Axial and tangential views of the acromioclavicular joint: the introduction of new projections.

BACKGROUND: Routine anteroposterior radiographs of the acromioclavicular (AC) joint with or without weight bearing have limitations in demonstrating the AC joint. Transarticular fixation with Kirschner wire is a treatment choice for AC dislocations. However, percutaneous fixation of the AC joint is technically demanding. The C-arm fluoroscopy can be used as routine intraoperative guidance to facilitate this procedure. The current study aims to introduce new projections, the axial and tangential views of AC joint, to help evaluate the severity of the injury and facilitate the percutaneous procedure. METHODS: Three shoulder specimens were used to find the projection directions of the axial and tangential views of the AC joint by using the digital radiography (DR) unit. The axial and tangential views were taken of 20 adult volunteers by referencing the projection directions determined in the shoulder specimens. The angles showed on the DR system and the angles between the coronal plane of the body and the vertical plane of the flat panel detector (FPD) during taking these radiographs were recorded. The C-arm fluoroscopy unit was used to take the axial and tangential views referencing the angles measured on the DR system. Routine anteroposterior radiographs of the AC joint were taken on the volunteers. The minimal distances from the distal clavicle to the acromion were measured on both tangential and anteroposterior radiographs. The data was statistically analyzed. RESULTS: The clear axial and tangential radiographs of AC joints of the volunteers were obtained using both DR and C-arm fluoroscopy units. The angles demonstrated on the DR window are (20.8 ± 2.4)° for male and (18.3 ± 2.3)° for female. During taking the axial views, the angles between the coronal plane of the body and vertical plane of FPD are (23.3 ± 3.2)° for male and (20.1 ± 2.4)° for female. During taking tangential views, the corresponding angles are (117.5 ± 3.7)° for male and (113.1 ± 3.3)° for female. On the tangential radiographs, the minimal distance from the distal clavicle to the acromion is (6.1 ± 1.2) mm, wider than the same measurement on the anteroposterior radiographs (P < 0.05). Statistical analyses showed no significant differences in the above-mentioned angles and the minimal distances between the left and right AC joints (P > 0.05). There were no significant differences in the above-mentioned angles between DR and C-arm fluoroscopy units (P > 0.05). CONCLUSIONS: The axial and tangential radiographs of the AC joint can demonstrate the joint clearly and they can be easily obtained with both DR system and C-arm fluoroscopy unit in similar projection directions.

Application of labeled radioimmunoimaging tracing in detecting pulmonary embolism in rabbits after bone cement perfusion and relevant treatment effects.

BACKGROUND: During the process of bone cement joint replacement, some patients show a series of complications, such as a sudden drop in blood pressure or dyspnea. The cause of the complication is considered to be due to emboli caused by the femur prosthesis insertion. The purpose of the present study was to detect the pulmonary embolism in rabbits after bone cement perfusion by radioimmunoimaging, and to explore its protective measures. METHODS: Forty rabbits, 2.5 - 3.0 kg weight, were randomly assigned to four groups, with ten rabbits in each group. Group I (no intervention): Bone cement perfusion was done after medullary cavity reaming and pressurizing. Group II (epinephrine hydrochloride intervention): The medullary cavity was rinsed with a 1:10 000 normal saline-diluted epinephrine hydrochloride solution followed by bone cement perfusion after medullary cavity reaming and pressurizing. Group III (fibrin sealant intervention): The medullary cavity was precoated with fibrin sealant followed by bone cement perfusion after medullary cavity reaming and pressurizing. Group IV (blank control group): The medullary cavity was not perfused with bone cement after reaming. In each group, the rabbits underwent femoral head resection and medullary cavity reaming. Before bone cement perfusion, 2 ml of developing tracer was injected through the ear vein. Radionuclide imaging was performed at 60, 120, and 180 minutes after bone cement perfusion, and the pulmonary radioactivity in vivo was measured. The rabbits were immediately sacrificed, and the pulmonary tissue was removed and its radioactivity was measured in vitro. Pulmonary tissue was then fixed and the pulmonary embolism and the associated pathological changes were observed. RESULTS: The pulmonary radioactivity in vivo was measured at 60, 120, and 180 minutes after bone cement perfusion. The radioactivities of the four groups were 11.67 ± 2.16, 14.59 ± 2.92 and 18.43 ± 4.83 in group I; 8.37 ± 3.05, 10.35 ± 2.24 and 11.48 ± 2.96 in group II; 3.91 ± 1.19, 5.53 ± 2.95 and 7.25 ± 1.26 in group III; 1.04 ± 0.35, 1.14 ± 0.87 and 1.43 ± 0.97 in group IV. The radioactivities of groups I, II, III at 60, 120 and 180 minutes were significantly higher than group IV (P < 0.05). The pulmonary embolism could be detected. Pretreatment with epinephrine hydrochloride and fibrin sealant significantly decreased the pulmonary radioactivity in group II and group III, but it was still higher than in the group IV. CONCLUSIONS: Radioimmunoimaging is an alternative method for the dynamic observation of rabbit pulmonary embolism after bone cement perfusion. Radioimmunoimaging is the optional way to evaluate the effect of pretreatment with epinephrine hydrochloride or fibrin sealant on pulmonary embolism after bone cement perfusion.

