Effects of glenoid component version on humeral head displacement and joint reaction forces: an experimental study

The purpose of this study was to determine whether changes in glenoid version are associated with humeral head displacement and changes in the joint reaction forces, as these might contribute to instability or loosening in total shoulder replacement. A total shoulder prosthesis was implanted in neutral version in 6 cadaveric shoulders. Glenoid version was then changed in steps of 4 degrees toward more anteversion and retroversion. An increase in anteversion resulted in anterior translation of the humeral head and in eccentric loading of the anterior part of the glenoid. Retroversion was associated with posterior displacement and posterior loading of the glenoid. A change in rotation of the humeral component did not compensate for altered version of the glenoid component. These results suggest that both instability and glenoid component loosening may be related to the version of the glenoid component. Therefore, assessment of loosening and instability justifies precise assessment of glenoid component version.

[The AO/ASIF Flexnail : A flexible intramedullary nail for the treatment of humeral shaft fractures]

BACKGROUND: The use of conventional implants for intramedullary nailing of humeral shaft fractures is associated with specific difficulties. During antegrade implantation structures of the rotator cuff can be affected leading to a reduced functional result of the shoulder. If the nail is implanted in a retrograde manner problems arise due to a relatively large hole close to or within the olecranon fossa, which is necessary for insertion of the nail. Supracondylar fractures as well as persistent elbow pain and loss of function are reported in the literature. To overcome these disadvantages a flexible nail has been developed that can be stiffened and locked after implantation. METHOD: Between October 2000 and February 2002, 34 patients were treated with the flexible nail at our institution; 29 were available for follow-up. Fracture healing was documented on radiographs and clinical outcome was evaluated with use of the Constant as well as the Kwasny score. RESULTS: Median duration until fracture consolidation was 10 weeks. In two patients fracture union was not achieved within the follow-up period. The median outcome measured with the Constant score was 93 points and 2.5 with the Kwasny score. Both values correspond to a very good functional outcome. CONCLUSION: We conclude that the flexible humeral nail is an excellent treatment option for humeral shaft fractures. Damage to the rotator cuff and the distal humerus can be avoided due to its unique flexible construction, improving the functional outcome of intramedullary nailing for the treatment of humeral shaft fractures.

Reattachment of the tuberosities with cable wires and bone graft in hemiarthroplasties done for proximal humeral fractures with cable wire and bone graft: 58 patients with a 22-month minimum follow-up

OBJECTIVE: The stability of 2 fixation techniques for the tuberosities in patients with 3- or 4-part proximal humerus fractures treated with hemiarthroplasties was compared. DESIGN: Retrospective review of a nonrandomized sequential series of patients. SETTING: Level I university orthopaedic surgery department. PATIENTS: A consecutive series of 58 patients (average age, 64 years) from 1990 to 1999 with 3- and 4-part fractures of the proximal humerus. INTERVENTION: In group 1, 31 patients were treated with either a Neer or Aequalis shoulder prosthesis using nonabsorbable sutures and no bone graft for the reattachment of the tuberosities. In group 2, 27 patients were treated with either an Aequalis or Epoca shoulder prosthesis and a combination of cable fixation and bone grafting. MAIN OUTCOME MEASUREMENTS: At follow-up (average, 32 months), radiographs were taken to confirm tuberosity fixation or degree of displacement or resorption. Functional outcome was assessed by the Constant-Murley Score. RESULTS: Significantly more dislocated tuberosities were found radiographically in group 1 (10 of 13 in total, P = 0.011), and significantly more tuberosities were resorbed in group 1 (9 of 12 in total, P = 0.012). Significant differences in functional results among healed versus failed tuberosity fixation were observed for activity of daily living (P = 0.05), range of motion (P = 0.002), strength (P = 0.01), the total score (P = 0.008), and the passive rotation amplitude (P = 0.04). CONCLUSION: In hemiarthroplasties for proximal humeral fractures, the reattachment of the tuberosities with cable wire and bone grafting gives consistently better radiographic and functional results than with suture fixation alone.

Lateral external fixation: a new surgical technique for displaced unreducible supracondylar humeral fractures in children

BACKGROUND: Percutaneous Kirschner wire fixation represents the classic treatment for displaced supracondylar humeral fractures in childhood. This type of treatment first requires satisfactory reduction of the fracture. Failure to achieve a satisfactory reduction or inadequate stabilization can result in instability of the fracture fragments, which can result in either an unsatisfactory cosmetic or functional outcome. In our experience, these problems can be overcome with the use of a small lateral external fixator. METHODS: Between 1999 and 2005, thirty-one of 170 Gartland type-III supracondylar humeral fractures were treated with a lateral external fixator. The outcome of treatment was analyzed with regard to limb alignment, elbow movement, cosmetic appearance, and patient satisfaction. RESULTS: In twenty-eight of the thirty-one patients, a satisfactory reduction was achieved with closed methods. All children except one had a normal or good range of movement. The cosmetic result was excellent in all cases. All of the children and their parents stated that they would choose this treatment again. CONCLUSIONS: The use of a small lateral external fixator seems to be a safe alternative for the treatment of displaced supracondylar fractures of the humerus when a closed reduction appears to be unattainable by means of manipulation alone or when sufficient stability is not achieved with standard methods of Kirschner wire fixation.

Lack of fifth anchoring point and violation of the insertion of the rotator cuff during antegrade humeral nailing: pitfalls in straight antegrade humeral nailing.

