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Biomedical subjects

S Kamineni

Publications and source records attributed to S Kamineni.

At least 19 recordsLinked to original sources
PubMed2005

Intrinsic constraint of unlinked total elbow replacements--the ulnotrochlear joint.

BACKGROUND: Many unlinked total elbow replacement designs with radically differing articular geometries exist, suggesting that there is no consensus regarding an optimal design. A feature inherent to the articular design is the intrinsic constraint afforded to the joint by the implant. Our aim was to compare the intrinsic constraints of unlinked implants with that of the normal ulnotrochlear joint. METHODS: We tested twelve cadaveric ulnotrochlear joints with a custom-made multiple-axis materials testing machine. With compressive loads ranging from 10 to 100 N, the joints were moved in either valgus or varus directions at 90 degrees of flexion. The ulnotrochlear components from a single example of five medium-sized unlinked elbow replacements (Ewald, Kudo, Pritchard ERS, Sorbie-Questor, and Souter-Strathclyde) were also tested. The recorded measurements included the torques and forces, angular displacement, and axial displacement of the humerus relative to the ulna. RESULTS: In general, the peak torque and the constraint ratio significantly increased with increasing compressive load for the implants as well as for the normal elbow. In valgus displacement, the Souter-Strathclyde implant had the highest and the Sorbie-Questor had the smallest peak torque and the Souter-Strathclyde had the highest and the Ewald had the smallest constraint ratio. In varus displacement, the Kudo had the highest and the Ewald had the smallest peak torque and constraint ratio. CONCLUSIONS: The constraint ratio is a characteristic that is useful for describing elbow joint behavior and for comparing the behavior of implants with that of the human elbow. Of the unlinked implants tested, the Souter-Strathclyde and Kudo prostheses most closely approximated the behavior of the human elbow joint. Implants that resemble the human elbow in appearance do not replicate normal behavior consistently, whereas other implants that do not resemble the human elbow closely do not deviate markedly from human behavior. Thus, much basic information about elbow form and function is needed to improve the performance of total elbow prostheses.

Aged↗
PubMed2005

Distal humeral fractures treated with noncustom total elbow replacement. Surgical technique.

BACKGROUND: The purpose of this study was to review the cases of patients with a distal humeral fracture that was treated with a noncustom total elbow arthroplasty. We hypothesized that, on the basis of the functional and clinical outcome, total elbow replacement is a reliable option for the treatment of elderly patients with a severe, comminuted fracture of the distal part of the humerus. METHODS: We retrospectively reviewed forty-nine acute distal humeral fractures in forty-eight patients who were treated with total elbow arthroplasty as the primary option. The average age of the patients was sixty-seven years. Forty-three fractures were followed for at least two years. According to the AO classification, five fractures were type A, five were type B, and thirty-three were type C. The average age of the forty-three patients was sixty-nine years and the average duration of follow-up was seven years. Fourteen patients died during the review period. Postoperative clinical function was assessed with use of the Mayo elbow performance score, and anteroposterior and lateral radiographs made at follow-up examinations were reviewed. RESULTS: At the latest follow-up examination, the average flexion arc was 24 degrees (range, 0 degrees to 75 degrees ) to 131 degrees (range, 100 degrees to 150 degrees ) and the Mayo elbow performance score averaged 93 of a possible 100 points. Heterotopic ossification was present to some extent in seven elbows, with radiographic abutment noted in two. Thirty-two (65%) of the forty-nine elbows had neither a complication nor any further surgery from the time of the index arthroplasty to the most recent follow-up evaluation. Fourteen elbows (29%) had a single complication, and most of them did not require further surgery. Ten additional procedures, including five revision arthroplasties, were required in nine elbows; five were related to soft tissue and five were related to the implant or bone. CONCLUSIONS: Complex distal humeral fractures should be assessed primarily for the reliability with which they can be reconstructed with osteosynthesis. When osteosynthesis is not considered to be feasible, especially in patients who are physiologically older and place lower demands on the joint, total elbow arthroplasty can be considered. This retrospective review supports a recommendation for total elbow arthroplasty for the treatment of an acute distal humeral fracture when strict inclusion criteria are observed.

