Tendon transfer in foot drop: a systematic review

Comparison of Staple, Anchor, and Tenodesis Screw for Posterior Tibialis Tendon Fixation: A Biomechanical Analysis

Various posterior tibialis tendon fixation techniques are described in literature. Suture anchor, staple and tenodesis screws are widely used for posterior tibialis tendon transfer, but their stiffness and the maximal ultimate failure load were not tested before. We aimed to compare the initial ultimate failure load and stiffnesses of suture anchor, staple and tenodesis screws on bovine tendon fixation to bovine metaphyseal bone. Thirty-five fresh bovine ankle joints and hooves were obtained from a local abattoir. Metatarsals bones with long extensor tendons were harvested. Staple group had 15, suture anchor group had 10, and tenodesis screw group had 10 samples. All fixations were tested with Instron® ElectroPuls® E10000 Test Instrument. Ultimate failure load and failure location were noted. Staple group's median ultimate failure load was 210.03 N (IQR: 133.43), suture anchor group's was 124.33 N (IQR: 63.67), and tenodesis screw group's was 394.46 N (IQR:115.09). Median stiffness of the staple group was 19.87 N/m (IQR: 15.29); the tenodesis screw group's was 20.28 N/m (IQR: 6.18), the anchor group's was 8.54 N/m (IQR: 4.35). Staples' failure occurred on tendon-staple interface, while suture anchors' occurred on anchor-suture interface and tenodesis screws' occurred on tendon-suture interface. Tenodesis screws' ultimate failure load was the highest (tenodesis vs anchor and staple p < .001 and p = .032, respectively). Staple fixation is less expensive than the other methods and can provide sufficient fixation strength but was weaker than the tenodesis screw fixation. Staples are still a good choice for tendon to bone fixation, whereas the suture anchors provide lower fixation strength at a higher cost.

Functional evaluation of a novel fibreglass-reinforced polyamide custom dynamic AFO for foot drop patients: A pilot study

BACKGROUND

Ankle-foot orthoses (AFOs) are orthopaedic devices often prescribed to treat foot drop. For patients who are not satisfied with off-the-shelf solutions, custom AFOs personalized to the patient's lower limb anatomy are required. Dynamic AFOs provide stability while allowing for physiological ankle mobility in the stance phase of walking.

RESEARCH QUESTION

Can a morphology-based dynamic custom AFO made of fiberglass-reinforced polyamide restore a quasi-normal gait pattern and improve comfort in patients with foot drop?

METHODS

In this pilot study, the legs and feet of ten foot drop patients (age=64.9 ± 11.4 years; BMI=26.2 ± 2.1 kg/m2) were scanned using a Kinect-based 3D scanner. A custom AFO was designed and produced for each patient using a fiberglass-reinforced polyamide through selective laser sintering. To assess kinematics, skin markers were placed on relevant bony landmarks according to a validated protocol. Each patient was instructed to walk at a self-selected comfortable speed under three conditions: wearing the custom AFO, wearing an off-the-shelf orthosis (Codivilla spring), and without any AFO (shod condition). Muscle activation in the tibialis anterior, gastrocnemius, rectus femoris and biceps femoris muscles in both legs was recorded using wireless sEMG sensors. The comfort and of each AFO was evaluated using a Visual Analogue Scale.

RESULTS

The custom AFO resulted in significant increase of stride length and walking speed compared to the shod condition. Except for the hip joint, which exhibited greater maximum flexion and reduced range of motion, the kinematic parameters of all other joints were similar to those observed in a healthy control population. Furthermore, the custom AFO received significantly higher comfort scores compared to the Codivilla spring.

SIGNIFICANCE

This study has provided evidence supporting the effectiveness of custom orthotic solutions in restoring lower limb kinematics and improving the perceived comfort in foot drop patients compared to off-the-shelf solutions.

[Rare nerve compression neuropathies]

UNCOMMON NERVE COMPRESSION SYNDROMES

In regard to the complex anatomical relationship of peripheral nerves and muscles, tendons, fasciae as well as their long course within those anatomical structures and additional close contact to bony structures, they are prone to suffer from local compression syndromes. Hence creating a vast majority of entrapment syndromes - well described in literature for almost every single nerve. The purpose of this article is to give an overview of symptoms, signs, diagnostic studies and treatment options, addressing especially the less known syndromes. Compression syndromes of the upper arm and shoulder region include the suprascapular nerve syndrome the compression of the axillary nerve within the spatium quadrilaterale and the compression of the long thoracic nerve at the chest wall. The upper extremity offers a variety of infrequent entrapment syndromes, as the pronator teres syndrome and anterior interosseus syndrome, both resulting from pressure to the median nerve in the forearm. Compression neuropathy in the course of the radial nerve in the distal upper extremity is also known as supinator syndrome. Guyon's canal syndrome is the ulnar side equivalent to the well-known carpal tunnel syndrome. In the case of a Cheiralgia paresthetica, a compression of a sensory branch of the superficial radial nerve can be seen. In the lower extremities, a variety of nerves especially in the groin and thigh area can be compressed as they pass through the narrow spaces between the abdominal muscles or underneath the inguinal ligament. Compression of the lateral femoral cutaneous nerve is the most common syndrome. Compression syndromes of the femoral and obturator nerves are most often iatrogenic. Pain around the knee, especially the lateral part and following orthopedic procedures of the knee, can arise from a compression or a lesion of a small infrapatellar branch of the saphenous nerve. Another probably underdiagnosed syndrome is piriformis syndrome, resulting from an entrapment of the sciatic nerve as it passes through certain muscular structures. In the distal lower extremity, the peroneal and tibial nerves can be compressed at multple sites, clinically known as peroneal nerve paralysis resulting from nerve compression around the fibular head, the anterior and posterior tarsal tunnel syndrome, and Morton's metatarsalgia.

