BackgroundThe mid-substance central defect injury has been used to investigate the primary healing capacity of the anterior cruciate ligament (ACL) in a goat model. The sagittal plane stability on this model has not been confirmed, and possible effects of fat pad excision on healing have not been evaluated. We hypothesize that excising the fat pad tissue results in poorer ligament healing as assessed histologically and decreased tensile strength of the healing ligament. We further hypothesize that the creation of a central defect does not affect sagittal plane knee stability.MethodsA mid-substance central defect was created with a 4-mm arthroscopic punch in the ACLs of right knees of all the subjects through a medial mini-arthrotomy. Goats were assigned to groups based on whether the fat pad was preserved (group 1, n = 5) or excised completely (group 2, n = 5). The left knees served as controls in each goat. Histopathology of the defect area along with measurement of type I collagen in one goat from each group were performed at 10th week postoperatively. The remaining knees were evaluated biomechanically at the 12th week, by measuring anterior tibial translation (ATT) of the knee joints at 90° of flexion and testing tensile properties (ultimate tensile load (UTL), ultimate elongation (UE), stiffness (S), failure mode (FM)) of the femur-ACL-tibia complex.Results and discussionHistopathology analysis revealed that the central defect area was fully filled macroscopically and microscopically. However, myxoid degeneration and fibrosis were observed in group 2 and increased collagen type I content was noted in group 2. There were no significant differences within and between groups in terms of ATT values (p = 0.715 and p = 0.149, respectively). There were no significance between or within groups in terms of ultimate tensile load and ultimate elongation; however, group 2 demonstrated greater stiffness than group 1 that was correlated with the fibrotic changes detected microscopically (p = 0.043).ConclusionsThe central defect type injury model was confirmed to be biomechanically stable in a goat model. Resection of the fat pad was noted to negatively affect defect healing and increase ligament stiffness in the central defect injury model.

We present the treatment course of a 29-year-old male patient with for a Type 3 FDP avulsion (Jersey's finger) of a fifth finger treated with umbrella handle technique. The patient had a volar base fracture of distal phalanx with dorsal subluxation of DIP joint after a fall. Following open reduction of the FDP avulsion fracture and fixation was achieved with a 0.9 mm one edge hooked Kirschner wire under fluoroscopy control. The straight edge of the wire was driven out in a central position in sterile nail matrix just distal to lunula. The wire was removed at the fifth week when the complete union of the fracture was observed. The patient achieved full flexion in DIP joint without an extension lag.

Objectives:The aim of this study is to investigate the primary healing capacity of the anterior cruciate ligament (ACL) and the possible effect of fat pad excision on it. For this purpose, a central defect type ACL injury model was performed. Histopathological and biomechanical studies were performed on this model.Methods:Total of ten female adolescent Anatolian Black Goats were included in the study. A midsubstance central defect was created successfully with a four mm. arthroscopic punch in the ACLs of right knees of all the subjects through a medial mini-arthrotomy and goats were assigned to groups whether the fat pad was preserved (group I, n=5) or excised completely (group II, n=5). The left knees served as control. The histopathological evaluations of the defect area were performed utilizing Hematoxylene-Eosine, Masson Trichrome, Van Gieson, and elastic Van Gieson staining as well as measurement of type I collagen immunohistochemically in one sample from each group at 10th week postoperatively. The remaining knees were evaluated biomechanically at the 12th week, measuring anterior tibial translation (ATT) of the knee joints at 90 degrees of flexion and tensile properties (Maximum Tensile Load (MTL), Maximum Elongation (ME), Stiffness (S), failure mode (FM)) of the femur-ACL-tibia complex. Statistical analysis was performed utilizing SPSS v18 package program. Mann – Whitney U and Wilcoxon’s signed rank test were used for inter and intragroup analysis, respectively. Statistical significance was set at 0.05.Results:Histopathological analysis revealed that the central defect area was fully filled macroscopically and microscopically. However, mucoid degeneration was observed in group II. Relative collagen type I content increased in group II. There was no significant difference both within and between groups in terms of ATT values (p=0.715 and p=0.149 respectively). There was no statistical significance between and within groups in terms of MTL and ME; however group II demonstrated greater stiffness than group I (p=0,043) Overall (n=16 knees), tibial avulsion was the commonest mode of failure (n=9) in both control and operated knees.Conclusion:These findings revealed that the central defect type partial ACL injury model acted stable on A-P direction and had full healing capacity. The excision of the fat-pad had no additional effect except increased stiffness. Tibial insertion site seemed to be the weakest portion of the femur-ACL-tibia complex in adolescent goat knees.

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