intact elbow in their valgus-varus orientation, however, the forearms were slightly externally rotated, probably due to a small amount of external rotation of the humeral components at the time of implantation. The valgus-varus laxity limit of the implants were greater than in the intact specimens averaging 8.0 and 5.6 degrees, respectively. Simulated muscle loading stabilized both the intact and the Norway elbows. Excision of the radial head after implant arthroplasty increased their valgus-varus laxity, suggesting that preservation of the radial head may be indicated if it is not too severely involved by the underlying disease process. The laxity permitted by the prosthesis articulation is greater than that measured after implantation of the Norway arthroplasty. This suggests that the prosthesis may behave as an unconstrained arthroplasty. This should minimize the stress experienced by the bone-cement interface and may reduce the incidence of loosening. The laxity of the elbows after joint arthroplasty were only slightly greater than normal, possibly explaining the low incidence of prosthesis dislocation which has been observed with clinical use.

Aged↗
PubMed1999

Inflammatory bowel disease and the craniocervical junction.

Rheumatological complications have been described in up to 30% of patients being followed for inflammatory bowel disease. The majority of these complications occur as spondylitic changes in the lumbar spine. Erosive arthritic disease associated with inflammatory bowel disease occurs less frequently, but it can result in ligamentous laxity and joint instability. To highlight the potential significance of the process at the craniocervical junction, the authors describe the long-term follow-up care of a complicated case. A 56-year-old woman, with a long history of ulcerative colitis, presented with atlantoaxial instability and underwent a C1-3 fusion; however, the presence of significant occipitoatlantal instability was not recognized. This resulted in high cervicomedullary quadriplegia, requiring traction reduction and a combined anterior transoral decompressive-posterior occipitocervical fusion. The patient's neurological deficit completely resolved postoperatively.

Journal Article↗
PubMedDate not supplied

Double calcaneal osteotomy: realignment considerations in eight patients.

Posterior calcaneal displacement and anterior calcaneal distraction osteotomies have been recommended for surgical management of flexible flatfoot deformity. We combined these procedures for surgical management of adolescent flatfoot and late stage II posterior tibial tendon dysfunction in the adult. Lateral column distraction has been shown to reduce rearfoot valgus and forefoot abduction by stabilizing the midtarsal joint. Posterior calcaneal displacement osteotomy, which results in medial translation of the tuberosity, converts the posterior muscle group from an everter to an inverter. A supinatory moment, therefore, is created about the subtalar joint axis, which results in supination during the midstance phase of gait. These procedures may be considered when calcaneal valgus, forefoot abduction, and midtarsal joint instability are clinically significant. We also include rearfoot alignment radiographs, long leg calcaneal axial radiographs, and malleolar valgus indices to further evaluate alignment of the foot, ankle, and leg. Ideal realignment is achieved when the heel is vertical in resting calcaneal stance position, the forefoot is parallel to the rearfoot in the frontal plane, and the medial column is stabilized, with elimination of forefoot abduction.

Adolescent↗
PubMed1991

Resection arthroplasty at the basilar joint of the thumb.

Resection arthroplasty at the base of the thumb has a long history in the surgical literature. It is a less complex procedure than other operative approaches; pain relief along with useful hand function is reliably achieved. Sixty-six trapezial resection arthroplasties using either a tendon or Gelfoam spacer (The Upjohn Co, Kalamazoo, MI) were reviewed with improvement noted in 62 patients.

Arthroplasty↗
PubMed1995

Failure of total shoulder arthroplasty: why does it occur?

From a historical perspective, shoulder arthroplasty has evolved significantly from its inception. Much like arthroplasty of the lower extremities, shoulder implant design had its roots in a constrained device. Unfortunately, the inherently high loads that these devices generated across the implant articulation and the glenoid bone interface resulted in an unacceptably high failure rate. Beginning with Neer's original hemiarthroplasty of the 1950s and the more recent implant designs, there has been a strong trend toward less constraint and a greater emphasis on soft tissue preservation in shoulder replacement. In the ideal arthroplasty patient with an intact rotator cuff and a stable, yet degenerative, glenohumeral joint, arthroplasty invariably yields good-to-excellent results 90% of the time. However, owing to the enormous functional range of motion of the joint and its inherent dependence on soft tissues for both stability and motion, there are many areas for potential complications. This article addresses the etiology, recognition, and treatment of these problems.

Humans↗