Biomedical subjects

D N Caborn

Publications and source records attributed to D N Caborn.

36 records · Page 2Linked to original sources

PubMed1998

Patellar tendon ACL reconstruction and rehabilitation practices and opinions (autograft versus allograft): orthopaedic sports medicine fellowship program survey.

We wanted to determine the bone-patellar tendon-bone (BPTB) anterior cruciate ligament (ACL) reconstruction practices of accredited orthopaedic sports medicine fellowship programs and their opinions about whether differences should exist in rehabilitation protocol, bracing, and timing of release to cutting/agility sports between autogeneic and allogeneic grafts. Our survey showed most programs did 51 to 100 BPTB ACL reconstructions during the 12 months before survey completion. Standard rehabilitation protocols were used without differences based on BPTB graft type or fixation concerns. Programs were equally divided regarding whether BPTB graft type should be a timing of release to cutting/agility sports factor. Programs were almost equally divided regarding routinely prescribed derotation braces. More programs used autograft rather than allograft BPTB tissue for ACL reconstruction, without rehabilitation protocol differences based on graft type or fixation concerns. Conflicting results regarding protocol and timing of release to cutting/agility sports indicate that several factors may contribute to the clinical decision-making process. Equivocal results regarding derotation brace prescription raises concerns regarding their necessity.

Anterior Cruciate Ligament↗

PubMed1997

Fatigue after eccentric quadriceps femoris work produces earlier gastrocnemius and delayed quadriceps femoris activation during crossover cutting among normal athletic women.

Athletic women are at greater risk of anterior cruciate ligament (ACL) injury than men. Twenty, healthy, athletic women were evaluated for the effect of preferred stance limb isokinetic quadriceps femoris and hamstring fatigue from eccentric work compared with controls on the activation onset of vastus medialis, rectus femoris, vastus lateralis, the medial hamstrings, biceps femoris, and gastrocnemius muscles. Following 3 weeks of crossover cut training, subjects were tested for fatigue effects (5 subjects/week, 3 conditions, 1 condition/day, order effect controlled) on muscle activation onsets prior to crossover cut landing heelstrike (mixed model, ANOVA, P < 0.05). Fatigue from eccentric quadriceps femoris work produced delayed vastus medialis (P = 0.03), rectus femoris (P = 0.007), and vastus lateralis (P = 0.03) activation onsets compared with control, but did not differ compared to hamstring fatigue. Neither hamstring nor quadriceps femoris fatigue produced differences (P > 0.05) in medial hamstring or biceps femoris activation onsets compared to control. Quadriceps femoris fatigue from eccentric work produced earlier gastrocnemius activation onsets (P = 0.048) than control, but did not differ for hamstring fatigue. The gastrocnemius appears to provide synergistic and compensatory dynamic knee stabilization in closed kinetic chain function during quadriceps femoris fatigue. This finding in a normal group at high risk of ACL injury while performing a maneuver with a high ACL injury risk supports gastrocnemius inclusion in knee rehabilitation and conditioning programs and suggests the need for comparative evaluations of knee injured/reconstructed subjects.

Analysis of Variance↗

PubMed1997

Biomechanical comparison between BioScrew and titanium alloy interference screws for bone-patellar tendon-bone graft fixation in anterior cruciate ligament reconstruction.

This investigation compared the maximum load at failure of BioScrew (Linvatec Corp, Largo, FL) and titanium alloy interference screw femoral fixation using a human cadaveric model that approximated the anatomical orientation and physiological strain rate of in vivo bone-patellar tendon-bone (BPTB) graft loading following anterior cruciate ligament reconstruction. Eighteen fresh-frozen human BPTB allografts (10-mm wide, 10-mm thick, 25-mm long bone plugs) with either BioScrew or titanium alloy (Ti 6A14V) screw (7 x 25 mm) fixation were compared for maximum load at failure at a strain rate of 20 mm/minute. Nine cadaver femurs with bone mineral densities of 0.88 +/- 0.18 g/cm2 (anterior/posterior) and 1.3 +/- 0.24 g/cm2 (lateral) received the allografts. No statistical differences were observed in maximum load at failure (P = .95) or failure mode (P = .11) between specimens fixed with either screw type. When biomechanically tested with anatomic orientation and at functionally relevant strain rates, the BioScrew provided maximum load at failure equal to a titanium alloy screw.

Absorption↗

PubMed1997

The effect of quadriceps femoris, hamstring, and placebo eccentric fatigue on knee and ankle dynamics during crossover cutting.

