Posterolateral instability of the knee.
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Biomechanical Phenomena↗
Biomedical subjects
R F Warren
Publications and source records attributed to R F Warren.
The surgical treatment of posterior shoulder instability.
Operative procedures for recurrent posterior instability range from glenoid osteotomy, posterior bone block procedures, posterior capsular plication with biceps tenodesis to arthroscopic stabilization with a biodegradable tac. The best results and the most commonly reported procedure(s) involve the reattachment of any labral detachment and a posterior capsular plication via a posterior approach.
Arm Injuries↗
Complications of shoulder instability surgery.
Complications of shoulder instability surgery may results from errors made during the preoperative, intraoperative, or postoperative periods. Some complications are preventable whereas the risk of others can be reduced. A few complications remain unpreventable. Two sources of error in the preoperative period that can lead to complications are an incorrect diagnosis and failure to address a patient's expectations of treatment. These errors and their subsequent complications are preventable. Preventing complications during the intraoperative period begins with proper patient positioning and a thorough knowledge of shoulder anatomy. Understanding the indications and limitations of the various stabilization procedures, as well as applying proper surgical technique, is essential to avoid a surgical misadventure. Complications recognized in the postoperative period include recurrent instability, limitation of motion, inability to return to the previous level of sport, problems related to hardware, pain, development of osteoarthritis, and neurovascular injuries. Infection and hematoma formation may also occur; both need to be recognized and treated early to maximize outcome. A protocol for treating each complication that may occur often is helpful. Knowledge of the complications that can arise is paramount to preventing their occurrence. This knowledge comes through experience, study, and continued research.
Arm Injuries↗
Arthroscopic anatomy of the lateral elbow: a comparison of three portals.
Ten fresh cadaveric elbows were used to evaluate the proximity of the radial nerve and its branches to three anterolateral portals. A proximal anterolateral portal used routinely at our institution and located 2 cm proximal and 1 cm anterior to the lateral epicondyle was compared with the distal anterolateral portal described by Andrews and with a mid-anterolateral portal. The three portals were initially established without joint distention while the elbows were flexed 90 degrees. Measurements were then obtained with and without joint distention at flexion angles of 0 degrees and 90 degrees. The radial nerve was found to be an average distance of 3.8 mm at extension and 7.2 mm at 90 degrees of flexion from the distal anterolateral portal, located 3 cm distal and 1 cm anterior to the lateral epicondyle. Conversely, the distance between the proximal anterolateral portal cannula and the nerve was statistically greater (p < 0.05), averaging 7.9 mm in extension and 13.7 mm in flexion. The remaining anterolateral portal, located 1 cm directly anterior to the lateral epicondyle, was found to be at a statistically greater average distance from the nerve than was the distal anterolateral portal but statistically closer than was the more proximal portal. The ability to visualize the joint arthroscopically was assessed using the three portals, and although the ulnohumeral joint could be adequately seen using all portals, radiohumeral joint visualization was most complete and technically easiest using the most proximal portal.(ABSTRACT TRUNCATED AT 250 WORDS)
Analysis of Variance↗
Symptomatic intraarticular ganglia of the cruciate ligaments of the knee.
This case report draws attention to the clinical presentation, differential diagnosis, and recommended diagnostic modality and treatment of symptomatic ganglia of the anterior and posterior cruciate ligaments. One patient presented with a recurrent inability to fully extend the left knee. Another patient presented with pain and soreness over the lateral aspect of the knee, including the lateral joint line. The diagnosis of ganglia of the cruciate ligaments was made after clinical, radiographic, and magnetic resonance examination. Both patients were treated successfully with resection of their ganglia using arthroscopic techniques.
Adult↗
Changes in the moment arms of the rotator cuff and deltoid muscles with abduction and rotation.
