Torbjörn Ahl

Periprosthetic proximal bone loss after uncemented hip arthroplasty is related to stem size: DXA measurements in 138 patients followed for 2-7 years.

Background Periprosthetic bone loss occurs around uncemented femoral stems and may be influenced by the stem size. Patients and methods We studied 138 consecutive patients, 3 (2–7) years on average after a total hip arthroplasty operation (THA) for unilateral osteoarthritis with the Bi-Metric uncemented femoral stem. We analyzed Harris hip score and bone mineral density. Results The mean Harris hip score was 97 at follow-up. Bone mineral density decreased proximally by 19% in both Gruen zones 1 and 7. Bone loss in zones 1, 2, 6, and 7 was significantly associated with stem size. Distally, a small gain in bone mass was found in zones 3 and 5 for medium femoral sizes. Interpretation We found a marked proximal BMD loss, especially for the larger stems, which may be specific for this particular implant. Long-term studies should reveal whether this proximal bone loss will affect the longevity of the THA.

Early mobilization of operated on ankle fractures: Prospective, controlled study of 40 bimalleolar cases

40 patients with dislocated bimalleolar and trimalleolar ankle fractures took part in this randomized study. All ankles were operated on using cerclage, staples and pins. Active ankle movement with weight bearing in an orthosis was compared with active ankle movement without weight bearing using a dorsal splint. Stereophotogrammetric analysis showed small movements in the ankle mortise in both groups but conventional radiography revealed no fracture redislocation. The clinical results did not differ. This study was designed as the second part of a consecutive project. In the first part, early and late weight bearing in a cast without ankle movements was compared (Ahl et al. 1987b). In comparing the first and the second parts of the study, a small but significant increase in fracture instability was observed in the early motion group. No lasting superior clinical result was achieved by early ankle movement. After operation on dislocated bimalleolar ankle fractures, early postoperative weight bearing in a walking cast is recommended.

Biodegradable fixation of ankle fractures A roentgen stereophotogrammetric study of 32 cases

We performed a prospective randomized study comparing fixation with biodegradable polyglycolic acid (PGA) rods (n 15) or screws (n 17) in 32 selected displaced supination-eversion fractures. Immediate postoperative weight bearing in a walking cast was encouraged. An exact reconstruction of the ankle mortise was achieved in 26/32 ankles. Roentgen stereophotogrammetric analysis (RSA) revealed rather small movements in the ankle mortise during fracture healing. A better stability was achieved by using screws. After 6 months the clinical results did not differ. One case of sinus formation and one with local effusion occurred; both healed without impairing the clinical result. To compare the results with a nondegradable osteosynthesis technique, a reference group of supination-eversion fractures previously operated on with cerclage-wires, staples and pins was used. RSA showed better fracture stability with nondegradable fixation. The clinical results, however, did not differ.

Early weight bearing of displaced ankle fractures

A prospective randomized study was performed comparing immediate and late weight bearing in 53 dislocated bimalleolar and trimalleolar fractures. Using cerlage, staples, and pins (Cedell 1967), an exact reconstruction of the ankle mortise was achieved in 41/53 ankles. At follow-up after 3 and 6 months, the two groups were equal regarding clinical results. Evaluation radiographically and by roentgen stereophotogrammetric analysis (Selvik 1974) indicated that the stability of the ankle mortise was sufficient to allow early postoperative weight bearing.

Early weight bearing of malleolar fractures

A prospective randomized investigation of early versus late weight bearing in 46 patients with fracture of the lateral malleolus was performed. In 43/46 patients an exact operative reconstruction of the ankle mortise could be achieved using pins, staples and cerclage (Cedell, 1967). Radiographic and stereophotogrammetric analysis of the ankles after 3 months showed no significant differences, nor did the clinical follow-up.

Acute spinal epidural abscess without concurrent spondylodiscitis: Successful closed treatment in 10 cases

We performed a retrospective survey of the clinical records and radiological examinations of 10 patients with a diagnosis of spinal epidural abscess, without spondylodiscitis. All patients had an acute onset of fever and local or radiating back pain. 3 patients had mild, and 1 patient severe neurological symptoms. The diagnosis and subsequent regression of the abscess after treatment were verified by MRI. In all cases, the imaging findings included signs of septic arthritis in an adjoining facet joint. 7/10 abscesses were located in the lumbar region. Blood cultures showed Staphylococcus aureus as the etiological agent in 8/10 patients. In 2 cases, no agent was found, probably due to ongoing antibiotic therapy when the cultures were taken. All patients were treated successfully using antibiotics alone, with complete regression of the neurological symptoms.