Safe drilling angles and depths for plate-screw fixation of the clavicle: avoidance of inadvertent iatrogenic subclavian neurovascular bundle injury.

BACKGROUND: Plate fixation is frequently used to repair clavicle fractures, but over drilling can cause subclavian neurovascular bundle damage. The aims of this study were to investigate the anatomic relationship between the clavicle and subclavian neurovascular bundle and to determine safe drilling angles and depths. METHODS: Twenty-six healthy subjects underwent magnetic resonance imaging. Coronal and sagittal images of the periclavicular region including the whole clavicle and nearby vital anatomic structures were obtained. The clavicle was divided into three sections: section I: between the sternoclavicular joint and point N (where the subclavian neurovascular bundle coursed below the midaxial level of the clavicle); section II: from N to the projection point of the coracoid process to the clavicle (CP'); and section III: from CP' to the acromioclavicular joint. Dangerous drilling depths and angles were determined for each section. RESULTS: In section I, the safe drilling angle was >59.7 degrees cephalad and >95.3 degrees caudad, while safe drilling depth was <17.0 +/- 2.4 mm. Corresponding values in section II were <1.2 degrees caudad and >142.4 degrees caudad. Safe drilling depth was no more than 36.2 mm +/- 12.4 mm. Depth and direction limitations were not assessed for section III, because the neurovascular bundle coursed well below the level of the coracoid process. CONCLUSIONS: We have used magnetic resonance imaging to determine safe drilling directions and depth for plate-screw fixation of the clavicle. On confirmation, these findings could be used in the clinical setting to reduce the risk of inadvertent iatrogenic subclavian neurovascular bundle injury during surgical clavicle fracture repair.

Modified distally based sural nerve flaps in acute traumatic forefeet reconstructions.

Conventional reversed sural flaps have been used to cover lower one-third of the leg defects. However, the experience of the authors indicates that when the soft-tissue defect located at the dorsum of the metatarsophalangeal joint, distal marginal necrosis of the flaps usually occurs, which is the exact part of the flap that one needs the most. Finding a new method to augment the blood supply of the flap can be a difficult task. The authors found there is a constant cutaneous branch emanate from the peroneal artery at the point 11.0 +/- 1.7-cm upon the lateral malleolus. Ten modified distally based reverse sural artery flaps, in which the cutaneous branches from the peroneal artery 11.0 +/- 1.7-cm upon the lateral malleolus were added, were performed for the distal-third of the foot reconstruction between 2003 and 2006. All of the flaps survived completely after the operation. Distal marginal necrosis did not occur in any of the flaps. When conventional local flaps are inadequate, this flap should be considered for its reliability and low associated morbidity.

The role of the calcar femorale in stress distribution in the proximal femur.

OBJECTIVE: To investigate the role of the calcar femorale in stress distribution in the proximal femur. METHODS: Twenty-five specimens of proximal femurs were fixed to simulate single-limb stance. Strain gauges were applied to record the strain under different loads. Strain values of 27 selected sites in the proximal femur were recorded and analyzed at the level of 100 N, 200 N, 300 N, 400 N, 500 N, 600 N and 700 N, respectively before and after disruption of the calcar femorale. RESULTS: When a normal load was being borne, strain values measured in the posterior and medial aspects of the proximal femur were greater than those measured in the anterior and lateral aspects, no matter whether the calcar femorale was disrupted or not. However after disruption of the calcar femorale, strain values in the posterior and medial aspects of the proximal femur increased significantly, whereas those of the anterior and lateral aspects decreased significantly. CONCLUSION: The calcar femorale redistributes stress in the proximal femur by decreasing the load in the posterior and medial aspects and increasing the load in the anterior and lateral aspects.

