Surgical repair of an obstetric cloaca with review of the literature.

A complete perineal wound breakdown of a fourth degree laceration leading to a cloaca is a rare but devastating complication of vaginal childbirth. A 32-year-old primiparous woman presented with an obstetric cloaca 4 months following delivery. She underwent preoperative evaluation and, following extensive counselling, elected to proceed with operative repair. The procedure is presented in 15 well-defined steps with photos. The repair was performed in standard fashion with three supplementary steps. These included: (1) division of the rectovaginal tissue into three distinct layers; (2) attachment of these layers individually to the reconstructed perineal body and sphincter and (3) incorporation of the levator muscles into the repair. The wound healed well within 6 weeks of repair. Now 3½ years postoperatively, the patient has no faecal incontinence or sexual dysfunction and only minimal defecatory dysfunction. The discussion describes our surgical approach in the context of a review of the literature.

Effects of cryotherapy on the regeneration process and muscular mechanical properties after lacerative injury model.

Cryotherapy is a therapeutic modality widely used for the treatment of muscle injuries to control pain and inflammatory processes. This study aimed to investigate the effects of cryotherapy on the inflammatory and oxidative stress parameters and mechanical properties of, and pain in, the skeletal muscles of rats with lacerative muscle injury. The rats were anesthetized with 4% isoflurane and subjected to gastrocnemius muscle laceration injury. After injury, all animals in the intervention groups received cryotherapy treatment for 20 minutes using plastic bags containing crushed ice. The protocol comprised three daily applications at 3-hour intervals on the day of injury, with reapplication 24 hours later. Seventy-two male Wistar rats were divided into three groups: sham, muscle injury (MI), and MI + cryotherapy (MI + cryo). Muscle mechanical properties were analyzed by mechanical tensile testing on day 7 after injury. The MI + cryo group showed reduced TNF-α, IFN-γ, and IL1ß levels; elevated IL4, IL6, and IL10 levels; reduced oxidant production and carbonyl levels; and elevated sulfhydryl contents. Animals that underwent tissue cooling showed superoxide dismutase activity and glutathione levels close to those of the animals in the sham group. The MI and MI + cryo groups showed reduced values of the evaluated mechanical properties and lower mechanical thresholds compared to those of the animals from the sham group. Our results demonstrated that the proposed cryotherapy protocol reduced the inflammatory process and controlled oxidative stress but did not reverse the changes in the mechanical properties of muscle tissues or provide analgesic effects within the time frame analyzed.

The effect of a longitudinal tear of the medial meniscus on medial meniscal extrusion in anterior cruciate ligament injury patients.

PURPOSE: The purpose of this study was to investigate the effect of a longitudinal tear of the medial meniscus (MM) and its meniscal repair on MM extrusion in anterior cruciate ligament (ACL)-injured patients. The hypothesis underlying this study was that a longitudinal tear of the MM is correlated with MM extrusion, and that the extrusion would persist after ACL reconstruction with concomitant MM repair. METHODS: Forty-three ACL-injured patients with a concomitant MM longitudinal tear were included in the MM tear group. Thirty-four solely ACL-injured patients without any meniscal injuries were included in the Control group. Medial meniscus extrusion width (MEW) was measured pre-operatively and three months after surgery on magnetic resonance imaging. RESULTS: Pre-operative MEW in the MM tear group was significantly larger than that in the Control group (MM tear group: 1.5 mm, Control: 0.3 mm, P < 0.001). The MEW change in the MM tear group was significantly greater than that in the Control group three months after operation (MM tear group: 0.8 mm, Control: -0.2 mm, P < 0.001). The number of sutures required for repair was correlated with MEW both pre-operatively and postoperatively in the MM tear group (pre-operative: P = 0.005, R = 0.42, postoperative: P < 0.001, R = 0.54). CONCLUSION: Longitudinal tear of the MM was correlated with MM extrusion and the MM extrusion persisted after ACL reconstruction with concomitant MM repair in the MM tear group. The initial meniscal tear size was directly correlated with the pre-operative MEW. Therefore, meniscal extrusion after longitudinal tears of the medial meniscus should be taken into careful consideration.

