Flexor Tendon Grafts Research Articles

Secondary reconstruction of flexor tendon function of the fingers

Among the various procedures to restore flexor tendon function after failed or omitted primary suture flexor tendon grafting is the most frequently applied technique. It can be performed in a one-stage procedure using a palmaris- or plantaris graft in cases with less scarring or in a two-stage procedure for cases in unsuitable conditions. The main purpose for using silicone rods is to prepare an artificial tendon sheath to avoid adhesions of the tendon graft. The disadvantage of two operations seems to be justified by better results. We performed this technique in 168 zone-II-lesions. According to the Buck-Gramcko score we achieved excellent results in 30.9% and good results in 25.6%. In 76 fingers we applied the combination of the Paneva-Holevich technique of using a pedicled superficialis tendon with Hunters method without obtaining better results (22.4% and 32.9% respectively). The various techniques of grafting are described as well as indication and technique of tenodesis and alternatively staged procedure for isolated profunda lesions.

Flexor tendon pulley reconstruction

The flexor tendon pulley mechanism causes the tendons to work with maximum efficiency. Without its competency,flexor tendons will bowstring causing significant losses of digital motion and strength. Without an intact pulley system, increased flexor tendon excursion is required to affect joint motion and flexion contractures may develop over time. Recent investigators have described the properties of the intact flexor pulley system as well as those of flexor pulley reconstructive techniques. Reconstruction of the flexor pulley system should take into account both strength and length of the construct and in most cases a loop of either flexor tendon graft or wrist extensor retinaculum is used. Other methods are available including the use of the palmar plate as well as the superficialis tendon.

Flexor digitorum profundus tendongrafting (extrasynovial donor tendons)

Although the prevalence of flexor tendon grafting has decreased since the early part of this century, the technique isstill an important part of a hand surgeons armamentarium. Primary and staged flexor tendon grafting are appropriate techniques used to restore digital function after failed or neglected repairs. Appropriate patient selection, meticulous reconstructive techniques, and respect for basic biological principles of healing and repair are essential elements for successful tendon grafting.

Flexor digitorum profundus tendongrafting (intrasynovial donor tendons)

Traditional single- and two-stage tendon grafting methods for flexor tendon reconstruction have been unable toconsistently restore satisfactory digital flexion. Although multiple factors may affect the ultimate outcome, the role of the donor tendon graft has only recently been examined. Current methods of flexor tendon grafting for failed zone II tendon repairs and neglected flexor tendon lacerations involve the use of extrasynovial donor grafts. Clinical and histological studies have shown significant adhesion formation as a result of early cellular necrosis and peritendinous tissue ingrowth into the extrasynovial donor graft. The formation of these adhesions may result in poor tendon excursion and limited proximal interphalangeal joint rotation. Recent studies have shown that intrasynovial donor tendon grafts are incorporated to the native tendon site by a unique intrinsic mechanism of repair. Improved functional characteristics of increased tendon excursion and increased digital rotation are primarily caused by this paucity of adhesion formation and will hopefully result in improved overall patient outcomes.

The effects of proximal load on the excursion of autogenous flexor tendon grafts

To determine the relationship between the intrinsic properties of tendon and tendon excursion in 2 types of autogenous tendon grafts, hindpaw intrasynovial and extrasynovial tendons were transferred to the lateral and medial forepaws of adult mongrel dogs (16 experimental and 16 control tendons). After each digit was marked with radiopaque markers, it was placed in a specialized jig, and weights of 25 g, 100 g, or 200 g were applied to the flexor tendons. Specialized radiographs were obtained with the digit in flexion and extension. Tendon excursion and joint rotation were calculated. There were no statistically significant differences between experimental groups for tendon excursion or for joint angular rotation (p > .05). For intrasynovial tendon grafts, the angular rotation per millimeter tendon excursion was 10.9 degrees +/- 2.4 degrees/mm, 9.4 degrees +/- 1.2 degrees/mm, and 9.0 degrees +/- 1.4 degrees/mm with 25-g, 100-g, and 200-g loads, respectively. Comparisons between experimental groups revealed that a statistically significant difference could not be determined (p > .05). With varying proximal loads, both intrasynovial and extrasynovial grafts showed similar amounts of tendon excursion. Variations in proximal load did not significantly influence the amount of excursion within the range of loads tested. Based on these data, it appears that the difference in repair potential for these 2 types of tendon grafts is not related to a differential in the amount of tendon graft excursion following transfer to the synovial space.

