Cementless ceramic total hip arthroplasty: a 5 to 16 year follow-up

BACKGROUND

Cementless total hip arthroplasty (THA) was invented to replace cemented THA and thus avoided cement disease, which shortened the longevity of implants. Ceramic THA was an early type of cementless THA which was used at our institution for several years. In the literature, reports about ceramic THA are very rare, moreover, the results of THA are controversial. This retrospective study was to report our experience.

MATERIALS AND METHODS

Seventy-two cementless ceramic THAs were performed and followed for at least 5 years (range, 5 to 16 years; average, 9.8 years) at our institution. Patients ranged in age from 23 to 68 years (average, 45 years) with a male to female ratio of 3 to 1. A modified d'Aubigne and Postels' method was used to evaluate the functional and radiographic outcomes.

RESULTS

Only 51.4% of the cases achieved a satisfactory result. Furthermore, the complication rate was very high, especially for aseptic loosening (34.7%). For ankylosing spondylitis cases, the satisfactory result rate was only 30% (2/7) and the unsatisfactory cases even had a loosening rate of 80% (4/5).

CONCLUSION

Compared to other types of cementless THA, the satisfactory result rate with ceramic THA was markedly lower and the complication rate was relatively higher. Therefore, we conclude that cementless ceramic THA is not an ideal implant and its usage should be strictly restricted.

Treatment of clavicular aseptic nonunion: comparison of plating and intramedullary nailing techniques

OBJECTIVE

The aim of this retrospective study was to investigate and compare the effects of plating and intramedullary nailing in the treatment of clavicular aseptic nonunion.

METHODS

Thirty-three consecutive patients with middle-third clavicular aseptic nonunions with previous nonoperative treatment were treated by plating (13 patients) and intramedullary nailing (20 patients) with supplementary cancellous bone grafting. The indications for such treatment were middle-third aseptic nonunions without previous operative treatment and with local pain or tenderness, deformity, or neurologic complaint. The choice of plating or intramedullary nailing was according to the surgeon's individual preference.

RESULTS

Twenty-nine patients were followed for at least 1 year (range, 1-7 years; median, 3 years; plating, 11; intramedullary nailing, 18). The union rate was 81.8% (9 of 11) for plating and 88.9% (16 of 18) for intramedullary nailing (p = 0.35, Fisher's exact test). The union period was 4.0 +/- 1.3 months for plating and 4.1 +/- 1.1 months for intramedullary nailing (p = 0.80, unpaired Student's t test). The complication rate was 27.3% (3 of 11) for plating and 11.1% (2 of 18) for intramedullary nailing (p = 0.21, Fisher's exact test). There were no significant differences in other parameters.

CONCLUSION

Intramedullary nailing may have a higher union rate with a lower complication rate than plating (p > 0.05). At least in common situations, it is not inferior to plating. Whenever possible, therefore, intramedullary nailing should be used preferentially to treat clavicular aseptic nonunion without previous operative treatment. Nevertheless, both techniques have relatively higher nonunion rates in the treatment of clavicular nonunion than in the treatment of other long-bone nonunions. Gentle handling of surrounding soft tissues to reduce bony fragments should be strictly executed.

Treatment of cutout of a lag screw of a dynamic hip screw in an intertrochanteric fracture

Sixteen consecutive patients with cutout of a lag screw of a dynamic hip screw fixation in an intertrochanteric fracture were treated with reinsertion of a lag screw, bone cement supplementation in the neck-trochanter, and subtrochanteric valgus osteotomy. Postoperatively, patients were permitted to ambulate with protected weight-bearing. Fourteen patients were followed-up for at least 1 year (median 2 years; range 1-3 years), and all had a solid union. The union period took a median of 5 months, with a range of 3-7 months. Usually, union of an intertrochanteric fracture was faster than that of subtrochanteric osteotomy (P < 0.01). There were no complications of wound infection, loss of reduction, cutout of a lag screw, or osteonecrosis of the femoral head. From clinical and theoretical considerations, we conclude that despite cutout of a lag screw of a dynamic hip screw fixation being difficult to treat, out technique still can provide an excellent outcome. Therefore, we strongly recommend its wide use.

