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Biomedical subjects

R F Warren

Publications and source records attributed to R F Warren.

At least 199 records · Page 11Linked to original sources
PubMedDate not supplied

Primary surgical treatment of anterior cruciate ligament lesions.

Seventy patients who underwent primary repair of the anterior cruciate ligament are reviewed in follow-up. The surgical technique consisted of multiple loop-varying depth sutures in both cruciate stumps in 61 patients. Nine patients had additional fascial augmentation done primarily. follow-up was from 12 to 90 months, the average being 29 months. All patients were scored on a 50-point normal knee score sheet. Average score at follow-up was 42.7. No patient was bothered by giving way, which is defined as an unpredictable instability. No patient has required subsequent meniscal surgery. Ninety-three percent of the patients were active in sports. Anterior drawer sign at 90 degrees showed increased excursion compared to the unaffected leg in all patients. However, Lachman's test showed a firm end point to excursion in all knees tested, and, in addition, 52% were rated as normal compared to the unaffected knee. We conclude that primary repairs of mid-substance tears are technically possible and recommended in an athlete.

Follow-Up Studies↗
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The microvasculature of the meniscus and its response to injury. An experimental study in the dog.

The normal vascular anatomy of the menisci was investigated in five dogs by histology and tissue-clearing (Spalteholz) techniques. The vessels were found to originate in the perimeniscal capsular and synovial tissues and penetrate the peripheral 25% of the meniscal tissues. The vascular response to complete midportion transection of the medial meniscus was evaluated in 15 dogs. This response originated from the peripheral synovial tissues and completely healed the lesion with fibrovascular scar tissue by 10 weeks. Longitudinal incisions in the avascular portion of the meniscus failed to heal. However, when these lesions were connected to the peripheral synovial tissues at their midportion by a vascular access channel, the entire lesion was healed with fibrovascular scar by 10 weeks.

Animals↗
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Quadriceps atrophy in the anterior cruciate insufficient knee.

Atrophy of the quadriceps musculature is frequently associated with chronic knee instability. This atrophy may persist despite the patient's ability to return to athletic competition. When open biopsies of the quadriceps muscle from unstable knees were compared with those from normal acutely injured knees, it was found that clinical evidence of atrophy correlated with a relative decrease in the size of Type II or fast twitch muscle fibers. This supports the subjective, clinical impression that the unstable knee is less effective in explosive push-off. The findings also indicate the necessity of including exercise specific for the training of Type II fast twitch fibers in any program designed to rehabilitate the injured knee.

Acute Disease↗
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Torque-velocity relationships of the knee extensor and flexor muscles in individuals sustaining injuries of the anterior cruciate ligament.

Muscle deficits in 58 patients with chronic anterior cruciate ligament (ACL) insufficiency were evaluated after completion of a 6 month rehabilitation program. Quadriceps and hamstring torques were measured on a modified Cybex II isokinetic dynamometer. Twenty-nine of our patients were tested just prior to undergoing ACL reconstruction, and patients who were continuing to tolerate their conditions served as controls. For the surgical group, significant quadriceps deficits (P less than 0.01) were found for all speeds and at both the 30 and 60 degrees positions. The nonsurgical group had significant deficits at the 30 degrees position at 180 degrees/sec, and at 60 degrees for the 0 degree/sec and 30 degrees/sec. However, in comparing the two groups no significant differences were noted. Regarding hamstring deficits in the surgical group, significant deficits were seen only at 30 degrees of flexion at 180 degrees/sec. The nonsurgical group had similar deficits. Of interest was the observation that the hamstring:quadriceps (H:Q) ratio was found to be both speed-position dependent. Overall, no correlation was found between the presence of strength deficits following a rehabilitation program and the need for surgery.

Adolescent↗
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A comparison of acute anterior cruciate ligament examinations. Initial versus examination under anesthesia.

The preoperative examination, the examination under anesthesia, and the findings at surgery were compared for acutely injured knees that were found at surgery to have anterior cruciate ligament (ACL) tears. The pivot shift was initially positive in only 35% of the knees; however, under anesthesia 98% were positive. The Lachman test was initially positive in 99% of the knees, and under anesthesia, 100%. The anterior drawer sign was present initially in 70% of the knees, and under anesthesia this increased to 91%. Of the 37 patients with isolated ACL tears, only 20 (54%) had initially positive anterior drawer signs. In the knees in which secondary restraints to anterior-posterior motion were injured, this percentage increased to 69% in medial meniscus injury, 82% in lateral meniscus injury and 89.5% in rupture of the medial collateral ligament (MCL). The Lachman test seems relatively unaffected by associated ligamentous or meniscal injuries, but the end point in the Lachman test is absent in all complete ACL tears. The pivot shift phenomenon, which was demonstrable in 98% of patients when tested under anesthesia, may be diminished when there is a MCL injury or absent in partial ACL tears. Experience in performing the Lachman test and in appreciating the quality of the end point will give the examiner a high degree of accuracy in making the diagnosis of an ACL tear without resorting to anesthesia, arthroscopy, or arthrography in most patients.

