Biomechanical Stability of Third-Generation Adjustable Suture Loop Devices Versus Continuous Loop Button Device for Cortical Fixation of ACL Tendon Grafts

Background

Concerns regarding the primary stability of early adjustable loop button (ALB) devices for cortical fixation of tendon grafts in anterior cruciate ligament reconstruction (ACLR) have led to the development of new implant designs.

Purpose

To evaluate biomechanical stability of recent ALB implants in comparison with a continuous loop button (CLB) device.

Study Design

Controlled laboratory study.

Methods

ACLR was performed in a porcine model (n = 40) using 2-strand porcine flexor tendons with a diameter of 8 mm. Three ALB devices (Infinity Button [ALB1 group]; Tightrope II RT [ALB2 group]; A-TACK [ALB3 group]) and 1 CLB device (FlippTack with polyethylene suture) were used for cortical tendon graft fixation. Cyclic loading (1000 cycles up to 250 N) with complete unloading were applied to the free end of the tendon graft using a uniaxial testing machine, followed by load to failure. Elongation, stiffness, yield load, and ultimate failure load were recorded and compared between the groups using a Kruskal-Wallis test with post hoc Dunn correction.

Results

Elongation after 1000 cycles at 250 N was similar between groups (ALB1, 4.5 ± 0.7 mm; ALB2, 4.8 ± 0.8 mm; ALB3, 4.5 ± 0.6 mm; CLB, 4.5 ± 0.8 mm), as was load to failure (ALB1, 838 ± 109 N; ALB2, 930 ± 89 N; ALB3, 809 ± 103 N; CLB, 842 ± 80 N). Stiffness was significantly higher in the ALB1 group compared with the CLB group (262.3 ± 21.6 vs 229.3 ± 15.1 N/mm; P < .05). No significant difference was found between the 4 groups regarding yield load. Constructs failed either by rupture of the loop, breakage of the button, or rupture of the tendon.

Conclusion

The tested third-generation ALB devices for cortical fixation in ACLR withstood cyclic loading with complete unloading without significant differences to a CLB device.

Clinical Relevance

The third-generation ALB devices tested in the present study provided biomechanical stability comparable with that of a CLB device. Furthermore, ultimate failure loads of all tested implants exceeded the loads expected to occur in the postoperative period after ACLR.

The anteromedial retinaculum in ACL-injured knees: An overlooked injury?

PURPOSE

The purpose of this study was to retrospectively analyse the pattern of injury to the medial knee structures in anterior cruciate ligament (ACL) injured patients. It was hypothesised that anteromedial injuries would be more common than posteromedial lesions.

METHODS

One hundred and twenty subjects aged 18-25 years with a primary ACL injury were included. Patients were excluded if the time between injury and magnetic resonance imaging (MRI) was more than 28 days or if a knee dislocation or fracture was present. The MRIs were analysed with particular emphasis on injuries to the medial knee structures, menisci and bone bruise patterns. Injuries to the ligaments and anteromedial retinaculum (AMR) were graded according to severity, ranging from periligamentous oedema (grade I), partial fibre disruption of less or more than 50% (grade IIa or IIb) to complete tears (grade III).

RESULTS

AMR injury was seen in 87 subjects (72.5%) on the coronal plane and in 88 (73.3%) on the axial plane, with grade III lesions observed in 27 (22.5%) and 29 knees (24.2%). Injuries to the superficial medial collateral ligament (sMCL), deep MCL (dMCL) and posterior oblique ligament (POL) were detected in 60 patients (50%), 93 patients (77.5%) and 38 patients (31.6%). However, grade III injuries to the POL were observed in only seven knees (5.8%). Medial meniscus injuries were associated with lesions of the sMCL and AMR (p < 0.05), while lateral meniscus injuries were significantly more common in patients with dMCL rupture (p < 0.05).

CONCLUSION

Data from this study suggest that injuries to the AMR are much more common than posteromedial lesions in subjects with ACL injuries.

LEVEL OF EVIDENCE

Level IV.