Arthroplasty, Replacement↗
PubMed2004

Anatomical considerations for percutaneous proximal humeral fracture fixation.

PURPOSE: To investigate the hypothesis that percutaneous wire fixation of proximal humeral fractures is prone to regional neurovascular injury. MATERIALS AND METHODS: 40 cadaveric shoulders had percutaneous wires inserted from anterior and lateral humeral shaft entry points into the humeral head. The shoulders were then dissected to identify the neurovascular structures in this area. RESULTS: The axillary nerve trunk and posterior circumflex humeral artery were found to be within the field of dissection. The axillary nerve was damaged on three occasions by the lateral wires, two of which were direct nerve penetrations. The anterior wires caused a single perineural injury of a terminal branch. The main neurovascular leash was 57 mm (range 35-70 mm) from the acromion tip laterally and 51 mm (range 35-85 mm) anteriorly, with a width of 6 mm (range 4-13 mm) laterally, and 12 mm (range 7-15 mm) anteriorly. CONCLUSIONS: Percutaneous wire stabilisation is an attractive fixation option but this study highlights the close proximity of the important neurovasculature. Such fixation should be performed utilising a limited open approach, with dissection to bone under direct vision, with the subsequent use of a drill-sleeve for soft-tissue protection.

Aged↗
PubMed2004

Distal humeral fractures treated with noncustom total elbow replacement.

BACKGROUND: The purpose of this study was to review the cases of patients with a distal humeral fracture that was treated with a noncustom total elbow arthroplasty. We hypothesized that, on the basis of the functional and clinical outcome, total elbow replacement is a reliable option for the treatment of elderly patients with a severe, comminuted fracture of the distal part of the humerus. METHODS: We retrospectively reviewed forty-nine acute distal humeral fractures in forty-eight patients who were treated with total elbow arthroplasty as the primary option. The average age of the patients was sixty-seven years. Forty-three fractures were followed for at least two years. According to the AO classification, five fractures were type A, five were type B, and thirty-three were type C. The average age of the forty-three patients was sixty-nine years and the average duration of follow-up was seven years. Fourteen patients died during the review period. Postoperative clinical function was assessed with use of the Mayo elbow performance score, and anteroposterior and lateral radiographs made at follow-up examinations were reviewed. RESULTS: At the latest follow-up examination, the average flexion arc was 24 degrees (range, 0 degrees to 75 degrees ) to 131 degrees (range, 100 degrees to 150 degrees ) and the Mayo elbow performance score averaged 93 of a possible 100 points. Heterotopic ossification was present to some extent in seven elbows, with radiographic abutment noted in two. Thirty-two (65%) of the forty-nine elbows had neither a complication nor any further surgery from the time of the index arthroplasty to the most recent follow-up evaluation. Fourteen elbows (29%) had a single complication, and most of them did not require further surgery. Ten additional procedures, including five revision arthroplasties, were required in nine elbows; five were related to soft tissue and five were related to the implant or bone. CONCLUSIONS: Complex distal humeral fractures should be assessed primarily for the reliability with which they can be reconstructed with osteosynthesis. When osteosynthesis is not considered to be feasible, especially in patients who are physiologically older and place lower demands on the joint, total elbow arthroplasty can be considered. This retrospective review supports a recommendation for total elbow arthroplasty for the treatment of an acute distal humeral fracture when strict inclusion criteria are observed.

Adult↗
PubMed2004

Proximal ulnar reconstruction with strut allograft in revision total elbow arthroplasty.