Adolescent↗
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Replacement of the anterior cruciate ligament using a synthetic prosthesis. An evaluation of graft biology in the dog.

The ACL of 21 adult mongrel dogs was replaced with a knitted dacron velour prosthesis. The biologic fate of these synthetic grafts was then evaluated at various intervals from 1 to 12 months postoperatively using routine histology and a vascular injection (Spalteholz) technique. Following implantation the knitted dacron prosthesis was encapsulated with a vascular synovial tissue in a manner similar to that observed with autogenous patellar tendon grafts. This revascularization process was followed by a proliferation of fibroblasts throughout the extent of the prosthesis. While the grafts appeared to support a fibrous tissue proliferation in and around the design of the prosthesis, this tissue demonstrated only a random orientation of collagen fibers as late as 1 year postoperatively. It would appear, therefore, that although the knitted dacron prosthesis is capable of inducing and supporting tissue encapsulation and ingrowth, it does not allow for the functional orientation of this tissue.

Animals↗
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Biologic fixation of ligament prostheses and augmentations. An evaluation of bone ingrowth in the dog.

The biologic fixation (bone ingrowth) of three prosthetic ligament devices (bovine xenograft Xenotech Laboratories, Inc., Irvine, CA; Gore-Tex, W. L. Gore and Associates, Flagstaff, AZ; and knitted dacron, Stryker, Kalamazoo, MI) and one ligament augmentation device (LAD, braided polypropylene, 3M, St. Paul, MN) were evaluated in vivo. The devices were placed unstressed, in an extraarticular location in the cortical-cancellous bone of the proximal femur and humerus of dogs. Six months following implantation tissue ingrowth was evaluated using high resolution radiography, routine histology, scanning electron microscopy, and biomechanical tensile tests to measure the ultimate (maximum) pull-out strength of the devices. The knitted dacron and Gore-Tex prosthesis showed marked ingrowth of trabecular bone into the interstices of the device with evidence of bone growth around individual fibers of the prosthesis. The bovine xenograft demonstrated bone immediately adjacent to the material with evidence of spicular ingrowth of bone into the natural clefts of the prosthesis. The LAD showed no evidence of bone ingrowth and demonstrated a fibrous tissue interface between the prosthesis and surrounding trabecular bone. Six months following implantation the pull-out strengths of the devices were as follows: knitted dacron, 445.7 +/- 151.0N; Gore-Tex, 438.1 +/- 131.94N; bovine xenograft, 332.8 +/- 64.2N; and LAD, 78.4 +/- 47.9N. Statistical analysis revealed no significant difference between the pull-out strengths of the knitted dacron, Gore-Tex, and bovine xenograft.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
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In vitro fibroblast seeding of prosthetic anterior cruciate ligaments. A preliminary study.

To evaluate the effect of in vitro seeding of fibroblasts on the connective tissue encapsulation of implanted ligament prostheses, canine skin fibroblasts were grown in tissue culture and seeded onto knitted Dacron prostheses. When the cells on the prostheses reached contact growth inhibition, as determined by growth curves, the prostheses were implanted into the dogs' knees as ACL replacements. Gross and histologic evaluation at 4 and 8 weeks revealed that the seeded prostheses consistently showed more uniform and abundant encapsulation with connective tissue than did the control (unseeded) prostheses. The giant cell response observed in the tissue surrounding the unseeded prostheses was not noted in the seeded prostheses. This may be because seeding a prosthesis with fibroblasts prior to implantation "walls off" the prosthesis from the environment of the joint, and therefore the prosthesis may not elicit as great a foreign body response as does an unseeded prosthesis. The results of this preliminary study suggest that the in vitro seeding of a ligament prosthesis with fibroblasts accelerates the connective tissue encapsulation of the implanted prosthesis.

Animals↗
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Long-term followup of anterior cruciate ligament reconstruction using the quadriceps tendon substitution for chronic anterior cruciate ligament insufficiency.