Bone healing of tibial lengthening is enhanced by hyperbaric oxygen therapy: a study of bone mineral density and torsional strength on rabbits

We investigated the effect of intermittent hyperbaric oxygen (HBO) therapy on the bone healing of tibial lengthening in rabbits. Twelve male rabbits were divided into two groups of six animals each. The first group went through 2.5 atmospheres absolute of hyperbaric oxygenation for 2 hours daily, and the second group did not go through hyperbaric oxygenation. Each animal's right tibia was lengthened 5 mm using an uniplanar lengthening device. Bone mineral density (BMD) study was performed for all of the animals at 1 day before operation and at 3, 4, 5, and 6 weeks after operation. All of the animals were killed at 6 weeks postoperatively for biomechanical testing. Using the preoperative BMD as an internal control, we found that the BMD of the HBO group was increased significantly compared with the non HBO group. The mean %BMD at 3, 4, 5, and 6 weeks were 69.5%, 80.1%, 87.8%, and 96.9%, respectively, in HBO group, whereas the mean %BMD were 51.6%, 67.7%, 70.5%, and 79.2%, respectively, in non-HBO group (two tailed t test, p < 0.01, p < 0.01, p < 0.01, and p < 0.01 at 3, 4, 5, and 6 weeks, respectively). Using the contralateral nonoperated tibia as an internal control, we found that torsional strength of lengthened tibia of the HBO group was increased significantly compared with the non-HBO group. The mean percent of maximal torque was 88.6% in HBO group at 6 weeks, whereas the mean percent of maximal torque was 76.0% in non-HBO group (two-tailed t test, p < 0.01). The results of this study suggest that the bone healing of tibial lengthening is enhanced by intermittent hyperbaric oxygen therapy.

Case report: Metachronous early gastric carcinoma in a reconstructed gastric tube after radical operation for oesophageal carcinoma

The incidence of double cancer has increased as a result of the significant advances in both diagnostic procedures and anti-cancer therapy, and as the outcome of oesophageal squamous cell carcinoma (ESCC) has improved, the number of cases of double cancer of the oesophagus and stomach has also increased. Two patients with metachronous early gastric carcinoma in a reconstructed gastric tube were successfully treated after subtotal oesophagectomy for ESCC. These cases have shown that early diagnosis of second cancer is very important for curative therapy.

Total hip arthroplasty in Salmonella coxitis: four cases report

Suppurative coxitis induced by salmonella is rarely reported in the literature. Furthermore, reconstruction with a total hip arthroplasty (THA) in such patients has never been reported. However, in this study, we present 4 cases; 2 normal male patients and 2 female patients with underlying systemic lupus erythematosus (SLE). The ages range from 26 to 61 years. All 4 cases revealed growth of group B salmonella from the cultures of synovial fluid. They all received THA after the infections were eradicated. The functional assessment of pain, range of motion, walking ability together with the radiographic assessment were used according to the new hip score system. After a minimum follow-up of 2 years, all of the reconstructed hips showed good to excellent results since no infections recurred during this period. Although the long-term results are uncertain, the short-term clinical advantage of THA in the treatment of quiescent salmonella coxitis is encouraging.

Simultaneous anterior dislocation of the shoulder and fracture of the ipsilateral humeral shaft. Two case reports

Two patients with anterior dislocation of the shoulder and ipsilateral fracture of the shaft of the humerus have been studied and the mechanism of their injuries has been documented. Closed reduction of the dislocations was performed under anaesthesia during surgery for humeral fixation with a dynamic compression plate. The fractures and dislocations healed without any problems at 6 to 9 months postoperatively. At recent follow-up, one patient had returned to work and regained normal mobility. The other patient had the sequelae of a brachial plexus injury. The literature on this subject is reviewed.

