Brian D. Solberg

AWARENESS OF TIP-APEX DISTANCE REDUCES FAILURE OF FIXATION OF TROCHANTERIC FRACTURES OF THE HIP

We compared the results of the surgical treatment of trochanteric hip fractures before and after surgeons had been introduced to the tip-apex distance (TAD) as a method of evaluating screw position. There were 198 fractures evaluated retrospectively and 118 after instruction. The TAD is the sum of the distance from the tip of the screw to the apex of the femoral head on anteroposterior and lateral views. This decreased from a mean of 25 mm in the control group to 20 mm in the study group (p = 0.0001). The number of mechanical failures by cut-out of the screw from the head decreased from 16 (8%) in the control group at a mean of 13 months to none in the study group at a mean of eight months (p = 0.0015). There were significantly fewer poor reductions in the study group. Our study confirms the importance of good surgical technique in the treatment of trochanteric fractures and supports the concept of the TAD as a clinically useful way of describing the position of the screw.

Surgical Treatment of Three and Four-Part Proximal Humeral Fractures

BACKGROUND Optimal surgical management of three and four-part proximal humeral fractures in osteoporotic patients is controversial, with many advocating prosthetic replacement of the humeral head. Fixed-angle locked plates that maintain angular stability under load have been proposed as an alternative to hemiarthroplasty for the treatment of some osteoporotic fracture types. METHODS The records of 122 consecutive patients who were fifty-five years of age or older and in whom a Neer three or four-part proximal humeral fracture had been treated surgically between January 2002 and November 2005 were studied retrospectively. After exclusions, thirty-eight patients treated with a locked-plate construct were compared with forty-eight patients who had undergone hemiarthroplasty. All patients had radiographic and clinical follow-up at a minimum of twenty-four months and an average of thirty-six months. Reduction and implant placement were evaluated radiographically. Clinical outcomes were measured with use of the Constant-Murley system. RESULTS The mean Constant score (and standard deviation) at the time of final follow-up was significantly better in the locked-plate group (68.6 +/- 9.5 points) than in the hemiarthroplasty group (60.6 +/- 5.9 points) (p < 0.001). The Constant scores for the three-part fractures in the locked-plate and hemiarthroplasty groups were 71.6 and 60.4 points (p < 0.001), respectively, and the scores for the four-part fractures in those groups were 64.7 and 60.1 points (p = 0.19), respectively. Patients with an initial varus extension deformity in the locked-plate group had significantly worse outcomes than those with a valgus impacted pattern (Constant score, 63.8 compared with 74.6 points, respectively; p < 0.001). Complications in the group treated with locked-plate fixation included osteonecrosis in six patients, screw perforation of the humeral head in six patients, loss of fixation in four patients, and wound infection in three patients. Loss of fixation was seen only in patients with >20 degrees of initial varus angulation of the humeral head. Complications in the hemiarthroplasty group included nonunion of the tuberosity in seven patients and wound infection in three patients. CONCLUSIONS In this series, open repair with use of a locked plate resulted in better outcome scores than did hemiarthroplasty in similar patients, especially in those with a three-part fracture, despite a higher overall complication rate. Open reduction and internal fixation of fractures with an initial varus extension pattern should be approached with caution.

Efficacy of gentamycin-impregnated resorbable hydroxyapatite cement in treating Osteomyelitis in a rat model

OBJECTIVE To test the effectiveness of a self-setting hydroxyapatite cement (HAC) as a carrier of gentamycin for the treatment of chronic osteomyelitis in a rat model by using a void-fill placement technique. DESIGN Osteomyelitis of the tibia was created with Staphylococcus aureus (ATCC 49230) in sixty retired female breeder Sprague-Dawley rats by using the model by Korkusuz et al. (J Bone Joint Surg 1993;75B:111-114). At seven weeks after infection, all animals demonstrated clinical and radiographic signs of osteomyelitis and were debrided and divided into four treatment groups: A, debridement only; B, debridement and daily intraperitoneal gentamycin (0.2 milligram per kilogram per day); C, debridement and gentamycin-impregnated HAC in a void-fill model (1.0 milligram per kilogram of gentamycin); and D, debridement and gentamycin-impregnated polymethylmethacrylate (PMMA) beads (1.0 milligram per kilogram of gentamycin). Tibiae were harvested at zero weeks (control, n = 6), three weeks (n = 3 per group), five weeks (n = 4 per group), and seven weeks (n = 4 per group) and analyzed with quantitative bacteriologic analysis. OUTCOME MEASUREMENT Qualitative bacteriologic analysis was performed by using serial dilution plating of homogenized tissue samples on standard soy trypticase agar plates. Reexamination by phage typing was performed to exclude contamination. RESULTS The quantitative counts for Groups C (HAC) and D (PMMA) were significantly less (p < 0.003) than those for Group A (debridement alone) or Group B (intraperitoneal gentamycin) at all time points after time zero. There was no difference between Groups C and D at any time point. CONCLUSION HAC is an effective adjuvant in treating chronic osteomyelitis in a rat model when using a void-fill placement technique.

Total hip replacements done without cement after acetabular fractures: A 4- to 8-year follow-up study

Twenty-one patients (21 hips) underwent cementless total hip replacement surgeries for previous acetabular fractures. The mean age at the time of hip replacement was 52 years (range, 23-78 years). The mean follow-up was 65 months (range, 48-104 months). One hip required revision of the stem secondary to a periprosthetic femur fracture from a fall at 3 months after surgery. Good to excellent clinical rating was achieved and maintained in 19 hips. Radiographic evaluation demonstrated stable cup and stem fixation in 17 and 15 hips. Only 1 patient with radiographic loosening of the components was sufficiently symptomatic. The results in this series appeared slightly better than those reported previously in hip replacements done with cement at comparable medium-term follow-up. The mechanical failure rates remained high in this patient population: 19% for the cups and 29% for the stems.

Femoral nerve palsy after pelvic fracture treated with INFIX: a case series.

Objective: The treatment of some pelvic injuries has evolved recently to include the use of a subcutaneous anterior pelvic fixator (INFIX). We present 8 cases of femoral nerve palsy in 6 patients after application of an INFIX to highlight this potentially devastating complication to pelvic surgeons using this technique and discuss how it might be avoided in the future. Design: Retrospective chart review. Case series. Setting: Five level 1 and 2 trauma centers, tertiary referral hospitals. Patients/Participants: Six patients with anterior pelvic ring injury treated with an INFIX who experienced 8 femoral nerve palsies (2 bilateral). Intervention: Removal of internal fixator, treatment for femoral nerve palsy. Main Outcome Measurements: Clinical and electromyographic evaluation of patients. Results: All 6 patients with a total of 8 femoral nerve palsies had their INFIX removed. Variable resolution of the nerve injuries was observed. Conclusions: Application of an INFIX for the treatment of pelvic ring injury carries a potentially devastating risk to the femoral nerve(s). Despite early implant removal after detection of nerve injury, some patients had residual quadriceps weakness, disturbance of the thighs skin sensation, and/or gait disturbance attributable to femoral nerve palsy at the time of early final follow-up. Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.