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Biomedical subjects

C H Rorabeck

Publications and source records attributed to C H Rorabeck.

At least 145 records · Page 8Linked to original sources
PubMed1984

In vitro strain distribution in the proximal tibia. Effect of varus-valgus loading in the normal and osteoarthritic knee.

Six human cadaver legs were tested with strain-gauge rosettes to determine the effects of varus/valgus loading on the distribution of strain on the cortical bone of the proximal tibia at loads of up to 250 kg. Changes in the femorotibial angle of 1.5 degrees and 3.1 degrees, to create varus/valgus deformities, produced significant unloading of the opposite aspect of the normal leg. A varus deformity of 3.1 degrees in the medial compartment osteoarthritic model virtually unloaded the lateral compartment and, because of the bending effect, placed the whole of the lateral aspect of the leg into axial tension. Under these conditions, the axial strains in almost the whole of the medial aspect of the tibia were doubled, from an initial value of 250 microstrain (compressive) to a value of approximately 500 microstrain (compressive). While a change in load-action, to simulate a 3.1 degrees valgus deformity in the medial compartment osteoarthritic model, did not completely unload the medial plateau of the tibia, it was suggested that such unloading could be achieved with slightly greater valgus loading. Successful clinical results, employing valgus osteotomies in patients with medial compartment osteoarthritis, are obtained by unloading the medial compartment while markedly increasing compressive loads on the whole of the lateral aspect of the leg.

Adolescent↗
PubMed1984

Supracondylar fractures of the femur: results of treatment of 61 patients.

A retrospective study of 61 fractures (60 patients) involving the supracondylar and intercondylar areas of the femur was made. All patients were younger than 60 years and sustained their injuries in motor vehicle accidents. Follow-up was from 1 to 9 years (mean 30 months). Clinical results of operative and nonoperative treatment were compared with respect to knee motion, pain and function. Extra-articular (type A) fractures had superior clinical ratings if treated operatively (45% excellent and 30% unsatisfactory). Intra-articular (type B) fractures had a substantial number of unsatisfactory ratings (45%) and results of operative and nonoperative treatment were comparable. Fractures of one condyle only did best with open reduction and internal fixation. Rates of nonunion were low (7%); malunion in varus led to poorer overall function. The most important factor for acceptable function was early knee mobilization. Early motion of the knee and quadriceps rehabilitation are facilitated by operative management or use of the cast brace.

Adolescent↗
PubMed1983

Intra-articular fractures of the distal tibia: the pilon fracture.

Forty-two patients with pilon fractures were followed 24 to 96 (mean, 53) months post-fracture. Fractures were classified as Type I (26%), Type II (29%), or Type III (45%) as defined by Ruedi and Allgower. Type I fractures were usually torsional in nature whereas Type II and III injures were usually the result of a fall from a height or motor vehicle accident. Type I and II pilon fractures were amenable to anatomic open reduction and stable internal fixation and 80% or more had satisfactory results. Only 44% of Type III fractures treated by open reduction and internal fixation produced a satisfactory outcome. Nonanatomic reduction, unstable fixation, infection, nonunion, and/or angulation were the usual causes of failure of this form of treatment.

Adult↗
PubMed1983

A practical approach to compartmental syndrome. Part III. Management.

Early diagnosis and appropriate treatment of an established compartment syndrome usually results in a functional extremity for the patient. In my experience, the commonest causes for failure of a fasciotomy are (1) delay in initiation of the operative procedure and (2) an incomplete fasciotomy. Thorough knowledge of the anatomy of the upper and lower extremity should allow the surgeon to confidently decompress any compartment with relative ease and safety for the patient. Most of these extremities have already suffered closed blunt trauma, and many are associated with an underlying fracture. It is mandatory that the surgeon minimize the operative trauma by careful handling of soft tissue and expeditious fixation of a coexistent fracture.

Arm↗
PubMed1983

The surgical treatment of exertional compartment syndrome in athletes.