An Alternative Treatment Option for Blauth III B Thumb Hypoplasia-Thumb Stabilization with Iliac Crest Bone Graft and Intermetacarpal Arthrodesis

Thumb hypoplasia modified Blauth III B is usually treated by pollicization or, less commonly, by toe transfer. Both procedures always result in the resection of a body part, but with good cosmesis and acceptable function. We describe an intermetacarpal I/II arthrodesis with autologous bone graft augmentation to lengthen and stabilize the loose thumb. Clinical data were collected from nine patients, median age at surgery 3 years 8 months, with more than 7 years of follow-up. The results showed a grip strength on the Jamar dynamometer of approximately 61% of the unoperated hand. The Quick-DASH score was 11. The reconstructed thumb was 0.8 cm thinner and 1.9 cm shorter. Overall satisfaction on the VAS, with an average of 1.5 out of 10, is excellent with a partially usable thumb on a hand with five rays. The described procedure is a reliable treatment option with satisfactory results. In addition, none of the patients lost pincer grip between the second and third digit, but their thumb gained new function. Especially in environments where physical integrity has a high value, thumb construction instead of replacement could be considered.

The Anterior Fibers of the Superficial MCL and the ACL Restrain Anteromedial Rotatory Instability

BACKGROUND

There is limited knowledge about how the anterior cruciate ligament (ACL) and capsuloligamentous structures on the medial side of the knee act to control anteromedial rotatory knee instability.

PURPOSE

To investigate the contribution of the medial retinaculum, capsular structures (anteromedial capsule, deep medial collateral ligament [MCL], and posterior oblique ligament), and different fiber regions of the superficial MCL to restraining knee laxity, including anteromedial rotatory instability.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eight fresh-frozen human cadaveric knees were tested using a 6 degrees of freedom robotic testing system in a position-controlled mode. Loads of 10 N·m valgus rotation, 5 N·m tibial external rotation, 5 N·m tibial internal rotation, and 134 N anterior tibial translation in 5 N·m external rotation were applied at different flexion angles. The motion of the intact knee at 0° to 120° of flexion was replicated after sequential excision of the sartorial fascia; anteromedial retinaculum; anteromedial capsule; anterior, middle, and posterior fibers of the superficial MCL; the deep MCL; the posterior oblique ligament; and the ACL. The reduction in force/torque indicated the contribution of each resected structure to resisting laxity. A repeated-measures analysis of variance with a post hoc Bonferroni test was used to analyze the relative force and torque changes from the intact state.

RESULTS

The superficial MCL was the most important restraint to valgus rotation from 0° to 120° and provided the largest contribution to resisting external rotation between 30° and 120° of knee flexion, gradually increasing from 25.2% ± 7.4% at 30° to 36.9% ± 15.4% at 90°. The posterior oblique ligament contributed significantly to resisting valgus rotation only in extension (17.2% ± 12.1%) but was the major restraint to internal rotation at 0° (46.7% ± 13.1%) and 30° (30.4% ± 17.7%) of flexion. The sartorial fascia and anteromedial retinaculum resisted ER at all knee flexion angles (P < .05) and was the single most important restraint in the extended knee (19.5% ± 11%). The capsular structures (anteromedial capsule and deep MCL) had a combined contribution of 20% ± 11.5% at 0° and 23.4% ± 10.5% at 120° of knee flexion but were less important from 30° to 90°. The ACL was the primary restraint to anterior tibial translation in external rotation between 0° and 60° of flexion (50.2% ± 16.9% at 30°), but the superficial MCL was more important at 90° to 120° of knee flexion (36.8% ± 16.4% at 90°). The anterior, middle, and posterior regions of the superficial MCL contributed differently to the simulated laxity tests. The anterior fibers were the most important part of the superficial MCL in resisting external rotation and combined anterior tibial translation in external rotation.