Antegrade nailing of proximal humeral fractures using a straight nail can damage the bony insertion of the supraspinatus tendon and may lead to varus failure of the construct. In order to establish the ideal anatomical landmarks for insertion of the nail and their clinical relevance we analysed CT scans of bilateral proximal humeri in 200 patients (mean age 45.1 years (sd 19.6; 18 to 97) without humeral fractures. The entry point of the nail was defined by the point of intersection of the anteroposterior and lateral vertical axes with the cortex of the humeral head. The critical point was defined as the intersection of the sagittal axis with the medial limit of the insertion of the supraspinatus tendon on the greater tuberosity. The region of interest, i.e. the biggest entry hole that would not encroach on the insertion of the supraspinatus tendon, was calculated setting a 3 mm minimal distance from the critical point. This identified that 38.5% of the humeral heads were categorised as 'critical types', due to morphology in which the predicted offset of the entry point would encroach on the insertion of the supraspinatus tendon that may damage the tendon and reduce the stability of fixation. We therefore emphasise the need for 'fastidious' pre-operative planning to minimise this risk.

Displaced supracondylar humeral fractures: influence of delay of surgery on the incidence of open reduction, complications and outcome.

BACKGROUND Closed reduction and pinning is the accepted treatment choice for dislocated supracondylar humeral fractures in children (SCHF). Rates of open reduction, complications and outcome are reported to be dependent on delay of surgery. We investigated whether delay of surgery had influence on the incidence of open reduction, complications and outcome of surgical treatment of SCHFs in the authors' institution. METHODS Three hundred and forty-one children with 343 supracondylar humeral fractures (Gartland II: 144; Gartland III: 199) who underwent surgery between 2000 and 2009 were retrospectively analysed. The group consisted of 194 males and 149 females. The average age was 6.3 years. Mean follow-up was 6.2 months. Time interval between trauma and surgical intervention was determined using our institutional database. Clinical and radiographical data were collected for each group. Influence of delay of treatment on rates of open reduction, complications and outcome was calculated using logistic regression analysis. Furthermore, patients were grouped into 4 groups of delay (<6 h, n = 166; 6-12 h, n = 95; 12-24 h, n = 68; >24 h, n = 14) and the aforementioned variables were compared among these groups. RESULTS The incidence of open procedures in 343 supracondylar humeral fractures was 2.6 %. Complication rates were similar to the literature (10.8 %) primarily consisting of transient neurological impairments (9.0 %) which all were fully reversible by conservative treatment. Poor outcome was seen in 1.7 % of the patients. Delay of surgical treatment had no influence on rates of open surgery (p = 0.662), complications (p = 0.365) or poor outcome (p = 0.942). CONCLUSIONS In this retrospective study delay of treatment of SCHF did not have significant influence on the incidence of open reduction, complications, and outcome. Therefore, in SCHF with sufficient blood perfusion and nerve function, elective treatment is reasonable to avoid surgical interventions in the middle of the night which are stressful and wearing both for patients and for surgeons. LEVEL OF EVIDENCE III (retrospective comparative study).

Treatment of posttraumatic cubitus varus in children and adolescents. Supracondylar humeral osteotomy using radial external fixation

OBJECTIVE Precise adaptable fixation of a supracondylar humerus osteotomy with a radial/lateral external fixator to correct posttraumatic cubitus varus. INDICATIONS Acquired, posttraumatic cubitus varus as a result of a malhealed and unsatisfactorily treated supracondylar humerus fracture. Idiopathic, congenital cubitus varus (very seldom) if the child (independent of age and after complete healing) is cosmetically impaired; stability of the elbow is reduced due to malalignment (hyperextension); secondary problems and pain (e. g., irritation of the ulnar nerve) are expected or already exist; or there is an explicit wish of the child/parents (relative indication). CONTRAINDICATIONS In principle there are no contraindications provided that the indication criteria are filled. The common argument of age does not represent a contraindication in our opinion, since angular remodeling at the distal end of the humerus is practically nonexistent. SURGICAL TECHNIQUE Basically, the surgical technique of the radial external fixator is used as previously described for stabilization of complex supracondylar humeral fractures. With the patient in supine position, the arm is placed freely on an arm table. Using a 4-5 cm long skin incision along the radial, supracondylar, the extracapsular part of the distal humerus is prepared, whereby great caution regarding the radial nerve is advised. In contrast to the procedure used in radial external fixation for supracondylar humeral fracture treatment, two Schanz screws are always fixed in each fragment at a distance of 1.5-2 cm. The osteotomy must allow the fragment to freely move in all directions. The proximal and distal two Schanz screws are then connected with short 4 mm carbon or stainless steel rods. These two rods are connected with each other over another rod using the tub-to-tub technique. Now the preliminary correction according the clinical situation can be performed and the clamps are tightened. Anatomical axis and function are checked. If these are radiologically and clinically perfect, all clamps are definitively tightened; if the alignment or the function is not perfect, then further adjustments can be made. POSTOPERATIVE MANAGEMENT Due to the excellent stability, further immobilization not necessary. Immediate functional follow-up treatment performed according to pain. RESULTS Adequate healing is usually expected within 6 weeks. At this time the external fixator can be removed in the fracture clinic. Because the whole operation is performed in an extraarticular manner and the mobility of the elbow is not affected, deterioration of function has never been observed. Also regarding the cosmetic/anatomical situation, good results are expected because they were already achieved intraoperatively.