BACKGROUND: The growing frequency of joint arthroplasty has led to increasing numbers of patients requiring revision surgery. In the treatment of a failed total elbow arthroplasty not associated with infection, one of the main issues is poor or absent proximal ulnar bone stock due to osteolysis. We report our experience with the use of strut allograft reconstruction of the proximal part of the ulna as an adjunct to revision total elbow arthroplasty with a noncustom implant. Our aim was to better define the indications, outcomes, and complications of this technique in a population of patients with a failed total elbow arthroplasty. METHODS: We reviewed the cases of patients with aseptic failure of a total elbow replacement and proximal ulnar bone deficiency who were treated with allograft bone struts. The patients had had an average of 2.5 (range, one to four) prior open osseous operations addressing the elbow joint. In addition to revision of the prosthetic components, the deficient bone stock was treated with allograft strut grafts in one of four ways: (1) discrete cortical defects were contained, (2) periprosthetic fractures were splinted, (3) deficient triceps attachments were reconstructed, and (4) expanded segments were augmented with struts and filled with impaction graft. Twenty-one patients (twenty-two elbows) were followed for an average of four years (range, two to eleven years). RESULTS: The mean Mayo Elbow Performance Score improved from 34 points preoperatively to 79 points at the time of the latest follow-up. The scores for pain, stability, and activities of daily living improved most; there was little change in motion. Complications, consisting of four soft-tissue and four osseous problems, occurred in eight patients. Three patients had incorporation of 26% to 50% of the graft; five, 51% to 75%; and fourteen, 76% to 100%. CONCLUSIONS: Most deficiencies of proximal ulnar bone stock and fractures complicating revision total elbow surgery can be treated with allograft strut grafting. Although the complication rate is high, this technique is suitable for discrete cortical lesions, periprosthetic fractures, and an expanded proximal part of the ulna, which also requires augmentation with impaction grafting. The technique has been unreliable, however, in restoring deficient olecranon bone stock.

Arthroplasty, Replacement↗
PubMed2003

Partial posteromedial olecranon resection: a kinematic study.

BACKGROUND: The posteromedial aspect of the olecranon process is a site of impingement and subsequent osteophyte development in throwing athletes. Treatment with débridement, with resection of osteophytes and varying amounts of normal olecranon bone, is common. We found no reports in the literature concerning the effects of resecting different amounts of normal bone from the posteromedial aspect of the olecranon. We hypothesized that excessive resection would increasingly alter elbow kinematics and that an optimum amount of olecranon resection could be identified. METHODS: We investigated the kinematic effects of increasing valgus and varus torques and posteromedial olecranon resections, in twelve cadaveric elbows, with use of an electromagnetic tracking device. Two valgus and two varus torques were applied, and three sequential resections were performed in 3-mm steps from 0 mm to 9 mm. Statistical analyses included paired t tests, 95% confidence intervals, a one-factor analysis of variance with repeated measures, and a post hoc test when significance was established. RESULTS: Sequential partial resection of the posteromedial aspect of the olecranon resulted in stepwise increases in valgus angulation with valgus torque. Clear differences were seen at each level of resection. A pattern of increased valgus angulation also was seen in association with increased valgus torque. Increased valgus torque resulted in a trend toward increased axial internal rotation of the ulna, whereas increased osseous resection resulted in a decrease in the absolute degree of internal rotation or, in some specimens, increased external rotation. CONCLUSIONS: Although no single critical amount of olecranon resection was identified, valgus angulation of the elbow increased in association with all resections, with a marked increase occurring in association with a 9-mm resection. Our findings challenge the rationale of removing any amount of normal olecranon bone in throwing athletes as doing so may increase strain on the medial collateral ligament. The implications for the professional throwing athlete are important, and we recommend that bone removal from the olecranon be limited to osteophytes, without the removal of normal bone.

Aged↗
PubMed2002

Metallic orthopaedic implants and airport metal detectors.