CONCLUSION

The superficial MCL not only was the primary restraint to valgus rotation throughout the range of knee flexion but also importantly contributed to resisting anterior tibial translation in external rotation, particularly in deeper flexion in the cadaveric model. The anterior fibers of the superficial MCL are the most important superficial MCL fibers in resisting anterior tibial translation in external rotation. This study suggests that a medial reconstruction that reproduces the function of the posterior MCL fibers and posterior oblique ligament may not best control anteromedial rotatory instability.

CLINICAL RELEVANCE

Based on these data, there is a need for an individualized medial reconstruction to address different types of medial injury patterns and instabilities.

[Intra-articular proximal tibia fractures]

The incidence of proximal intra-articular tibial fractures is continuously increasing. In addition to high-energy trauma in young patients, osteoporotic fractures occur more frequently in geriatric patients. After a thorough clinical examination including X‑ray and computed tomography (CT) imaging, consolidation of the soft tissue is followed by surgical treatment to achieve the best possible anatomic reconstruction of the articular surface. Nonanatomic reduction with articular gaps >2.5 mm leads to a significantly increased risk of osteoarthritis. Selection of the surgical approach and planning of the osteosynthesis are based on the fracture morphology and the existing soft tissue damage. In addition to arthroscopically assisted percutaneous procedures, sophisticated osteosynthesis is often necessary, which requires several surgical approaches. In this context, posterior surgical approaches are becoming increasingly more important. Primary knee arthroplasty can also play a role, particularly in older patients.

Missed Essex-Lopresti Injury-Development of a Combined Proximal and Distal Radio-Ulnar Joint Prosthesis as a Treatment Option and Proof of Concept

Essex-Lopresti injuries are characterized by injuries to the proximal radio-ulnar joint, the distal radio-ulnar joint, and the interosseous membrane. This can lead to osteoarthritis, impaction syndrome, or instability. If all three structures are injured and lead to instability, the situation is almost unmanageable and many times ends in a one-bone forearm. In this article, we demonstrate a new way to reconstruct the proximal and distal radio-ulnar joint with two patient-specific coupled prostheses. These have been developed with the biomechanical conditions of the forearm in mind, where there are very large forces between the bones. As a result, we are able to present a patient previously severely restricted in the use of his hand and arm via a splint that compressed the forearm, who is now able to perform everyday activities and even light sports, such as badminton, without pain.

Three-Loop Technique for Pulley Reconstruction-A Retrospective Cohort Analysis of 23 Patients

Twenty-three patients with a mean age of 52.7 years underwent pulley reconstruction using the Okutsu double- or triple-loop technique after iatrogenic or traumatic rupture of at least two adjacent flexor tendon pulleys in the finger and distal palm; mean age of injury was 4.77 years. The mean follow-up was 4.66 years after reconstruction of mostly A2 pulleys in a single surgeon setting. Outcome measures included ROM, NRS pain, satisfaction, Disabilities of Arm, Shoulder and Hand Questionnaire (DASH) and Krimmer score, Buck-Gramcko score, Jamar grip strength, pinch grip, and vigorimetry compared to the uninjured side. The median patient satisfaction score was 6.6/10. Hand function using the DASH score was 9.5. Grip strength on the Jamar Dynamometer showed only a slight reduction of 13% compared to the uninjured side. The resultant force of the operated fingers on the vigorimeter is almost 60% of that of the contralateral side, and the finger-palm distance of the operated finger was reduced from 2.2 cm to 1.45 cm. Other functional scores, such as Krimmer (82.2) and Buck-Gramcko (10.9), support these good results. The follow-up of patients more than 4.5 years after reconstruction of the A2 and A3 flexor tendon pulley using the double- or triple-loop technique showed acceptable patient satisfaction and good function of the finger in everyday life.

Recurrent Instability Rate and Subjective Knee Function following Accelerated Rehabilitation after ACL Reconstruction in Comparison to a Conservative Rehabilitation Protocol

INTRODUCTION

The Purpose of the present study was to assess the outcome of anterior cruciate ligament reconstruction (ACLR) with an accelerated rehabilitation protocol and to compare it to a conservative rehabilitation protocol. It was hypothesized that an accelerated rehabilitation protocol, including brace-free early weight bearing, would result in a higher rate of recurrent instability and revision surgery compared to a conservative rehabilitation protocol.

