William W. Brien

Ipsilateral Fractures of the Femoral Neck and Shaft

Summary Thirty-three patients with ipsilateral intracapsular femoral neck and shaft fractures were treated with antegrade reamed intramedullary (IM) nails and cancellous screw fixation of the femoral neck. The shaft fractures were fixed prior to definitive neck stabilization. A “reversed” nail construct was used in 13 patients, a conventional interlocked nail was used in 6, and a reconstruction nail was used in the remaining 14. Thirty-one (94%) of the femoral shaft fractures healed primarily. In two patients, the shaft fracture failed to unite and was bone grafted and plated, respectively; the fractures subsequently healed. However, only 27 (82%) of the femoral neck fractures healed after initial fixation. In six patients (18%), a symptomatic varus nonunion developed, requiring a valgus osteotomy. Five of the six femoral neck non-unions and all of the osteotomy sites united; however, two of these patients later developed osteonecrosis of their femoral heads. Closed reamed antegrade IM nailing with supplemental screw fixation of ipsilateral femoral neck and shaft fractures did not produce uniformly successful results because of high rates of varus nonunion of the femoral neck fracture.

Tinel's sign and Phalen's test in carpal tunnel syndrome.

Tinels sign and Phalens test are two provocative tests used in the diagnosis of carpal tunnel syndrome. A review of the literature reveals a wide range of sensitivity for these tests. Analyzing the historical data and comparing these to the Tinels sign and Phalens test results of 100 individuals without carpal tunnel syndrome (200 wrists), we conclude that the Tinels sign is not useful in the evaluation of patients with carpal tunnel syndrome, whereas Phalens test, which has a greater sensitivity and specificity, can be of use.

Antibiotic impregnated bone cement in total hip arthroplasty. An in vivo comparison of the elution properties of tobramycin and vancomycin.

A prospective in vivo quantification was performed to measure the elution of tobramycin and vancomycin antibiotics from two commonly used bone cements. Forty patients were divided into four groups: Group I, tobramycin-Simplex; Group II, tobramycin-Palacos-R; Group III, vancomycin-Simplex; and Group IV, vancomycin-Palacos-R. Antibiotic levels were measured from hemovac wound drainage, urine, and serum and compared with control groups who received either intravenous tobramycin or vancomycin. There were no significant differences in daily mean tobramycin levels in hemovac samples between Groups I and II. Tobramycin hemovac levels from Groups I and II were significantly higher than the tobramycin control group. Similarly, no differences were seen in daily mean vancomycin levels of the hemovac samples between Group III and IV; however, the intravenous vancomycin control group had significantly higher levels in the hemovac fluid than Groups III or IV. Tobramycin in the hemovac fluid from Groups I and II was highly bioactive against the control organism. Vancomycin in the hemovac fluid from Groups III and IV had variable bioactivity against the control organism. In 30% of the cases, no vancomycin was detected in the hemovac fluid, and in these cases, the hemovac fluid had no effect on the control organism. Tobramycin elutes to give adequate local tissue levels and releases antibiotic effects when used in an antibiotic bone cement combination. Vancomycin has variable elution properties and is not a predictable additive for the bone cements tested.

Metal levels in cemented total hip arthroplasty. A comparison of well-fixed and loose implants.

In a prospective study, synovial fluid metal levels from stainless steel, cobalt-chromium, and titanium-alloy cemented total hip implants were measured. There were 37 well-fixed and 44 loose hip arthroplasties. Tissue-metal levels were quantitated in the cases revised for loosening. Retrieval analysis for implant wear was performed. Synovial fluid analysis showed a fivefold increase in metal levels of loose compared with well-fixed stainless steel implants. There was a sevenfold increase in metal levels of loose compared with well-fixed cobalt-chromium implants. There was a 21-fold increase in metal levels of loose compared with well-fixed titanium-alloy (Ti-6Al-4V) implants. Tissue-metal levels from revised cobalt-chromium implants averaged 45 micrograms/g dry tissue weight compared to 4,470 micrograms/g dry tissue weight from revised titanium-alloy implants, a 100-fold increase. Implant retrieval analysis showed severe burnishing and scratching in all titanium-alloy femoral heads and extensive burnishing and scratching in the majority of the femoral stems. Well-fixed cemented implants have similar low synovial fluid metal levels. However, when loosening of implants occurs, titanium-alloy implants release disproportionate levels of metal into synovial fluid and local tissues compared to stainless steel or cobalt-chromium.

