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Biomedical subjects

R H Gelberman

Publications and source records attributed to R H Gelberman.

At least 19 recordsLinked to original sources
PubMed2005

Supplementary core sutures increase resistance to gapping for flexor digitorum profundus tendon to bone surface repair - an in vitro biomechanical analysis.

We evaluated the effects of two types of supplementary core sutures on the tensile properties and resistance to gap formation of flexor digitorum profundus (FDP) tendon-bone repairs. Forty-five human cadaver FDP tendons were sharply released from their insertion sites and repaired to bone utilizing one of three repair techniques: four-strand modified Becker core suture (Becker only), modified Becker plus a figure-of-eight supplementary core suture (Becker plus figure-of-eight), and modified Becker plus a supplementary core suture using a bone anchor (Becker plus anchor). Ultimate (maximum) force did not differ between repair groups. However, addition of a supplementary suture significantly increased repair-site stiffness and the 1, 2 and 3 mm gap forces, while decreasing the gap at 20 N compared to the Becker only suture (P<0.05). The only difference between the two supplementary suture groups was that the Becker plus anchor group had increased stiffness compared to the Becker plus figure-of-eight group. In conclusion, a supplementary figure-of-eight suture and a supplementary suture using a bone anchor provide enhanced resistance to gap formation for FDP tendon-bone repairs.

Adult↗
PubMed2001

Quantitative variation in vascular endothelial growth factor mRNA expression during early flexor tendon healing: an investigation in a canine model.

Vascular endothelial growth factor (VEGF) is a potent mediator of angiogenesis, with direct mitogenic activity on cells of endothelial origin. We quantified the temporal accumulation of VEGF mRNA at the repair site of an in vivo canine intrasynovial flexor tendon repair and rehabilitation model by means of quantitative Northern blot analysis, in order to detail a molecular signal involved in the intrinsic angiogenic process that accompanies early flexor tendon healing. Significant accumulation of VEGF mRNA occurred at the flexor tendon repair site at 7 days post-operatively, with peak levels seen at post-operative days 7 and 10. Levels returned to baseline by day 14. Local VEGF mRNA accumulation at the repair site temporally precedes and is spatially distinct from the vascular ingrowth itself, which has been shown to occur maximally at day 17. These data suggest that cells within the flexor tendon repair site are involved in molecular processes other than the synthesis of extracellular matrix, such as modulation of angiogenesis.

Animals↗
PubMed2001

The effect of variations in applied rehabilitation force on collagen concentration and maturation at the intrasynovial flexor tendon repair site.

The biochemical means by which accelerated rehabilitation alters intrasynovial flexor tendon repair site collagen synthesis and extracellular matrix maturation are not fully understood. We hypothesized that an increased level of applied rehabilitative force in a clinically relevant animal model would hasten the maturation of the repair site extracellular matrix as demonstrated by total collagen and collagen cross-link assessment. Twenty-eight flexor digitorum profundus tendons from 14 adult dogs were transected and repaired. The animals received either low- or high-force rehabilitation and were killed 10, 21, and 42 days after surgery. A 10-mm segment of tendon surrounding the repair site was obtained. Biochemical analysis showed that total collagen concentration was significantly reduced at each time point, that the reducible cross-link ratio of dihydroxylysinonorleucine to hydroxylysinonorleucine was significantly increased at each time point, and that the nonreducible pyridinoline cross-link content was significantly decreased at 10 days in both rehabilitative groups. Total collagen content did not vary to a statistically significant degree with either time or as a function of rehabilitation type. Based on these findings several clinically relevant observations can be made. Increasing collagen concentration and repair site maturation do not explain the previously demonstrated increased tensile properties of tendon that occur between 3 and 6 weeks after repair. Higher force rehabilitation does not alter the biochemical composition of the healing tendon through 6 weeks. Coupled with other recent data these findings suggest that high-force rehabilitation does not stimulate accelerated healing after intrasynovial flexor tendon repair.

Animals↗
PubMed2001

The influence of cross-sectional area on the tensile properties of flexor tendons.