This study attempted to determine the effect of eccentric quadriceps femoris, hamstring, and placebo fatigue on stance limb dynamics during the plant-and-cut phase of a crossover cut. Twenty female college students (task trained) were tested. Hamstring fatigue resulted in decreased peak impact knee flexion moments (p < or = .01), increased internal tibial rotation at peak knee flexion (p < or = .05), and decreased peak ankle dorisflexion (p < or = .05). Quadriceps fatigue resulted in increased peak ankle dorsiflexion moments (p < .01), decreased peak posterior braking forces (p < or .01), decreased peak knee extension moments (p < or = .01), delayed peak knee flexion (p < or = .01), delayed peak propulsive forces (p < .01), and delayed subtalar peak inversion moments (p < or = .05). Fatigue of either muscle group produced earlier peak ankle plantar flexion moments (p < = .05) and decreased peak propulsive knee flexion moments (p < or = .05). Variables requiring further study (p < or = .1) provide discussion data. Soleus, gastrocnemius, tibialis anterior, and deep posterior compartment calf muscles serve as dynamic impact force attenuators, compensating for fatigued proximal muscles.

Adult↗

PubMed1997

Results of the Kentucky high school football knee injury survey.

The study attempted to: 1) determine knee injury and reinjury incidence of Kentucky high school football players; 2) relate results to initial care provider, treatment following initial physician exam, time lost from injury, injury type, player position, and team size; and 3) assess coaches opinions and practices about lateral prophylactic knee brace (LPKB) usage and effectiveness. A post season, mail-in coaches' survey (50.2% return, 101/201) collected these data. Returned surveys represented 4690 players with average team size (x +/- SD) of 43 +/- 13. Two hundred fifty seven reported knee injuries yielded .055 knee injuries/player with .04 knee injuries/player being "new" and .015 knee injuries/player recurring (27% of reported knee injuries) during the season. Games accounted for 56.4% (56/101) of reported knee injuries. Coaches generally believed that LPKB usage prevented knee injuries (56.4%, 56/101) and allowed LPKB usage (92.1%, 93/101), however only 8.3% (8/101) required their wear (interior linemen 50%, linebackers 25%, entire team (25%). Interior linemen had the greatest number of knee injuries, followed by offensive backs and linebackers. Most knee injuries (81%, 208/257) were out 3-6 weeks or less, 64% (164/257) involved sprains or contusions, 38% (97/257) were treated surgically (alone or with rehabilitation) and 36% (92/257) were treated solely with rehabilitation. Total knee injury and reinjury incidence were under-estimated compared to existing reports. Improved injury recording methods, and post-symposia coaches evaluation are recommended.

Adolescent↗

PubMed1996

The dimpling phenomenon: articular cartilage injury overlying an occult osteochondral lesion at the time of anterior cruciate ligament reconstruction.

The authors report the arthroscopic finding of articular cartilage "dimpling" when a probe is placed onto the discrete chondral area involved over the geographic bone bruise incurred during traumatic anterior cruciate ligament disruption. As we develop an understanding of the pathology and sequelae of this osteochondral injury, this finding may be useful to document injury extent and possibly guide treatment including weight-bearing status and rehabilitation.

Anterior Cruciate Ligament↗

PubMed1996

Electrodiagnostic study of carpal tunnel syndrome in wheelchair basketball players.

UNLABELLED: OBJECTIVE-DESIGN-SUBJECTS: Compression neuropathies are common injuries about the wrist in wheelchair athletes. Thirty-three world-class wheelchair basketball players were studied electrodiagnostically to determine the prevalence and severity of median neuropathy at the wrist in these athletes. RESULTS: Thirty percent of these athletes had symptoms consistent with carpal tunnel syndrome (CTS), and 70% of these had electrodiagnostic confirmation of this injury. Overall, 52% of the 33 athletes had electrodiagnostic findings of median neuropathy at the wrist with nine athletes (27%) exhibiting bilateral abnormalities. Four athletes (12%) had abnormal electrodiagnostic findings involving the ulnar nerve at the wrist. CONCLUSIONS: This prevalence of CTS in wheelchair basketball players appears to be similar to that found in the general paraplegic population. Early recognition and treatment of CTS in these athletes are recommended to avoid chronic problems.

Adult↗

PubMed1995

Suprascapular neuropathy in athletes: case reports.

Shoulder pain and dysfunction is a common problem among athletes, and a great deal of attention is being given to scapular stability and rotator cuff pathology. Two athletes who were first seen with posterolateral shoulder pain and weakness were found to have isolated entrapment of the suprascapular nerve, causing their impairment. Both athletes responded well to conservative treatment, but this entity occasionally requires operative decompression. This article reviews the most common presentation, etiologies, and treatments of suprascapular neuropathy and how it can affect athletic performance.

