Aymeric Lim

Bone marrow-derived mesenchymal stem cells influence early tendon-healing in a rabbit achilles tendon model.

BACKGROUND A repaired tendon needs to be protected for weeks until it has accrued enough strength to handle physiological loads. Tissue-engineering techniques have shown promise in the treatment of tendon and ligament defects. The present study tested the hypothesis that bone marrow-derived mesenchymal stem cells can accelerate tendon-healing after primary repair of a tendon injury in a rabbit model. METHODS Fifty-seven New Zealand White rabbits were used as the experimental animals, and seven others were used as the source of bone marrow-derived mesenchymal stem cells. The injury model was a sharp complete transection through the midsubstance of the Achilles tendon. The transected tendon was immediately repaired with use of a modified Kessler suture and a running epitendinous suture. Both limbs were used, and each side was randomized to receive either bone marrow-derived mesenchymal stem cells in a fibrin carrier or fibrin carrier alone (control). Postoperatively, the rabbits were not immobilized. Specimens were harvested at one, three, six, and twelve weeks for analysis, which included evaluation of gross morphology (sixty-two specimens), cell tracing (twelve specimens), histological assessment (forty specimens), immunohistochemistry studies (thirty specimens), morphometric analysis (forty specimens), and mechanical testing (sixty-two specimens). RESULTS There were no differences between the two groups with regard to the gross morphology of the tendons. The fibrin had degraded by three weeks. Cell tracing showed that labeled bone marrow-derived mesenchymal stem cells remained viable and present in the intratendinous region for at least six weeks, becoming more diffuse at later time-periods. At three weeks, collagen fibers appeared more organized and there were better morphometric nuclear parameters in the treatment group (p < 0.05). At six and twelve weeks, there were no differences between the groups with regard to morphometric nuclear parameters. Biomechanical testing showed improved modulus in the treatment group as compared with the control group at three weeks (p < 0.05) but not at subsequent time-periods. CONCLUSIONS Intratendinous cell therapy with bone marrow-derived mesenchymal stem cells following primary tendon repair can improve histological and biomechanical parameters in the early stages of tendon-healing.

The Prevalence of Absence of the Palmaris Longus – A Study in a Chinese Population and a Review of the Literature:

Most standard textbooks of hand surgery quote the prevalence of absence of palmaris longus at around 15%. However, this figure varies considerably in reports from different ethnic groups. We studied 329 Chinese men and women and found palmaris longus to be absent unilaterally in 3.3%, and bilaterally in 1.2%, with an overall prevalence of absence of 4.6%. There was no significant difference in its absence with regard to the body side or the sex. Our literature review revealed a low prevalence of absence in Asian, Black and Native American populations and a much higher prevalence of absence in Caucasian populations. It is clear that a standard prevalence of absence of the palmaris longus cannot be applied to all populations.

Intraoperative single-shot "3-in-1" femoral nerve block with ropivacaine 0.25%, ropivacaine 0.5% or bupivacaine 0.25% provides comparable 48-hr analgesia after unilateral total knee replacement.