Clinicians have long noted substantial variation in the cross-sectional size of flexor tendons in the hand; however, data indicating that surgical repair techniques of lacerated flexor tendons should be altered according to size are unavailable. Our objectives were to evaluate the cross-sectional size differences among tendons within the same hand and to correlate tendon size with tensile mechanical properties after suture repair. Fifty human cadaver flexor digitorum profundus tendons were measured with digital calipers to determine radioulnar and volardorsal diameters. Twenty tendons were used to measure resistance to suture pull-through; tendons were transected at the A2 pulley, and a transverse double-stranded 4-0 Supramid suture (S. Jackson, Inc, Alexandria, VA) was passed through the radioulnar plane of the tendon 1 cm from the transection site. The remaining tendons were transected and repaired by using a modified Kessler repair with double-stranded 4-0 Supramid suture. Both tendon repairs and tendon-suture pull-through specimens were tested to failure in tension by using a material testing machine. Dorsovolar tendon height and tendon cross-sectional area varied significantly between digits, with an average difference of approximately 40% between the values of the smallest (fifth) and largest (third) fingers. Yield and ultimate force determined by pull-through tests of the simple transverse suture correlated positively with tendon radioulnar width. Tensile properties of tendons repaired with a double-stranded modified Kessler repair, however, did not depend significantly on tendon size. These results indicate that the strength of the commonly used Kessler suture technique is not dependent on tendon cross-sectional size within the clinically relevant range of tendons evaluated.

Humans↗
PubMed2001

Arterial patterns of the deep and superficial palmar arches.

The vascular patterns of the palmar arches and their interconnecting branches present a complex and challenging area of study. Improvements in microsurgical techniques have made a better understanding of vascular patterns and vessel diameters more important. Forty-five fresh limbs from cadavers were amputated at the level of the midhumerus. Ward's red latex or Batson's compound was injected under pressure to visualize the arterial system in the hand. After hardening of the injected material, the skin, subcutaneous tissues, and tendons were removed. The specimens were digested in concentrated potassium or sodium hydroxide leaving the bony elements and a cast of the arterial system. The superficial palmar arch is most easily classified into two categories: complete or incomplete. An arch is considered to be complete if an anastomosis is found between the vessels constituting it. An incomplete arch has an absence of a communication or anastomosis between the vessels constituting the arch. Complete superficial palmar arches were seen in 84.4% of specimens. In the most common type, the superficial arch was formed by anastomosis between the superficial volar branch of the radial artery and the ulnar artery. This was seen in 35.5% of specimens. In 31.1%, the arch was formed entirely of the ulnar artery. Incomplete superficial arches were seen in 15.5% of specimens. In 11.1%, the ulnar artery forms the superficial arch but does not contribute to the blood supply to the thumb and index finger. The deep palmar arch was found to be less variable with 44.4% formed by an anastomosis between the deep volar branch of the radial artery and the inferior deep branch of the ulnar artery. Injection followed by chemical debridement allows direct visualization and measurement of the arches and the smaller arterial branches that are visualized poorly with other techniques. Based on the vessel measured, vessels of the superficial and deep arches are of sufficient size to allow microvascular repair, although repair of the communicating branches, the dorsal carpal rete, and its branches, probably is not feasible because of their small size.

Hand↗
PubMed2001

Vascularity of the carpus.

Relatively few studies investigating the vascular patterns of the carpus have been performed. Technical difficulties in identifying small vessels in three dimensions and in determining their location within the thick ligaments about the wrist have led to conflicting anatomic reports. Studies on cadavers in which improved techniques with arterial injection, chemical debridement, and decalcification were used allowed the arterial anatomy of the carpus to be delineated more accurately. The current authors review these arterial patterns, with attention given to the extraosseous and intraosseous vascularities.

Carpal Bones↗
PubMed2001

Carpal instability.

Explore the source record for details and available documents.

Biomechanical Phenomena↗
PubMed2001

Intrasynovial flexor tendon repair. An experimental study comparing low and high levels of in vivo force during rehabilitation in canines.

