The deep gluteal (piriformis) syndrome

Piriformisa syndrome is a subgroup of the deep gluteal syndrome, an important differential diagnosis of sciatica. Piriformis is a short external rotator muscle of the hip joint passing close to the sciatic nerve as it passes through the great sciatic foramen. Compression causes numbness, ache or tingling in the buttocks, posterolateral aspect of the leg and foot. The causes of sciatic nerve entrapment in the deep gluteal syndrome are best shown by endoscopic exploration. The frequency of anatomical variants in normal subjects however, should caution that such anomalies are not necessarily the cause of symptoms.

Comparison of postoperative effectiveness of less invasive short external rotator sparing approach versus standard posterior approach for total hip arthroplasty

Background: Most of the studies assessing the corrective posterior total hip arthroplasty (THA) mainly focused on the mini-incision approach. Studies exploring the short external rotator sparing approach are rare. Therefore, this study aimed to compare the effectiveness of standard posterior approach and short external rotator sparing approach.Methods: This prospective observational study included 126 patients who underwent THAin 06/2017-06/2018. Patients were assigned to standard (standard posterior approach) and corrective (short external rotator sparing approach) groups based on the surgical method. Surgical data were recorded postoperatively. Postoperative hip joint recovery was assessed using the times to ambulation and independent stair use, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, Harris score, and Oxford hip score (OHS) at 2 and 8 postoperative weeks. The visual analog scale (VAS) was used for postoperative pain assessment.Results: Postoperative changes of creatine kinase (CK), myoglobin, CRP, and prosthesis position were similar in both groups (P > 0.05). However, intraoperative blood loss (P < 0.001) and postoperative 6-hour drainage volume (P = 0.03), hospital stay, blood transfusion rate, and times to ambulation and independent stair use were significantly reduced in the corrective group. Postoperatively, Oxford and WOMAC scores significantly decreased in both groups. After surgery, the VAS score was more overtly decreased in the corrective group compared with the standard group.Conclusions: This study concluded that the less invasive short external rotator sparing approach for THA caused less damage, reducing perioperative blood loss, shortening functional recovery time, maintaining prosthesis stability, and improving postoperative pain.

Comparison of postoperative effectiveness of less invasive short external rotator sparing approach versus standard posterior approach for total hip arthroplasty

Background Studies assessing corrective posterior total hip arthroplasty (THA) mostly focused on the mini-incision approach, with few exploring the short external rotator sparing approach. This study aimed to compare the effectiveness of standard posterior approach versus short external rotator sparing approach. Methods This prospective observational study included patients treated in the Orthopedics Department of Jinhua Central Hospital in 06/2017-06/2018. Patient grouping was based on the surgical methods. Surgical data were recorded postoperatively. Postoperative hip joint recovery was assessed by the times to ambulation and independent stair use, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score and Harris score and Oxford hip score (OHS) at 2 and 8 postoperative weeks. The visual analog scale (VAS) was used for postoperative pain assessment. Results Postoperative changes of creatine kinase (CK), myoglobin, CRP, and prosthesis position were similar in both groups. However, intraoperative blood loss and postoperative 6-h drainage volume, hospital stay, and blood transfusion rate were significantly reduced in the corrective (short external rotator sparing) group, as well as times to ambulation and independent stair use. Oxford and WOMAC scores in both groups decreased significantly postoperatively. The VAS score was more overtly decreased postoperatively in the corrective group compared with the standard group. Conclusions The corrective THA causes less damage and reduces perioperative blood loss, shortening functional recovery time, maintaining prosthesis stability and improving pain postoperatively.

Bipolar hip arthroplasty in geriatric patients using a conjoined tendon-preserving posterior approach

Background In bipolar hemiarthroplasty (BHA), it is important to preserve soft tissue to reduce the risk of postoperative dislocation. While a variety of surgical approaches have been reported recently, extra care is needed with muscle- and tendon-preserving approaches in geriatric patients due to the fragility of their soft tissue. We investigated the usefulness of BHA using a conjoined tendon-preserving posterior (CPP) approach, which only dissects the external obturator muscle, in geriatric patients. Methods This retrospective study included 40 femoral neck fracture patients (10 men, 30 women) aged ≥ 80 years who underwent BHA using the CPP approach. The average age of the subjects was 85.8 years (80–94 years). We examined operation time, bleeding, preservation of short external rotator muscles, complications, and stem alignment and subsidence from postoperative radiographs. Results Although, gemellus inferior muscle injury was detected in 4 patients (10%), hip joint stability was very excellent in all cases. There was no intraoperative fracture and postoperative dislocation. On postoperative radiographs, all femoral stems were in a neutral position. There was no stem subsidence in all the patients. Conclusions BHA using the CPP approach was not associated with postoperative dislocation and appeared to be useful even in geriatric patients with soft tissue fragility.

Architecture of the Short External Rotator Muscles of the Hip

Background Muscle architecture, or the arrangement of sarcomeres and fibers within muscles, defines functional capacity. There are limited data that provide an understanding of hip short external rotator muscle architecture. The purpose of this study was thus to characterize the architecture of these small hip muscles. Methods Eight muscles from 10 independent human cadaver hips were used in this study (n = 80 muscles). Architectural measurements were made on pectineus, piriformis, gemelli, obturators, quadratus femoris, and gluteus minimus. Muscle mass, fiber length, sarcomere length, and pennation angle were used to calculate the normalized muscle fiber length, which defines excursion, and physiological cross-sectional area (PCSA), which defines force-producing capacity. Results Gluteus minimus had the largest PCSA (8.29 cm2) followed by obturator externus (4.54 cm2), whereas superior gemellus had the smallest PCSA (0.68 cm2). Fiber lengths clustered into long (pectineus - 10.38 cm and gluteus minimus - 10.30 cm), moderate (obturator internus - 8.77 cm and externus - 8.04 cm), or short (inferior gemellus - 5.64 and superior gemellus - 4.85). There were no significant differences among muscles in pennation angle which were all nearly zero. When the gemelli and obturators were considered as a single functional unit, their collective PCSA (10.00 cm2) exceeded that of gluteus minimus as a substantial force-producing group. Conclusions The key findings are that these muscles have relatively small individual PCSAs, short fiber lengths, and low pennation angles. The large collective PCSA and short fiber lengths of the gemelli and obturators suggest that they primarily play a stabilizing role rather than a joint rotating role.

Bipolar hip arthroplasty in geriatric patients using a conjoined tendon-preserving posterior approach

Background In bipolar hemiarthroplasty (BHA), it is important to preserve soft tissue to reduce the risk of postoperative dislocation. While a variety of surgical approaches have been reported recently with this in mind, extra care is needed with muscle- and tendon-preserving approaches in geriatric patients due to the fragility of their soft tissue. We investigated the usefulness of BHA using a conjoined tendon-preserving posterior (CPP) approach, which only dissects the external obturator muscle, in geriatric patients. Methods This retrospective study included 40 femoral neck fracture patients (10 men, 30 women) aged ≥80 years who underwent BHA using the CPP approach. The average age of the subjects was 85.8 years (80 - 94 years). We examined operation time, bleeding, preservation of short external rotator muscles, complications, and stem alignment and subsidence from postoperative radiographs. Results Although, gemellus inferior muscle injury was detected in 4 patients (10%), hip joint stability was very excellent in all cases. There was no intraoperative fracture and postoperative dislocation. On postoperative radiographs, all femoral stems were in a neutral position. There was no stem subsidence in all the patients. Conclusions BHA using the CPP approach was not associated with postoperative dislocation and appeared to be useful even in geriatric patients with soft tissue fragility.