A biomechanical evaluation of a cannulated compressive screw for use in fractures of the scaphoid

The compressive force generated by a 3.5 mm ASIF cannulated cancellous screw with a 5 mm head was compared with that generated by a standard 3.5 mm ASIF screw (6 mm head), a 2.7 mm ASIF screw (5 mm head), and a Herbert screw. The screws were evaluated in the laboratory with the use of a custom-designed load washer (transducer) to the maximum compressive force generated by each screw until failure, either by thread stripping or by head migration into the specimen. Testing was done on paired cadaver scaphoids. To minimize the variability that occurs with human bone, and because of the cost and difficulty of obtaining human tissue specimens, a study was also done on polyurethane foam simulated bones. The 3.5 cannulated screw generated greater compressive forces than the Herbert screw but less compression than the 2.7 mm and 3.5 mm ASIF cortical screws. The 3.5 mm cannulated screw offers more rigid internal fixation for scaphoid fractures than the Herbert screw and gives the added advantage of placement over a guide wire.

Interface corrosion of a modular head total hip prosthesis

Wear and corrosion products released from metallic prosthetic joints can stimulate adverse reactions in the surrounding tissues that may eventually require revision of the prostheses. The authors report here a case of a modular total hip prosthesis removed after 35 months that showed evidence of corrosion and fretting at the Morse taper interface between the titanium alloy femoral stem and the cobalt-chromium ball.

Subtrochanteric fractures of the femur : results of treatment by interlocking nailing

Ninety-five subtrochanteric femoral fractures were treated with an interlocking nail. There were 69 closed and 26 open fractures. This injury was the result of high-energy trauma in 77% of the cases. The average time to healing was 25 weeks. There were three delayed unions, one nonunion, and six malunions. Essentially all nonpathologic, subtrochanteric femur fractures can be stabilized by interlocking nailing, regardless of the fracture pattern or degree of comminution. Favorable mechanical characteristics of interlocking nails have eliminated the requirement of surgically reconstituting the medial femoral cortex. Closed interlocking nailing is the preferred treatment for subtrochanteric fractures of the femur resulting from trauma.

DISLOCATION FOLLOWING THA: COMPARISON OF TWO ACETABULAR COMPONENT DESIGNS

One hundred ninety-seven consecutive primary cemented total hip arthroplasties using 22 mm heads were evaluated for the rate of dislocation. All surgery was performed by one surgeon through a posterior approach. A Charnley type femoral component was used in each case. Patients were divided into three groups based on the acetabular component used. Group I had 60 Charnley HPW cups implanted between January 1985 and December 1986; group II had 70 Tibac cups implanted between January 1987 and August 1987; and group III had 67 Charnley HPW cups implanted between September 1987 and February 1988. The groups were similar with regards to age, sex, original diagnosis, and surgical technique. There was a total of 11 dislocations (5.6%), of which 8 (11.4%) occurred in group II (Tibac cup). Furthermore, 6 patients (3%) developed recurrent hip dislocations, 5 (7.1%) of which were from group II. Group II had a statistically significant increase in the dislocation rate (P < .05). The authors conclude that the dislocation rate with the 22 mm Tibac cup is unacceptably high and that the design of the Charnley cup affords greater stability to the artificial hip joint than the hemispherical design of the Tibac cup.

Hip joint arthrodesis utilizing anterior compression plate fixation

Sixteen patients who had undergone hip arthrodesis utilizing an anteriorly placed compression plate were evaluated at an average of 4.5 years after surgery. The technique was designed to facilitate future conversion to a total hip arthroplasty by preserving the abductor musculature. Of the 11 patients who underwent primary fusions, 5 failed to unite (45%). Nonunion occurred in all five (100%) patients undergoing refusion for a failed surgical arthrodesis. The authors conclude that an anterior compression plate alone in patients with limited bone stock does not provide adequate fixation and predisposes the patient to failure of fixation and nonunion.

CONCOMITANT INJURIES OF THE HIP JOINT AND ABDOMEN RESULTING FROM GUNSHOT WOUNDS

Septic arthritis is a devastating complication of transabdominal gunshot wounds to the hip. Five patients sustained gunshot wounds to the hip which violated the alimentary tract. Diagnosis was established with plain radiographs in three patients, arthrogram in one patient, and a gastrointestinal series in one patient. Three patients had an exploratory laparotomy with diverting colostomy followed by immediate hip arthrotomy within 24 hours and no joint infections occurred. In the other two patients, hip involvement was identified late after septic arthritis occurred. Early diagnosis, diverting colostomy, and immediate arthrotomy are recommended for gunshot wounds to the hip which involve the alimentary tract.