We studied the cases of twelve patients who had bilateral exertional compartment syndrome involving one or all of the compartments of the lower extremities. The patients were divided into three groups based on the clinical findings. Group I consisted of seven patients with symptoms involving the anterior or lateral compartments only; Group II, of three patients with involvement of the deep posterior compartments alone; and Group III, of two patients with involvement of both the anterior and deep posterior compartments. On the basis of their clinical signs and symptoms each patient underwent dynamic tissue-pressure measurements using a slit catheter before, during, and for as long as thirty minutes after exercise. All patients had elevated resting and peak-to-peak dynamic pressure measurements. Treatment consisted of bilateral compartmental fasciotomy, as indicated. All of the patients in Group I had complete relief of symptoms; however, one patient in Group II and one in Group III had a recurrence of symptoms in the deep posterior compartment.

Adolescent↗
PubMed1983

Fractures of the tibia treated by flexible external fixation.

Thirty-four patients with fractures of the tibial diaphyseal shaft were treated by flexible anterior half-frame external fixation. The average time to union in the frame was 12 weeks for a simple closed tibial fracture and 26 weeks for a complex open tibial fracture. Complications included malalignment and loss of initial reduction. Most of the complications could have been avoided if special attention had been paid to technical details of reduction of the fracture and insertion of the pins.

Adult↗
PubMed1981

Factors affecting the prognosis of brachial plexus injuries.

The clinical results in a series of 131 patients with 134 brachial plexus injuries were analysed to determine the factors affecting prognosis. Isolated injuries to the upper trunk had the best prognosis, but the prognoses of isolated injuries to the cords, upper roots and lower trunk were not as good. Complete injuries of the plexus had the worst prognosis. Pain which persisted for more than six months was a bad prognostic sign for neurological recovery regardless of the location of the lesion. Horner's syndrome was not always accompanied by a bad prognosis. Operation did not affect the prognosis except in open lacerations. A pseudomeningocele detected by myelography usually precluded recovery in the root at the level of the pseudomeningocele.

Adolescent↗
PubMed1981

Compartmental pressure measurements: an experimental investigation using the slit catheter.

A new catheter employing a different technique to monitor compartmental pressure has been developed. The accuracy of the catheter was compared to a wick catheter and to the needle manometer technique for monitoring compartmental pressure. The slit catheter is the most accurate of the three techniques for continuous pressure monitoring for periods of up to 24 hours in the experimental canine model. The slit catheter is as accurate as the wick catheter for pressure measurements from 0 through 10 mm Hg. The needle technique has proven to be the least accurate of the three.

Animals↗
PubMed1980

Tourniquet-induced nerve ischemia: an experimental investigation.

This experimental investigation has demonstrated that an inflated pneumatic tourniquet causes slowing in conduction velocity of the sicatic nerve. The amount of slowing and recovery time vary according to inflation pressure and to the duration of applied pressure. The conduction velocity always returned to normal provided the tourniquet was inflated for 2 hours or less, and pressures were below 500 mm Hg. The nerve directly under the tourniquet was most susceptible to injury. Inflation pressure should be as low as possible and be determined according to systolic blood pressure. An Esmarch bandage should not be used as a pneumatic tourniquet because of its very small surface area. The cause of the nerve injury demonstrated is likely related to arterial ischemia.

Animals↗
PubMed1980

The management of the flail upper extremity in brachial plexus injuries.

Twenty-three patients with total complete brachial plexus injuries were reviewed an average of 5.5 years from the time of injury. Three different treatment approaches were used; no surgery (four), above-elbow amputation alone (14), and shoulder arthrodesis combined with above-elbow amputation (five). Return to gainful employment and prosthetic wearing habits were best achieved with early (within the first year) above-elbow amputation alone. There seemed little to recommend arthrodesis of the shoulder combined with above elbow amputation.

Adolescent↗
PubMed1979

Pyogenic infections of the adult spine.

A retrospective analysis of 61 patients forms the basis for this paper's comment on three major types of pyogenic spinal disease. The first group consists of 22 patients with vertebral osteomyelitis and intervertebral discitis. The second group comprises 22 patients in whom the diagnosis of pyogenic spinal disease was made only after failure of discectomy. In retrospect they were shown to have atypical degenerative disc disease and were similar to the first group. The third group of 17 patients, while demonstrating some similarities to the second group, represents true postdiscectomy wound infection. An understanding of the clinical presentation and pathophysiology of pyogenic disease of the spine allows it to be distinguished preoperatively from degenerative disc disease which superficially it resembles. Further, true postdiscectomy wound infection can be distinguished from pyogenic spinal disease misdiagnosed preoperatively. The differences in the results of treatment of these three groups warrant such distinctions.