Airport security can detect in vivo metallic implants. We hypothesized that a soft tissue shield and fast transit through archway detectors would decrease implant detectability, whereas greater implant mass would increase detectability. Twelve patients with 8 orthopaedic implants in vivo and 60 trauma and arthroplasty implants in vitro were subjected to standard airport security measures at Stanstead Airport (British Airports Authority), including arch and standard and nonstandard hand-held detectors. Archway detectors failed to detect some implants; hand-held detectors detected almost all implants except an ankle arthroplasty. Positive archway detection was related to implant transit speed through the detection field. The implant mass consistently affected detection in stainless steel and titanium implants, and a 1-inch wax shield had no effect. Patients with metallic implants should prepare routinely with documentation of their implant before traveling through security ports.

Aviation↗
PubMed2002

Synovial osteochondromatosis of the elbow.

We present 12 patients with synovial osteochondromatosis of the elbow treated by synovectomy. Histological review showed that seven cases were primary and five secondary osteochondromatosis. The patients with primary disease had a mean improvement in the flexion arc from a preoperative value of 40 degrees to 123 degrees to 5 degrees to 128 degrees when reviewed at a mean of nine years after operation. The secondary group had a mean improvement in the flexion arc from a preoperative value of 21 degrees to 98 degrees to 4 degrees to 131 degrees at a mean of 6.8 years after operation. There was recurrence in two of seven patients in the primary group and three of five in the secondary group. Osteoarthritis developed in six elbows in the primary and in three in the secondary group. Osteoarthritis secondary to synovial osteochondromatosis is progressive. In the established condition, the distinction between primary and secondary disease may be of greater histological than clinical relevance.

Adolescent↗
PubMed2001

Osteofibrous dysplasia of the ulna.

Osteofibrous dysplasia is a rare condition usually ffecting the tibiae and fibulae of males in the first two decades of life. Involvement at the ulna has also been reported in some cases. We describe an extensive, rapidly progressive lesion of the ulna in a three-year-old girl. The progression of the disease accelerated after a local marginal removal, and required extensive resection of the ulna with reconstruction using a fibular autograft. The particular features of this case are the change in the aggressive nature of the condition, which has not been previously reported. We believe that this is only the second recorded case of histologically proven involvement of the ulna.

Bone Transplantation↗
PubMed2000

Idiopathic tumoral calcinosis of the index finger. Case report.

Tumoral calcinosis of the hand is rare, and we present a case report of idiopathic tumoral calcinosis of the index finger, which posed a diagnostic problem as it looked like an infection. We successfully removed the calcific deposit and there had been no recurrence one year after the operation.

Calcinosis↗
PubMed1999

The Mennen plate: unsuitable for elderly femoral peri-prosthetic fractures.

The Mennen plate has been advocated for femoral shaft and femoral peri-prosthetic fractures. We utilised this fixation system in five patients with peri-prosthetic femoral shaft fractures. The operative technique was that described by the CMW laboratories. The postoperative regimen deviated from that recommended, i.e. prolonged bed-rest, since the patients were elderly and complicated by chest problems and pressure sores. Once the surgical wounds had healed, at an average of 11 days (range 10-14 days), one patient achieved non-weight-bearing mobilisation. Four patients were managed with bed-to-chair transfer only. All five plates failed at an average of 32 days (range 15-42 days). Only one patient had an identifiable accident to account for the failure. Two patients underwent revision hip arthroplasty and two had revision fixation with Dall-Miles (Howmedica), and Cable Ready (Zimmer) plate and cables. Femoral shaft peri-prosthetic fractures are not adequately stabilised with the Mennen plate system, and prolonged recumbency in such an elderly population often worsens pre-existing medical problems. We advocate the use of one of the many available plate and cable fixation systems for such fractures in the elderly and in those in whom revision arthroplasty may not be possible.

Aged↗
PubMed1999

Peri-prosthetic femoral shaft fractures treated with plate and cable fixation.