Altered p16/MTS1/CDKN2 and cyclin D1/PRAD-1 gene expression is associated with the prognosis of squamous cell carcinoma of the esophagus

The p16/MTS1/CDKN2 gene and the cyclin D1/PRAD-1 gene cooperatively regulate cyclin-dependent kinase 4-mediated phosphorylation of pRB in the cell cycle of normal cells. p16/CDKN2 gene and cyclin D1/PRAD-1 gene alterations have been detected in squamous cell carcinoma cell lines and in several primary squamous cell carcinomas of the esophagus. We immunohistochemically assessed p16 and cyclin D1 expression in 111 squamous cell carcinomas of the esophagus after evaluation of the antibodies against p16 and cyclin D1 protein using four squamous cell carcinoma cell lines. Loss of p16 expression was detected in 56 of 111 cases (50%). The mean number of metastatic lymph nodes without p16 expression was significantly higher than the number of nodes with p16 expression (P = 0.04). The postoperative survival rate for patients without p16 expression was significantly lower than that of patients with p16 expression (P = 0.04). Cyclin D1 overexpression was found in 28 of the 111 cases (25%) and correlated with distant organ metastasis after curative surgery (P = 0.05). The survival rate of patients with cyclin D1 overexpression was significantly lower than that of patients without cyclin D1 overexpression (P = 0.01). A positive correlation between the loss of p16 expression and cyclin D1 overexpression was observed (P = 0. 03). The loss of p16 expression and overexpression of cyclin D1 may be useful prognostic indicators in patients with squamous cell carcinomas of the esophagus. It may be possible to select more suitable treatment for patients with squamous cell carcinomas of the esophagus by evaluating the status of p16 and cyclin D1 expression.

Staged management of infected humeral nonunion

Fourteen patients with infected humeral nonunion complicated by sinus discharge were treated with a staged protocol consisting of (1) radical debridement with local antibiotic beads implantation, and (2) external skeletal fixation with autologous bone grafting. In the first stage, a thorough debridement and sequestrectomy were done. Antibiotic beads were used to obliterate the bone defect, and the wound was then directly closed. In the second stage, the bead chains were replaced with autogenous cancellous bone graft. Unilateral Hoffman external skeletal fixators were applied simultaneously. The mean follow-up period was 73.6 months (range, 29 months to 9 years). The length of time to achieve bony union ranged from 3.5 to 8 months (average, 4.3 months). Hoffman pin complication was found in two cases, which were then shifted to plate internal fixation. All the infections were eradicated, and the wounds healed without further skin graft or flap coverage. All the fractures achieved bony union except for one in a patient who died. Most patients acquired satisfactory function of elbow motion after removal of external fixation and physical therapy. The method of two-stage management was effective for infected humeral nonunion. Not only was the infection eradicated and osseous union achieved, but also the limb function and joint motion were preserved.

Augmentative plate fixation for the management of femoral nonunion after intramedullary nailing

Seventeen femoral nonunions after intramedullary nail internal fixation were treated with augmentative plate internal fixation. Six of them were initially managed with a Küntscher nail internal fixation; the other 11 fractures were managed with a locked nail internal fixation. All the femoral nonunions were caused by insecure fixation of the intramedullary nailing, in which a rotational instability of the fracture site was verified in all cases during operation. Leaving the intramedullary nail in situ, an augmentative plate fixation was applied to the fracture site to counter the rotational instability. A simultaneous bone grafting was performed in seven of them to repair the bony defect. All these patients walked bearing full weight on the extremity without aching at the fracture site within 3 months and all these 17 fractures obtained a bony union within an average of 7 months after this treatment. From our experience, we have found this method is a useful treatment for the nonunion of the femoral shaft fracture after an intramedullary nail internal fixation. The technique is simple and does not require any special instrument. It facilitates an early weight bearing and gives a quick recovery from nonunion.