Clinical Outcomes of Zone 2 Flexor Tendon Repairs Using the Modified Lim/Tsai Technique.

BACKGROUND: The single looped suture modified Lim/Tsai technique is widely used for flexor tendon repairs. It has been shown to possess better biomechanical properties and require less repair time per tendon as compared to the double looped suture original Lim/Tsai technique. However, there is no clinical data on the modified technique. METHODS: The retrospective study included zone 2 flexor tendon repairs made using the modified Lim/Tsai technique from January 2008 to December 2014. Clinical outcome was assessed using the revised Strickland and Glogovac criteria, which categorises repairs based on the total active motion of the repaired digit. RESULTS: Sixty-two patients with 74 digits were included. The overall mean total active motion was 122°. The overall satisfactory outcome of the modified Lim/Tsai technique was 81.1%. The rupture rate of the modified Lim/Tsai technique was 2.7%. Using multivariate linear regression model, we found that outcomes were negatively influenced by subzone 2C and crush/saw injuries, but not by concomitant neurovascular injuries or post-operative follow-up duration. CONCLUSIONS: Based on this retrospective study of patients with zone 2 flexor tendon injuries, the clinical outcomes of modified and original Lim/Tsai techniques are comparable. As such, there is no clinical evidence favouring one over the other.

TRAFFIC ACCIDENT-RELATED OPEN GLOBE INJURIES.

PURPOSE: To evaluate the clinical characteristics and visual outcomes of patients with traffic accident-related open globe injuries, and to examine preoperative factors influencing the visual prognosis after pars plana vitrectomy, as compared with common open globe injuries. METHODS: Patients with open globe injuries, who underwent pars plana vitrectomy, were identified. Patients' demographic and clinical data were entered into a computerized database for review and analysis; data included age, sex, initial visual acuity, duration between onset of injury and surgery, information about the type and cause of injury, wound location and length, presence of ocular complications, and final visual acuity. RESULTS: Of the 355 open globe injuries, 14 were sustained during a traffic-related accident; the average age was 50.4 years (range: 20-85) and most (78.6%) were men. Of these 14 patients, 9 (64.3%) presented with rupture and 5 (35.7%) with laceration. Injuries were caused while driving (6 eyes; 42.9%), riding a bicycle (5 eyes; 35.7%), involved in car accident while walking (2 eyes; 14.3%), and riding a motorbike (1 eye; 7.1%). Initial visual acuity was significantly related to final visual acuity (P = 0.003, R = 0.80). The final visual acuity in patients with traffic accident-related open globe injuries was significantly better than that of the total group (P = 0.01). CONCLUSION: Traffic accident-related open globe injuries had better visual outcomes than common open globe injuries. Visual outcomes in patients with traffic accident-related open globe injuries were related to the initial visual acuity. No eyes developed endophthalmitis in patients with traffic accident-related open globe injuries.

Is the distance from punctum a factor in the anatomical and functional success of canalicular laceration repairs?