METHODS

From 2016 to 2017, two different rehabilitation protocols for isolated ACLR were used at a high-volume knee surgery center. A total of 65 consecutive patients with isolated hamstring ACLR, of whom n = 33 had been treated with an accelerated (AccRehab) and n = 32 with a conservative rehabilitation protocol (ConRehab), were retrospectively included in the study. Patients were evaluated for recurrent instability, revision surgery, and other complications at a mean follow-up period of 64 ± 7.4 months. In addition, Tegner Activity Scale, Lysholm Score, and IKDC-subjective Score were evaluated. Statistical comparison between the two groups was performed utilizing Fisher's exact test and Student's t-test.

RESULTS

Mean age (29.3 vs. 26.6 years) and preoperative Tegner Score (6.4 vs. 5.9) were comparable between both groups. At 64 ± 7.4 months after ACLR, six cases of recurrent instability were reported in the AccRehab group (18%) in comparison to three cases (9%) in the ConRehab group (p = n.s.). There was no significant difference regarding revision surgery and further complications. Furthermore, no significant difference was found between both groups regarding Tegner (5.5 ± 1.9 vs. 5.5 ± 1.2), Lysholm (93.6 ± 6.3 vs. 89.3 ± 10.7), and IKDC score (89.7 ± 7.9 vs. 86.7 ± 12.1).

CONCLUSION

No significant disadvantage of an accelerated rehabilitation protocol following ACLR was found in terms of recurrent instability rate, revision surgery, or patient-reported outcome. However, a trend towards a higher reinstability rate was found for an accelerated rehabilitation protocol. Future level one trials evaluating brace-free early weight bearing following ACLR are desirable.

Scapholunate ligament reconstruction using a part of the extensor carpi radialis brevis tendon through a dorsal approach

Thirty-six patients were assessed after scapholunate ligament reconstruction using a portion of the extensor carpi radialis brevis through a dorsal approach. The median age was 53 years. Most (27/38) were graded as scapholunate advanced collapse Grade I. At a median of 47 months after treatment, hand function using the Disabilities of Arm, Shoulder and Hand Questionnaire was 12. The postoperative range of wrist flexion and extension movement was 77% and grip strength 92% compared with the uninjured side. The median patient satisfaction was rated as 9/10. Median pain scores without and with load, using the numeric pain scale (0-10), were 1 and 3, respectively. This reconstruction leads to initial normalization of radiological features, such as scapholunate interval, scapholunate and radiolunate angles, but a notable loss of the immediate postoperative reduction was observed in long-term follow-up, which was not accompanied by any deterioration in the clinical examination. This technique, even in scapholunate advanced collapse type I wrists, resulted in long-term, improved outcomes compared with other techniques.Level of evidence: IV.

The Biomechanical Stability of Bone Staples in Cortical Fixation of Tendon Grafts for Medial Collateral Ligament Reconstruction Depends on the Implant Design

BACKGROUND

The promising biomechanical stability of bone staples (BSs) in cortical fixation of tendon grafts for medial collateral ligament (MCL) reconstruction has been revealed by a previous investigation. However, it is currently unknown if the biomechanical stability of cortical fixation of tendon grafts depends on the BS design.

PURPOSE

To assess the biomechanical stability of cortical fixation of tendon grafts in knee surgery using 4 different BS designs.

STUDY DESIGN

Controlled laboratory study.

METHODS

Cortical fixation of tendon grafts was performed in a porcine knee model at the tibial insertion area of the MCL using 4 different BS designs (n = 40): 8-mm width without spikes (n = 10), 8-mm width with spikes (n = 10), 14-mm width with spikes (n = 10), and 13 mm-wide 4-prong staples with spikes (n = 10). Specimens were mounted in a materials testing machine, and cyclic loading was applied to the tendon graft (500 cycles at 50 and 100 N, respectively), followed by load-to-failure testing. The Kruskal-Wallis test was performed for statistical analysis (P < .05), and the post hoc Dunn test was performed for multiple comparisons.