Fibular (peroneal) neuropathy

Fibular neuropathy has variable presenting features depending on the site of the lesion. Anatomical features make it susceptible to injury from extrinsic factors, particularly the superficial location of the nerve at the head of the fibula. There are many mechanisms of compression or other traumatic injury of the fibular nerve, as well as entrapment and intrinsic nerve lesions. Intraneural ganglion cysts are increasingly recognized when the mechanism of neuropathy is not clear from the medical history. Electrodiagnostic testing can contribute to the localization as well as the characterization of the pathologic process affecting the nerve. When the mechanism of injury is unclear from the analysis of the presentation, imaging with MRI and ultrasound may identify nerve lesions that warrant surgical intervention. The differential diagnosis of foot drop includes fibular neuropathy and other neurologic conditions, which can be distinguished through clinical and electrodiagnostic assessment. Rehabilitation measures, including ankle splinting, are important to improve function and safety when foot drop is present. Fibular neuropathy is less frequently painful than many other nerve lesions, but when it is painful, neuropathic medication may be required. Failure to spontaneously recover or the detection of a mass lesion may require surgical management.

Muscle Architecture of Leg Muscles: Functional and Clinical Significance

Background

Architectural properties of the muscles are the prime predictors of functional attributes and force-generating capacity of the muscles. This data is vital for musculoskeletal modelling and selecting the appropriate muscle-tendon units for tendon transfers.Cadaveric data for architectural properties is the gold standard and primary input for musculoskeletal modelling. There is a paucity of these datasets, especially in the leg muscles.

Methods

Sixty muscles of the anterior and lateral compartments from twelve formalin-fixed lower limbs were studied for gross architecture, including the peculiar fibre arrangements and architectural properties of muscles. Muscle weight, muscle length, fibre length, pennation angle and sarcomere length were measured. Normalised fibre length, fibre length to muscle length ratio (FL/ML ratio), and the physiological cross-sectional area (PCSA) were calculated from the obtained data.

Results

Muscles displayed a combination of architectural strategies and were partly fusiform and partly pennate. The tibialis anterior and peroneus longus were the heaviest muscles in their respective compartments and showed more extensive origin from the nearby deep facial sheets.Long fibre length and less pennation angle were seen in muscles of the extensor compartment. Potential muscle power was highest in the tibialis anterior and peroneus longus and least in the extensor hallucis longus.

Conclusions

Arching of the foot and eversion are peculiar to humans and recent in evolution. Due to the functional demand of maintaining the medial longitudinal arch and eversion, the tibialis anterior and peroneus longus have more muscle weight and larger physiological cross-sectional area and are potentially more powerful.Extensor compartment muscles were architecturally more suited for excursions because of the long fibre length and less pennation angle.This study contributes baseline normative data for musculoskeletal modelling platforms and simulation tools - an emerging area in biomechanics and tendon transfers.

Surgical outcome of avulsion fractures of the distal fibula: a systematic literature review

PURPOSE

To provide a systematic overview of clinical and radiographic outcomes in patients who underwent surgical treatment of a painful avulsion fragment of the distal fibula also known as posttraumatic os subfibulare.

METHODS

A systematic literature search across two major sources (PubMed and Scopus) was performed. Twenty-seven studies were included and analyzed using the modified Coleman score to assess the methodologic quality.

RESULTS

The surgical treatment of symptomatic os subfibulare, with or without concomitant ankle instability, generally results in substantial improvement in clinical and radiographic outcomes with relative low complication rates. Clinical outcome measures may not be affected by the presence of ankle instability or by the fragment size. The methodological quality of analyzed studies was satisfactory.

CONCLUSION

Posttraumatic os subfibulare may result in chronic pain and ankle instability. If surgery is indicated, ankle instability should be concomitantly addressed when present. Based on available literature, satisfactory postoperative outcomes can be reliably expected following surgical treatment.

LEVEL OF EVIDENCE

Systematic Review of Level III and Level IV Studies, Level IV.

Useful functional recovery and quality of life after surgical treatment of peroneal nerve injuries

Closed injuries to the peroneal nerve recover spontaneously in about a third of patients, but surgery may be needed in the remaining 2/3. The recovery after surgery is not always satisfactory and the patients may need an orthosis or a walking aid to cope with regular daily activities. This study aimed to evaluate the useful functional recovery and quality of life (QoL) in surgically treated patients with peroneal nerve (PN) injuries. The study involved 51 patients who have undergone surgical treatment due to PN injury in our department, within a 15-year period (2006-2020). Thirty patients (59%) were treated with neurolysis, 12 (23%) with nerve repair techniques, and 9 (18%) with tendon transfer (TT). Neurolysis is employed in the least extensive nerve injuries when nerve continuity is preserved and yields a motor recovery ratio of almost 80%. Nerve repairs were followed by 58.33% of patients achieving M3+ recovery, while 41.66% recovered to the useful functional state (M4 or M5) With the use of TTs, all patients recovered to the M3+, while 66.7% recovered to M4. All our results correspond to the results of previous studies. No statistically significant differences were found regarding the QoL of the groups. There is an apparent advantage of neurolysis, over nerve repair, over TT procedure, both in terms of useful functional recovery, and foot-drop-related QoL. However, when involving all aspects of QoL, these advantages diminish. The individual approach leads to optimal results in all groups of patients.