PURPOSE: The aim is to analyze the influence of the location of lacrimal canalicular laceration over the eventual anatomical and functional success after surgery. METHODS: Retrospective, observational study of proximal canalicular laceration (PCL) and distal canalicular laceration (DCL) repairs by a single surgeon (MS). The distance between lacrimal punctum and the lateral canalicular lacerated end was defined as proximal (<6 mm) and distal (≥6 mm). The operation theater setup, microscopic magnified view, local adrenaline, and pigtail probe were used to locate the medial canalicular lacerated end. All patients underwent lacrimal stenting and the stents were removed after 3 months (12th week visit). After stent removal, a fluorescein dye disappearance test and lacrimal irrigation were performed to assess the anatomical and functional success of the operation. RESULTS: Of 36 canalicular lacerations, 30 (83.33%) were monocanalicular lacerations which were repaired using monocanalicular stents. Of 6 (16.67%) bicanalicular lacerations, three were repaired using bicanalicular stents while in the remaining three, one monocanalicular stent was placed in each lacerated canaliculi. The medial cut end was identified by magnified visualization in 27 (75%), with adjunctive local adrenaline in four (11.11%) and pigtail probe in five (13.89%) patients. The mean post stent removal follow-up was 44 weeks. The DCL (n = 24, 66.67%) showed better functional and complete success as compared to PCL (75% vs. 33.33%, P = 0.03). Eight (22.22%) had spontaneous stent extrusion, two (5.56%) had loop prolapse, four (11.11%) had punctum granuloma, and three (8.33%) had medial canthus dystopia. CONCLUSION: The location of canalicular laceration may help to prognosticate the functional and qualified success rate. We experienced better-qualified success in the distal canalicular laceration group.

Effects of PDGF-BB delivery from heparinized collagen sutures on the healing of lacerated chicken flexor tendon in vivo.

Flexor tendon lacerations are traditionally repaired by using non-absorbable monofilament sutures. Recent investigations have explored to improve the healing process by growth factor delivery from the sutures. However, it is difficult to conjugate growth factors to nylon or other synthetic sutures. This study explores the performance of a novel electrochemically aligned collagen suture in a flexor tendon repair model with and without platelet derived growth factor following complete tendon laceration in vivo. Collagen suture was fabricated via electrochemical alignment process. Heparin was covalently bound to electrochemically aligned collagen sutures (ELAS) to facilitate affinity bound delivery of platelet-derived growth factor-BB (PDGF-BB). Complete laceration of the flexor digitorum profundus in the third digit of the foot was performed in 36 skeletally mature White Leghorn chickens. The left foot was used as the positive control. Animals were randomly divided into three groups: control specimens treated with standard nylon suture (n=12), specimens repaired with heparinated ELAS suture without PDGF-BB (n=12) and specimens repaired with heparinated ELAS suture with affinity bound PDGF-BB (n=12). Specimens were harvested at either 4weeks or 12weeks following tendon repair. Differences between groups were evaluated by the degree of gross tendon excursion, failure load/stress, stiffness/modulus, absorbed energy at failure, elongation/strain at failure. Quantitative histological scoring was performed to assess cellularity and vascularity. Closed flexion angle measurements demonstrated no significant differences in tendon excursion between the study groups at 4 or 12weeks. Biomechanical testing showed that the group treated with PDGF-BB bound heparinated ELAS suture had significantly higher stiffness and failure load (p<0.05) at 12-weeks relative to both heparinated ELAS suture and nylon suture. Similarly, the group treated with PDGF-BB bound suture had significantly higher ultimate tensile strength and Young's modulus (p<0.05) at 12-weeks relative to both ELAS suture and nylon suture. Compared to nylon controls, heparinized ELAS with PDGF-BB improved biomechanics and vascularity during tendon healing by 12-weeks following primary repair. The ability of ELAS to deliver PDGF-BB to the lacerated area of tendon presents investigators with a functional bioinductive platform to improve repair outcomes following flexor tendon repair. STATEMENT OF SIGNIFICANCE: A high strength aligned collagen suture was fabricated via linear electrocompaction and heparinized for prolonged delivery of PDFG-BB. When it was used to suture a complete lacerated flexor tendon in a chicken model controlled release of the PDGF-BB improved the strength of treated tendon after 12 weeks compared to tendon sutured with commercial nylon suture. Furthermore, Collagen suture with affinity bound PDGF-BB enhanced the vascularization and remodeling of lacerated tendon when it compare to synthetic nylon suture. Overall, electrocompacted collagen sutures holds potential to improve repair outcome in flexor tendon surgeries by improving repair strength and stiffness, vascularity, and remodeling via sustained delivery of the PDGF-BB. The bioinductive collagen suture introduces a platform for sustained delivery of other growth factors for a wide-array of applications.