Cauda equina syndrome as a postoperative complication in five patients operated for lumbar disc herniation.

Study Design. A retrospective analysis of records and radiographs in five patients who developed acute cauda equina syndrome after surgery for lumbar disc herniation. Objectives. To postulate as a possible pathophysiologic mechanism the venous congestion caused by preexisting spinal stenosis and to present a management plan: extended decompression within 48 hours. Summary of Background Data. Cauda equina syndrome is reported as a sequela in 0.2%–1% of the surgeries for lumbar disc herniation. There is, however, no consensus on the possible pathophysiologic mechanism to the complication or to its management. Methods. Preoperative investigations consisted of magnetic resonance imaging, or myelography and computed tomography. There was a good correlation between clinical appearance and radiographic findings in all patients. When the complication became apparent in four of the patients, they were investigated with magnetic resonance imaging and reoperated on within 48 hours with wide decompressions. Results. The index operation was reported uneventful in all patients. Postoperative magnetic resonance imaging did not show the cause of the cauda equina syndrome, nor could this be established at the reoperation. Before surgery, all five patients had preexisting narrowing of the spinal canal. In no case was the lumbosacral disc the index level. Two patients recovered fully, whereas the other three experienced varying degrees of residual symptoms. There was no correlation between the end result and the delay until secondary decompression. Conclusion. Relative spinal stenosis may contribute to the development of cauda equina syndrome after surgery for lumbar disc herniation. A venous congestion can be triggered by postoperative edema, leading to nerve root ischemia. The treatment of choice seems to be extended decompression within 48 hours.

The effect of weekly risedronate on periprosthetic bone resorption following total hip arthroplasty: a randomized, double-blind, placebo-controlled trial.

BACKGROUND Bone loss leading to late-occurring periprosthetic femoral fracture is a mode of failure in cementless total hip arthroplasty. The aim of this trial was to investigate the effect of a bisphosphonate, risedronate, on femoral periprosthetic bone resorption following total hip arthroplasty in patients with osteoarthritis of the hip. METHODS We enrolled seventy-three patients between the ages of forty and seventy years who were scheduled to undergo total hip arthroplasty in a single-center, randomized, double-blind, placebo-controlled trial. Subjects were randomly assigned to receive either 35 mg of risedronate (n = 36) or a placebo (n = 37) orally once weekly for six months. The primary end point was the change in bone mineral density in Gruen femoral zones 1 and 7. Bone mineral density scans were made preoperatively and at two days and three, six, twelve, and twenty-four months postoperatively. Secondary end points included migration of the femoral stem and clinical outcome. RESULTS Seventy of the seventy-three patients (thirty-three in the risedronate group and thirty-seven in the placebo group) were analyzed for the primary end point. The mean bone mineral density in zone 1 was 9.2% higher (95% confidence interval [CI], 4.2% to 14.1%) in the risedronate group than in the placebo group at six months postoperatively and 7.2% higher (95% CI, 1.0% to 13.3%) at one year. The mean bone mineral density in zone 7 was 8.0% higher (95% CI, 2.7% to 13.4%) in the risedronate group than in the placebo group at six months postoperatively and 4.3% higher (95% CI, -1.5% to 10.1%) at one year. Migration of the femoral stem, the clinical outcome, and the frequency of adverse events did not differ between the groups. CONCLUSIONS Risedronate taken once weekly for six months following total hip arthroplasty was effective in reducing periprosthetic bone resorption around an uncemented femoral stem up to one year after surgery but had no discernible effect on implant migration or clinical outcome. Future studies of bisphosphonate treatment following total hip arthroplasty should focus on clinically relevant end points such as the risks of fracture and revision arthroplasty.

Mobility of the ankle mortise: a roentgen stereophotogrammetric analysis

In 7 adult volunteers, a roentgen stereophotogrammetric technique was used to analyze the tibiofibular relationship during active unloaded movements of the ankle. The greatest movements were observed during plantar to dorsiflexion with an average widening of the ankle mortise of 1.0 mm and an average dorsal translation of the fibula of 0.9 mm. No significant rotation of the fibula could be revealed.

Urinary tract infection in patients with hip fractures

We found that 23% of 435 patients treated for a femoral neck fracture in our department also were treated for a urinary tract infection during their hospital stay. The most common pathogen was Escherichia coli, sensitive for mecillinam in 98% of the cases. The most frequently used antimicrobial agent was a broad-spectrum antibiotic, fluoroquinolon, although the most reasonable choice would have been a non broad-spectrum agent such as mecillinam. Catheterization was not a predisposing factor for urinary tract infection, but a poor medical condition and female sex were. We did not find a higher mortality rate among patients with a urinary tract infection.