The Marshall R. Urist Young Investigator Award

To examine the hypothesis that different types of dense regular connective tissue may have different repair mechanisms within the synovial space, intrasynovial and extrasynovial autogenous donor flexor tendon grafts were placed within the synovial sheaths of the medial and lateral forepaw digits of dogs. Histologic, ultrastructural, biochemical, and biomechanical analyses were done between 10 days and 6 weeks after tendon grafting. Intrasynovial tendon grafts remained viable when transferred to the synovial space and appeared to heal through an intrinsic process with preservation of the gliding surface and improved functional characteristics. Extrasynovial tendon grafts functioned as a scaffolding for the early ingrowth of new vessels and cells. Early cellular necrosis consistently was followed by the ingrowth of fibrovascular adhesions from the periphery. The formation of dense peripheral adhesions, obliterating the gliding surface of the tendon, led to diminished tendon excursion and proximal interphalangeal joint rotation.

Flexor tendon graft for late management of isolated rupture of the profundus tendon.

Late management options for the neglected flexor tendon injury include arthrodesis, tenodesis, tendon advancement, or tendon grafting. Although the clinical outcomes of single-stage and second-stage flexor tendon grafting are satisfactory, many controversies exist. The present study retrospectively reviewed the clinical outcomes of flexor tendon grafting for 15 patients with isolated profundus rupture. Fifteen cases of isolated rupture of the flexor profundus tendon were treated by free tendon graft. The age of the patients ranged from 13 to 21 years (mean, 17.3 years). The time from injury to operation ranged from 4 to 14 weeks (mean, 8.3 weeks). All tendon grafts were passed through the intact superficialis tendon to repair the injured profundus tendon. These patient were followed up from 14 to 62 months after treatment mean, 31.3 months). All but one patient had less than 3.2 cm of flexion from fingertip to mid-palmar crease. Fourteen patients achieved active distal interphalangeal (DIP) joint flexion of more than 20 degrees. Four patients developed extension loss of the proximal interphalangeal (PIP) joint of more than 30 degrees after surgery. The mean active flexion after surgery was 33 degrees (range, 15-55 degrees) for DIP joints and 91.3 degrees (range, 80-100 degrees) for PIP joints. Three patients had combined extension loss of PIP and DIP joints of more than 40 degrees for the index and middle fingers. Twelve patients (80%) had satisfactory results, whereas treatment of the other 3 patients was considered unsuccessful. Flexor tendon graft can be used to reconstruct the isolated rupture of the profundus tendon and achieve satisfactory results for properly selected patients.

Early active mobilization after second stage flexor tendon grafts

We assessed the results of nine two-stage tendon reconstructions. The tendon graft was the ipsilateral palmaris longus tendon inserted into a tunnel which had been previously created by a silicone spacer. Early active mobilization was commenced 48 hours after surgery according to a previously described protocol (Small et al, 1989). Using the grading system of Kleinert and Verdan (1983) the results were: one excellent, two good, five fair and one poor. Using the Buck-Gramcko et al (1976) grading system there were three excellent, two good, two satisfactory and two poor results. There were no cases of tendon graft rupture or dehiscence of the junction between tendon and graft.