Early Versus Late Canalicular Laceration Repair Outcomes.

PURPOSE: To determine whether delayed repair of traumatic canalicular laceration affects the final outcome. DESIGN: Retrospective case series. METHODS: The medical records of 334 patients who underwent primary traumatic canalicular laceration repair were retrospectively reviewed. Patients were divided into 2 groups according to the surgical timing within 48 hours (early) or after 48 hours (delayed). The anatomic results were compared between these 2 groups. The causes of delayed repair and the mean operation time were also analyzed. RESULTS: There were 23 failed cases among 301 patients (7.6%) who had a repair within 48 hours and 3 failed cases among 33 patients (9.1%) who had a repair after 48 hours (P = .732). The mean operation time was 62 minutes in the early group and 66.3 minutes in the delayed group, which showed no significant difference (P = .371). The major cause of delayed surgery was traumatic brain injury, followed by facial or orbital fracture, long bone fracture, and chest injury. CONCLUSIONS: Delayed canalicular repair in unstable patients did not lead to poor results. An elective scheduling surgery, instead of an urgent repair, is feasible for an experienced surgeon.

In Silico and In Vivo Experiments Reveal M-CSF Injections Accelerate Regeneration Following Muscle Laceration.

Numerous studies have pharmacologically modulated the muscle milieu in the hopes of promoting muscle regeneration; however, the timing and duration of these interventions are difficult to determine. This study utilized a combination of in silico and in vivo experiments to investigate how inflammation manipulation improves muscle recovery following injury. First, we measured macrophage populations following laceration injury in the rat tibialis anterior (TA). Then we calibrated an agent-based model (ABM) of muscle injury to mimic the observed inflammation profiles. The calibrated ABM was used to simulate macrophage and satellite stem cell (SC) dynamics, and suggested that delivering macrophage colony stimulating factor (M-CSF) prior to injury would promote SC-mediated injury recovery. Next, we performed an experiment wherein 1 day prior to injury, we injected M-CSF into the rat TA muscle. M-CSF increased the number of macrophages during the first 4 days post-injury. Furthermore, treated muscles experienced a swifter increase in the appearance of PAX7+ SCs and regenerating muscle fibers. Our study suggests that computational models of muscle injury provide novel insights into cellular dynamics during regeneration, and further, that pharmacologically altering inflammation dynamics prior to injury can accelerate the muscle regeneration process.

Models of wound healing: an emphasis on clinical studies.

BACKGROUND: The healing of wounds has always provided challenges for the medical community whether chronic or acute. Understanding the processes which enable wounds to heal is primarily carried out by the use of models, in vitro, animal and human. It is generally accepted that the use of human models offers the best opportunity to understand the factors that influence wound healing as well as to evaluate efficacy of treatments applied to wounds. OBJECTIVES: The objective of this article is to provide an overview of the different methodologies that are currently used to experimentally induce wounds of various depths in human volunteers and examines the information that may be gained from them. METHODS: There is a number of human volunteer healing models available varying in their invasiveness to reflect the different possible depth levels of wounds. RESULTS: Currently available wound healing models include sequential tape stripping, suction blister, abrasion, laser, dermatome, and biopsy techniques. The various techniques can be utilized to induce wounds of variable depth, from removing solely the stratum corneum barrier, the epidermis to even split-thickness or full thickness wounds. CONCLUSION: Depending on the study objective, a number of models exist to study wound healing in humans. These models provide efficient and reliable results to evaluate treatment modalities.

Skin property can predict the development of skin tears among elderly patients: a prospective cohort study.

