Umut Akgun

Measurement of human gracilis muscle isometric forces as a function of knee angle, intraoperatively.

The goals of the present study were (1) to measure the previously unstudied isometric forces of activated human Gracilis (G) muscle as a function of knee joint angle and (2) to test whether length history effects are important also for human muscle. Experiments were conducted intraoperatively during anterior cruciate ligament (ACL) reconstruction surgery (n=8). Mean peak G muscle force, mean peak G tendon stress and mean optimal knee angle equals 178.5±270.3N, 24.4±20.6 MPa and 67.5±41.7 °, respectively. The substantial inter-subject variability found (e.g., peak G force ranges between 17.2 and 490.5 N) indicate that the contribution of the G muscle to knee flexion moment may vary considerably among subjects. Moreover, typical subject anthropometrics did not appear to provide a sound estimate of the peak G force: only a limited insignificant correlation was found between peak G force and subject mass as well as mid-thigh perimeter and no correlation was found between peak G force and thigh length. The functional joint range of motion for human G muscle was determined to be at least as wide as full knee extension to 120 ° of knee flexion. However; the portion of the knee angle-muscle force relationship operationalized is not unique but individual specific: our data suggest for most subjects that G muscle operates in both ascending and descending limbs of its length-force characteristics whereas, for the remainder of the subjects, its function is limited to the descending limb, exclusively. Previous activity of G muscle at high muscle length attained during collection of a complete set of knee angle-force data showed for the first time that such length history effects are important also for human muscles: a significant correlation was found between optimal knee angle and absolute value of % force change. Except for two of the subjects, G muscle force measured at low length was lower than that measured during collection of knee joint-force data (maximally by 42.3%).

Modified Fulkerson osteotomy in recurrent patellofemoral dislocations

OBJECTIVES We evaluated the results of a modified Fulkerson technique performed for the treatment of recurrent patellofemoral dislocations. METHODS The study included 17 knees of 16 patients (11 males, 5 females; mean age 25 years; range 15 to 43 years) who were operated on by the same surgeon for patellofemoral alignment disorders. The mean duration of complaints was 3.4 years (range 1 to 12 years). Preoperatively, the number of recurring dislocations were 1 to 5 in three knees, 6 to 10 in five knees, and more than 10 in nine knees, and all the patients had a positive apprehension test and a Q angle exceeding 15 degrees. All the knees were assessed by preoperative and postoperative radiographs and computed tomography, which showed both subluxation and patellar tilt in all the knees, and trochlear dysplasia in two knees preoperatively. During surgery, diagnostic arthroscopy was performed in all the patients. The skin incision consisted of two horizontal incisions for cosmetic reasons. Surgical treatment was comprised of lateral patellar release to correct patellar tilt, and a modified Fulkerson osteotomy to correct patellofemoral malalignment, and medial plication in three knees. The patellofemoral congruity following lateral release, and the position of the patella following osteotomy and anteromedialization of the tibial tuberosity were checked arthroscopically. On control examinations, the patients were administered functional scoring questionnaires developed by Kujala et al. and Crosby and Insall. Radiographic grading of osteoarthritis was made according to the classification developed by Iwano et al. and modified by Palmer et al. The mean follow-up period was 2.6 years (range 24 to 53 months). RESULTS During arthroscopy, eight knees had severe (Outerbridge grade III-IV) and nine knees had moderate (grade I-II) retropatellar cartilage damage. Follow-up evaluations showed effusion in two knees, subluxation in two knees, and a positive apprehension test in three knees. The mean flexion loss was 8 degrees (range 0 degrees to 20 degrees ). One patient who had an extension loss of 10 degrees regained full extension following a six-week physical therapy program. Postoperative computed tomography scans showed that patellar tilt and subluxation were corrected in all but two knees. Preoperative radiographies showed degenerative arthritis in the tibiofemoral joint in one knee (5.9%), and in the patellofemoral joint in seven knees (41.2%). The number of knees with degenerative changes increased postoperatively to three knees (17.3%) in the tibiofemoral joint, and to 11 knees (64.7%) in the patellofemoral joint. According to the Crosby-Insall scoring system, five knees had excellent, seven knees had good, and five knees had moderate scores. The mean Kujala score was 82.6 (range 44 to 100) postoperatively. CONCLUSION Our results show that, with appropriate indications, the modified Fulkerson method is associated with successful results in the treatment of recurrent patellofemoral dislocations.