BACKGROUND: Rehabilitation methods that generate increased tendon force and motion have been advocated to improve results following intrasynovial flexor tendon repair. However, the effects of rehabilitation force and motion on tendon-healing may be masked by the high stiffness produced by newer suture methods. Our objective was to determine whether the biomechanical properties of tendons repaired by one of two multistrand suture methods were sensitive to an increased level of applied rehabilitation force. METHODS: Two hundred and fourteen flexor digitorum profundus tendons from 107 adult dogs were transected and repaired. Dogs were assigned to one of four groups based on the rehabilitation method (low force [<5 N] or high force [17 N]) and the repair technique (four-strand or eight-strand core suture) and were killed between five and forty-two days after the procedure. Repair-site structural properties were determined by tensile testing, and digital range of motion was assessed with use of a motion-analysis system. RESULTS: Tensile properties did not differ between the low and high-force rehabilitation groups, regardless of the repair technique (p > 0.05). In contrast, tensile properties were strongly affected by the repair technique, with tendons in the eight-strand group having an approximately 35% increase in ultimate force and rigidity compared with those in the four-strand group (p < 0.05). Ultimate force did not change significantly with time during the first twenty-one days (p > 0.05); there was no evidence of softening in either of the repair or rehabilitation groups. Force increased significantly from twenty-one to forty-two days, while rigidity increased throughout the forty-two-day period (p < 0.05). CONCLUSIONS: Increasing the level of force applied during postoperative rehabilitation from 5 to 17 N did not accelerate the time-dependent accrual of stiffness or strength. Suture technique was of primary importance in providing a stiff and strong repair throughout the early healing interval. CLINICAL RELEVANCE: Our findings suggest that there be a reexamination of the concept that increases in force produced by more vigorous mobilization protocols are beneficial to tendon-healing. While more vigorous rehabilitation may help to improve hand function, we found no evidence that it enhances tissue-healing or strength in the context of a modern suture repair.

Animals↗
PubMed2000

Expression of mRNA for vascular endothelial growth factor at the repair site of healing canine flexor tendon.

Neovascularization is an important and prominent feature of tendon healing that contributes to wound repair and potentially to adhesion formation. To define the location of cell populations that recruit and organize the angiogenic response during early healing of flexor tendon, we examined the gene expression pattern of the prototypic angiogenic factor, vascular endothelial growth factor, at and around the tenorrhaphy site in a canine model of flexor tendon repair. In situ hybridization with radiolabeled antisense riboprobes was used to identify tendon cell populations that contribute to the neovascularization process by expressing vascular endothelial growth factor and to relate this cell population to the previously described cell populations that participate in matrix synthesis (express type alpha1(I) collagen) and mitotic renewal (express histone H4). The majority of cells (approximately 67%) within the repair site itself express vascular endothelial growth factor mRNA; however, minimal levels accumulate within cells of the epitenon (approximately 10% of cells; p < 0.0002). By contrast, expression of type alpha1(I) collagen and histone H4 does not differ significantly between the epitenon and the repair site (uniformly approximately 30% of cells). Thus, a gradient of cell populations expressing vascular endothelial growth factor exists in the repairing tendon. These data suggest a potential contribution of cells within the repair site to the organization of angiogenesis during the early postoperative phase of tendon healing.

Animals↗
PubMed2000

Capitolunate arthrodesis with scaphoid and triquetrum excision.

A retrospective two-center outcome study was designed to evaluate the results of capitolunate arthrodesis with scaphoid and triquetrum excision mainly for scapholunate advanced collapse patterns of arthritis. Fourteen wrists in 14 patients were evaluated objectively by standard parameters and subjectively by the Short Musculoskeletal Functional Assessment at an average of 28 months after surgery (range, 14-51 months). All patients were men between the ages of 20 and 70 years (average, 49 years). Two patients had a painful nonunion and one had persistent pain despite conversion to a solid wrist arthrodesis. One patient had x-ray evidence of progressive radiolunate narrowing, but only occasional pain. Postoperative wrist flexion-extension arc was 53 degrees and radioulnar deviation arc was 18 degrees. Grip and pinch strengths were 71% and 75%, respectively, of the normal contralateral wrist. The results of our study indicate that capitolunate arthrodesis with scaphoid and triquetrum excision is comparable to other motion-preserving operative procedures for scapholunate advance collapse.

Adult↗
PubMed2000

The resistance of a four- and eight-strand suture technique to gap formation during tensile testing: an experimental study of repaired canine flexor tendons after 10 days of in vivo healing.