The aim of this study was to identify skin properties that may be used to predict the development of a skin tear (ST) among elderly patients. A prospective cohort study was conducted among elderly patients aged 65 and older (N = 149) at a long-term medical facility in Japan over an 8-month period. Skin properties at baseline were measured on the forearm using a 20-MHz ultrasound scanner, which measured the thickness of the dermis layer and low-echogenic pixels, and skin blotting method, which evaluated the levels of collagen type IV, matrix metalloproteinase-2 and tumour necrosis factor-alpha. Adjusted hazard ratios (HRs) for the main confounders were obtained using the Cox proportional hazard model. A total of 52 STs were recorded among the 21 patients, resulting in an incidence rate of 1·13/1000 person-days. The predictor of STs was dermis thickness (HR = 0·52; 95% confidence interval = 0·33-0·81; P-value = 0·004). The cut-off point for dermis thickness was 0·80 mm (area under the curve = 0·77; 95% confidence interval = 0·66-0·88; P-value = 0·006). Our results suggest that measuring the dermis thickness at baseline is an easy and accurate way to identify a high-risk patient.

Trauma versus no trauma: an analysis of the effect of tear mechanism on tendon healing in 1300 consecutive patients after arthroscopic rotator cuff repair.

BACKGROUND: Patients with rotator cuff tears often recall a specific initiating event (traumatic), whereas many cannot (nontraumatic). It is unclear how important a history of trauma is to the outcomes of rotator cuff repair. METHODS: This question was addressed in a study cohort of 1300 consecutive patients who completed a preoperative questionnaire regarding their shoulder injury and had a systematic evaluation of shoulder range of motion and strength, a primary arthroscopic rotator cuff repair performed by a single surgeon, an ultrasound scan, and the same subjective and objective measurements made of their shoulder 6 months after surgery. Post hoc, this cohort was separated into 2 groups: those who reported no history of trauma on presentation (n = 489) and those with a history of traumatic injury (n = 811). RESULTS: The retear rate in the group with no history of trauma was 12%, whereas that of the group with a history of trauma was 14% (P = .36). Those patients with a history of shoulder trauma who waited longer than 24 months had higher retear rates (20%) than those who had their surgery earlier (13%) (P = .040). CONCLUSION: Recollection of a traumatic initiating event had little effect on the outcome of arthroscopic rotator cuff repair. Duration of symptoms was important in predicting retears if patients recalled a specific initiating event but not in patients who did not recall any specific initiating event. Patients with a history of trauma should be encouraged to have their rotator cuff tear repaired within 2 years.

Combined Subscapularis Tears in Massive Posterosuperior Rotator Cuff Tears: Do They Affect Postoperative Shoulder Function and Rotator Cuff Integrity?

BACKGROUND: Previous studies on massive rotator cuff tears have not addressed the outcomes of tears extending to the subscapularis tendon. HYPOTHESIS: The retear rate in patients with a massive posterosuperior rotator cuff tear combined with a subscapularis tear is higher than that in patients with a massive posterosuperior rotator cuff tear with an intact subscapularis tendon. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Data were collected and analyzed from 92 consecutive patients who underwent arthroscopic repair of a massive posterosuperior rotator cuff tear. Patients were divided into 3 groups according to the status of the subscapularis tendon: intact subscapularis tendon (I-massive tear; n = 42), tear involving half or less than half of the subscapularis tendon (S-massive tear; n = 22), and tear involving more than half of the subscapularis tendon (L-massive tear; n = 28). The integrity of the rotator cuff was determined by ultrasonography at 4.5 and 12 months or later after surgery. Clinical evaluations were performed using the visual analog scale (VAS) pain score, the American Shoulder and Elbow Surgeons (ASES) score, the Constant score, and active shoulder range of motion. Data were collected on the day before surgery and at final follow-up (at least 24 months postoperatively). RESULTS: A total of 25 retears (27%) were identified based on an ultrasonographic evaluation. Although statistical significance was not found, there was a trend toward a higher retear rate in patients with an L-massive tear (43%) compared with those with an S-massive tear (18%; P = .050) or I-massive tear (21%; P = .059) at final follow-up. The subclassification of retears according to the involved tendons revealed that subsequent retears of the subscapularis tendon were noted only in patients with an L-massive tear. In patients with an L-massive tear, postoperative data comparison between patients with intact subscapularis tendons and those with failed subscapularis tendons revealed that a significant difference was noted in the VAS (1.1 vs 3.8, respectively) and ASES (90.6 vs 58.5, respectively) scores. The improvement in clinical scores after repair was statistically significant in all groups but not different between the groups. CONCLUSION: The arthroscopic repair of massive tears results in substantial improvements in shoulder function, regardless of the presence of combined subscapularis tears. However, this study showed a trend toward a high failure rate for the repair of massive posterosuperior rotator cuff tears extending over half of the subscapularis tendon. Therefore, other treatment options should also be considered for this type of rotator cuff tear.