Management of post-operative peri-prosthetic femoral shaft fractures remains difficult and controversial, with no widely accepted form of treatment. Fractures at the tip of a femoral component are associated with poor union rates. We present a series of 15 fractures at the component tip extending proximally in association with a loose cement mantle. All 15 patients were treated with open reduction and internal fixation using a plate and cable system. They were followed to clinical and radiological union, at an average of 3.5 months (range 3-5 months). At final review examination, 13 patients had achieved pre-fracture mobility, with one patient requiring a single walking stick, and one requiring a Zimmer frame. Three patients under-went revision surgery after successful fracture union and rehabilitation, with long stemmed femoral components. The plate and cable procedure is not technically demanding and avoids hip exposure. This form of internal fixation provides immediate fracture stability, allowing early ambulation, hence avoiding the complications and difficulties of other methods of treatment. Such fractures should be acutely treated to achieve fracture union with a plate, cable, and screw internal fixation technique. The loose components can be revised electively, preferably by a revision hip surgeon.

Aged↗
PubMed1999

Percutaneous fixation of scaphoid fractures. An anatomical study.

Percutaneous scaphoid fracture fixation has many advantages over the open method of fixation. We describe the anatomical basis for a safe percutaneous approach. Cannulated screws were inserted into 32 cadaveric scaphoids through 1 cm palmar incisions under fluoroscopic control. We then measured the distance between the entry point in the scaphoid and important local neurovascular structures. We also measured the angle of entry of the guide wire in two planes. The mean distance of the entry point from the main radial artery was 14 mm (range, 7-24 mm); from the radial nerve 19 mm (range, 7-35 mm); from the recurrent branch of the median nerve 29 mm (range, 14-45 mm); and from the superficial branch of the radial artery 5 mm (range, 0-8 mm) The mean radial angle of insertion was 34 degrees and the mean palmar angle of insertion was 58 degrees. Percutaneous fixation of scaphoid fractures puts the superficial palmar branch of the radial artery at risk. We recommend a 1 cm incision centred over the scaphotrapezial joint and dissection under direct vision to the entry point in the scaphoid rather than a completely percutaneous approach.

Bone Screws↗
PubMed1998

The posterior interosseous nerve and the posterolateral approach to the proximal radius.

We dissected 21 cadaver elbows to determine the relationship of the posterior interosseous nerve to the posterolateral approach to the elbow and head of the radius. At the distal end of the exposure the first branches at risk, those to extensor carpi ulnaris, were on average 6.0 +/- 1.0 cm (4.0 to 8.4) from the articular surface of the radial head. When using the posterolateral approach it is important that the interval between extensor carpi ulnaris and anconeus is clearly identified with the forearm fully pronated. The supinator should be released close to its ulnar border. It is safe to expose the proximal radius as far as the distal aspect of the bicipital tuberosity.

Adult↗
PubMed1997

Eccrine porocarcinoma.

Eccrine porocarcinoma is a malignant tumor of eccrine sweat glands. It is a very rare, slow growing tumor and clinically resembles other skin cancers. We report a case and review its clinical and pathological features. These tumors have a propensity for local recurrence, and wide excision with negative margins is recommended.

Acrospiroma↗
PubMed1994

Recurrent symptoms of urinary tract infection in eight patients with refluxing ureteric stumps.

OBJECTIVES: To evaluate and discuss the recurrent symptoms presented by eight patients with refluxing ureteric stumps. PATIENTS AND METHODS: Eight patients (three boys, five girls; mean age: 8 years, range 11 months-14 years) with refluxing ureteric stumps presented with recurrent urinary tract infections. Six developed symptoms mimicking pyelonephritis, even though the kidney had been partially [5] or totally [3] removed. The stump was removed in all patients. RESULTS: The stumps that were excised measured between 5 and 10 cm in length and were always dilated and inflamed. The results of histological examination and follow-up are reported. CONCLUSIONS: A dual approach is recommended when complete excision of the kidney and ureter is required. Symptoms of pyelonephritis are not pathognomonic of parenchymal infection but reflect infection above the vesico-ureteric junction. The distinction between supra-junctional and infra-junctional urinary tract infections seems more appropriate and is discussed.

Adolescent↗