Anatomical Study of the Medialis Pedis Flap and its clinical applications in Asian Singaporean Patients.

PURPOSE: The purpose of this study was to revisit the medial plantar artery's anatomy and study its distribution for raising the medialis pedis flap. Several investigators have reported their clinical experience with the use of this flap for reconstruction of soft tissue defects of the hand. However, many have reported difficulty raising the flap due to variations in its arterial anatomy and the confusion that exists with respect to the nomenclature in our literature. METHODS: This study was divided into 2 parts: an anatomic study and clinical application. In the anatomic study, 12 cadaveric feet specimens from 6 patients were injected with latex and barium-gelatin injections and the medial branch of the deep division of the medial plantar artery distribution was studied. We then described the use of a medialis pedis flap in four clinical cases to cover defects of the digits. RESULTS: The anatomic study revealed that the average pedicle length of the deep division of the medial plantar artery was 1.94cm. In the four illustrative clinical cases where the flap was used, the average flap size was 4.5 × 3.75cm. Donor sites were either closed primarily or with skin grafts. The vessels used for this flap were the medial branch of the deep division of the medial plantar artery and venae commitantes, or subcutaneous veins which provided the superficial drainage. All flaps were successful without any significant complications. The study is novel in that it describes the anatomic variability of length of the medial branch of the deep division of the medial plantar artery that exits in nature. CONCLUSIONS: This paper describes the medial branch of the deep division of the medial plantar artery and the anatomic variations that exist in the raising of the medialis pedis flap. We have shown how a medialis pedis flap is an ideal option for reconstructing soft tissue defects of the hand because of its texture, bulkiness and pliability in the context of like for like reconstruction.

An Exploratory Study Using Semi-Tabular Plate in Zone II Flexor Tendon Repair.

BACKGROUND: This study evaluated the feasibility of using a low-profile titanium (Ti) plate implant, also known as the Ti-button, for Zone II flexor tendon repair. We hypothesize that the use of the Ti-button can distribute the tensile force on the digital flexor tendons to achieve better biomechanical performance. METHODS: Twenty lacerated porcine flexor tendons were randomly divided into two groups and repaired using Ti-button or 6-strand modified Lim-Tsai technique. Ultimate tensile strength, load to 2 mm gap force, and mode of failure were recorded during a single cycle loading test. We also harvested twelve fingers with lacerated flexor digitorum profundus tendons from six fresh-frozen cadaver hands and repaired the tendons using either Ti-button method or modified Lim-Tsai technique. A custom-made bio-friction measurement jig was used to measure the gliding resistance and coefficient of friction of the tendon sheath interface at the A2 pulley. RESULTS: The ultimate tensile strength, load to 2 mm gap force, stiffness, and gliding resistance of the Ti-button repairs were 101.5 N, 25.7 N, 7.8 N/mm, and 2.2 N respectively. Ti-button repairs had significantly higher ultimate tensile strength and stiffness than the modified Lim-Tsai repair. However, Ti-button also increased the gliding resistance and coefficient of friction but there was no significant difference between the two repair techniques. CONCLUSIONS: Ti-button repair displayed comparable mechanical properties to the traditional repair in terms of 2-mm gap formation and gliding resistance, but with a stronger repair construct. Thus, this deepened our interest to further investigate the potential of using Ti-button implant in Zone II flexor tendon repair by studying both the mechanical and biochemical (tendon healing) properties in more in-depth.

Free tissue transfer to the traumatized upper extremity: Risk factors for postoperative complications in 282 cases.

BACKGROUND: Complex traumatic upper extremity injuries frequently possess compromised local vasculature or extensive defects that are not amenable to local flap reconstruction. Free tissue transfer is required to provide adequate soft tissue coverage. The present study aimed to evaluate risk factors that contribute to postoperative complications and flap loss in complex upper extremity reconstruction. METHODS: Retrospective chart review was performed for all patients undergoing free tissue transfer for upper extremity reconstruction from 1976 to 2001. Data collected included patient demographic characteristics, timing of reconstruction, location of injury, fracture characteristics, operative interventions, and postoperative complications. Statistical analysis was performed using χ(2) and Fisher exact tests. RESULTS: In total, 238 patients underwent 285 free tissue transfers and met inclusion criteria, from which 3 were excluded because of inadequate information (n = 282). Extremities were repaired within 24 h (75 cases; 27%), in days 2-7 (32 cases; 12%), or after day 7 (172 cases; 62%). Timing of reconstruction did not significantly affect postoperative outcomes. Proximal location of injury was significantly associated with superficial (relative risk [RR], 6.5; P < .01) and deep infection (RR, 5.3; P < .01), and osteomyelitis (RR, 4.0; P < .01), although not with flap failure (P = .30). Presence of an open fracture was significantly associated with developing superficial (RR, 3.1; P = .01) and deep (RR, 1.9; P < .01) infection, as well as osteomyelitis (RR, 1.6; P < .01). Having a closed fracture did not negatively influence postoperative outcomes. CONCLUSIONS: This study supports the safety of early free tissue transfer for reconstruction of traumatized upper extremities. Injuries proximal to the elbow and open fracture were associated with a significantly higher infection rate. Gustilo grade IIIC fractures, need for interpositional vein grafts, and anastomotic revision at index operation resulted in significantly higher risk of flap loss, whereas the presence of fracture, fracture fixation, and injury location were not predictors of flap failure.