Incidence of hepatitis C infection in a hepatitis C endemic township in southern Taiwan

To realize the incidence of hepatitis C virus (HCV) infection in an HCV endemic township, Tzukuan, in Taiwan, we conducted a follow-up community-based survey. A total of 173 adults, 82 males and 91 females, with mean age of 55.5 +/- 9.9 years received initial and follow-up anti-HCV tests with one-year interval. One (1.2%, 95% CI: 0%-5.5%) of 84 anti-HCV-positive subjects was negative-seroconversion, and 4 (4.5%, 95% CI: 0.2%-8.8%) of 89 anti-HCV-negative subjects were positive-seroconversion. The results indicated that hepatitis C might be still spreading in the HCV-endemic area now.

Management of large infected tibial defects with antibiotic beads local therapy and staged fibular osteoseptocutaneous free transfer

Fifteen patients with tibial fractures complicated by large infected tibial defects were treated with a two-stage protocol. In the first stage, antibiotic-impregnated polymethylmethacrylate bead chains were used to obliterate the debrided osseous defect, and a meshed porcine skin was used for temporary wound coverage. In the second stage, the bead chains were removed, and the defects were reconstructed with a microvascularized fibular osteoseptocutaneous free transfer. The time between the first and second stages of treatment was 2 to 6 weeks. The bone defects ranged from 6 to 16 cm, and the skin defect areas ranged from 10 to 82 cm2. Wound healing and bony union were achieved in all 15 cases. An additional muscle flap or skin graft was required for only three patients with a large skin defect. Minor pin tract infections were seen in two patients. Stress fractures in three cases were successfully managed with bracing, external skeletal fixation or plating, and cancellous bone grafting. All of the most recent roentgenograms showed good consolidation and hypertrophy of grafted fibular bones. No recurrence of osteomyelitis was observed during an average follow-up period of 50 months (range, 36-86 months). We therefore conclude that this treatment protocol provides rapid recovery from osteomyelitis. The fibular osteoseptocutaneous graft is a useful method for the reconstruction of a large tibial defect, and it also offers the unique advantage of simultaneously reconstructing a moderate skin defect.

Slipped capital femoral epiphyses in a patient with primary hyperparathyroidism

Slipped capital femoral epiphyses are rarely associated with primary hyperparathyroidism, and only four cases have been documented in the English literature. We report such a case. A 13-year-old boy presented with bilateral slipped capital femoral epiphyses. Investigation showed that he had primary hyperparathyroidism due to a parathyroid adenoma. The adenoma was removed, and then the epiphyses were pinned in situ 3 weeks later. The pins were removed 3 months postoperatively when the physes had closed. The patient had a painless hip 1 year later at follow-up. We concluded that identification and excision of the hyperparathyroid adenoma and in situ pinning of the slipped epiphyses results in satisfactory treatment of the condition.

Different viral aetiology of hepatocellular carcinoma between two hepatitis B and C endemic townships in Taiwan

In Taiwan, we found two hepatitis B virus (HBV)- and hepatitis C virus (HCV)-endemic townships, Paisha and Tzukuan, with an anti-HCV prevalence of 19 and 37% in men, and 26 and 38% in women, respectively. The hepatitis B surface antigen (HBsAg)-positive rates were 25 and 18%, for men and women in Paisha, and 25 and 22% in Tzukuan, respectively. According to the national death certification database (1982 to 1991), the annual age-adjusted mortality rates per 100,000 population for liver cancer among men and women were 83.0 and 13.8, respectively, in Paisha, and 55.9 and 17.0 in Tzukuan compared with 30.9 and 9.1 in Taiwan as a whole. The male-to-female ratios were 6.0 in Paisha and 3.3 in Tzukuan. Aetiology of 11 cases of hepatocellular carcinoma (HCC) from Paisha and 14 cases from Tzukuan were analysed. All HCC cases from Paisha were HBsAg positive, while 13/14 HCC cases from Tzukuan were anti-HCV positive. The endemic duration of HCV in Tzukuan seemed long enough to induce HCC, but the HCV appeared to be a newly introduced infection in Paisha.