The behavior of the moment arms of the rotator cuff and deltoid muscles was studied during simple and combine movements of abduction and rotation about the glenohumeral joint. This was done by experimental measurement of excursions of the muscles in an in vitro cadaver model and by use of a multiple-regression analysis to delineate the changes in the moment arms as a function of abduction and rotation. The results demonstrated the potential of some rotator cuff muscles to contribute to both abduction and rotation, the sensitivity of the abductor moment-arm lengths to internal and external rotation and of the rotator moment-arm lengths to the degree of abduction, and the capacity of the abductor moment-arm lengths of the deltoid to increase with increasing abduction. Characterization of this behavior resulted in an increased understanding of the complex role of the rotator cuff and deltoid muscles about the gleno-humeral joint and provided quantitative descriptions of functional relationships. This study demonstrates the capacity of the infraspinatus and subscapularis muscles to contribute not only to external and internal rotation, respectively, but also to elevation of the arm in the plane of the scapula, a role for which these muscles have been given little or no consideration. Furthermore, it demonstrates that the contribution of the infraspinatus to abduction is enhanced with internal rotation while that of the subscapularis is enhanced with external rotation. Thus, dysfunction of the supraspinatus muscle need not preclude good elevation of the arm, and rehabilitation to reprogram and strengthen the remaining muscles becomes an important consideration.
Aged↗
Biomechanical evaluation of a simulated Bankart lesion.
The purpose of this study was to determine the effect of sectioning of the anterior part of the inferior glenohumeral ligament (a simulated Bankart lesion) on load-induced multidirectional glenohumeral motion. Nine fresh, intact cadaveric shoulders were tested on a special apparatus that constrained three rotations but allowed simultaneous measurement of anterior-posterior, superior-inferior, and medial-lateral translation. Coupled anterior-posterior and superior-posterior translations were recorded while anterior, posterior, superior, and inferior forces of fifty newtons were applied sequentially. Testing was done in three positions of humeral elevation in the scapular plane, in three positions of humeral rotation, and with an externally applied joint-compression load of twenty-two newtons. A liquid-metal strain-gauge was placed on the posterior band of the inferior glenohumeral ligament to assess concomitant posterior capsular strain during the various test conditions. All shoulders were tested intact and again after the inferior glenohumeral ligament and the labrum had been detached from the glenoid from just superior to the anterior band of the inferior glenohumeral ligament to a point just posterior to the infraglenoid tubercle. The simulated Bankart lesion resulted in selected increases in anterior translation at all positions of elevation, in posterior translation at 90 degrees of elevation, and in inferior translation at all positions of elevation. However, these increases were very small; the maximum mean increase in translation seen over-all was only 3.4 millimeters, which occurred during inferior translation at 45 degrees of elevation.(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗
Knee injuries and Alpine skiing. Treatment and rehabilitation.
Alpine skiing is an increasingly popular recreational sport worldwide. While the overall injury rate has declined and the pattern of injury changed over the years, the incidence of knee injuries has not changed substantially and accounts for 20 to 30% of all alpine skiing injuries. Medial collateral ligament (MCL) injuries are the most common in skiing, accounting for 15 to 20% of all skiing injuries and 60% of knee injuries in skiers. Tears are commonly isolated, but may occur in association with other ligamentous injuries. Associated meniscal pathology is rare. Isolated MCL injuries are treated nonoperatively with a programme of initial immobilisation, early range-of-motion, and isometric quadriceps strengthening exercises. When full range of motion is achieved, a programme of progressive resistance exercises, isokinetic and closed chain exercises, and functional rehabilitation is instituted. Good results with return to skiing can be expected in most cases. Isolated lateral collateral ligament (LCL) injuries are rare in skiers. There is usually associated cruciate or arcuate ligament complex. Careful physical examination is essential to rule out associated ligament injuries and more complex instability patterns. In the rare case of isolated LCL injury, a similar approach to isolated MCL injury should be instituted. Anterior cruciate ligament (ACL) injuries have become increasingly common in skiers. This may reflect a true increase in the incidence or an improved awareness and ability to diagnose ACL injury. Physical examination and arthrometric analysis are important in assessing the integrity of the ACL. Radiographic and magnetic resonance imaging (MRI) evaluation may be helpful in assessing associated meniscal pathology. Treatment of the ACL-deficient knee is usually surgical. However, prior to reconstruction, a programme aimed at reducing effusion and regaining a full, pain-free range of motion is recommended. Surgical reconstruction is usually with the central third of the patella tendon using a bone-tendon-bone autograft. Postoperative rehabilitation employs a functional staged approach, requiring vigilant supervision by the surgeon. Isolated posterior cruciate ligament (PCL) injury is rare in skiing, constituting less than 1% of all knee injuries in most series. Careful physical examination must be employed to rule out associated arcuate ligament complex injury and more complex patterns of instability. Most isolated PCL injuries are treated nonoperatively with a programme of initial immobilisation in extension, ice, protected weight-bearing, early range-of-motion exercises and progressive isometric strengthening.(ABSTRACT TRUNCATED AT 400 WORDS)
Anterior Cruciate Ligament Injuries↗
Modular shoulder hemiarthroplasty for acute fractures. Surgical considerations.
