The effect of experimentally induced gluteal muscle weakness on joint kinematics, reaction forces, and dynamic balance performance during deep bilateral squats

Squatting is a common daily activity and fundamental exercise in resistance training and closed kinetic chain programs. The aim of this study was to investigate the effects of an experimentally induced weakness of the gluteal muscles on joint kinematics, reactions forces (JRFs), and dynamic balance performance during deep bilateral squats in healthy young adults. Ten healthy adults received sequential blocks of (1) branch of the superior gluteal nerve to the tensor fasciae latae (SGNtfl) muscle, (2) superior gluteal nerve (SGN), and (3) inferior gluteal nerve (IGN) on the dominant right leg. At the control condition and following each block, the participants were instructed to perform deep bilateral squats standing on two force plates. Hip, knee, ankle, and pelvis kinematics did not differ significantly following iatrogenic weakness of gluteal muscles. The most important finding was the significant differences in JRFs following SGN and IGN block, with the affected hip, patellofemoral, and ankle joint demonstrating lower JRFs, whereas the contralateral joints demonstrated significantly higher JRFs, especially the patellofemoral joint which demonstrated an average maximum difference of 1.43 x body weight compared with the control condition. When performing a deep bilateral leg squat under SGN and IGN block, the subjects demonstrated an increased center of pressure (CoP) range and standard deviation (SD) in mediolateral compared with the control condition. These results imply that squat performance changes significantly following weakness of gluteal muscles and should be considered when assessing and training athletes or patients with these injuries.

Superior Gluteal Nerve Anatomy and Its Injuries: Aiming for a More Secure Surgical Approach of the Pelvic Region

Because most of the recognized causes of superior gluteal nerve (SGN) injury are iatrogenic, detailed knowledge of the anatomy of the SGN is crucial to prevent its injury associated with surgical procedures. This study aims to describe the precise location of SGN or its branches at the greater sciatic foramen, measure the distances of these neural structures to palpable bony landmarks, and evaluate the possible correlation between these parameters and pelvis size. Twenty human cadaveric hemipelvises were studied. After dissection to expose the SGN or its branches at the greater sciatic foramen, the distances from these neural structures to the greater trochanter (GT), to the anterior superior iliac spine (ASIS), to the posterior superior iliac spine (PSIS), to the ischial tuberosity (IT), and to the greater sciatic notch apex were measured. We found that at the greater sciatic foramen, the SGN emerges as a common trunk in 75% of hemipelvises, and already divided in its superior and inferior branches in 25% of hemipelvises. When the SGN exits the pelvis as a common trunk, it does so, in most cases, in contact with the bone at the apex of the greater sciatic notch or superior to the level of the apex. The median distance from the SGN at the greater sciatic notch to the PSIS, ASIS, GT and IT is 7.6 cm, 10.9 cm, 7.5 cm and 10.8 cm, respectively. We found a positive correlation between some of the analyzed parameters and the size of the pelvis. The anatomical data of this study may serve as pivotal guides during orthopedic pelvic surgery, contributing to minimize SNG iatrogenic lesions with significant implications in the patient's quality of life.

Protection of the innervation of the tensor fasciae latae in hip direct anterior and anterolateral approaches: a cadaver study

PURPOSE

This study aims to reveal the exact course of the superior gluteal nerve (SGN) branch innervating the tensor fascia lata (TFL) and show how it can be protected in the direct anterior approach (DAA) and anterolateral approach (ALA).

METHODS

The anterolateral regions of 22 thighs from formalin-fixed cadavers were dissected. 3 anatomical points were determined. Point A, B, C indicates where the SGN enters the gluteus minimus (GMin) fibres, the SGN leaves the gluteal muscles, the SGN enters the TFL, respectively. Measurements were made on 3 separate lines.

RESULTS

On the anterior superior iliac spine (ASIS) and the head of the fibula line (Line 1), the horizontal-vertical distances from point B and C to the ASIS were 7.99 ± 3.65 mm-40.40 ± 11.50 mm and 11.74 ± 6.61 mm-70.35 ± 14.11 mm respectively. The horizontal-vertical distances from point A, B, C to the greater trochanter (GT) were 32.41 ± 9.97 mm-55.28 ± 12.25 mm; 67.70 ± 8.54 mm-17.76 ± 13.57 mm; 63.92 ± 9.96 mm-13.00 ± 7.92 mm on the GT and the head of the fibula line (Line 2), respectively. The horizontal-vertical distances from point A, B, C to the GT were 24.58 ± 9.83 mm-42.54 ± 12.86 mm; 9.45 ± 7.92 mm-36.25 ± 9.06 mm; 26.18 ± 11.12 mm-64.05 ± 11.67 mm on the ASIS and the GT line (Line 3).

CONCLUSIONS

In the DAA, the increased risk of damaging the branch of the SGN that innervates the TFL must be kept in mind. The protection of this branch can be ensured with easy and applicable rules.