At The Hospital for Special Surgery, the quadriceps tendon substitution (QTS), as described by Marshall, was performed for ACL insufficiency from 1973 to 1980. A review of the initial 60 patients with a minimum of 4 years followup (average, 5.5 years) has been concluded. Thirty-eight patients returned for examinations, and 11 returned questionnaires. Associated medial procedures were performed in 29 of the 38 examined patients. Medial meniscus surgery was performed in 86% and lateral meniscus surgery in 28.9%. At followup, giving way, which was the main preoperative complaint, was eliminated in 30/38 examined and 9/11 questionnaire patients (79%). In the examined group, three patients were clear failures and five had mild transient instability. The pivot shift was present in 17 of 38 (45%) patients examined: 21 patients were negative, 9 were 1+ or a grind, 8 were 2+, and none were 3+. We have concluded that the QTS procedure will eliminate symptomatic instability in 79% of our patients, but the high rate of a residual pivot shift (45%) and symptoms of instability (21%) require the addition of an extraarticular sling procedure. This appears to be related to the relatively poor strength characteristics of the tissue used in the QTS substitution.

Adult↗
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The pivot shift phenomenon: results and description of a modified clinical test for anterior cruciate ligament insufficiency.

Clinical evaluation of knee instability is often difficult to reproduce, and several different physical tests have become popular. In an attempt to elucidate reasons for variations in the degree of pivot shift phenomenon seen with the use of the various tests, we have prospectively evaluated a group of 37 patients with surgically documented ACL injuries, noting the effects of hip position and tibial rotation. The patients were examined under anesthesia, and the pivot shift was graded as 0 (absent, or negative), 0.5+ (trace), 1+, 2+, or 3+ (with locking). All knees were tested in hip abduction, neutral, and hip adduction, and with the tibia in external and internal rotation, so that six positions were evaluated. Hip position strongly correlated with the degree of pivot shift regardless of tibial rotation. Overall, abduction produced the greatest degree of pivot shift, followed by neutral and finally adduction. External tibial rotation increased the pivot shift score in abduction and neutral, but not in adduction. A grading system for the subject population showed that abduction/external rotation (ABDER) resulted in the highest pivot shift scores, and that adduction/external rotation (ADDER) and adduction/internal rotation (ADDIR) resulted in the lowest scores. Nine patients out of 20 with a 3+ pivot shift in ABDER were negative in ADDER. The pivot shift score was dampened at least one grade from ABDER to ADDER in 92% of the patients. We conclude that hip position and tibial rotation affect the degree of pivot shift phenomenon, and it is our impression that the iliotibial band plays a significant role in controlling the degree of pivot shift observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
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Primary repair with semitendinosus tendon augmentation of acute anterior cruciate ligament injuries.

A retrospective review of 72 acute ACL injuries in 70 athletically active patients (50 recreational and 20 competitive athletes) treated with primary repair and semitendinosus tendon augmentation was conducted (mean follow-up time, 38.5 months). All patients had open primary multiple loop depth-varying suture repair and semitendinosus tendon augmentation at a mean injury to surgery interval of 9.1 days. Fifty-one cases (70.8%) were supplemented with an extraarticular procedure consisting in all cases of an iliotibial band lateral sling reinforcement. All patients underwent 6 weeks of postoperative immobilization followed by a graduated rehabilitation regimen lasting a mean 7.2 months. In 22 of the ACL tears, no other associated injury could be defined at arthrotomy, while in 27, significant medial collateral ligament injuries were noted. Lateral meniscal injuries (24) were more commonly noted than medial meniscal injuries (19). Good to excellent subjective results were reported in 82%, while 77.1% returned to preinjury sport level and participation without limitation. One patient developed "giving way" symptoms and overall, only four patients did not return to sports participation. Objective examination revealed 93.1% to have a 1+ or less Lachman test and 86.1% to have a negative pivot shift. Of 60 knees tested, 93.3% had KT-1000 side-to-side difference values (measured at 25 degrees +/- 5 degrees of flexion with an 89 N load) of less than or equal to 3 mm of anterior displacement. A 100 point Hospital for Special Surgery ligament rating score was used with 25 points assigned to subjective, 45 points to objective, and 30 points to functional assessment. The mean score at followup was 93.1. Analysis of results in patients with or without an extraarticular reinforcement revealed no difference in objective outcome. The incidence of patellofemoral pain was 27.8%. Thirty knees had some degree of loss of range of motion. Loss of terminal flexion was noted in 29, while 5 had loss of terminal extension. No correlation could be found between patellofemoral pain and diminished range of motion. Generalized ligamentous laxity was found in 37.1% of the patients; this was not associated with a poor result. This study suggests that primary repair with semitendinosus tendon augmentation of acute ACL injuries with a graduated rehabilitation regimen provides good subjective, and excellent functional and objective, results in active patients that were followed for more than 3 years.