Survivorship analysis of DKS instrumentation in the treatment of spondylolisthesis

This retrospective study analyzed the survivorship of DKS instrumentation and the clinical outcomes in 185 patients with spondylolisthesis. These patients were treated with Zielke DKS instrumentation for a mean followup period of 3.5 years. Eight (4.3%) patients had late removal of implants, 25 (14%) had rod breakage, three (1.7%) had screw breakage, and 16 (8.7%) had nut loosening. The survivor rate of DKS instrumentation was 96% within 3 months after operation, 80% at 2 years, and 61% at 5 years after surgery. One hundred sixty-three (88%) patients had solid posterolateral fusion, and 167 (90%) patients had good to excellent results. Adjacent instability developed in 18 (9.7%) patients. Although Zielke DKS instrumentation has a smaller rod and relatively insecure locking system between the rod and screw, it is an effective implant for the treatment of spondylolisthesis.

Primary uncemented Osteonics total hip arthroplasty: preliminary results of 2-6 year follow-up

BACKGROUND

Cemented total hip arthroplasty (THA) bears the inherent disadvantages of cement complications. A research toward the improvement of uncemented prosthesis design continues to evolve. The purpose of this report is to present the preliminary results and to identify common problems in uncemented THA.

METHODS

The results of 402 primary Osteonics total hip prostheses were reviewed with an average follow-up period of 3.1 years. The postoperative rating according to the modified D' Aubigne & Postel hip score included functional and radiographic analysis.

RESULTS

The results were rated as good or excellent in 95% of hips. Stable fixation of the prosthesis was shown in 97% of radiographs. The most common zone of focal osteolysis was in the periarticular area.

CONCLUSION

The clinical results in a 2 to 6 year follow-up was encouraging. A relatively high incidence of thigh pain did not correlate with femoral canal filling of prosthesis. Periarticular osteolysis is still an unsettled problem in uncemented prostheses and needs further investigation.

Measurement of polyethylene wear in cementless total hip arthroplasty

We made a clinical study of polyethylene wear in 240 hips of 187 patients having primary total hip arthroplasties from 1989 to 1990, using uncemented Osteonics components, with a head size of 26 mm. We excluded cups with anteversion of over 20 degrees and measured linear wear by a new method using a digitiser and special software of our design. Follow-up was from two to five years (mean 4.3). The mean age at operation was 50.3 years, with more men than women (1.4:1). The mean linear wear per year was 0.15 mm; this did not increase with the longevity of the prosthesis (p = 0.54). In 59 hips showing evidence of osteolysis, the mean linear wear rate was significantly higher at 0.23 mm/year (p <0.001). The mean linear wear rate also correlated significantly with age at the time of operation (p = 0.008), but we found no significant correlations with body-weight, gender, aetiology of the disease, thickness of polyethylene, or cup position. Our new method of measurement is time-saving and reproducible. The results confirm the greater rate of linear wear of polyethylene in patients showing osteolysis and in those who are younger.

Pyomyositis of the calf muscles mimicking distal deep venous thrombosis: a case report

Pyomyositis is a pyogenic infection of skeletal muscle. It is relatively rare in temperate climates. Unfamiliarity with the lesion may lead to a delay in diagnosis. This report describes pyomyositis of the calf muscles in a patient with chronic hepatitis whose clinical symptoms simulated those of distal deep venous thrombosis. The correct diagnosis was not made until computed tomography revealed a local abscess in the calf muscles.