RESULTS

In 4 of 10 specimens with graft fixation using BSs without spikes, slippage of the tendon underneath the BS led to failure of the construct during cyclic loading to 100 N. In the other groups, no fixation failure was observed during cyclic loading. Furthermore, graft fixation using BSs without spikes was found to have significantly more elongation during cyclic loading (8.2 ± 1.9 mm) and a lower ultimate failure load (170 ± 120 N) compared with graft fixation using narrow BSs with spikes (3.4 ± 1.2 mm [P < .0001] and 364 ± 85 N [P < .05], respectively) and graft fixation using broad BSs with spikes (4.5 ± 1.4 mm [P < .05] and 429 ± 67 N [P < .001], respectively). No statistical differences in elongation during cyclic loading or ultimate failure load were found between 4-prong staples with spikes (5.0 ± 1.3 mm and 304 ± 85 N) and narrow or broad staples with spikes.

CONCLUSION

The biomechanical stability of cortical fixation of an MCL graft was comparable between each BS design with spikes (narrow, broad, and 4-prong) in a porcine knee model, whereas BSs without spikes led to failure of the fixation construct during cyclic loading in 4 of 10 specimens and increased elongation and lower ultimate failure loads in the remainder of the group. BSs without spikes may therefore not be recommended for graft fixation.

CLINICAL RELEVANCE

The use of BSs can help to avoid the conflict of converging tunnels in multiligament reconstruction surgery. An implant design with spikes yields significantly higher biomechanical stability than BSs without spikes.

[Ligament injuries in tibial plateau fractures]

Fracture dislocations of the proximal tibia are associated with a markedly high incidence of ligament ruptures. Despite knowledge on the frequency of accompanying ligament injuries, even now neither adequate diagnostics nor targeted treatment of associated ligament injuries are the gold standard in the treatment algorithm for tibial plateau fractures. To be able to assess the risk and the type of accompanying ligament injuries in tibial plateau fractures, it is recommended to decidedly analyze the fracture morphology. For example, flexion varus fractures are very frequently associated with injuries to the anterior cruciate ligament, whereas valgus fractures are prone to ruptures of the medial collateral ligament and (hyper)extension fractures facilitate ruptures of the posterior cruciate ligament and the posterolateral corner. In order not to overlook high-grade instability, magnetic resonance imaging or intraoperative dynamic fluoroscopy can be carried out after completing osteosynthesis. Bony avulsions should either be addressed directly during osteosynthesis or indirectly retained via interfragmentary compression. In cases of direct visualization or relevant instability, intraligamentous tears should at least be intraoperatively reduced. If patients suffer from persistent instability a secondary ligament reconstruction with autologous tendons can be carried out following bony consolidation of the tibial plateau fracture.

A lateral fracture step-off of 2mm increases intra-articular pressure following tibial plateau fracture

INTRODUCTION

The aim of this study was to evaluate the effects of increasing posttraumatic step-offs after lateral tibial plateau fracture reduction on the intra-articular pressure.

MATERIALS AND METHODS

In eight fresh-frozen human cadaveric knees with intact menisci, a standardized sagittal osteotomy of the lateral tibial condyle was performed as an OTA/AO type 41-B1 fracture-model. The fragment was fixed by a customized sled including an angular stable tibia plate to evaluate step-offs from 0 mm to 8 mm in 1mm increments. In a servo-hydraulic testing machine, an axial force was applied to the tibial plateau in 0° (700N), 15° (700N), 30° (700N), 60° (350N), and 90 ° (350N) of flexion while the joint pressure was recorded by two pressure sensors.