L'histoire de la chirurgie des tendons fléchisseurs

Flexor tendon injuries were already treated in antiquity by Hippocrates, Galien and Avicenne. Since the Renaissance, other surgeons have attempted to repair flexor tendon injuries, but without success due to problems related to unsuitable materials and ignorance of the basic rules of asepsis and the absence of antiseptics until the second half of the 19th century. The first successful flexor tendon grafts in man were performed by K. Biesalski in 1910, E. Lexer in 1912 and L. Mayer in 1916. These three authors published their series of grafts and described in detail the anatomical, physiological and technical principles to be respected. St. Bunnell, in 1918, developed various pull-out direct suture procedures, but faced with the problems of adhesions, he abandoned this technique and proposed not to repair flexors in the digital tunnels but to graft them. He defined the famous zone which he called No man's land, which subsequently became Claude Verdan's zone II, in 1959. In 1960, C. Verdan published his first series of sutures maintained by 2 pins in zone II with comparable results to those obtained after grafting. In 1967, H. Kleinert, with his mobile suture, became the leader of direct tendon repair in zone II. 2-stage grafts were introduced in 1965 under the impetus of J. Hunter, who revised and popularized the studies conducted by A. Bassett and R.E. Caroll in 1950.

A new technique of attachment of flexor tendons to the distal phalanx without a button tie-over

A new technique of attachment of the flexor digitorum profundus tendon and flexor tendon grafts to the distal phalanx, without using a button on the nail, is described and its use reported in 14 cases.

Les lésions anciennes des tendons fléchisseurs traitées par greffe tendineuse en deux temps

46 fingers in 42 patients undergoing 2-stage flexor tendon grafting for traumatic injury in zone 2 were evaluated with an average follow up of 13 months (range 6 to 120 months). 24 anastomoses between FDS and FDP were performed according to the Paneva Holevitch procedure. In all other cases, palmaris longus or plantaris were used as tendon grafts during the second stage. Proximal fixation was always performed in the palm. 3 or more pulleys were reconstructed in all cases. In 21 cases, pulley reconstruction required the use of excised tendon remnants or retina-culum dorsalis. Distal fixation was performed to the distal phalanx in 42 cases and to the second phalanx in 4 cases, during the second stage. Overall, 85% patients obtained a good or fair result in terms of TAM (total active motion) with <<useful function>>. 7 cases obtained a poor result. 12 fingers required complementary surgery: --2 cases with poor active flexion had been treated by shortened suture. --3 ruptures of tendon graft required P2 fixation and DIP arthrodesis in distal rupture (2 cases), and anastomosis with next flexor tendon in proximal rupture (1 case). --7 cases of PIP stiffness were treated by PIP arthrolysis. DIP arthrodesis was associated in 2 cases.

The flexor digitorum longus: An anatomic and microscopic study for use as a tendon graft

Recent experimental studies have shown that intrasynovial donor tendons have the capacity to heal with minimal alteration in the gliding surface when grafted to an intrasynovial location. In order to evaluate the flexor digitorum longus of the foot as a potential matched donor tendon for use in flexor tendon grafting, we dissected 15 feet (75 toes) and 10 hands (50 fingers) to determine the intrasynovial lengths of the flexor digitorum longus and flexor digitorum profundus and to determine a method of tendon graft harvest. Specimens were taken from the intrasynovial portion of each tendon for evaluation by light and electron microscopy. The intrasynovial tendons of the hand and foot were similar in vascularity, cellularity, gliding surface, and ultrastructure. The flexor digitorum longus tendon of the foot was a mean length of 12 cm to the area of tendon confluence in the midfoot, which will usually provide enough tendon length for grafting from the distal phalanx to the palm of the hand. Because of the difference in length of the synovial sheaths of the fingers and toes, some extrasynovial tendon will be transferred to the synovial space when a flexor digitorum longus tendon is used.

Autogenous intrasynovial and extrasynovial tendon grafts: an experimental study of pro alpha 1(I) collagen mRNA expression in dogs.