[Comparison of two kinds of fractures involving posterior malleolar fracture].

OBJECTIVE: To investigate the difference between the spiral tibial shaft fracture combined with ipsilateral posterior malleolar fracture.(TSPMF) and simple ipsilateral posterior malleolar fracture in ankle joint fracture in adults. METHODS: The sex, age, and type and mechanism of fracture of 82 patients with tibial shaft fracture associated with ankle joint fracture (TAF) and 28 patients with tibial shaft spiral fracture associated with ipsilateral posterior malleolar fracture (TSPMF) among 1685 cases of adult tibial and fibular shaft fracture and 330 patients with posterior malleolar fracture among 1871 cases of simple ankle joint fracture were analyzed. RESULTS: The mean age of the 28 cases with TSPMF, 24 males and 4 females, was (41.1 +/- 11.8). The mean age of the 330 cases with simple posterior malleolar fracture, 187 males and 143 females, was (42.6 +/- 15.9). The incidence of posterior malleolar fracture in the TAF patients was 34.1% (28/82), significantly higher than that of the simple ankle joint fracture [17.6%, 330/1871, P = 0.000]. The rate of combined external malleolus and posterior malleolus in the TSPMF patients was 17.9% (5/28), significantly that in the patients with simple ankle joint fracture (73.7%, 159/330, P = 0.000). The fibular fracture line of 75.0% (21/28) of the TSPMF patients was located over the level of the lower tibiofibular ligament union, a rate significantly higher than that in the simple malleolus fracture (24.8%, 82/330, P = 0.000). CONCLUSION: Spiral tibial shaft fracture associated with ipsilateral posterior malleolar fracture is a special kind of fracture; the cause and mechanism of TSPMF are difference from those of the ankle joint fracture.

[Clinical epidemiological analysis of adult spiral tibial shaft fracture associated with ipsilateral posterior malleolar fracture].

OBJECTIVE: To investigate the clinical epidemiological features of adult spiral tibial shaft fracture associated with ipsilateral posterior malleolar fracture, a special kind of fracture. METHODS: The clinical data of 1685 cases of adult tibial and fibular shaft fracture were analyzed retrospectively. The cause and mechanism of spiral tibial shaft fracture associated with ipsilateral posterior malleolar fracture were studied in detail. RESULTS: The male and female ratio in adult tibial and fibular shaft fracture was 4.52:1. Most of adult tibial and fibular shaft fracture occurred in the persons aged 31 - 40 (26.0%) and type A fracture accounted for 57.7% of the cases. The male and female ratio in adult spiral tibial fracture was 2.95:1. Most of the adult spiral tibial fracture occurred in those aged 41 - 50 (32.6%). With a male and female ratio of 6:1 (24:4) and mostly occurring in the persons aged 41 - 50, spiral tibial shaft fracture associated with ipsilateral posterior malleolar fracture composed 9.7% (28/288) of total tibial fractures and 1.7% (28/1685) of total spiral tibial and fibular fractures. Missed diagnosis rate of spiral tibial shaft fracture associated with ipsilateral posterior malleolar fracture was 67.9% (19/28) in the Department of Radiology and 53.6% in the Department of Orthopedics. CONCLUSION: With a high incidence, spiral tibial shaft fracture associated with ipsilateral posterior malleolar fracture was caused by a low energy but not an iatrogenic damage. With a high rate of missed diagnosis, the spiral tibial shaft fracture associated with ipsilateral posterior malleolar fracture should be paid more attention to clinically.

[Treatment of complex calcaneal fractures under computer navigation: report of 130 feet].

OBJECTIVE: To investigate the effects of computer navigation in the treatment of intra-articular calcaneal fractures. METHODS: 130 feet in 110 patients with intra-articular calcaneal fractures, 57 calcanei with fracture of Sander's type II, 45 of type III, and 28 cases of type IV, were treated with internal fixation under computer navigation, and were followed up for 16.3 months (6 - 24 months). RESULTS: According to the Maryland Foot Score system, excellent result was noted in 63 feet, good result in 57 feet, and fair result in 10 feet, with the excellent and good rates being 92.31% together. CONCLUSION: Using computer navigation to treat intra-articular calcaneal fractures is one of the best ways for treatment of calcaneal fractures.