Early results of combined palmar-dorsal scapholunate ligament reconstruction.

Isolated dorsal scapholunate reconstruction may be inadequate to stabilize and restore physiological scapholunate kinematics in the setting of combined dorsal and palmar ligamental incompetence. To address this entity, a combined reconstruction that encompass both dorsal and palmar scapholunate reconstruction was performed in 20 patients followed up to 19.8 (6-84) months. Compared to the contralateral wrist, the results were extension (67 ± 1.6 to 85.7%, p < 0.01), flexion (84.5 ± 3.2 to 81 ± 2.3%, p = 0.38), grip strength (62 ± 1.6 to 88.3 ± 1.9%, p < 0.01), and pain score (rest: 1.55 ± 0.26 to 0.2 ± 0.09, p < 0.01; activity: 3.2 ± 0.09 to 0.4 ± 0.17, p < 0.01). Based on Mayo wrist score, five excellent, 13 good, and two fair results were reported.

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 changes in the tensile properties of tendons after freeze storage in saline solution.

The objective of this study is to evaluate the influence of saline solution (0.9 per cent NaCl) on the tensile properties of freeze-stored tendons. Firstly, 170 pieces of chicken flexor digitorum profundus tendons were retrieved and wrapped in saline-soaked gauze before they were stored at -40degreesC. Then specimens were tensile tested at various time points over 360 days, scanning electron microscopy (SEM) was performed on fresh specimens, and specimens were freeze-stored for 233 days to investigate microstructure change after freeze storage. The mean values of strain ultimate tensile strength (UTS) did not deviate significantly (analysis of variance; p = 0.249) following freeze storage while the UTS and elastic modulus increased gradually with the duration of freeze storage and the growth became significant (p < 0.01) for durations longer than 70 and 40 days respectively. The SEM study showed that the collagen fibre density of specimens stored for 233 days decreased because of porosity growth. These findings suggested that the saline increased the tensile strength and modulus of the collagen.

Intraoperative interfragmentary radial nerve compression in a medially plated humeral shaft fracture: a case report.

Persistent secondary radial nerve palsy following open reduction and plating of humeral shaft fractures is rare, as the nerve is usually identified and protected throughout surgery. However, it is very difficult to identify and protect the radial nerve during medial and posteromedial approaches and closed intramedullary nailing, thus increasing the risk of damaging it. This case of interfragmentary radial nerve compression at the fracture site occurred during posteromedial plating of a laterally displaced and angulated segmental fracture of the middle and distal thirds of the humeral shaft. Exploration and nerve grafting was later required to regain function. It is important that the radial nerve be identified and protected in fixation of humeral shaft fractures with high-risk fracture configurations.

Second metatarsophalangeal joint: biomechanics and reconstruction potential.

A damaged distal radioulnar joint results in instability, pain, and loss of motion. This amounts to function loss. Of the many proposed reconstructive procedures, only a vascularized joint transfer offers growth potential in children and durability. The well-studied vascular anatomy and minimal donor morbidity of the second metatarsophalangeal joint makes it a potentially useful source. The authors evaluated various biomechanical aspects of the second metatarsophalangeal joint, which included the mediolateral arc of movement of the second metatarsophalangeal joint in hyperextension when subjected to lateral stress loading; the different patterns of disruption at peak load; and the flexion and extension range of movement. Twenty-six cadaveric specimens were tested with a customized jig. The results showed that the mediolateral arc of movement of 114 degrees approximates that of the flexion and extension range of movement of 114.2 degrees. However, it differed in that it was equal in both directions, compared with an extension arc that was greater than a flexion arc. The peak load was approximately 100 N, and this resulted in fracture, avulsion, and ligament tear. These biomechanical results may be useful to reconstructive surgeons.

Reverse anterior tibial artery flap for reconstruction of foot donor site.

The foot offers numerous useful options for hand reconstruction. Hallux transfer, dorsalis pedis flap, second toe transfers, and toe joint transfers offer good functional results in reconstructed hands. However, when the donor site is repaired with skin grafts, delayed wound healing, scarring, and contractures often result. Poor cosmesis of the donor site and altered gait are the main drawbacks of the procedures. The authors propose a new concept of primary reconstruction of the donor foot using a reverse-flow anterior tibial flap from the same leg. Two flaps are raised from the same anterior tibial vessel system in continuity as a distal free flap for hand reconstruction and as a proximal reverse-flow pedicled flap to resurface the donor defect. This technique allows good flap reconstruction of the foot donor site, reducing morbidity and limiting the operation to the same limb. The authors report their experience of 33 cases. There were no failures. Primary wound healing was achieved in the foot donor site, with acceptable cosmesis and satisfactory function.