On the basis of recent evidence that the healing processes of tendon grafts are donor-tissue specific, in situ hybridization, using a 372 bp cDNA fragment complementary to a portion of pro alpha 1(I) collagen mRNA, was utilized to compare the cellular responses to transplantation exhibited by autogenous intrasynovial and extrasynovial flexor tendon grafts. Intrasynovial and extrasynovial tendons from the hindpaw were transferred to synovial sheaths in the forepaw of 12 mongrel dogs (24 tendons) and treated with immediate controlled passive motion. The tendon grafts were harvested at 2, 4, and 6 weeks, and each was divided into a proximal, central (8 mm), and distal portion. Sections from the central portion were embedded in paraffin and subjected to in situ hybridization, autoradiography, and staining; levels of procollagen mRNA then were assessed by microscopic examination. The two types of tendon grafts exhibited different levels of pro alpha 1(I) collagen mRNA expression at all three time points. Intrasynovial tendon grafts displayed no areas of increased type-I procollagen mRNA at 2, 4, and 6 weeks. The extrasynovial tendon grafts displayed increased surface levels of type-I procollagen mRNA at 2 and 4 weeks; the levels decreased to background levels by 6 weeks. The high levels of procollagen mRNA exhibited by the extrasynovial grafts suggest increased collagen synthetic activity, indicative of a cellular response to injury, whereas the preservation of low levels of expression in the intrasynovial grafts may signify a less inflammatory cellular response.

Autogenous flexor tendon grafts: Fibroblast activity and matrix remodeling in dogs

To investigate rates of cellular proliferation and matrix turnover in autogenous flexor tendon grafts, hindlimb intrasynovial (flexor digitorum profundus) and extrasynovial (peroneus longus) tendons were placed within the synovial sheaths of the medial and lateral forepaw digits of 18 dogs and treated with controlled early passive motion. After the dogs had been killed, short-term culture and labeling in vitro were utilized to determine rates of DNA, proteoglycan, collagen, and noncollagen protein synthesis. Schiff base covalent collagen crosslink concentrations and total collagen and protein content also were evaluated at intervals through 6 weeks. Tendon grafts of extrasynovial origin showed greater rates of DNA synthesis and significantly elevated levels of proteoglycan, collagen, and noncollagen protein synthesis and Schiff base covalent collagen crosslink concentrations (dihydroxylysinonorleucine) compared with intrasynovial tendon grafts. It was not clear to what extent the increased activity in the extrasynovial graft was due to actual differences between the intrasynovial and extrasynovial tendons or to the responses of the connective tissue surrounding the extrasynovial tendon graft. Since both types of grafts demonstrated similar unaltered levels of collagen and protein content over time, these data suggest greater rates of matrix turnover in tendon grafts of extrasynovial origin than in those of intrasynovial origin. Coupled with previous findings showing increased cellular proliferation in extrasynovial tendon grafts, these data indicate that the process of translation to an intrasynovial environment necessitates a more active process of soft-tissue repair and remodeling when extrasynovial donor tendons are used.

Migration of silicone rods

Two cases of migration of silastic rods into the forearm after the first stage of flexor tendon grafting are reported. A CT scan shows the rods well if they are not visible on a plain X-ray. Possible factors involved in distal detachment of the rods are the composition of the tendon spacer, method of distal fixation, method of proximal fixation and the time between the stages of reconstruction.

Cellular survival and proliferation in autogenous flexor tendon grafts

In order to investigate fibroblast survival and proliferation in autogenous flexor tendon grafts, hindlimb intrasynovial and extrasynovial donor tendons were placed within the synovial sheaths of the medial and lateral forepaw digits of 21 dogs (42 tendons) and treated with controlled early passive motion. Intravital histologic evaluations with confocal microscopy and biochemical determinations of total DNA content and DNA synthesis were carried out at 10 days, 3 weeks, and 6 weeks. Intravital staining of the extrasynovial tendon grafts demonstrated variable degrees of cellular necrosis at the earliest intervals followed by cellular repopulation with fibroblasts and neovascularization from surface vessels. In contrast, intrasynovial tendon grafts were populated predomnantly by viable cells at each interval, with occasional patches of cell necrosis and fibroblast ingrowth. Total DNA content and DNA synthesis values in the intrasynovial donor tendons were significantly lower than those seen in the extrasynovial tendon grafts at each interval. Extrasynovial tendons appear to act as scaffolds, undergoing extensive cellular death followed by a rapid repair response. Findings that intrasynovial tendon fibroblasts survive the tendon grafting process suggest that the nutritional supplies and metabolic requirements of intrasynovial and extrasynovial donor tendons differ largely.