Back Pain↗
PubMed1978

The pathophysiology of the anterior tibial compartment syndrome: an experimental investigation.

In an experimental study in dogs of the anterior tibial compartment syndrome, three measurements were taken before, during, and following raising pressure in the compartment: blood flow, muscle function, and peroneal nerve conduction. If fasciotomy was performed within 4 hours, peroneal nerve conduction velocity always returned to normal regardless of amount of pressure or length of time pressure was applied; if performed after 12 hours peroneal nerve conduction velocity did not return to normal at any pressure or time condition, suggesting that irreversible damage to the nerve had occurred. Blood flow, as measured by rate of clearance of Xe133, always returned to normal within 2 hours of fasciotomy regardless of the time postinjury or amount of pressure applied. Muscle function (CPK and LDH) did not always return to baseline with fasciotomy and in some instances the absolute values were higher after fasciotomy. Further clinical studies using these measurements are recommended.

Animals↗
PubMed1976

Acute dislocation of the patella with osteochondral fracture: a review of eighteen cases.

Eighteen patients with acute dislocation of the patella had associated osteochondral fractures. This fracture complicates approximately 5% of all acute dislocations of the patella occurring in children. Three types of fracture patterns were noted. All patients who were treated by immediate arthrotomy and excision or replacement of the osteochondral fragment and repair of the acute dislocation of the patella made an uneventful recovery with no recurrence of the dislocation. In those patients in whom the osteochondral fragment was removed but with no repair the dislocation recurred.

Acute Disease↗
PubMed1976

Anterior tibial-compartment syndrome complicating fractures of the shaft of the tibia.

Twenty-five cases of anterior tibial-compartment syndrome in twenty-four patients were seen as complications of fractures of the shaft of the tibia. Six patients had fasciotomy within the first six hours of the onset of their symptoms and signs and all made an uneventful recovery. Eighteen patients, in whom treatment was withheld for an average of eighteen hours, were left with a variety of complications including persistent weakness of dorsiflexion in fourteen, a complete footdrop in three, and the necessity for a below-the-knee amputation in one.

Adolescent↗
PubMed1975

Non-union of the odontoid process. An experimental investigation.

A clinical study of fractures of the odontoid process showed a 62 per cent failure on union. Of many features studied, only displacement and its direction had a definite bearing on non-union of the fracture. Blood supply was considered as a possible etiological factor. The blood supply of the human odontoid was elucidated by means of studying 19 human autopsies by means of microangiography. The dog was found to have a similar blood supply and hence, was used as the experimental model. Two osteotomies were performed; one below the accessory ligaments and one above the accessory ligaments. All osteotomies carried out below the accessory ligament united and all carried out above failed to unite. Microangiographic studies revealed however, that avascular necrosis was not the cause of non-union. Further anatomic studies revealed that different size gaps occurred depending on the level of the osteotomy, with a large gap occurring in the osteotomy of the odontoid which was performed above the accessory ligament. First the result of immobilization and the healing of the odontoid osteotomy was derived, by carrying out an instant occipito-cervical fusion by means of wire loops and methylmethacrylate. In distinction to the free floating apical segment of non-immobolized spines, with a high odontoid osteotomy, the occipito-cervical fusion resulted in a dense fibrous tissue stabilizing the apical fragment but at no time was bony union observed. A final attempt was to secure immobilization and reduce the gap, by carrying out only a partial osteotomy. The osteotomy was performed in such a way that the posterior cortex was left intact. Union occurred in all instances. The fracture gap and movement play a definite role in the pathogenesis of pseudarthrosis of the odontoid process. Where gap and movement were eliminated, union occurred. It is difficult to transpose this experimental situation to the clinical one, for the assessment of gap clinically, is only radiographic. This method is much too imprecise to be of value in this assessment. The fact however, that a high rate of non-union is associated with a high degree of displacement, supports the experimental thesis.

Animals↗