A Morse-code recognition system with LMS and matching algorithms for persons with disabilities

Single-switch communication is an effective auxiliary method for persons with disabilities. However, it is not easy to recognize the Morse codes typed by them. In our earlier proposed Morse code auto-recognition method, using the Least-Mean-Square (LMS) adaptive algorithm, it was demonstrated that the system could successfully recognize the Morse-coded messages at unstable typing speeds. However, the speed variation had to be limited to a range between 0.67 and two times the present speed. In the case of beginners or those with heavy disabilities, this rule can not always be complied with, producing a low recognition rate of 20%. To address this limitation, this paper offers an advanced recognition method which combines the Least-Mean-Square algorithm with a character-by-character matching technique. The recognition rate for this method from simulated and real data from various sources is as high as 75% or more on average. This practical application of the single-switch method means a step forward toward alternative communication for disabled persons.

Effect of emergency physician-performed pelvic sonography on length of stay in the emergency department

STUDY OBJECTIVE

To evaluate the sensitivity and specificity of emergency physician-performed pelvic sonography (EPPPS) and its effect on length of stay (LOS) in the emergency department.

METHODS

The study involved a prospective observational convenience sample of women in early pregnancy requiring ED pelvic ultrasound evaluation. Differences in LOS were analyzed with the use of the Mann-Whitney test, with EPPPS and consultation status as classification variables. Results were stratified by diagnosis to identify patient subsets in which EPPPS had the greatest impact. A multivariate model was used to determine the independent associations of EPPPS and consultation status with LOS.

RESULTS

Among 115 pregnant patients, those who underwent EPPPS had a decreased median LOS compared with those who received pelvic sonography administered by radiologists or obstetrics-gynecology consultants (60 versus 180 minutes; P < .001). Obstetrics-gynecology consultation was associated with an increase in LOS from 60 to 170 minutes (P < .001). Stratification revealed that the decreased LOS was most significant in patients with viable intrauterine pregnancies (IUPs) and was not seen in those with abnormal pregnancies. This result was attributed primarily to the need for consultation in the latter group. Multivariate analysis demonstrated that EPPPS remained significantly associated with decreased LOS overall, after adjustment for the potentially confounding effect of consultation status (P < 001). The sensitivity of EPPPS for IUP was 94% (95% confidence interval [CI], 82% to 98%), and the specificity was 100% (95% CI, 83% to 100%). All 10 ectopic pregnancies, six of which were detected by EPPS and are included in the aforementioned sensitivity and specificity analysis, plus four detected by NEPPPS, were correctly identified; none was missed. No patient had an adverse outcome as a result of EPPPS.

CONCLUSION

Pelvic ultrasound performed by emergency physicians after a brief period of training shortens ED LOS in women in early pregnancy, particularly in those with viable IUPs. This practice appears to be sensitive, specific, and safe.

Effect of intermittent cigarette smoke inhalation on tibial lengthening: experimental study on rabbits

We investigated the effect of intermittent cigarette smoke inhalation on the bone healing of tibial lengthening in rabbits. Thirty-eight male rabbits were divided into two groups of 19 animals each. The first group went through intermittent cigarette smoke inhalation, and the second group did not go through intermittent cigarette smoke inhalation. Each animal's right tibia was lengthened 5 mm using an uniplanar lengthening device. Five animals of each group were killed at 4, 6, and 8 weeks postoperatively for biomechanical testing, and one animal of each group was killed at 2, 4, 6, and 8 weeks postoperatively for histologic study. Using the contralateral nonoperated tibia as an internal control, we found that torsional strength of the lengthened tibia of the smoke inhalation group was decreased significantly compared with the non-smoke inhalation group. The mean percent of maximal torque at 4, 6, and 8 weeks were 22.0, 66.3, and 78.6%, respectively, in the smoke inhalation group, whereas the mean percent of maximal torque were 48.0, 84.1, and 90.8% %, respectively, in non-smoke inhalation group (one-tailed t test, p < 0.01, p < 0.01, and p < 0.05 at 4, 6, and 8 weeks, respectively). Our histologic observations revealed that the granulation tissue resorption, bone formation, and remodeling were delayed in smoke inhalation group. The results of this study suggest that intermittent inhalation of cigarette smoke delays, but does not prevent, the bone healing in tibial lengthening.