PurposeTo compare analgesia after intraoperative single shot “3-in-1” femoral nerve block (FNB) in combination with general anesthesia using ropivacaine 0.25%, ropivacaine 0.5% with bupivacaine 0.25% for total knee replacement (TKR).MethodsWe performed a randomized, double-blind study in 48 patients for elective TKR under general anesthesia. Patients were randomized to one of four groups (C: sham block, R1: “3-in-1” FNB using 30 mL of ropivacaine 0.25%, R2: “3-in-1 ” FNB using 30 mL of ropivacaine 0.5%, B: “3-in-1” FNB using 30 mL of bupivacaine 0.25%). Verbal pain score (VPS) both at rest and movement were assessed for 48 hr after TKR (0 = none; 1 =mild; 2 = moderate; 3=severe). Total morphine consumption and its associated side effects, duration of hospitalization after operation were also compared.ResultsThere were no differences in patients’ physical characteristics, intraoperative morphine usage, operation time, tourniquet time or length of hospitalization between the four groups. When compared with group C, the VPS was significantly lower in groups R1, R2 and B at one, four, eight, 24 and 48 hr after TKR(P < 0.05). The morphine requirement of groups R1, R2 and B were also significantly lower when comparing with group C up to 48 hr postoperatively (P < 0.05). There were no significant differences in VPS and postoperative morphine requirement at any time between groups R1, R2 and B.Conclusion“3-in-1” FNB with ropivacaine provided analgesia that was clinically comparable to that of bupivacaine up to 48 hr after TKR. Increasing the concentration of ropivacaine from 0.25% to 0.5% failed to improve the postoperative analgesia of “3-in-1” FNB.RésuméObjectifComparer l’analgésie fournie par l’administration peropératolre d’un bloc “3 en 1” du nerf fémoral (BNF) en une dose unique, combinée à l’anesthésle générale, avec de la ropivacaïne à 0,25 %, ou à 0,5 %, ou de la bupivacaïne à 0,25 % pour la mise en place d’une prothèse totale de genou (PTG).MéthodeL’étude randomisée et à double Insu comprend 48 patients qui reçoivent une PTG non urgente sous anesthésie générale. On forme quatre groupes (T: groupe témoin avec bloc fictif, R1: BNF “3 en 1” avec 30 mL de roplvacaïne à 0,25 %, R2: BNF “3 en 1” avec 30 mL de roplvacaïne à 0,5 %, B: BNF “3 en 1” avec 30 mL de bupivacaïne à 0,25 %). Les scores de l’échelle verbale de douleur (EVD) au repos et pendant le mouvement sont notés pendant 48 h après la PTG (0 = aucune; 1 = légère; 2 = modérée; 3 = sévère). La consommation totale de morphine et ses effets secondaires et la durée de l’hospitalisation postopératoire sont comparés.RésultatsLes caractéristiques physiques des patients, la consommation de morphine peropératolre, la durée de l’intervention, le temps de garrot ou la durée de l’hospitalisation sont comparables dans les quatre groupes. Comparé à celui du groupe T, le score à l’EVD des groupes R1, R2 et B est slgnlfcatlvement plus bas à une, quatre, huit, 24 et 48 h après la PTG (P < 0,05). Les besoins de morphine dans les groupes R1, R2 et B sont aussi slgnlfcatlvement plus bas que ceux du groupe C jusqu’à 48 h après l’opération (P < 0,05). Les scores EVD et la consommation de morphine postopératoire demeurent comparables en tout temps dans les groupes R1, R2 et B.ConclusionLe BNF “3 en 1” avec de la roplvacaïne fournit une analgésie expérimentale comparable à celle de la bupivacaïne jusqu’à 48 h après une PTG. L’augmentation de la concentration de roplvacame de 0,25 % à 0,5 % ne permet pas d’améliorer l’analgésie postopératoire du BNF “3 en 1”.

Treatment of complex interphalangeal joint fractures with dynamic external traction: A series of 20 cases

&NA; Data are reported for a series of 20 patients who were treated with the pins and rubbers traction system for fractures of the proximal interphalangeal joints of the long fingers. This technique allows fracture reduction with external dynamic traction and immediate active mobilization. Two patients in the series were lost to follow‐up monitoring. For two others, the pins and rubbers traction system needed to be removed early (during the first week) because of intolerance or infection. Sixteen patients who were reexamined after minimal follow‐up periods of 1 year demonstrated a mean active range of motion of 85.9 degrees for the injured joint; only one patient experienced intermittent pain. (Plast. Reconstr. Surg. 111: 1623, 2003.)

the Neuromuscular Compartments of the Flexor Carpi Ulnaris

LEARNING OBJECTIVES After studying this article, the participant should be able to: 1. Report on the vascular supply and innervation pattern of the flexor carpi ulnaris. 2. Describe the muscle architecture of the flexor carpi ulnaris, including the physiological cross-sectional area and fiber length. 3. State the uses of the flexor carpi ulnaris both for resurfacing defects in the vicinity of the elbow and in local functional tendon transfers. 4. Understand the principles of splitting skeletal muscles based on neurovascular supply to enhance its utilization in reconstructive procedures. The aim of this study was to describe the intramuscular innervation and vascular supply of the human flexor carpi ulnaris, with confirmation of findings by a similar study in the primate. Two distinct intramuscular nerve branches running parallel to each other, on either side of a central tendon, from the proximal quarter of the muscle belly to its insertion were found. The muscle could then be split into a humeral and an ulnar compartment, each with its own primary nerve branch. Perfusion studies confirmed the adequacy of circulation to the two compartments. In the primate flexor carpi ulnaris, electrical stimulation of the respective branches revealed independent contraction of each compartment. This study provides useful information for enabling the local transfer of the muscle as a whole, both for resurfacing in the vicinity of the elbow and for functional tendon transfers. It will also enable the transfer of the muscle as one or two separate compartments (for resurfacing, in tendon transfers for muscle paralysis, congenital defects, and muscle defects resulting from trauma, and after resections for neoplasm and infection).

Intramuscular innervation of upper-limb skeletal muscles.

We studied 150 skeletal muscles from 8 upper limbs using the modified Sihlers staining technique. Based on the pattern of the intramuscular innervation and shape, the muscles were grouped into trapezoidal‐shaped (Class I), spindle‐shaped (Class II), and muscles that were combinations of these two classes (Class III). Such distinctions are clinically important for limb reconstruction procedures. Bipennate, spindle‐shaped muscles with the aponeurosis of the tendons of insertion extending proximally into the muscle belly and Class III muscles with multiple tendons of origin may be split for separate independent functional transfers. Muscle Nerve 29: 523–530, 2004

Free flap coverage of upper and lower limb tissue defects in children: a series of 22 patients.