Hamstring branches of the sciatic nerve as donors for neurotization of the superior gluteal nerve: A cadaveric feasibility study

Although superior gluteal nerve (SGN) injury can have significant morbidity, to date, surgical strategies for its repair are scant in the literature. Specifically, neurotization options have not been explored. To address this deficiency in the literature, the current cadaveric feasibility study was performed. Via a transgluteal approach on 16 cadaveric sides, the proximal sciatic nerve and the entrance of the SGN into the gluteus medius and minimus were identified. Additionally, branches from the sciatic nerve to the hamstring muscles were traced proximally to confirm their position in relation to the sciatic nerve as a whole. These branches were cut at the level of the ischial tuberosity and teased away from the sciatic nerve proximally to the greater sciatic foramen and transferred superolateral to the SGN. The diameter of each nerve branch was measured as well as its available length for reaching the SGN. All branches of the sciatic nerve to the hamstring muscles arose from the anteromedial part of the nerve. The mean diameters of the branches to the semimembranosus, semitendinosus, and biceps femoris muscles were 2.1, 1.9, and 1.5 mm, respectively. The mean diameter of the SGN was 3.1 mm and the mean distance from this entrance point to the ischial spine was 7.2 cm. The mean length of the donor nerve was 8.5 cm. Based on our study, use of a tibial-innervated hamstring branch as a donor for nerve transfer to the SGN is feasible.

The Anatomical Course of the Superior Gluteal Nerve With Regard to the Direct Anterior Approach for Primary and Revision Total Hip Arthroplasty

BACKGROUND

During primary and revision total hip arthroplasty (THA) lesions of the superior gluteal nerve (SGN) can substantially compromise patient outcome. For the primary direct anterior approach (DAA) and its proximal approach extensions, especially the muscular branch entering the tensor fasciae latae (TFL) muscle is at risk. SGN lesions can result in fatty atrophy and functional loss of the TFL. Therefore, the course and branching pattern of the SGN were examined and related to the DAA and its proximal approach extension. The aim of the study is to describe safe and danger zones for the SGN with regard to the DAA and its proximal extensions.

METHODS

Twenty-five formalin-fixed cadavers with 48 hemipelves were dissected. The course, distribution, and branching pattern of the SGN and its muscular branch inserting into the TFL muscle were investigated with regard to the DAA with the help of anatomical landmarks like the greater trochanter and the iliac tubercle.

RESULTS

In 72.9% of the specimens the SGN passed the greater sciatic foramen superior to the piriformis muscle with one main trunk. The muscular branch of the SGN supplying the TFL divided from the main branch in 89.6% of the specimens at the level of the greater sciatic foramen. Before entering the TFL muscle the muscular branch showed a variable branching pattern in the interval between the gluteus medius and minimus. A danger zone for the SGN with regard to the DAA was found in the proximal fourth of the skin incision.

CONCLUSION

Special care in proximal instrument placement should be taken during the DAA. When extending the DAA proximally manipulations in the proximal, caudal surgical window should be performed with the utmost care.

Superior gluteal nerve injury following landmark-guided corticosteroid injection for greater trochanteric pain: A case report

This report describes an isolated superior gluteal nerve injection injury following a corticosteroid injection for greater trochanteric pain syndrome. Ultrasound-guided injections may be beneficial to target multiple pain-producing regions of the hip while avoiding nerves and tendons.

Radiofrequency denervation of the hip joint for pain management: case report and literature review

BACKGROUND

A 55-year-old male presented with severe pain and functional limitations as a result of left hip osteoarthritis. He had failed multiple treatments while waiting for a hip arthroplasty, including physical therapy, medications, and various intra-articular injections. Thermal radiofrequency lesioning of the obturator and femoral articular branches to the hip joint was offered in the interim.

OBJECTIVES

To our knowledge, this is the first report to describe an inferior-lateral approach for lesioning the obturator branch, the clinical application of successive lesions to increase denervation area, and outcomes in a patient receiving a second treatment with previously good results.

METHODS

To discuss relevant and technical factors for this specific case, we reviewed previous literature on hip joint radiofrequency and critically evaluated previous anatomic studies in the context of radiofrequency.

RESULTS

The first treatment provided significant benefit for a period of 6 months. A second treatment was employed providing only mild to moderate benefit until his joint replacement surgery 4 months later. Literature review revealed studies of low quality secondary to small sample sizes, patient selection methodology, inclusion of patients with heterogenous etiologies for pain, variable needle placement techniques, and lack of measurement of functional outcomes.

LIMITATIONS

Case report and low quality studies in existing literature.

CONCLUSIONS

Hip joint radiofrequency denervation is a promising avenue for adjunctive treatment of hip pain. Further cadaveric studies are required to clarify a multitude of technical parameters. Once these are well defined, future clinical studies should consider pain, functional, and economic outcomes in their design.