RESULTS

A 1mm step-off did not result in an increased joint pressure. At 60° of flexion a 2mm step-off increased the lateral joint pressure by 61.84kPa (P = 0.0027). In 30° of flexion, a 3mm step raised the lateral joint pressure by 66.80kPa (p = 0.0017), whereas in 0°, 15° and 90° of flexion, a 4mm step increased the pressure by >50kPa (P < 0.05). Concomitant medial joint pressure increments were lower than those in the lateral plateau. A significant increase of 19-24kPa in the medial joint pressure was detected in 90° of flexion with a 1mm lateral step (P = 0.0075), in 15° and 60° of flexion with a 2mm step (P < 0.05), in 0° of flexion with a 4mm step (P = 0.0215) and in 30° of flexion with a 7mm step (P = 0.0487).

CONCLUSION

Lateral fracture step-offs of 2mm or larger should be reduced intraoperatively to avoid large increases in lateral joint pressure.

[Paronychia and Felons - Surgical Treatment]

Infections of the distal phalanx are the most common of all hand infections. There are dorsal localised infections, which develop in the area of the nail and are called paronychia, and palmar infections, which affect the fingertip and are the typical felons. The acute paronychia must be specifically opened depending on the site of infection. This requires precise anatomical knowledge of nail structure. Chronic paronychia usually have other causes and treatment is much more difficult. Felons are often extremely painful. There is a complex system of fibrous septa and swelling is limited. If the septa are destroyed a spread into the bones or the flexor tendon sheath is possible.

[Pyogenic Flexor Tenosynovitis]

Pyogenic flexor tenosynovitis (PFT) is still the most serious infections of the hand. If the typical cardinal signs of PFT according to Kanavel exist, the indication for surgery should be made immediately. The consequential damage of a delayed surgery with enormous restrictions on the movement of the fingers due to the destruction of the sliding layers and massive adhesions are so serious that conservative therapy attempts are very difficult to justify. The results of Hand therapy after delayed surgery are often disappointing. The rapid surgical intervention and the early opening and relief as well as the irrigation of the tendon sheath can end the disease, the destruction of the sliding layers and the severe pain almost immediately. Quick recognition and quick action are important. With early intervention, normal hand function can often be completely restored.

[Resection arthoplasty of the trapezium with ligament reconstruction and tendon interposition and variations]

OBJECTIVE

Creation of a pain-free, flexible and stable (pseudo) joint between the carpus and the base of the 1st metacarpal bone.

INDICATIONS

Painful carpometacarpal (CMC)‑I joint due to primary or secondary osteoarthritis, CMC‑I instability.

CONTRAINDICATIONS

Carpal instability, local infection, tumors.

SURGICAL TECHNIQUE

Resection of the trapezium (and of the arthritic joint surfaces in CMC‑I and STT [scaphoid-trapezium-trapezoid-joint]), stabilization of the base of the 1st metacarpal bone by suspension with a distally pedicled strip of the flexor carpi radialis tendon or variants thereof.

POSTOPERATIVE MANAGEMENT

Immobilization in a splint for 3-5 weeks, followed by hand therapy.

RESULTS

Worldwide for almost 40 years, regardless of the exact technique, almost always (90%) significant pain reduction, increased strength in the grip and slightly less in the pinch grip, very good mobility, 85-95% very satisfied patients and very good long-term results.

Metacarpal shaft fixation: a biomechanical comparison of dorsal plating, lag screws, and headless compression screws

Background

Metacarpal shaft fractures are common and can be treated nonoperatively. Shortening, angulation, and rotational deformity are indications for surgical treatment. Various forms of treatment with advantages and disadvantages have been documented. The purpose of the study was to determine the stability of fracture fixation with intramedullary headless compression screws in two types of metacarpal shaft fractures and compare them to other common forms of rigid fixation: dorsal plating and lag screw fixation. It was hypothesized that headless compression screws would demonstrate a biomechanical stronger construct.