Adolescent↗

PubMed1995

The ankle ligaments: consideration of syndesmotic injury and implications for rehabilitation.

Injury to the distal tibiofibular syndesmosis (DTFS) may be more common than previously reported. This injury is typically caused by external forces which produce sudden ankle dorsiflexion or plantar flexion in combination with external rotation of the foot. Common mechanisms include direct contact with another player or uneven physical terrain. Improper diagnosis of this injury may greatly delay the return to normal functional status and promote the development of chronic instability, degenerative joint changes, and pain. The purpose of this clinical commentary is to review the ligamentous anatomy of the ankle and the incidence of injury to the lateral ligaments of the ankle, with emphasis on DTFS injury. Special tests which enhance the recognition of DTFS injury, such as the external rotation stress test and the distal tibiofibular compression test, and a rehabilitation progression are presented.

Ankle Injuries↗

PubMed1993

The natural history of the anterior cruciate ligament-deficient knee. A review.

The ACL-deficient knee has been a management dilemma for many years and, to this day, no refutable plan exists for treatment of this injury. No true prospective study has been performed that evaluates all types of individuals at a variety of activity levels, and, in this day of apparently reliable methods of reconstructing the ACL, it is doubtful that one will occur. The ACL injury is no longer a mystery to the general public; it has received extensive publicity because of injuries of professional athletes and the successful reconstruction in many of these athletes. This article has not completely cleared up the issue of the future of an ACL-deficient knee. It has provided, however, convincing evidence that an active individual with a nonfunctional ACL is susceptible to meniscus injury (R. Barrack, J. Bruckner, J. Kneisl, et al, personal communication, 1990). There is also the risk of more tears occurring with time. Bray and Dandy found in their follow-up of patients with ACL repairs that, if the pivot shift returned, these patients had a much higher incidence of meniscus tears. Many of these studies indicate that, if the meniscus cannot be repaired and requires partial meniscectomy or worse, the articular surface will deteriorate (R. Barrack, J. Bruckner, J. Kneisl, et al, personal communication, 1990). Satku et al showed only 11% incidence of radiographic changes in patients with ACL-deficient knees with no evidence of meniscus tears compared with 100% in those having meniscectomy more than 5 years previously. Activity levels in general also change following this injury. This is probably the most difficult area to assess. Even though a substantial number of persons returned to their preinjury level of activity, it is not always possible to determine if they are playing with the same behavior and attitude. In other words, athletes who are involved in sports with cutting and jumping may modify the need for these activities and yet remain relatively competitive depending on their previous level of skill and the position they play. It has also been shown that many athletes return to their preinjury level initially but with time have significant increase in their symptoms and must modify their level of participation. More individuals limited their activities from the beginning than returned to their preinjury level (R. Barrack, J. Bruckner, J. Kneisl, et al, personal communication, 1990). Instability varies in these individuals and, as in Chick and Jackson's patients, those with mild instability (no rotatory instability) may do reasonably well.(ABSTRACT TRUNCATED AT 400 WORDS)

Anterior Cruciate Ligament↗

PubMedDate not supplied

Cause of long thoracic nerve palsy: a possible dynamic fascial sling cause.

Long thoracic nerve palsy can result from sudden or repetitive external biomechanical forces. This investigation describes a possible dynamic cause from internal forces. Six fresh cadaveric shoulders (3 female, 3 male, 4 left, 2 right) with full range of motion were systematically dissected to evaluate the anatomic course of the long thoracic nerve. In all specimens a tight fascial band of tissue arose from the inferior aspect of the brachial plexus, extended just superior to the middle scalene muscle insertion on the first rib, and presented a digitation that extended to the proximal aspect of the serratus anterior muscle. With progressive manual abduction and external rotation, the long thoracic nerve was found to "bow-string" across the fascial band. Medial and upward migration of the superior most aspect of the scapula was found to further compress the long thoracic nerve. Previous investigations have reported that nerves tolerate a 10% increase in their resting length before a stretch-induced neuropraxia develops. Previous studies postulated that long thoracic nerve palsy resulted from the tethering effect of the scalenus medius muscle as it actively or passively compressed the nerve; however, similar neuromuscular relationships occur in many other anatomic sites without ill effect. We propose that the cause of long thoracic nerve palsy may be this "bow-stringing" phenomenon of the nerve across this tight fascial band. This condition may be further exacerbated with medial and upward migration of the superior aspect of the scapula as is commonly seen with scapulothoracic dyskinesia and fatigue of the scapular stabilizers. Rehabilitation for long thoracic nerve palsy may therefore benefit from special attention to scapulothoracic muscle stabilization.