Displaced fractures of the proximal humerus with concomitant comminution, interruption of vascular supply, and articular incongruity often require prosthetic replacement for successful treatment. In these difficult cases, the success of prosthetic replacement is dependent on proper patient selection, appropriate surgical technique, and a well-supervised postoperative rehabilitation program. Careful surgical technique should ensure proper placement of the humeral component at the correct height and version, and proper position and fixation of the displaced tuberosities. Supervised rehabilitation emphasizing early range of motion and strength when the tuberosities have healed improves results. The authors found that a modular design humeral implant allows for improved tensioning of the soft tissues and reconstruction of the tuberosities.
Arthroplasty↗
Anatomy, biomechanics, and physical findings in posterolateral knee instability.
Posterolateral injury is often associated with additional ligamentous injury to the knee. Proper evaluation of these injuries requires a knowledge of the anatomy and biomechanics of the posterolateral corner. Biomechanical studies reveal that the popliteal tendon, the popliteofibular ligament, the arcuate ligament, and the LCL are the principal structures responsible for maintaining stability of the posterolateral corner. Knowledge of the biomechanics of the posterolateral corner provide insight into the clinical evaluation and treatment of posterolateral knee instability. Patients with acute and chronic posterolateral instability present with complaints of knee pain and instability of the knee in extension. Patients may also complain of dysthesias or motor weakness owing to associated peroneal nerve injury. Patients may also present with symptoms pertaining to associated ligamentous injury to the knee. Thorough examination is needed to document neurovascular status, and the presence of posterolateral and associated knee instability. Although many tests are used to document posterolateral knee instability, the authors prefer varus stress testing and the prone external rotation test. Accurate diagnosis of all knee ligament pathology will allow appropriate planning for the surgical treatment of isolated posterolateral knee instability and combined instability patterns.
Anterior Cruciate Ligament↗
Operative treatment of posterolateral instability of the knee.
Acute and chronic posterolateral instability is often associated with cruciate injury. The results of surgical reconstructions for acute posterolateral instability are better than for chronic posterolateral instability. The authors recommend acute reconstruction of posterolateral injury when possible. In either acute or chronic instability, we first reconstruct any associated cruciate injury, and then expose the posterolateral corner through an open lateral incision. The authors believe that the LCL, popliteal attachment to the tibia, and the popliteofibular ligament are the most important posterolateral static stabilizers. Accordingly, we attempt to anatomically repair or reconstruct these structures in acute and chronic posterolateral instability. In acute injury the authors first attempt direct repair, advancement and recession, or augmentation of the LCL, the popliteal attachment to the fibula and popliteofibular ligament. Occasionally, reconstruction with patellar tendon autografts or allografts, or achilles allografts will be needed. In the patient with chronic posterolateral instability and varus alignment, a proximal, valgus tibial osteotomy is performed. Additional posterolateral reconstruction can be performed on a staged basis. In the patient with chronic posterolateral instability and valgus alignment, direct repair, advancement and recession, or augmentation can be attempted, but reconstruction with patellar tendon or achilles allograft often will be required. Proper anatomic reconstruction of all injured structures is recommended to achieve the best results in the operative treatment of posterolateral instability.
Anterior Cruciate Ligament↗
Current status of allograft meniscal transplantation.