Free tissue transfer has become the most important means of limb salvage treatment after severe trauma. This one-step procedure shortens healing and hospitalization time and minimizes the danger of infection. However, very few studies have considered the use of free tissue transfer for the reconstruction of traumatic limb injuries in children. This study reports 22 such cases treated in the authors’ unit between 1993 and 2000 (17 boys and 5 girls; mean age, 8.9 years; age range, 18 months–15 years; 16 lower and 6 upper limbs). All flaps were indicated for repair of acute traumatic defects (20–500 cm2). Five different flaps were used: 12 scapular, 4 latissimus dorsi, 4 serratus anterior, 1 groin, and 1 temporalis fascia. All were successful, except for partial necrosis with the free groin flap. Three flaps requiring reexploration for venous insufficiency had a successful outcome. The microsurgical success rate in this pediatric population is very high, and the state and size of the donor site and recipient vessels have caused no problems. No long-term complications have been noted (mean follow-up, 3.8 years).

Split flexor carpi radialis muscle.

A detailed anatomic and intramuscular neural staining study in 22 human and 5 monkey upper limbs revealed that the flexor carpi radialis can be raised on its proximal neurovascular pedicle and that the muscle can be split along its tendon into two independently functioning neuromuscular compartments, each with its own nerve and blood supply. A study of the muscle architecture in the human specimens found the radial compartment to have significantly longer fiber length and a larger physiologic cross-sectional area than the ulnar compartment. Independence of function of each compartment was demonstrated in electrical stimulation studies in six monkeys (Macaca fascicularis), but no significant difference was noted in the peak isometric load between the two compartments (p = 0.68) in the monkey. The extra functioning muscle units become important in local transfers for restoring function in multiple nerve palsies as in Hansens disease, severe traumatic loss of muscle in crush injuries and compartment syndromes, and after wide resection in infective and neoplastic conditions in the forearm and hand.

The long head of the triceps brachii as a free functioning muscle transfer.

This anatomic study investigates the possibility of using the long head of the triceps brachii muscle as a free functioning muscle transfer for the upper limb. It has been reported that the long head is not difficult to harvest and that its loss does not create significant donor‐site morbidity. The muscle was studied in 23 fresh frozen upper limbs. The long head in all 23 specimens had a constant and proximal vascular pedicle from the profunda brachii artery and vein. The mean pedicle was long (4 cm) and had large‐caliber vessels (diameter, 3‐mm artery and 4‐mm vein). Angiograms were carried out in five specimens and dye perfusion studies in six specimens. A single branch from the radial nerve of at least 7 cm in length innervated the muscle. Muscle architecture was studied in 12 specimens and revealed that the long head of the triceps is better suited for forearm reconstruction than either the gracilis or the latissimus dorsi muscles. The mean physiologic cross‐sectional area (8.36 cm2) and fiber length (10.8 cm on the superficial surface and 8.2 cm on the deep surface) of the long head match more closely those of the flexor digitorum profundus and the extensor digitorum communis, the muscles most commonly replaced. (Plast. Reconstr. Surg. 107: 1746, 2001.)

Application of the dorsal metacarpal artery perforator flap for resurfacing soft-tissue defects proximal to the fingertip.

Background: The dorsal metacarpal artery perforator flap is a versatile solution for resurfacing soft-tissue defects of fingers. The authors present their experience in applying this flap for a variety of finger wounds for which conventional means may not be amenable. Methods: Fifty-eight dorsal metacarpal artery perforator flaps were used to resurface 60 finger soft-tissue defects in 56 patients over a 5-year period. Fifty-two patients were men and their average age was 37 years. This flap was used to reconstruct soft-tissue defects after débridement of infected wounds in 28 patients, traumatic wounds in 26 patients, and electrical burns in two patients. Results: The average flap size was 4.6 × 2.3 cm; 34 flaps were based on the second dorsal metacarpal artery perforator, 14 were based on the third dorsal metacarpal artery perforator, and 10 were based on the fourth dorsal metacarpal artery perforator. Twenty-one flaps were used to resurface defects distal to the proximal interphalangeal joint, and 37 flaps were used to resurface defects over the proximal interphalangeal joint and proximal to it. Skin grafting was needed to close the donor defect in seven patients. Complications included venous congestion in six flaps and arterial insufficiency in three flaps, with total loss of two flaps and infection in one case. Conclusion: The dorsal metacarpal artery perforator flap is a thin, pliable flap that is simple to raise, has minimal donor-site morbidity, and can reliably cover soft-tissue defects up to the proximal half of the middle phalanx. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.