Adult↗

PubMedDate not supplied

Technique for selecting capsular tightness in repair of anterior-inferior shoulder instability.

Part I of our study consisted of sending a survey questionnaire to all members of the American Shoulder and Elbow Surgeons in which specific questions were asked about their technique of surgical repair in patients with anterior instability who had capsular laxity or injury in conjunction with marked inferior laxity. Part II is a description of the technique and preliminary results in 18 patients of a modified anterior-inferior capsular shift technique that tightens the inferior capsule with the shoulder positioned in abduction and external rotation and the superior capsule with the shoulder in adduction and external rotation. Of the members of the Society of the American Shoulder and Elbow Surgeons who responded to the survey, 80% agreed that preservation of external rotation was important and that shoulder position at the time of capsular repair might influence the ultimate range of motion obtained. However, no more than 50% of the respondents agreed on any one position for the arm when repairing the capsule. The most common responses for each position were flexion 0 degrees (49%) (range, 0 degrees to 40 degrees), abduction 30 degrees (24%) (range, 0 degrees to 80 degrees), and external rotation 30 degrees (37%) (range, 0 degrees to 70 degrees). The average postoperative follow-up period for the 18 patients was 27 months (range, 24 to 39 months). Of the 18 patients, 11 (61%) maintained symmetric motion; the others had minimal loss of external rotation compared with that of the contralateral shoulder. Six of eight patients with repair on the dominant side were able to return to full premorbid recreational throwing or racquet sports, and seven with repair on the nondominant side returned to full participation in overhead sports such as basketball and swimming. We conclude that this method of "selective" capsular repair may be a useful guideline to gauge the degree of capsular tightening in patients who have capsular injury or laxity.

Adult↗

PubMedDate not supplied

The effect of a geographic lateral bone bruise on knee inflammation after acute anterior cruciate ligament rupture.

We prospectively evaluated 40 patients who had knee inflammation after isolated anterior cruciate ligament rupture with or without an associated "geographic" bone bruise/subchondral fracture of the lateral femoral condyle. All patients with acute ruptures documented by magnetic resonance imaging within 1 week of injury were evaluated for a geographic bone bruise/subchondral fracture of the lateral femoral condyle. Two groups of 20 patients each (bone bruise versus no bone bruise) were then enrolled. Variables measured at 1, 2, 3, and 4 weeks after injury included pain, range of motion, effusion, and number of days with an antalgic gait. Patients with a bone bruise had increased size and duration of effusion, increased number of days required to nonantalgic gait without external aids, increased days to achieve normal range of motion, and increased pain scores at measured time intervals. This study confirms results of previous clinical and histologic studies showing an associated articular cartilage lesion, otherwise known as bone bruise/subchondral fracture, is clinically significant. There appears to be an association between a geographic bone bruise and increased disability in patients with acute anterior cruciate ligament ruptures. Patients with a geographic bone bruise may require longer to reach normal homeostasis (range of motion, pain, neuromuscular control) before undergoing anterior cruciate ligament reconstruction.

Anterior Cruciate Ligament Injuries↗

PubMedDate not supplied

Interference screw fixation strength of a quadrupled hamstring tendon graft is directly related to bone mineral density and insertion torque.

The purpose of this study was to determine whether bone mineral density of the host bone, measured using conventional dual photon absorptiometry techniques, and insertion torque can predict part of the ultimate failure strength of interference screw fixation of quadrupled hamstring tendon grafts. The semitendinosus and gracilis tendons were harvested from 10 human cadaveric knees, mean age 66.5 years (range, 53 to 81). The bone tunnel was sized within 0.5 mm of the graft. The graft was fixed with a biodegradable screw (7 x 25 mm for the femur, and 9 x 25 mm for the tibia) directly against the tendon and at the joint surfaces. Tibial fixation and femoral fixation were tested to failure using a materials testing system. Bone mineral density was measured in the metaphyseal region of the tibia and femur. The results of multiple regression analyses showed that both insertion torque and bone mineral density were related to the maximum load the graft withstood. These two variables explained 77.1% of the maximum load observed. We concluded that bone mineral density measurements of the host bone site are an important determinant of postoperative graft strength and thus have an important, but previously unrecognized, clinical role in establishing individual postsurgery rehabilitation protocols. Insertion torque in this study was a useful predictor of graft fixation strength.

Aged↗

PubMedDate not supplied

Graft fixation in cruciate ligament reconstruction.

