Biomedical subjects
Publications and source records attributed to R F Warren.
Experimental work has shown that dislocation of the shoulder may involve disruption of the capsule from its lateral humeral attachment. We report two patients with recurrent dislocation due to this injury. Lateral repair gave good results. It is suggested that this injury be considered and looked for when glenoid labral injury is minimal or absent.
There are two technical aspects of ACL reconstructive surgery that always present some difficulty. One is determining how much notchplasty is sufficient prior to passage of the graft. The other is passing the suture leader of the graft through the tibial and femoral bone tunnels. We have used a plastic disposable Yankauer suction tip to facilitate both of these tasks.
Shoulder arthroscopy is most commonly performed in some variation of the lateral decubitus position with the arm in traction. Because of reports of neuropraxia associated with the traction, we have investigated the use of the "beachchair" or sitting position for shoulder arthroscopy. We have used this position for over 50 consecutive patients for arthroscopic debridements, arthroscopic subacromial decompressions, and arthroscopic shoulder stabilizations.
The progression from chronic anterior cruciate instability to degeneration of the knee has been well documented in animal studies. However, the literature is unclear as to the overall consequences with respect to the development of osteoarthritis. The long-term consequences of the anterior cruciate insufficient knee with or without associated medial collateral ligament insufficiency was investigated in 127 consecutive patients. The effects of meniscal injury and/or meniscectomy in the presence of ligamentous insufficiency was correlated with roentgenographic observations. A scoring system was devised and found to show that anterior cruciate insufficiency naturally progresses toward degenerative osteoarthritis. Meniscectomy with and without an associated medial collateral ligament insufficiency hastens the degenerative process. Progressive functional deterioration was shown to correlate with roentgenographic evidence of degenerative changes. The ultimate success of surgical repairs and reconstructions of the anterior cruciate ligament will not be based only upon functional return to activity or objective stability, but will also depend on the procedure's ability to prevent later development of degenerative osteoarthritis.
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UNLABELLED: To evaluate the ability of a fibrin clot to stimulate and support a reparative response in the avascular portion of the meniscus, two-millimeter-diameter full-thickness lesions in the avascular portion of the medial meniscus of twelve adult dogs were filled with an exogenous fibrin clot that had been prepared from each animal. The healing response was then examined using histology and autoradiography with 35SO4 at intervals from one week to six months. The defects that had been filled with a fibrin clot healed through a proliferation of fibrous connective tissue that eventually modulated into fibrocartilaginous tissue. The fibrin clot appeared to act as a chemotactic and mitogenic stimulus for reparative cells and to provide a scaffolding for the reparative process. The origin of these reparative cells was not determined in this study, but they were thought to arise from the synovial membrane as well as the adjacent meniscal tissue. Control defects remained empty. While the reparative tissue was grossly and histologically different from the normal adjacent meniscal tissue, it was morphologically similar to the reparative tissue that was previously observed in the vascular area of the meniscus. CLINICAL RELEVANCE: The ability of an exogenous fibrin clot to stimulate and support a reparative response in the avascular portion of the meniscus may represent a potential method of avascular meniscal repair.
Patients with injury to the anterior cruciate ligament (ACL) frequently develop tears of the menisci. Removal of the meniscus, while relieving some complaints, may increase the patient's instability. To evaluate our success and quantify the reasons for failure, we evaluated 48 patients who underwent arthroscopic partial meniscectomy from 1979 to 1982. Patients were evaluated as to their subjective complaints, scored on a 100-point knee evaluation, and evaluated with standing x-rays. In addition, measurement using the KT-1000 knee arthrometer was made to assess the degree of tibial translation. Follow-up averaged 32 months, with a range of 24-50. At followup, 29 patients (60%) were judged to be clinical successes with resolution of their complaints and no aggravation of their instability. Nineteen patients (40%) were judged to be clinical failures in that their complaints persisted (14 patients) or ACL reconstruction was required (5 patients). Eight patients noted some increase in their instability, and three required a repeat meniscectomy. Arthroscopic partial meniscectomy can be a useful procedure in some patients with injury to the ACL. Patients more likely to do well are those with a torn medial meniscus with a chief complaint of locking. Examination would demonstrate a mild pivot shift, absence of generalized ligamentous laxity, and an anterior tibial translation difference of less than 5 mm.
A phenazine antibiotic (mp, 243 to 244 degrees C), isolated in a yield of 134 micrograms/ml from cultures of Pseudomonas fluorescens 2-79 (NRRL B-15132), was indistinguishable in all of its measured physicochemical (melting point, UV and infrared spectra, and gas chromatography-mass spectrometry data) and biological properties from synthetic phenazine-1-carboxylic acid. Gurusiddaiah et al. (S. Gurusiddaiah, D. M. Weller, A. Sarkar, and R. J. Cook, Antimicrob. Agents Chemother. 29:488-495, 1986) attributed a dimeric phenazine structure to an antibiotic with demonstrably similar properties obtained from the same bacterial strain. Direct comparison of the physicochemical properties of the authentic antibiotic obtained from D. M. Weller with synthetic phenazine-1-carboxylic acid and with the natural product from the present study established that all three samples were indistinguishable within the experimental error of each method. No evidence to support the existence of a biologically active dimeric species was obtained. Phenazine-1-carboxylic acid has a pKa of 4.24 +/- 0.01 (25 degrees C; I = 0.09), and its carboxylate anion shows no detectable antimicrobial activity compared with the active uncharged carboxylic acid species. These data suggest that phenazine-1-carboxylic acid is probably not an effective biological control agent for phytopathogens in environments with a pH greater than 7.