Biomechanical comparison of arthroscopic repair constructs for radial tears of the meniscus.

BACKGROUND: Radial tears of the meniscus represent a challenging clinical scenario because benign neglect and partial meniscectomy have both been shown to have negative biomechanical and long-term clinical consequences. HYPOTHESIS: Complex suture repair constructs have higher failure loads and stiffness values compared with simple constructs. STUDY DESIGN: Controlled laboratory study. METHODS: After radial transection of human cadaveric menisci, simulated tears were repaired arthroscopically by use of 1 of 4 repair constructs: (1) 2 inside-out horizontal sutures, (2) 2 all-inside horizontal sutures, (3) an all-inside Mason-Allen construct consisting of 4 sutures, or (4) an all-inside construct consisting of a figure-of-8 suture plus 1 horizontal suture. Meniscus specimens were harvested and tested to failure on an Instron machine. The Kruskal-Wallis test was used to evaluate for significance of maximal failure load and stiffness between groups. RESULTS: The mean maximum failure loads were 64 ± 20 N (inside-out horizontal construct), 75 ± 16 N (all-inside horizontal construct), 86 ± 19 N (Mason-Allen construct), and 113 ± 22 N (figure-of-8 plus horizontal construct). Interconstruct comparison revealed a statistically significant difference between the figure-of-8 plus horizontal construct and all 3 remaining constructs (P < .02) as well as the Mason-Allen construct when compared with the inside-out horizontal construct (P < .01). Statistical significance was not found between the all-inside horizontal construct and the Mason-Allen construct or between the all-inside horizontal construct and the inside-out horizontal construct (P = .2 and .7, respectively). Stiffness values were lower for the inside-out construct compared with the all-inside constructs (P < .05). CONCLUSION: Complex all-inside repair constructs had significantly higher failure loads than a conventional, simple inside-out suture repair construct for repair of radial meniscal tears. Stiffness values among the all-inside groups were greater than those for the inside-out group. CLINICAL RELEVANCE: Arthroscopic techniques are presented to produce stronger radial meniscal tear repairs.

Effects of Remnant Tissue Preservation on Clinical and Arthroscopic Results After Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction.