Variations in cellular proliferation and matrix synthesis in intrasynovial and extrasynovial tendons: An in vitro study in dogs

Intrasynovial and extrasynovial flexor tendon grafts recently have been shown to have dissimilar patterns of cellular survival and host integration within the digital sheath. In an effort to determine if fundamental differences exist between these two types of tendons, we investigated the biochemical composition and cellular activity of intrasynovial and extrasynovial tendon segments of 12 adult mongrel dogs in short-term explant culture in MCDB 105 and in DMEM media. Proteoglycan, collagen and noncollagen protein synthesis and content and DNA synthesis were determined following culture in both media. Intrasynovial tendon segments cultured in MCDB 105 medium synthesized significantly less collagen, noncollagen protein, and DNA and had similar amounts of proteoglycans compared to extrasynovial tendons. Comparison of intrasynovial and extrasynovial tendon segment responses in DMEM medium showed that intrasynovial tendons synthesized more proteoglycan, protein, and DNA than they did in MCDB 105. Extrasynovial tendons had similar rates of matrix component and DNA synthesis in both media. Findings that the synthesis of matrix components and DNA between intrasynovial flexor and extrasynovial peroneal tendon segments differ significantly indicate that intrasynovial flexor tendons may be specially adapted to the nutritional milieu provided by an intrasynovial environment. These data are supported by the selective successful stimulation of fibrocartilaginous segments within intrasynovial flexor tendons in media favored for the culture of cartilaginous tissue.

Flexor tendon grafting

With continuing improvement in the results obtained from early direct repair of flexor tendon injuries there are only rare occasions when one-stage flexor tendon grafts will be needed. When indicated in minimally scarred situations, careful attention to technical details and closely supervised postoperative care will yield good return of function.

Autogenous flexor-tendon grafts. A biomechanical and morphological study in dogs.

Intrasynovial and extrasynovial donor autogenous flexor-tendon grafts were placed in the synovial sheaths of the medial and lateral digits of the forepaw in twenty dogs (forty tendons). Postoperatively, the dogs were managed with early, controlled, passive mobilization. Histological and ultrastructural evaluations were carried out at ten days, three weeks, and six weeks, and biomechanical analyses were performed at three and six weeks. The intrasynovial and extrasynovial tendon grafts showed different healing processes histologically. The extrasynovial tendon grafts healed with early ingrowth of peripheral adhesions, which appeared to become larger and more dense over time. These grafts exhibited decreased cellularity and early neovascularization at ten days, and there was evidence of progressive revascularization and cellular repopulation at three and six weeks. In contrast, the intrasynovial tendon grafts demonstrated minimum adhesions, and both cellularity and collagen organization were normal at each time-interval. The intrasynovial grafts had significantly more angular rotation at the proximal interphalangeal joint at three and six weeks than did the extrasynovial grafts (p < 0.05).

Angiogenesis in healing autogenous flexor-tendon grafts.

On the basis of recent evidence that flexor tendon grafts may heal without the ingrowth of vascular adhesions, eighteen autogenous donor tendons of intrasynovial and extrasynovial origin were transferred to the synovial sheaths in the forepaws of nine dogs, and controlled passive mobilization was instituted early in the postoperative period. The angiogenic responses of the tendon grafts were determined with perfusion studies with India ink followed by cleaing of the tissues with the Spalteholz technique at two, four, and six weeks. A consistent pattern of neovascularization was noted in the donor tendons of extrasynovial origin. Vascular adhesions arising from the flexor digitorum superficialis and the tendon sheath enveloped the tendon grafts by two weeks. By six weeks, the vascularity of the tendon grafts of extrasynovial origin appeared completely integrated with that of the surrounding tissues. Examination of cross sections revealed that the segments of tendon had been completely vascularized by obliquely oriented intratendinous vessels. In contrast, the flexor tendon grafts of intrasynovial origin healed without ingrowth of vascular adhesions. Primary intrinsic neovascularization took place from the proximal and, to a lesser extent, distal sites of the sutures. Examination of cross sections revealed vessels extending through the surface layer of the tendon graft, with small vessels penetrating the interior of the tendons at regular intervals.