[Metastatic spine disease: surgical treatment by anterior corpectomy and Ziekel's VDS fixation]

The spine is the common site of skeletal metastases. The goal of surgical treatment of metastatic spine disease is to improve the quality of remaining life, by relief of pain, the preservation or restoration of neurologic function, and reconstruction of the spinal stability. From 1984 through June 1993, 40 consecutive patients underwent surgical treatment by anterior corpectomy, and bone cement with VDS fixation for corporal metastatic diseases. There were 28 men and 12 women. The average age was 53.2 years, range from 21 to 76 years. Twenty-four patients had metastasis to the thoracic spine, 12 to the lumbar spine, and 4 had both thoracic and lumbar metastases. The primary malignancies were lung cancers in 10 cases, colorectal carcinomata in 6, hepatomas in 5, thyroid cancers in 4, cancer of stomach, renal, breast, nasopharynx, long bone, skin, cervical in 1 case respectively. A primary carcinoma was never identified in 8 patients. In the present series, 4 patients died within one month, 36 patients were allowed for follow-up study. Thirty-two patients (89%) attained pain relief. Thirty patients presented with neurologic compromise. After operation, neurologic improvement was noted in 21 (70%). No patient's neurologic function deteriorated secondary to surgical intervention. We conclude that anterior corpectomy to decompress neural encroachment with VDS and cement fixation to stabilize the collapsed spine is an adjunctive treatment to reduce pain and restore the neurologic function in these highly selected patients.

Biomechanical analysis of location of lag screw of a dynamic hip screw in treatment of unstable intertrochanteric fracture

OBJECTIVE

The aim of this study was to assess the most adequate location of a lag screw of a dynamic hip screw in the treatment of an unstable intertrochanteric fracture.

METHODS

Six pairs of proximal femora obtained from fresh adult cadavers were inflicted with iatrogenic unstable intertrochanteric fractures. Fractures of both sides were stabilized with two different favored locations of a lag screw and tested by a Material Testing System machine with increased loads to evaluate the relative migration of the femoral head.

RESULTS

There was significant difference (p < 0.05) with less migration of the femoral head by inferior insertion of a lag screw in the frontal plane and central insertion in the coronal plane.

CONCLUSIONS

Based on theoretical and experimental considerations, the most adequate location of a lag screw of a dynamic hip screw should be inferior in the frontal plane and central in the coronal plane.

Reduction-fixation spinal system in spondylolisthesis

Posterior transpedicular instrumentation with short segmental fixation represents a current trend in surgery for unstable spinal problems, such as spondylolisthesis. A reduction-fixation spinal system with 5.75- to 6.25-mm diameter pedicle screws of variable angles and an 8-mm diameter rod can achieve a rather rigid, short-segment fixation and satisfactory reduction of spondylolisthetic deformities. In clinical applications, 84% of 85 patients with spinal instability had good-to-excellent results for back pain, 88% for sciatica, and 86% for claudication; 91% achieved solid posterolateral fusion from the roentgenographic studies. This reduction-fixation system achieved a reduction of 71% +/- 5.3% of slipping width in this population. Posterior lumbar interbody fusion is mandatory for effective and lasting reduction. Complications from reduction fixation including pedicle-screw loosening (12%), pedicle screw breakage (7%), adjacent instability (7%), and nerve root injury (2%).

Adaptive Morse-coded single-switch communication system for the disabled

Automatic recognition of Morse-code is generally developed at a fixed typing rate. However, this is not suitable for the disabled due to their difficulty in maintaining a stable typing rate. In this paper, a system recognizing varying typing speeds is developed using an adaptive technique, the Least-Mean Square (LMS) algorithm. This system helps the disabled have a wide latitude and varying typing speeds in single-switch communication with the Morse-code.