BACKGROUND: Clinical utility of remnant tissue preservation after single-bundle anterior cruciate ligament (ACL) reconstruction has not been established. In addition, no studies have evaluated the clinical utility of remnant preservation after anatomic double-bundle ACL reconstruction. HYPOTHESIS: The study hypotheses were as follows: (1) Subjective and functional clinical results may be comparable between anatomic double-bundle reconstructions that preserve the remnant tissue and those that resect the remnant tissue, (2) postoperative knee stability and the second-look arthroscopic evaluation may be significantly more favorable with the remnant-preserving reconstruction, and (3) the degree of the initial graft coverage may significantly affect postoperative knee stability. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: A total of 179 patients underwent anatomic double-bundle ACL reconstruction. Based on the Crain classification of ACL remnant tissue, 81 patients underwent the remnant-preserving procedure (group P) and the remaining 98 patients underwent the remnant-resecting procedure (group R). There were no differences between the 2 groups concerning all background factors, including preoperative knee instability and intraoperative tunnel positions. The patients were followed for 2 years or more. RESULTS: The subjective and functional clinical results were comparable between the 2 reconstruction procedures. Side-to-side anterior laxity was significantly less (P = .0277) in group P (0.9 mm) than in group R (1.5 mm). The pivot-shift test was negative in 89% of group P and 78% of group R patients; the result for group R was significantly lower (P = .0460). In the arthroscopic observations, results for group P were significantly better than for group R concerning postoperative laceration and fibrous tissue coverage of the grafts (P = .0479). CONCLUSION: Remnant preservation in anatomic double-bundle ACL reconstruction did not significantly improve subjective and functional results in the short-term evaluation, but it significantly improved postoperative knee stability. The degree of initial graft coverage significantly affected postoperative knee stability.

Effect of tear location on propagation of isolated supraspinatus tendon tears during increasing levels of cyclic loading.

BACKGROUND: The morphology of the supraspinatus tendon may affect tear propagation. It was hypothesized that tears located in the anterior third of the supraspinatus tendon would propagate more readily and would require lower loads to reach critical amounts of tear propagation than those located in the middle third of the supraspinatus tendon. METHODS: Twenty-three fresh-frozen human cadaveric shoulders were tested under increasing levels of cyclic loading. Tears were created in the anterior third (Group A, n=10) or the middle third (Group M, n=13) of the supraspinatus tendon. The maximum load at which a critical tear retraction was reached and the tear area for the final loading set were compared between groups. A correlation analysis was also performed for age compared with maximum load. RESULTS: No significant differences were found between the anterior-third tear group (Group A) and the middle-third tear group (Group M) in maximum load (p=0.09) or tear area (p=0.6). However, Group A first reached a 100% increase in tear size at a significantly lower load than Group M (p=0.03). Strong negative correlations were detected between age and maximum load in Group A (τ=-0.82) and Group M (r=-0.63). CONCLUSIONS: Other factors being equal, tears in the anterior supraspinatus tendon may propagate more readily than tears in the tendon's middle part. Age may be a factor for tear propagation. CLINICAL RELEVANCE: Older patients and patients with tears in the anterior supraspinatus should be followed especially carefully.

Laceration in rat gastrocnemius. Following-up muscle repairing by ultrasound biomicroscopy (in vivo), contractility test (ex vivo) and histopathology.

PURPOSE: Implement a laceration protocol of the rat lateral gastrocnemius (LG) and following-up its repair with ultrasound biomicroscopy (UBM), contractility tests and histology. METHODS: Sixty-three male Wistar rats were distributed into two groups. One, with sub-groups GI, GII and GIII (n=12), each containing right LG lacerated (n=6), control and sham (n=3) animals. LG muscles in GI, GII and GIII were inspected by UBM (40 MHz) immediately after, 14 and 28 days post-surgery and thereafter excised with four (GI), 14 (GII) and 28 (GIII) days post-surgery for histology. Animals in second group were distributed into right LG lacerated and control sub-groups. LG muscles in lacerated sub-group were submitted to contractility tests at four (n=8), 14 (n=8) and 28 (n=8) days post-surgery, while in the control sub-group (n=5) were submitted to contractility tests along the course of the experiments. RESULTS: Descriptive findings agreed between the lesion model, muscle repair, UBM images and histology. Contractility results for right LG were different (p<0.05) between control and injured muscle with four and 14 days post-surgery, at tetanic stimulating frequencies (50 and 70 Hz). CONCLUSION: A laceration protocol of the lateral gastrocnemius was implemented and ultrasound biomicroscopy, contractility and histology findings agreed regarding the following-up of injured muscle repair.