The meniscus has several roles that contribute to knee function. Many clinical studies have documented the detrimental effects of loss of meniscus function. Meniscal repair is recommended when technically and anatomically feasible to preserve meniscal function. Techniques for meniscal repair can be used to transplant meniscal allografts. Animal studies have documented that meniscal allografts can heal in the recipient. There are few clinical studies of meniscal allograft transplantation in humans. Indications, techniques, results, and complications of meniscal allograft transplantation in humans are described.
Adult↗
Use of clonidine to treat hot flashes secondary to leuprolide or goserelin.
OBJECTIVE: To determine the effects of clonidine, a centrally acting adrenergic agonist, in abating symptoms of hot flashes in men receiving either leuprolide or goserelin for prostate cancer. DESIGN: Patients were administered transdermal or oral clonidine 0.1-0.2 mg/d. Dosages were increased in increments of 0.1-0.3 mg/d every two to four weeks if symptoms persisted or until adverse effects developed. SETTING: Medical oncology clinic at the University of Illinois and the hypertension clinic at the Veterans Affairs West Side Medical Center. PARTICIPANTS: Consenting male patients were eligible for the study if they were receiving leuprolide or goserelin for prostate cancer and were experiencing hot flashes. Exclusion criteria included diastolic blood pressure of 75 mm Hg or below or a history of adverse reactions to clonidine. MAIN OUTCOME MEASURES: Effectiveness of clonidine was determined by questioning patients about frequency, severity, and duration of hot flashes at baseline and at two- to four-week intervals. RESULTS: All four patients receiving clonidine experienced a partial response within two weeks of starting treatment. No dose-dependent response was observed. Adverse effects were noted in one patient but did not result in discontinuation. CONCLUSIONS: Our results document the first report of the use of clonidine to treat hot flashes secondary to leuprolide or goserelin therapy. Symptomatic improvement was noted in all four patients. Further evaluation of clonidine as well as other centrally acting adrenergic agonists is needed.
Climacteric↗
Diastasis of bipartite sesamoids of the first metatarsophalangeal joint.
Injury to the metatarsophalangeal (MP) joint of the great toe, often termed "turf-toe", is a common occurrence in football. We have identified four cases of first MP plantar capsular injury with diastasis of a bipartite sesamoid. In three cases, observation and protection resulted in progressive widening of the fragments associated with pain and disability. These players required resection of the distal sesamoid fragment and repair of the volar capsule. The fourth player underwent acute repair of the medial retinaculum and capsule. All players have had a full return to sports activity. Diastasis of components of a partite sesamoid provides objective evidence of disruption of the plantar capsular mechanism. Early recognition of this condition confirmed by stress radiographs is recommended. Treatment may include early protection followed by resection, if painful, or acute repair of the retinaculum. Previous descriptions of turf-toe have not included injuries to the sesamoid complex of the first MP joint. In our opinion, the term turf-toe should represent the consequences of a hyperextension injury to the first MP joint in which the volar capsule has been disrupted proximal to the sesamoid. A classification for first MP joint injuries is presented.
Adult↗
Instability of the shoulder after arthroplasty.
A replacement arthroplasty was performed in 236 shoulders at The Hospital for Special Surgery from 1984 through 1989. Ten patients (eight women and two men) from that group were identified as having instability of the shoulder at the time of follow-up, and the results for these patients were reviewed retrospectively. The ages of the patients ranged from fifty-six to seventy-nine years. The instability was anterior in seven of the patients and posterior in three. The anterior instability was caused by a rupture of the repaired subscapularis tendon. The operative treatment of the anterior instability consisted of mobilization and repair of the tendon, but three of the seven patients continued to have instability. A static stabilizer, consisting of an allograft of Achilles tendon, was inserted in these three patients, and the result was a success. The etiology of the posterior instability (three patients) was multifactorial. Treatment consisted of correction of any soft-tissue imbalance and revision of the prosthetic components as necessary. All ten patients were followed clinically and radiographically for at least two years. All of the patients had some loss of motion of the shoulder as compared with the motion before the dislocation. There were no neurovascular complications, problems related to the allografts, or any other complications. We concluded that proper balancing of the soft tissues and positioning of the prosthetic components are essential to a successful arthroplasty of the shoulder. The postoperative rehabilitation should include a physical therapy program in which the range of motion of the arm that was achieved in the operating room is not exceeded.(ABSTRACT TRUNCATED AT 250 WORDS)
Achilles Tendon↗
The effects of sectioning of the posterior cruciate ligament and the posterolateral complex on the articular contact pressures within the knee.
