Strain Response in the Facet Joint Capsule During Physiological Joint Rotation and Translation Following a Simulated Impact Exposure: an in Vitro Porcine Model

Low back pain (LBP) is frequently reported following rear impact collisions. Knowledge of how the facet joint capsule (FJC) mechanically behaves before and after rear impact collisions may help explain LBP development despite negative radiographic evidence of gross tissue failure. This study quantified the Green strain tensor in the facet joint capsule during rotation and translation range-of-motion tests completed before and following an in vitro simulation of a rear impact collision. Eight FSUs (4 C3-C4, 4 C5-C6) were tested. Following a preload test, FSUs were flexed and extended at 0.5 degrees/second until an ±8 Nm moment was achieved. Anterior and posterior joint translation was then applied at 0.2 mm/s until a target ±400 N shear load was imposed. Markers were drawn on the facet capsule surface and their coordinates were tracked during pre- and post-impact range-of-motion tests. Strain was defined as the change in point configuration relative to the determined neutral joint posture. There were no significant differences (p > 0.05) observed in all calculated FJC strain components in rotation and translation before and after the simulated impact. Our results suggest that LBP development resulting from the initiation of strain-induced mechanoreceptors and nociceptors with the facet joint capsule is unlikely following a severe rear impact collision within the boundaries of physiological joint motion.

Comparison of magnetic resonance imaging and computed tomography for bone assessment of neurogenic heterotopic ossification of the hip: a preliminary study

Background Neurogenic heterotopic ossification (NHO) is a frequent complication, often involving the hip. The functional impact may require surgical management and pre-surgical imaging assessment is necessary, usually by computed tomography (CT). We aimed to compare the performances of magnetic resonance imaging (MRI) and CT for bone assessment on pre-surgical imaging of the heterotopic ossifications and their features in NHO of the hip. Methods This single-center prospective preliminary study included all patients who underwent surgery for NHO with joint limitation from July 2019 to March 2020. All patients had a CT after biphasic iodinated solution injection and an MRI including T1-weighted, STIR and ZTE sequences. Standardized reports were completed for both exams for each patient, evaluating location, implantation and fragmentation of NHO, relation to the joint capsule and bone mineralization, then were compared. Results Seven patients from 32 to 70 years old (mean = 50.2 ± 17.2 years) were evaluated. NHO were bilateral in 2 patients, for a total of nine hips: six right hips and three left hips. Observed concordance rates between MRI and CT were, respectively, 94.4% for location, 100% for circumferential extension, 87.3% for implantation 88.9% for fragmentation, 77.8% for relation to the joint capsule and 66.7% for bone mineralization. It was 100% for femoral neck fracture and osteonecrosis of the femoral head. Conclusion This preliminary study suggests that pre-surgical MRI imaging should be considered as effective as CT for bone assessment of NHO and their features. Trial registration: ClinicalTrials.gov, NCT03832556. Registered February 6, 2019, https://clinicaltrials.gov/ct2/show/NCT03832556.

Application Value of Musculoskeletal Ultrasound in DAA-THA with Conjoined Tendon Repair

Objective: To observe the ultrasonographic characteristics of conjoined tendon repair in direct anterior approach for total hip arthroplasty (DAA-THA), and to evaluate the efficacy of musculoskeletal ultrasound in determining the healing after joint tendon repair. Methods: A total of 60 patients who required primary total hip arthroplasty in Yulin Orthopedic Hospital of Chinese and Western Medicine from July 2020 to July 2021 were selected; the patients were divided into two groups, an observation group, group A (n = 30), and a control group, group B (n = 30), according to different intraoperative methods. There was no significant difference in gender, age, and diagnosis between the two groups. Direct anterior approach was used for both the groups. For group A, the joint capsule and conjoined tendon (superior gemellus, obturator internus, and inferior gemellus) were repaired in situ, whereas for group B, only the joint capsule was repaired in situ, while the conjoined tendon was not repaired. The healing of the tendon was observed. Results: (1) in terms of diagnosis, after conjoined tendon repair, 26 cases in group A showed good tendon continuity, good tension, and a small amount of effusion echo around, three cases showed partial interruption of tendon echo, low echo, or no echo inside with insufficient structural clarity, and a case showed complete interruption; in group B, all 30 cases had continuous interruption, poor tension, tendon retraction, and thickening; the healing rate of group A’s conjoined tendon repair was 96.67%; (2) in terms of prognostic assessment, one month after the surgery, the Harris score of group A was significantly higher than that of group B (P < 0.05); however, there was no significant difference in the terms of the Harris score between the two groups 3-6 months after surgery (P > 0.05); the effective tension of conjoined tendon and the effective muscle strength of group A were significantly higher than those of group B (P < 0.05). Conclusion: Musculoskeletal ultrasound has high diagnostic value in the healing of conjoined tendon and provides dynamic clinical observation after conjoined tendon repair in DAA-THA; it is proven that DAA-THA with conjoined tendon repair on the premise of reconstructing the joint capsule can well restore its tension, enhance its muscle strength, significantly improve early joint stability and joint function, as well as facilitate the rapid recovery of patients.