Methods

Five matched paired hands (age 60.9 ± 4.6 years), utilizing non-thumb metacarpals, were used for comparative fixation in two fracture types created by an osteotomy. In transverse diaphyseal fractures, fixation by headless compression screws (n = 7) and plating (n = 8) were compared. In long oblique diaphyseal fractures, headless compression screws (n = 8) were compared with plating (n = 8) and lag screws (n = 7). Testing was performed using an MTS frame producing an apex dorsal, three point bending force. Peak load to failure and stiffness were calculated from the load-displacement curve generated.

Results

For transverse fractures, headless compression screws had a significantly higher stiffness and peak load to failure, means 249.4 N/mm and 584.8 N, than plates, means 129.02 N/mm and 303.9 N (both p < 0.001). For long oblique fractures, stiffness and peak load to failure for headless compression screws were means 209 N/mm and 758.4 N, for plates 258.7 N/mm and 518.5 N, and for lag screws 172.18 N/mm and 234.11 N. There was significance in peak load to failure for headless compression screws vs plates (p = 0.023), headless compression screws vs lag screws (p < 0.001), and plates vs lag screws (p = 0.009). There was no significant difference in stiffness between groups.

Conclusion

Intramedullary fixation of diaphyseal metacarpal fractures with a headless compression screw provides excellent biomechanical stability. Coupled with lower risks for adverse effects, headless compression screws may be a preferable option for those requiring rapid return to sport or work.

Level of evidence

Basic Science Study, Biomechanics.

[Extensor tendon injuries of fingers in the region of the metacarpophalangeal joint (zone V)]

Due to the exposed situation of the extension side of the metacarpophalangeal joint when the fingers are bent, injuries in this region are not uncommon. The extensor apparatus lies directly below the skin and the various parts can be easily injured. Due to the complex anatomical structure, the different clinical appearances and the various forms of treatment, injuries of the extensor tendons in the region of the metacarpophalangeal joint must be examined in a very differentiated manner. The not uncommonly occurring deviation phenomenon makes all injuries in zone V suspicious and special attention must be paid to them. The alarming multitude of revision surgeries with tenolysis, arthrolysis and restoration of the balance of extensor tendons or centering show that these operations are much more demanding than the way they are appreciated in the literature and by many surgeons (beginner's operation). The article presents the surgical treatment with suture techniques and reconstruction possibilities as well as the aftercare, in addition to the special anatomy and diagnostics.

[Secondary reconstruction of flexor tendons]

The secondary reconstruction of flexor tendons is in most cases very demanding and tedious. The indications, selection of the correct surgical procedure, operative technique and further treatment have to be individually adjusted and are mostly very difficult. Due to the previous operations unpleasant surprises may occur intraoperatively, which must be recognized and treated by the surgeon. Nevertheless, a significant improvement of the function of the whole hand can be achieved for most patients, e.g. by a two-stage flexor tendon transplantation or other techniques described in this article.

[Dorsal plate arthrodesis of the thumb metacarpophalangeal joint]

OBJECTIVE

Elimination of pain or instability by arthrodesis of the thumb joint in functional position by dorsal plateosteosynthesis.

INDICATIONS

Painful primary or secondary arthrosis of the thumb, nonreconstructable ulnar, radial or palmar instability, posttraumatic dislocation, defect injuries, bone tumors in the region of the thumb metacarpophalangeal joint.

CONTRAINDICATIONS

Local infection of the thumb metacarpophalangeal joint area.

SURGICAL TECHNIQUE

Dorsal approach to the thumb metacarpophalangeal (MP) joint, splitting of the extensor aponeurosis between the extensor pollicis longus and extensor pollicis brevis tendon. Opening of the anterior capsule and separation of the collateral ligaments, open up the joint, narrow concave and convex joint surface resections, adjustment of the arthrodesis position in 10-20° flexion and K‑wire transfixation, dorsal plateosteosynthesis, fine adjustment of the flexion, axis and pronation position. Closure of the capsule and the periosteal gliding tissue over the plate, reconstruction of the extensor aponeurosis.

POSTOPERATIVE MANAGEMENT

Splint for 3 weeks. Full load after 6-8 weeks.