Current concepts for the diagnosis and treatment of anterior dislocation and subluxation, including classification of injuries, are presented. The pathophysiology, clinical and radiologic examination, and treatment protocols are discussed.
The incidence, basic pathophysiology, and clinical and radiologic examination in posterior instability of the shoulder are discussed. Conservative treatment protocols and surgical procedures are presented.
Injury to the posterolateral structures of the knee, including the popliteus tendon and arcuate complex, frequently results in poorly understood patterns of instability. To evaluate the static function of these tissues, we used a mechanical testing apparatus that allowed five degrees of freedom to test seventeen specimens from human cadavera at angles of flexion that ranged from zero to 90 degrees. Selective section of the lateral collateral ligament, popliteus-arcuate (deep) ligament complex, anterior cruciate ligament, and posterior cruciate ligament was performed. At all angles of flexion, the lateral collateral ligament and deep ligament complex functioned together as the principal structures preventing varus rotation and external rotation of the tibia, while the posterior cruciate ligament was the principal structure preventing posterior translation. However, at angles of flexion of 30 degrees or less, the amount of posterior translation after section of only the lateral collateral ligament and the deep structures was similar to that noted after isolated section of the posterior cruciate ligament. Isolated section of the posterior cruciate ligament did not affect varus or external rotation of the tibia at any position of flexion of the knee. When the posterior cruciate ligament was sectioned after the lateral collateral ligament and deep ligament complex had been cut, a large increase in posterior translation and varus rotation resulted at all angles of flexion. In addition, at angles of flexion of more than 30 degrees, external rotation of the tibia also increased. The application of internal tibial torque resulted in no increase in tibial rotation after isolated section of the anterior cruciate ligament or combined section of the lateral collateral ligament and deep ligament complex. However, combined section of all three structures increased internal rotation at 30 and 60 degrees of flexion. The increases in external rotation that were produced by section of the lateral collateral ligament and deep ligament complex were not changed by the addition of the section of the anterior cruciate ligament.
The anterior cruciate ligament of twenty-five adult dogs was replaced using fresh or deep-frozen patellar-tendon allografts. The morphology of these transplanted allografts was then evaluated using routine histological studies and a vascular-injection (Spalteholz) technique at various intervals from two weeks to one year postoperatively. The fresh patellar-tendon allografts incited a marked inflammatory and rejection response which was characterized by perivascular cuffing and lymphocyte invasion. Deep-frozen patellar-tendon allografts appeared to be benign within the joint and underwent alterations that were comparable with those observed in autogenous patellar-tendon grafts. These included avascular necrosis followed by revascularization and cellular proliferation. At one year, the gross and histological appearance of the patellar tendon allograft resembled that of a normal anterior cruciate ligament.
The chondroitin sulfate-rich region was cleaved from cartilage proteoglycans of experimental osteoarthritic canine joints to establish whether changes in this region of the molecule contribute to the well-documented increase in the chondroitin sulfate to keratan sulfate ratio in osteoarthritis. Experimental osteoarthritis was induced in eight dogs by severance of the right anterior cruciate ligament, the left joint serving as a control. Proteoglycans were extracted from the femoral cartilage of both joints, isolated as A1 fractions by associative density gradient centrifugation and cleaved with hydroxylamine. The chondroitin sulfate-rich region was isolated by either gel chromatography or dissociative density gradient centrifugation. The chondroitin sulfate-rich region from the proteoglycans of the experimental osteoarthritic joints was slightly larger in hydrodynamic size and had both a higher uronate/protein weight ratio and galactosamine/glucosamine molar ratio than the corresponding control. We conclude that the chondroitin sulfate-rich region of proteoglycans in articular cartilage of experimental osteoarthritic joints is larger and has more chondroitin sulfate than that of proteoglycans of normal cartilage.
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The response of the meniscus to partial meniscectomy (in the avascular zone) was evaluated in 15 dogs. Following surgery 10 of the 15 dogs (67%) demonstrated a remodeling of the cut surface of the meniscus. This process appeared to begin with a fibrin clot which adhered to the meniscectomy surface. The organized clot was then populated by fibrocytes and eventually modulated into a fibrocartilage-like tissue by 12 weeks. The origin of the cells is unknown and may represent a migration of cells from the synovium, a proliferation of meniscal fibrochondrocytes, or both. The remodeling process appears to be associated with the presence of a fibrin clot, presumably from residual hemarthrosis. In those menisci that did not remodel [five of 15 (33%)], the meniscectomy surface remained relatively unchanged with no signs of progressive degeneration.
Lesions of the long head of the biceps tendon are generally a component of a diffuse degenerative process involving the subacromial space including the rotator cuff, bursa, biceps tendon, and possibly the acromioclavicular joint. As such, surgical approaches should be designed to treat each component not restricting the surgery to a biceps tenodesis. On occasion bony injury directly to the bicipital groove may result in an inflammatory process in the tendon or even dislocation of the tendon if there was damage to the lesser tuberosity and subscapularis tendon. In these patients biceps tenodesis and coracoacromial ligament excision is advised. The entity of a "subluxating biceps tendon" without damage to the lesser tuberosity or subscapularis is a diagnosis that we are unable to reliably arrive at. It appears that most patients with biceps instability have combined tuberosity or rotator cuff injury allowing the tendon to migrate medially. Ruptures of the long head of the biceps are generally associated with rotator cuff disease, but a localized process secondary to trauma or injections may account for some ruptures. Nearly all are managed conservatively, but the patient is followed closely and forewarned regarding possible rotator cuff degeneration. In young patients a more aggressive approach including shoulder arthrography and early repair, if a cuff tear is noticed, would be recommended if one would hopefully arrest the degenerative process.