Articular contact pressures in ten cadaveric knees with intact ligaments were measured with the use of film and a model that simulated non-weight-bearing resistive extension of the knee. The measurements were repeated after sequential sectioning of the posterior cruciate ligament and the posterolateral complex (the posterolateral capsule, the popliteus muscle and tendon, and the lateral collateral ligament). Patellofemoral pressures and quadriceps load were most significantly elevated after combined sectioning of the posterior cruciate ligament and the posterolateral complex. Medial compartment pressure was significantly elevated after sectioning of the posterior cruciate ligament. The results coincided with, and may partially explain, the clinical findings associated with these types of ligamentous injuries.
Aged↗
Arthroscopically assisted reconstruction of the anterior cruciate ligament with use of autogenous patellar-ligament grafts. Results after twenty-four to forty-two months.
The results of the first sixty-nine consecutive patients who had had seventy arthroscopically assisted reconstructions of the anterior cruciate ligament with use of an autogenous patellar-ligament graft at our institution were reviewed retrospectively. Sixty-seven patients (sixty-eight knees) were available for evaluation after a minimum of two years. All patients had been managed with early, postoperative range-of-motion exercises and a standardized program of physical therapy. At the time of the most recent follow-up evaluation, the median ligament score, according to the rating system of The Hospital for Special Surgery, was 93 of a possible 100 points. Of the sixty-eight knees, forty-four were rated excellent; fifteen, good; six, fair; and three, poor. Eighteen knees had symptoms related to the patellofemoral joint and sixty-three had a full range of motion; two knees had had manipulation for loss of flexion. At the follow-up evaluation, KT-1000 arthrometric measurements were obtained for both knees of fifty-six patients. Eighty-four per cent of the patients had an increase of three millimeters or less in anterior-posterior displacement of the tibia on the reconstructed side compared with the normal side, while 93 per cent had an increase of four millimeters or less. Postoperatively, there was no apparent association between changes in the Insall-Salvati patellar ligament-to-patella ratios and pain in the patellofemoral joint. The results of the arthroscopically assisted reconstructions combined with use of early range-of-motion exercises were comparable with those reported after open reconstruction and immobilization of the limb in a plaster cast. The frequency of pain in the patellofemoral joint and the need for manipulation because of loss of motion were decreased after the arthroscopically assisted procedures.
Adolescent↗
Tendon-healing in a bone tunnel. A biomechanical and histological study in the dog.
Our study evaluated tendon-to-bone healing in a dog model. Twenty adult mongrel dogs had a transplantation of the long digital extensor tendon into a 4.8-millimeter drill-hole in the proximal tibial metaphysis. Four dogs were killed at each of five time-periods (two, four, eight, twelve, and twenty-six weeks after the transplantation), and the histological and biomechanical characteristics of the tendon-bone interface were evaluated. Serial histological analysis revealed progressive reestablishment of collagen-fiber continuity between the bone and the tendon. A layer of cellular, fibrous tissue was noted between the tendon and the bone, along the length of the bone tunnel; this layer progressively matured and reorganized during the healing process. The collagen fibers that attached the tendon to the bone resembled Sharpey fibers. High-resolution radiographs showed remodeling of the trabecular bone that surrounded the tendon. At the two, four, and eight-week time-periods, all specimens had failed by pull-out of the tendon from the bone tunnel. The strength of the interface was noted to have significantly and progressively increased between the second and the twelfth week after the transplantation. At the twelve and twenty-six-week time-periods, all specimens had failed by pull-out of the tendon from the clamp or by mid-substance rupture of the tendon. The progressive increase in strength was correlated with the degree of bone ingrowth, mineralization, and maturation of the healing tissue, noted histologically.
Animals↗