Correlation of basic motor skills with arthroscopic experience

OBJECTIVES One of the methods in motor skill teaching is to furnish the students with the individual skills drawn from the target procedure. This method requires identification and defining of all components of the target procedure. This study aimed to define basic motor skills composing arthroscopic skillfulness. METHODS A total of 42 orthopedists (mean age 38+/-8 years) were enrolled. The study group was comprised of 17 experienced orthopedists working at least for 10 years as a specialist and performing more than 50 arthroscopic procedures per year. The control group included 25 young orthopedists or residents having an arthroscopic experience of less than three years. All the participants were assessed simultaneously and in the same experimental setting. Each participant was tested after having been shown to use in vitro skill development instruments simulating arthroscopic basic motor skills. RESULTS Compared to the control group, the experienced group had significantly higher mean age (42 vs. 34.4 years), longer duration of arthroscopic experience (12.4 vs. 1.6 years), and greater number of the arthroscopies performed per year (93.9 vs. 26.9) (p=0.000). The mean anticipation time (p=0.028) and two-arm coordination time (p=0.043) were significantly shorter in the experienced group. In correlation analysis, duration of arthroscopic experience was correlated with the mean anticipation time (r=-0.41, p=0.008) and two-arm coordination time (r=-0.33, p=0.033). In addition, the mean anticipation time decreased significantly as the number of arthroscopies increased (r=-0.446, p=0.003). CONCLUSION Some basic motor skills correlate with arthroscopic competence. The use of these motor skill instruments in arthroscopy training may aid to improve arthroscopic skills.

Possible reflex pathway between medial meniscus and semimembranosus muscle: an experimental study in rabbits

Meniscus is a well innervated tissue with four types of receptors. These receptors are mainly concentrated at the anterior and posterior horns. Although they are intended to be a part in reflex arc, this function has not been thoroughly evaluated. We hypothesized that electrical stimulation of the normal meniscus would elicit electromyographic activity of the hamstring muscle via the reflex arc. Five adult domestic male rabbits were used in this study. Under general anesthesia, knee arthrotomy and thigh dissection were done to expose medial meniscus and semimembranosus muscle. Menisci were stimulated by Teflon-coated bipolar needle electrodes. Needles were placed in the posterior horn of the medial menisci. Two Teflon-coated monopolar needle electrodes were placed in semimembranosus muscle. A four-channel electromyograph was used for recording. Two different potentials were recorded from the target muscle. The first response had a very short distal latency and its amplitude was changing in accordance with the strength of the stimulus, suggesting that this response was being elicited by direct muscle stimulation. The second delayed response with less amplitude also appeared in some traces. The latency and the amplitude of this second response were fairly stable stating that this delayed response was being generated by a reflex pathway and seen in all subjects.

A case of multiple congenital anomalies including agenesis of the anterior cruciate ligament

Congenital absence of the anterior cruciate ligament (ACL) is a very rare anomaly. It is usually diagnosed during arthroscopic intervention. We presented a 15-year old male patient whose diagnosis was based on findings of physical examination and magnetic resonance imaging. Congenital absence of the ACL was associated with femoral shortening, dysplasia of the tibial intercondylar eminence, valgus knee, and compensatory scoliosis. Since the patient had no instability symptoms, and due to the presence of a negative pivot-shift test and multiple congenital anomalies, surgical treatment was not considered.

The Pretzel knot: a new simple locking slip-knot

Arthroscopic knot tying is an important part of arthroscopic shoulder surgery. The “Pretzel” knot is a new locking slip—knot, which is simple to learn and prepare. It can slide easily to maintain desired tension and can be locked by a simple maneuver.