Adolescent↗
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Torque production in the shoulder of the normal young adult male. The interaction of function, dominance, joint angle, and angular velocity.

Shoulder torque measurements were obtained from 36 normal young adult males during flexion, abduction, internal rotation, and external rotation. Normative, angle-specific torque measurements were determined under isometric conditions and isokinetically at 48 deg/sec. The effects of dominance, angular velocity, and joint position were determined and a method provided for determining the expected maximal torque at a specific speed and position based upon torque measurements from the contralateral shoulder. This method can be used in cases of unilateral shoulder abnormalities to predict normative torque values for the affected side based on torque measurements from the unaffected shoulder.

Adult↗
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Turf-toe: an analysis of metatarsophalangeal joint sprains in professional football players.

Metatarsophalangeal joint injuries of the great toe (turf-toe) are receiving increasing attention in the literature because of the prevalence of synthetic surfaces and lighter, more flexible shoes. Eighty active professional football players were evaluated. The mechanism of injury was hyperextension in 85% of the players. Eighty-three percent reported their initial injury on artificial turf (P less than 0.05). Other factors significantly related to the incidence of turf-toe included player age (P less than 0.01), number of years in professional football (P less than 0.01), and range of ankle dorsiflexion (P less than 0.05). Turf-toe injury resulted in significantly decreased range of motion of the first metatarsophalangeal joint (P less than 0.01).

Adult↗
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Primary surgical treatment of anterior cruciate ligament ruptures. A long-term follow-up study.

We reviewed 52 patients who underwent primary surgical repair of their acutely injured ACL using a multiple loop, varying depth suture technique. The average followup was 6 years and 10 months. Nine patients (17%) were considered as having failed repairs, with failure based on the presence of clinical instability (giving way) with sports participation and a positive Lachman test and/or pivot shift maneuver. In addition, of 26 patients in whom KT-1000 (MEDmetric Corp., San Diego, CA) measurements were performed, 42% were found to have abnormal laxity. Although using multiple sutures in primary repair of the anterior cruciate may work in some patients, it is an unpredictable operative procedure and resulted in a 17% failure rate in our study.

Adolescent↗
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The anatomy and histology of the inferior glenohumeral ligament complex of the shoulder.

The gross and histologic anatomy of the inferior glenohumeral ligament was studied in 11 fresh frozen cadaver shoulders. Arthroscopic observations of the joint capsule through the normal range of motion revealed that the inferior glenohumeral ligament is actually a complex of structures consisting of an anterior band, a posterior band, and an interposed axillary pouch. While these components of the inferior glenohumeral ligament complex were present in all 11 specimens, they were best demonstrated in some shoulders by placing the humeral head in internal or external rotation in varying degrees of abduction. Histologic examination of the joint capsule revealed that the anterior and posterior bands of the inferior glenohumeral ligament complex were readily identifiable as distinct structures comprised of thickened bands of well-organized collagen bundles. Although slight variations were noted in the attachment sites of the anterior and posterior bands to the glenoid, the inferior glenohumeral ligament complex was observed to attach to the humeral neck in one of two distinct configurations. A collar-like attachment, in which the entire inferior glenohumeral ligament complex attaches just inferior to the articular edge of the humeral head, was observed in six specimens. In the remaining five specimens, the attachment was in the shape of a "V," with the anterior and posterior bands attaching adjacent to the articular edge of the humeral head and the axillary pouch attaching at the apex of the "V" distal to the articular edge. The orientation and design of the inferior glenohumeral ligament complex supports the functional concept of this single structure as an important anterior and posterior stabilizer of the shoulder joint.

Arthroscopy↗
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The iliotibial band lateral sling procedure and its effect on the results of anterior cruciate ligament reconstruction.

The effect of iliotibial band "lateral sling" augmentation on long-term outcome in ACL reconstruction using free autogenous central-third patellar tendon was evaluated retrospectively. Eighty reconstructions were reviewed; the minimum followup was 2 years and the average was 4 years. Sixty percent of the procedures involved supplementation with a lateral sling. By both clinical evaluation and KT-1000 measurement, there were no differences in the results of patients with lateral sling augmentation and those without it. In addition, 40% of patients had chronic pain and/or swelling related to the lateral sling. We do not currently recommend the routine use of a lateral sling augmentation for ACL reconstruction using central-third patellar tendon.

Adolescent↗