Spatial distribution of loose connective tissues on the anterior hip joint capsule: a combination of cadaveric and in-vivo study

Recently, pathological changes in the fat pad on the anterior inferior iliac spine (AIIS), between the proximal rectus femoris and joint capsule, have been highlighted as a cause of anterior hip pain. However, precise fat pad features, such as the spatial distribution distal to the AIIS, histological features, and in vivo tissue elasticity, remain unclear. This study aimed to investigate the morphological characteristics of the fat pad on the AIIS. Four hips from four cadaveric donors were both macroscopically and histologically investigated, and eight hips from four volunteers were assessed using ultrasonography. The fat pad on the AIIS was also surrounded by the iliopsoas and gluteus minimus, extending distally to the superficial portion of the vastus lateralis, and the anterior portion of the gluteus maximus tendon. Histological analysis revealed that the fat pad was composed of loose connective tissue. Based on the ultrasonography, the shear wave velocity in the fat pad was significantly lower than that in the joint capsule. Conclusively, the pathological adhesion between the joint capsule and pericapsular muscles, if caused by fat pad fibrosis, may occur following the abovementioned fat pad spatial distribution.

Improved Outside-In Suture through the Joint Capsule to Repair the Palmer I-B Triangular Fibrocartilage Complex Superficial Injury

Background. The treatment of type I-B triangular fibrocartilage complex superficial injury is always a challenge to orthopedists. The traditional outside-in suture method often causes a risk of nervous irritation. We designed a modified outside-in suture through the joint capsule to repair the Palmer I-B triangular fibrocartilage complex superficial injury. Methods. From December 2014 to December 2018, we retrospectively collected the medical records of 18 patients in our hospital who used the modified outside-in suture through the joint capsule to repair type I-B triangular fibrocartilage complex superficial injury. Among them, there were 12 males and 6 females, with an average age of 36.2 years. There were 6 cases on the left side and 12 cases on the right side. Record the healing time of all patients after surgery and the occurrence of related complications, and record the pain visual analogue scale (VAS), grip strength, wrist flexion and extension, radioulnar deviation and forearm rotation range of motion, modified Mayo wrist joint function score, and disability of arm-shoulder-hand (DASH) score before operation and at the last follow-up. Results. One patient was lost to follow-up, and a total of 17 patients received the final follow-up. Patients were followed up for 24 to 36 months, with an average of 29.6 ± 3.0 months. No wound infection, nerve damage, or irritation occurred after the operation. At the last follow-up, 15 cases of wrist pain disappeared completely, and 2 cases had mild discomfort during exercise. At the last follow-up, VAS decreased from 3.8 ± 0.7 points before operation to 0.8 ± 0.7 points ( P < 0.05 ); grip strength increased from 15.1 ± 3.1 kg before operation to 23.2 ± 1.5 kg ( P < 0.05 ); wrist flexion and extension, radioulnar deflection, and forearm rotational mobility increased from 116.3 ± 2.2 °, 37.0 ± 3.5 °, and 141.6 ± 2.2 ° before operation to 117.2 ± 2.5 ° ( P < 0.05 ), 38.9 ± 3.0 ° ( P < 0.05 ), and 142.4 ± 1.9 ° ( P < 0.05 ), respectively; the modified Mayo wrist joint function score increased from 66.1 ± 3.6 points to 82.5 ± 3.9 points ( P < 0.05 ), of which 10 cases were excellent, 5 cases were good, 2 cases were fair, and the excellent and good rate was 88.2%; DASH score improved from 37.0 ± 5.7 points preoperatively to 8.0 ± 2.5 points ( P < 0.05 ). Conclusion. The modified outside-in suture through the joint capsule to repair the superficial injury of Palmer I-B triangular fibrocartilage complex has a good clinical effect and is worthy of clinical widespread promotion.