The effect of organic silicon injection on Achilles tendon healing in rats

OBJECTIVE The aim of this study was to assess the efficacy of a soluble absorbable silicon compound on healing of the Achilles tendon. METHODS The Achilles tendons of 21 Wistar albino rats were cut and repaired. A 0.01 ml organic silicon solution (silanol) was injected peri/intratendinously into the left leg of all rats and the same dose of saline into the right leg postoperatively. Rats were randomly divided into 3 groups for biomechanical testing on Day 10 (7 rats) and Day 20 (7 rats) and histological and immunohistochemical assessment on Day 20 (7 rats). Fibroblast cell count and diameter, tissue vascularity and blood vessel diameter were evaluated by histomorphometry. Basic fibroblast growth factor (bFGF) immunoreactivity was analyzed with immunohistochemistry on Day 20. Failure load and stiffness of the repaired tendons were measured on Days 10 and 20. RESULTS The number of fibroblasts per area, average fibroblast diameter, number of vessels parallel to collagen bundles per area and average vessel diameter were significantly higher in the organic silicon group than in the control group (p<0.05). Strong immunoreactivity of bFGF in the silicon group was detected. Failure load was significantly higher in the silicon group than in the control group on Day 10 (p=0.041). On Day 20, while a difference still existed, this difference was not significant. There was no effect of the silicon injection on stiffness of healing tendons. CONCLUSION Organic silicon appears to have a positive effect on tendon healing and is suitable for further studies on host healing response modification.

Intraoperative measurement of human gracilis muscle isometric forces as a function of knee angle

In this study, it is aimed at measuring for the first time the isometric force of human gracilis (G) muscle as a function of joint angle, intraoperatively. Experiments were conducted during anterior cruciate ligament reconstruction surgery. The knee angle was fixed at 120°, 90°, 60°, 30° and 0° respectively and active isometric forces of this muscle were measured using a buckle force transducer. Limited correlation was found between the anthropometric data of the subjects and the maximal G muscle force. Accordingly, we suggest that in interventions targeting G muscle, a patient specific approach needs to be planned for achieving optimal results. G muscle was shown to be functional for almost all of the knee angle range studied. This result indicates that G muscle contributes to the knee moment for even very low muscle lengths during major daily activities including walking and sit-to-stand motion.

Effect of adjuvant hyperbaric oxygen on healing of cartilage lesions treated with microfracture: an experimental study in rats

Purpose The purpose of this experimental study was to investigate the effect of hyperbaric oxygen (HBO2) therapy combined with microfracture technique in the treatment of cartilage lesions. Methods Adult Wistar rats (n=44) were divided into six groups. In Groups A, B, C and D, ICRS* (* International Cartilage Repair Society) grade 4 cartilage lesions were made on the femoral sulcus of both knees. Lesions were microfractured on the left knees; the right knees had no further procedure. Groups E and F had no surgery. Groups A, C and E received HBO2 therapy once a day, six days a week postoperatively. Groups B, D and F had no HBO2 therapy. The animals in Groups A, B, E and F were sacrificed after two weeks; Groups C and D were sacrificed after four weeks. Semiquantitative scale - including filling of defect (microfracture hole), reparative tissue thickness, cell morphology and subchondral bone maturation - was used for evaluation. The Mann-Whitney test was used to compare individual and total scores. Results Total scores of the two-week group with adjuvant HBO2 therapy were significantly higher (P=0.0007) than the two-week standard treatment group. Except for subchondral bone maturation, individual scores were significantly higher in the two-week group with adjuvant HBO2 therapy. Total scores of the four-week groups were similar. Among individual scores of the four-week groups, filling of the defect (microfracture hole), and subchondral bone maturation were significantly higher (P=0.01, P=0.03) in groups with adjuvant HBO2 therapy. Conclusions Adjuvant HBO2 therapy accelerates the healing process of cartilage lesions treated with microfracture in rats.

Biological Properties of Suture Materials

Suture is a general term for all materials used to stitch torn tissues. Sutures can be synthetic or natural and have a monofilament or braided construction. Through the history of mankind, various materials were tried to serve this purpose. Plants such as flax, hemp, and cotton and animal tissues such as hair, tendon, silk, and intestines are some examples. The oldest, known suture was on a mummy in ancient Egypt on 1100 BC, and the first written description on surgical wound suturing belongs to the Indian physician Sushruta in 500 BC.