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Biomedical subjects

P M Ballmer

Publications and source records attributed to P M Ballmer.

10 recordsLinked to original sources
PubMed2006

Is restricted femoral navigation sufficient for accuracy of total knee arthroplasty?

A total knee arthroplasty performed with navigation results in more accurate component positioning with fewer outliers. It is not known whether image-based or image-free-systems are preferable and if navigation for only one component leads to equal accuracy in leg alignment than navigation of both components. We evaluated the results of total knee arthroplasties performed with femoral navigation. We studied 90 knees in 88 patients who had conventional total knee arthroplasties, image-based total knee arthroplasties, or total knee arthroplasties with image-free navigation. We compared patients' perioperative times, component alignment accuracy, and short-term outcomes. The total surgical time was longer in the image-based total knee arthroplasty group (109 +/- 7 minutes) compared with the image-free (101 +/- 17 minutes) and conventional total knee arthroplasty groups (87 +/- 20 minutes). The mechanical axis of the leg was within 3 degrees of neutral alignment, although the conventional total knee arthroplasty group showed more (10.6 degrees ) variance than the navigated groups (5.8 degrees and 6.4 degrees , respectively). We found a positive correlation between femoral component malalignment and the total mechanical axis in the conventional group. Our results suggest image-based navigation is not necessary, and image-free femoral navigation may be sufficient for accurate component alignment.

Aged↗
PubMed1992

[Results of repositioning osteotomies in delayed healing or pseudarthrosis of the proximal femur].

The results after valgus osteotomy for delayed or nonunion in 20 patients with femoral neck fractures (9 Pauwels type II and 11 type III) and 10 intertrochanteric fractures are reported. The mean age of the patients at presentation with delayed/nonunion of femoral neck fractures and intertrochanteric fractures was 37.5 and 60 years, respectively. The average interval between injury and valgus osteotomy in the first and second group was 8 and 13 months, respectively. The average size of the preoperatively determined and intraoperatively removed wedge was 30 degrees in both groups. The results of the two fracture groups were analyzed separately. All but one osteotomy in a patient with a nonunion of a femoral neck fracture consolidated without complications. This case developed a nonunion at the osteotomy and required additional surgery consisting of bone graft and refixation to heal. Of the femoral neck delayed/nonunion cases, 15 (75%) healed immediately following valgus osteotomy. In the intertrochanteric delayed/nonunion patients, valgus osteotomy led directly to bone consolidation in 6 (60%). In each fracture group 3 additional cases healed following reoperation for a total consolidation rate of 90%. In the femoral neck group one union was complicated by infection, resulting in ankylosis of the hip and 3.5 years later another patient with a revascularized femoral head required total hip arthroplasty because of a large, loose osteochondral fragment. In two cases union of the former femoral neck fracture could not be achieved. Partial avascular necrosis determined the course and total hip arthroplasty was required for both cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Reconstruction of the anterior cruciate ligament alone in the treatment of a combined instability with complete rupture of the medial collateral ligament. A prospective study.

In a prospective study, 14 patients with a complete rupture of both the anterior cruciate ligament (ACL) and the medial collateral ligament (MCL) were treated by reconstruction of the ACL alone. The torn MCL was not addressed. The initial instability was documented clinically and by stress radiographs (20 kp) taken under anaesthesia. The postoperative management involved immediate mobilization and partial weight bearing for 6-8 weeks. Follow-up examination at an average of 14 months demonstrated excellent results in 11 cases, good in 2 cases, and fair in 1 case. With the exception of one residual anterior tibial translation of 8 mm, all knees showed almost normal stability in the frontal and sagittal plane, with full range of motion. These result confirm that ACL reconstruction utilizing the patellar tendon alone is sufficient in the treatment of combined instability due to ACL and MCL injuries.

Adult↗
PubMed1990

[Alternative treatment methods in complex fractures and fracture-dislocations of the anterior tarsus].

Obtaining and maintaining an anatomic reduction are the keystones in the treatment of severe midtarsal injuries to avoid long-term disability. The use of the small external fixator or the minidistractor allows an indirect reduction with careful management of the soft tissues. By leaving the external fixation for at least 8 weeks the important length of the medial and lateral longitudinal arch can be maintained. Further advantages are the postoperative observation of the soft tissues and circulation without cast immobilisation.

Adult↗
PubMed1990

Pauwels osteotomy for nonunions of the femoral neck.

The concept of the Pauwels osteotomy seems to be a valuable method of treating nonunions of the femoral neck. If there is concomitant avascular necrosis, the involved area should be small and the patient younger than 60 years old.

Adolescent↗
PubMed1989

Proximal tibial osteotomy. A new fixation device.

A new internal fixation device was applied to 41 proximal tibial osteotomies to ensure against loss of postoperative correction. An oblique osteotomy was stabilized by two screws and a five-hole one-half tubular plate. Thirty-six patients with 41 proximal tibial osteotomies were reviewed for an average roentgenographic follow-up time of 22.6 months (range, six to 48 months) with no loss of correction. In addition, 16 patients with 19 osteotomies and a minimum clinical follow-up time of two years were reviewed using the Hospital for Special Surgery knee scoring system; these early results demonstrated a similar outcome to previously published series. The new fixation device is simple to use, permits early postoperative motion, and maintains the exact correction obtained at the time of surgery.

Arthritis↗
PubMed1988

The non operative treatment of isolated complete tears of the medial collateral ligament of the knee. A prospective study.

In a prospective randomized study, 20 patients with isolated grade-III injuries to the medial collateral ligament (MCL) of the knee were treated by two different conservative methods: immediate mobilization (group A) or plaster immobilization (group B). All patients were examined while under anesthesia. Valgus-stress radiographs were performed to document a 2+ opening (6-10 mm) on the medial side. Associated damage to other structures (cruciate ligaments, menisci, cartilage) was ruled out arthroscopically. Average follow-up was 1.5 years. All patients rated good or excellent, although a minimal laxity of 3 mm on valgus-stress radiographs was present in 60% of the cases. No significant differences between the two treatment modalities were identified, except that group-A patients returned to work sooner. These results confirm that isolated grade-III MCL tears can be treated successfully by immediate mobilization.

Bandages↗
PubMedDate not supplied

[Results following sub-capital and Imhäuser-Weber osteotomy in femur head epiphyseolysis].

63 slipped capital femoral epiphysis were treated either by a femoral neck osteotomy or by an intertrochanteric osteotomy. In almost all cases a normal anatomical relationship of the proximal capital femoral epiphysis to the neck of the femur was achieved. At an average follow-up of 10 years (2 to 19 years) 90% were rated good to excellent clinically. In 33 hips with a follow-up period of more than 10 years mild degenerative arthritis was present in 36%. Slipping of 60 degrees or less is best treated by an intertrochanteric osteotomy to avoid the higher complication rate in the femoral neck osteotomy.

Adolescent↗