Acromioclavicular Joint Instability on Cross-Body Adduction View: The Biomechanical Effect of Acromioclavicular and Coracoclavicular Ligaments Sectioning

Background The relationship between acromioclavicular (AC) joint dislocation, corresponding radiological evaluation, and ligament injuries remains controversial. We hypothesized that AC and trapezoid ligament injuries induce AC joint instability, and the clavicle can override the acromion on cross-body adduction view without conoid ligament injury. We aimed to investigate how biomechanically sectioning the AC and coracoclavicular (CC) ligaments contributes to AC joint instability in the cross-body adduction position using fresh-frozen cadaver models. Methods Six fresh-frozen cadaveric shoulders were used in this study, comprising five male and one female specimen, with a mean age of 68.7 (range, 51–87) years). The left side of the trunk and upper limb, and the cervical and thoracic vertebrae and sternum were firmly fixed with an external fixator. The displacement of the distal end of the clavicle relative to the acromion was measured using an electromagnetic tracking device. We simulated AC joint dislocation by sequential resection of AC ligament, AC joint capsule, and CC ligaments in the following order of stages. Stage 0: Intact AC and CC ligaments and acromioclavicular joint capsule; stage 1: Completely sectioned AC ligament and joint disc; stage 2: Sectioned trapezoid ligament; and stage 3: Sectioned conoid ligament. The superior clavicle displacement related to the acromion was measured in the horizontal adduction position, and clavicle overriding on the acromion was assessed radiologically at each stage. Data were analyzed using a one-way analysis of variance and post-hoc tests. Results Superior displacement was 0.3 mm at stage 1, 6.5 mm at stage 2, and 10.7 mm at stage 3. On the cross-body adduction view, there was no distal clavicle overriding at stages 0 and 1, and distal clavicle overriding was observed in five cases (5/6: 83%) at stage 2 and in six cases (6/6: 100%) at stage 3. Conclusion We found that AC and trapezoid ligament sectioning induced AC joint instability and that the clavicle could override the acromion on cross-body adduction view regardless of conoid ligament sectioning. AC and trapezoid ligament injuries may lead to significant AC joint instability, and the distal clavicle may subsequently override the acromion.

ANTEROLATERAL LIGAMENT AS ROTATION STABILISER OF KNEE- JOINT. THE ROLE OF MRT AND ULTRASONOGRAPHY IN UNDERSTANDING ITS ANATOMY AND IN SELECTING SURGICAL TREATMENT STRATEGY FOR ITS INJURIES

Objective. To assess the variability of the anterolateral ligament according to MRT and ultrasonography data and to coordinate it with surgical treatment strategy for its injuries. Methods. The anterolateral ligament was analyzed on 100 series of MRI images of knee joints without traumatic pathology on Philips Achieva 1.5 T tomograph using the standard research protocol in three mutually perpendicular planes and 150 series of MRT images of knee joints with injuries and without injuries of the anterolateral ligament obtained on different tomographs from 0.2 to 3 Tesla. The quality of visualization of anterolateral ligament separate portions, the number of layers, and the contact with the joint capsule were evaluated. Both knee joints were analyzed by ultrasonography in 30 patients with anterior cruciate ligament injuries of one of the knee-joint and in 30 patients with intact knee-joints. Results. During the studies in the identification of anterolateral ligament with magnetic resonance tomography (MRT 1.5T)it was revealed at least partially in 92% of cases (in 68% as a two-layer structure; in 24% as a single-layer structure; in 14% as a thickening of the capsule or in 10% as a separate extracapsular structure), ultrasound examination - in 100% (the structure was not determined, however, in 26.67% of patients without clinically pronounced pathology of the knee-joint and significant trauma in anamnesis ultrasound scan revealed a violation of the integrity of the cortical layer at the tibial attachment site), Conclusion. According to MRT and ultrasonography data, the anterolateral ligament is a constant structure of the knee-joint, but very variable in its anatomical parameters, which in some cases may be poorly visualized on MRT, may have a two-layer structure, may be located either extracapsular or as a thickening of the knee-joint capsule. The variability of its anatomical structure makes it impossible to make the theoretical substantiation of the advantages of one separate method of its restoration, but, on the contrary, justifies a differentiated approach to the selection of optimal surgical treatment. What this paper adds With the help of current research methods, the normal anatomical parameters and anatomical variants of the anterolateral ligament of the knee joint have been clarified and detailed. It is necessary to emphasize the importance of a differentiated approach to choosethe optimal methods of surgical treatment for its injuries.