RESULTS

The dorsal plate arthrodesis of the thumb MP joint is a reliable surgical method with very good functional results.

[Anatomy and biomechanics of the scaphoid]

The scaphoid is biomechanically and clinically of great importance for function of the wrist. In the literature, its anatomy and biomechanics are clearly underrepresented as well as underestimated. In the following review the scaphoid will be presented in more detail, according to recent information and findings. Not only will the origin of the name and the history of previous names, such as cotyloid or navicular, be introduced, but also for the first time in medical literature the significant phylogeny and ontogeny of the scaphoid will be shown. Moreover, the clinically very important blood supply, the ligaments of the scaphoid and relevant biomechanical details will be described.

[Treatment of instability of the metacarpophalangeal and trapeziometacarpal joints of the thumb]

Restoration of stability of the thumb represents an enormous gain of function for the patient and can be achieved by arthrodesis or ligament reconstruction. Ligament reconstruction should only be performed if good stability and mobility and a pain-free grip can also be achieved. In every case surgery must protect the delicate soft tissues and should be based on a profound knowledge of the anatomical and biomechanical circumstances. Instability of the trapeziometacarpal joint is rare but metacarpophalangeal joint instability (ulnar, palmar and radial) is relatively frequent. For both conditions arthrodesis is the most frequently used and easier surgical procedure. Ligament reconstruction is more difficult to perform but can maintain the mobility of these joints.

[The fibrous skeleton of the hand : Changes with Dupuytren's contracture]

The exact knowledge of the anatomy of the fibrous skeleton of the hand is an absolute prerequisite for any treatment of Dupuytren's disease. The fibrous skeleton does not only include the palmar aponeurosis, but also numerous retinacula cutis, which are not found in current anatomy books. Here, eponyms facilitate the otherwise difficult and over-pronounced names of the fiber systems. Skoog, Legueu and Juvara, Gosset, Grapow, Grayson, Cleland, Thomine, and Barton are the most important. This systematic review of the fibers and strands is designed to help reduce iatrogenic complications.

Intramyocardially Transplanted Neonatal Cardiomyocytes (NCMs) Show Structural and Electrophysiological Maturation and Integration and Dose-Dependently Stabilize Function of Infarcted Rat Hearts

Cardiac cell replacement therapy is a promising therapy to improve cardiac function in heart failure. Persistence, structural and functional maturation, and integration of transplanted cardiomyocytes into recipients' hearts are crucial for a safe and efficient replacement of lost cells. We studied histology, electrophysiology, and quantity of intramyocardially transplanted rat neonatal cardiomyocytes (NCMs) and performed a detailed functional study with repeated invasive (pressure-volume catheter) and noninvasive (echocardiography) analyses of infarcted female rat hearts including pharmacological stress before and 3 weeks after intramyocardial injection of 5 × 106 (low NCM) or 25 × 106 (high NCM) syngeneic male NCMs or medium as placebo (Ctrl). Quantitative real-time polymerase chain reaction (PCR) for Y-chromosome confirmed a fivefold higher persisting male cell number in high NCM versus low NCM after 3 weeks. Sharp electrode measurements within viable slices of recipient hearts demonstrated that transplanted NCMs integrate into host myocardium and mature to an almost adult phenotype, which might be facilitated through gap junctions between host myocardium and transplanted NCMs as indicated by connexin43 in histology. Ejection fraction of recipient hearts was severely impaired after ligation of left anterior descending (LAD; pressure-volume catheter: 39.2 ± 3.6%, echocardiography: 39.9 ± 1.4%). Repeated analyses revealed a significant further decline within 3 weeks in Ctrl and a dose-dependent stabilization in cell-treated groups. Consistently, stabilized cardiac function/morphology in cell-treated groups was seen in stroke volume, cardiac output, ventricle length, and wall thickness. Our findings confirm that cardiac cell replacement is a promising therapy for ischemic heart disease since immature cardiomyocytes persist, integrate, and mature after intramyocardial transplantation, and they dose-dependently stabilize cardiac function after myocardial infarction.