There is a high incidence of gap formation at the repair site following tendon repair. Our goal was to determine the resistance of a 4- and an 8-strand suture technique to gap formation during tensile testing. We hypothesized that the 8-strand repair would sustain higher force levels at the onset of 1- and 3-mm gaps than the 4- strand repair. Twenty-two canine flexor tendons were transected, repaired, and tested to failure after 10 days of in vivo healing. Tests were recorded using a 60-Hz video system that allowed frame-by-frame playback for assessment of gap formation. The 8-strand repairs sustained 80% higher force at a gap of 1 mm than the 4-strand repairs (average force, 70 vs 39 N), but the force sustained at a gap of 3 mm did not differ between groups (35 N for both groups). For both repair types, a 1-mm gap typically occurred near the point of ultimate (maximum) force while a 3-mm gap occurred after the ultimate force. We conclude that the 8-strand repair is significantly more resistant to initial gapping during ex vivo tensile testing than the 4-strand repair but that the two repairs are equally susceptible to rupture if a gap of 3 mm or greater forms.

Animals↗
PubMed2000

Flexor tendon grafting to the hand: an assessment of the intrasynovial donor tendon-A preliminary single-cohort study.

We report the results of a pilot study using intrasynovial donor tendons for flexor tendon reconstruction in 8 patients (10 digits) at a mean follow-up time of 3.8 years for neglected or failed primary repair of zone 2 lacerations and for neglected flexor digitorum profundus avulsions. The flexor digitorum longus to the second toe was used as the donor tendon graft. Four patients (4 digits) underwent single-stage reconstruction and 4 patients (6 digits) had multistage reconstruction. The overall patient satisfaction using a standardized visual analog reporting scale was excellent. There was 1 excellent, 1 good, 1 fair, and 1 poor result in the single-stage reconstruction group, including 1 repair site rupture and 1 digit requiring tenolysis. In the multistage reconstruction group there was 1 excellent, 3 good, 1 fair, and no poor results, including 1 digit requiring tenolysis. One patient was lost to follow-up. There was no donor site morbidity. The average active motion recovery was 64% and 56% for single-stage and multistage reconstructions, respectively, and was 73% overall for single digit reconstructions. The results of this pilot study suggest that intrasynovial tendon grafting may offer an improved alternative for tendon grafting to the synovial spaces of the digit.

Adolescent↗
PubMed1999

Effects of increased in vivo excursion on digital range of motion and tendon strength following flexor tendon repair.

Postoperative rehabilitation is an important factor in determining functional outcome following intrasynovial flexor tendon repair. We hypothesized that a rehabilitation protocol that produced increased in vivo excursion would lead to increased digital range of motion and tendon strength and decreased adhesion formation in a canine model. Ninety-six flexor digitorum profundus tendons from 48 dogs were cut transversely and repaired by a multistrand suture technique. Postoperative rehabilitation was performed daily with a low excursion-low force (1.7-mm average excursion; < 10 N force) or a high excursion-low force (3.6 mm excursion; < 10 N force) protocol. After death of the dogs at 10, 21, or 42 days, specimens were evaluated for digital range of motion, tensile mechanical properties, elongation of the repair site, and adhesion formation. Our data indicate that the range of motion of digits whose tendons were at low or high excursion was similar to that of controls. Increased in vivo tendon excursion due to synergistic wrist motion did not significantly affect ex vivo flexion of the distal and proximal interphalangeal joints or tendon displacement (p > 0.05). Similarly, tensile properties (ultimate load, repair site rigidity, and repair site strain at 20 N and at failure) and length of the gap at the repair site were not significantly affected by increased excursion (p > 0.05). Severity of adhesion formation was reduced slightly by increased excursion (p = 0.04). Our findings indicate that 1.7 mm of tendon excursion is sufficient to prevent adhesion formation following sharp transection of the canine flexor tendon and that additional excursion provides little added benefit.

Animals↗
PubMed1999

Wrist and digital joint motion produce unique flexor tendon force and excursion in the canine forelimb.