Cruciate ligament reconstruction has progressed dramatically in the last 20 years. Anatomic placement of ligament substitutes has fostered rehabilitation efforts that stress immediate and full range of motion, immediate weightbearing, neuromuscular strength and coordination, and early return to athletic competition (3 months). This has placed extreme importance on secure graft fixation at the time of ligament reconstruction. Current ligament substitutes require a bony or soft tissue component to be fixed within a bone tunnel or on the periosteum at a distance from the normal ligament attachment site. Fixation devices have progressed from metal to biodegradable and from far to near-normal native ligament attachment sites. Ideally, the biomechanical properties of the entire graft construct would approach those of the native ligament and facilitate biologic incorporation of the graft. Fixation should be done at the normal anatomic attachment site of the native ligament (aperture fixation) and, over time, allow the biologic return of the histologic transition zone from ligament to fibrocartilage, to calcified fibrocartilage, to bone. The purpose of this article is to review current fixation devices and techniques in cruciate ligament surgery.

Anterior Cruciate Ligament↗

PubMedDate not supplied

Effect of screw length on bioabsorbable interference screw fixation in a tibial bone tunnel.

Initial tibial fixation strength is the weak link after anterior cruciate ligament reconstruction with a quadrupled hamstring tendon graft fixed with bioabsorbable interference screws. The purpose of this study was to determine the biomechanical differences between 28-mm and tapered 35-mm interference screws for tibial fixation of a soft tissue graft in 16 young cadaveric tibias. Failure mode, displacement before failure, and ultimate failure load were tested with a testing machine aligned with the tibial tunnel to simulate a worst-case scenario. The mode of failure was graft slippage past the screw in all but one of the specimens. The mean maximum load at failure of the 28-mm screw was 594.9 +/- 141.0 N, with mean displacement at failure of 10.97 +/- 2.20 mm. The mean maximum load at failure of the 35-mm screw was 824.9 +/- 124.3 N, with a mean displacement to failure of 14.38 +/- 2.15 mm. The 38% difference in mean maximal load at failure was significant. Important variables in hamstring tendon graft fixation within a bone tunnel include bone mineral density, dilatation, gap size, screw placement, and screw width and length. Attention to these variables will help to provide secure graft fixation during biologic incorporation throughout the rehabilitation period.

Absorbable Implants↗

PubMedDate not supplied

The effect of ankle stabilizers on athletic performance. A randomized prospective study.

The ankle is the site of more than one third of all injuries that occur to male basketball players. Although ankle bracing may prevent injury, many players believe that braces restrict athletic performance. This belief discourages use of braces and obviates the injury protection that bracing provides. The objectives of this study were to 1) determine whether athletic performance (in four basketball-related activities) was affected by three ankle brace designs (Universal, Kallassy, and Air-Stirrup ankle training brace), 2) determine whether specific braces are better for specific athletic activities, and 3) determine whether athletic performance changes with brace use. Twelve high school basketball players wore each brace type while vertical jumping, standing long jumping, cone running, and 18.3-meter shuttle running at two test times (initially and after 1 week of acclimation). Our data showed that these braces had no significant effects on athletic performance. No brace affected athletic performance in one specific activity more than another, and athletic performance did not change with brace use. We concluded that prophylactic ankle bracing does not inhibit athletic performance.

Adaptation, Physiological↗

PubMedDate not supplied

Articular cartilage changes seen with magnetic resonance imaging-detected bone bruises associated with acute anterior cruciate ligament rupture.

Occult osteochondral lesions (bone bruises) have been documented on magnetic resonance images in more than 80% of patients sustaining acute anterior cruciate ligament ruptures. Despite the high prevalence of these lesions, little is known about the histologic changes in the adjacent articular cartilage. Ten patients with acute anterior cruciate ligament ruptures who had a preoperatively documented (by magnetic resonance imaging) geographic bone bruise at the sulcus terminalis on the lateral femoral condyle underwent a 3-mm diameter trephine biopsy of the articular cartilage and subchondral bone overlying the bone bruise at the time of anterior cruciate ligament reconstruction. Biopsy samples of the articular cartilage and subchondral bone were stained with hematoxylin and eosin and toluidine blue. All patients had significant arthroscopic and histologic articular cartilage irregularity in the area overlying the bone bruise. Arthroscopic findings of the articular cartilage included softening (dimpling), fissuring, or overt chondral fracture. Histologic examination revealed degeneration of the chondrocytes and loss of toluidine blue staining in the articular cartilage (loss of proteoglycan). There was necrosis of osteocytes in the subchondral bone, and empty lacuna were visible. This study defines the exact histologic changes of the articular cartilage overlying a geographic bone bruise secondary to an acute anterior cruciate ligament tear. Our findings suggest that a geographic bone bruise found on magnetic resonance imaging indicates substantial damage to normal articular cartilage homeostasis.

Adolescent↗