The force and excursion within the canine digital flexor tendons were measured during passive joint manipulations that simulate those used during rehabilitation after flexor tendon repair and during active muscle contraction, simulating the active rehabilitation protocol. Tendon force was measured using a small buckle placed upon the tendon while excursion was measured using a suture marker and video analysis method. Passive finger motion imposed with the wrist flexed resulted in dramatically lower tendon force (approximately 5 N) compared to passive motion imposed with the wrist extended (approximately 17 N). Lower excursions were seen at the level of the proximal interphalangeal joint with the wrist flexed (approximately 1.5 mm) while high excursion was observed when the wrist was extended or when synergistic finger and wrist motion were imposed (approximately 3.5 mm). Bivariate discriminant analysis of both force and excursion data revealed a natural clustering of the data into three general mechanical paradigms. With the wrist extended and with either one finger or four fingers manipulated, tendons experienced high loads of approximately 1500 g and high excursions of approximately 3.5 mm. In contrast, the same manipulations performed with the wrist flexed resulted in low tendon forces (4-8 N) and low tendon excursions of approximately 1.5 mm. Synergistic wrist and finger manipulation provided the third paradigm where tendon force was relatively low (approximately 4 N) but excursion was as high as those seen in the groups which were manipulated with the wrist extended. Active muscle contraction produced a modest tendon excursion (approximately 1 mm) and high or low tendon force with the wrist extended or flexed, respectively. These data provide the basis for experimentally testable hypotheses with regard to the factors that most significantly affect functional recovery after digital flexor tendon injury and define the normal mechanical operating characteristics of these tendons.

Animals↗
PubMed1999

The effect of dorsal carpal ganglion excision on the scaphoid shift test.

A clinical and radiographic review was performed on 18 patients (19 wrists) with dorsal carpal ganglia and associated positive scaphoid shift test. All patients underwent excision of the ganglion followed by 2 weeks of postoperative immobilization with the wrist in 20 degrees extension. All patients had wrist pain, a painful clunk on the Watson scaphoid shift test, localized tenderness on palpation of the scapholunate articulation and normal radiographs. Patients were assessed postoperatively by questionnaire and physical examination. Improved functional activity and decreased pain were noted in all patients. In 17 of 19 wrists, the positive preoperative Watson scaphoid shift test become negative. We believe that dorsal wrist ganglia are frequently associated with a positive scaphoid shift test and that excision of the ganglion followed by 2 weeks immobilization may lead to resolution of the signs and symptoms of instability, at least in the short term.

Adolescent↗
PubMed1999

The effect of gap formation at the repair site on the strength and excursion of intrasynovial flexor tendons. An experimental study on the early stages of tendon-healing in dogs.

BACKGROUND: Elongation (gap formation) at the repair site has been associated with the formation of adhesions and a poor functional outcome after repair of flexor tendons. Our objectives were to evaluate the prevalence of gap formation in a clinically relevant canine model and to assess the effect of gap size on the range of motion of the digits and the mechanical properties of the tendons. METHODS: We performed operative repairs after sharp transection of sixty-four flexor tendons in thirty-two adult dogs. Rehabilitation with passive motion was performed daily until the dogs were killed at ten, twenty-one, or forty-two days postoperatively. Eight tendons ruptured in vivo. In the fifty-six intact specimens, the change in the angles of the proximal and distal interphalangeal joints and the linear excursion of the flexor tendon were measured as a 1.5-newton force was applied to the tendon. The gap at the repair site was then measured, and the isolated tendons were tested to failure in tension. RESULTS: Twenty-nine tendons had a gap of less than one millimeter, twelve had a gap of one to three millimeters, and fifteen had a gap of more than three millimeters. Neither the time after the repair nor the size of the gap was found to have a significant effect on motion parameters (p > 0.05); however, the ultimate force, repair-site rigidity, and repair-site strain at twenty newtons were significantly affected by these parameters (p < 0.05). Testing of the tendons with a gap of three millimeters or less revealed that, compared with the ten-day specimens, the forty-two-day specimens failed at a significantly (90 percent) higher force (p < 0.01) and had a significantly (320 percent) increased rigidity (p < 0.01) and a significantly (60 percent) decreased strain at twenty newtons (p < 0.05). In contrast, the tensile properties of the tendons that had a gap of more than three millimeters did not change significantly with time. CONCLUSIONS: Our data indicate that, in a dog model involving sharp transection followed by repair, a gap at the repair site of more than three millimeters does not increase the prevalence of adhesions or impair the range of motion but does prevent the accrual of strength and stiffness that normally occurs with time.

Animals↗