Management of large infected tibial defects with radical debridement and staged double-rib composite free transfer

Seven patients with tibial fractures complicated by large infected tibial defects were treated with a two-stage protocol. In the first stage, antibiotic-impregnated polymethylmethacrylate (PMMA) bead chains were used to obliterate the debrided osseous defect, and a meshed porcine skin was used for temporary wound coverage. In the second stage, the bead chains were removed, and the defects were reconstructed with a microvascularized double-rib and serratus anterior muscle composite free transfer. The interval between the first and second operations was 2 to 4 weeks. The bone defects ranged from 6 to 9 cm, and the skin defect areas ranged from 20 to 40 cm2. Wound healing and bony union was achieved in all seven cases. Minor pin track infection was seen in one patient. Stress fractures in two cases were successfully managed with patellar tendon short-leg bracing for 6 months in one case and a plate internal fixation in the other case. Within 2 years, all seven patients returned to light work without any external support, and all of their most recent radiographs showed good consolidation and hypertrophy of grafted rib bones. No occurrence of osteomyelitis was observed during an average follow-up of 37 months (out of a range of 24 to 50 months). We conclude that this treatment protocol provides rapid recovery from osteomyelitis and the double-rib graft is a useful, durable alternative for large tibial defect management.

Vastus lateralis flaps for chronic recalcitrant hip infection

Between January 1991 and May 1994, 11 patients with chronic recalcitrant infection of the hip joint were successfully treated by transposition of a vastus lateralis flap. The average duration of the infection was 7.9 months. The patients had undergone an average of 2.8 procedures in an attempt to eradicate the infection before transposition of the flap. Three patients had recurrence of drainage after the procedure and were successfully treated with antibiotics and local debridement. Delayed exchange total hip arthroplasty was performed in 2 patients. All the patients achieved wound healing and infection resolution. This flap has several advantages. The donor site has not usually been scarred from previous operations; the flap has a consistent vascular pedicle which permits a wide arc of rotation; knee extension is unaffected; the transposed portion of the vastus lateralis can act as a cushion between the acetabulum and the proximal femur; it may also act as a tether to prevent extreme proximal migration of the femur. In the management of chronic recalcitrant infection of the hip, use of a transposition flap can be combined with a Girdlestone arthroplasty. It can also be an interim procedure before a further total joint arthroplasty.

Calorimetric characterization of the formation of acrylic type bone cements

The formation of acrylic bone cements upon heating was investigated by differential scanning calorimetry (DSC). The effects of the contents of initiators, accelerator, biocompatibilizer, and crosslinking agents on the rate and the heat of polymerization during DSC heating were studied. The rate and the heat of polymerization (delta H) were characterized by the peak temperature and the area of the DSC exotherm, respectively. It was found that both the rate and heat of polymerization decreased with increasing heating rate. The delta H was increased considerably with increasing benzoyl peroxide (BPO) initiator concentration from 1 to 10% (w/v), whereas the rate of polymerization was reduced significantly. An increase in azobisisobutyronitrile (AIBN) initiator concentration also induced an increase in delta H, but the rate of reaction was not affected considerably. The addition of accelerator promoted the rate of reaction but resulted in a drop in delta H. The rate of polymerization for the system containing BPO initiator was increased quite significantly with the addition of hydroxyethyl methacrylate (HEMA) biocompatibilizer, while the delta H was slightly increased. For the system using AIBN as the initiator, the rate of polymerization was decreased slightly and the delta H dropped significantly with the addition of HEMA. The effect of ethylene glycol dimethacrylate (EGDMA) crosslinking agent was also examined. Polymerization became more rapid with the addition of EGDMA in the bone cement using BPO initiator, while it remained approximately constant for the system using AIBN as the initiator. No systematic change in delta H was observed with the addition of EGDMA in both systems. This study demonstrated that DSC is a potential tool to measure the amount of heat released and also the rate of polymerization for bone cements.

Distal tibial nonunion treated by intramedullary reaming with external immobilization

Seventeen distal tibial nonunions were treated by a combination of metal removal with closed intramedullary reaming for internal bone graft and application of a long leg cast for aseptic nonunions and an external fixator for quiescent septic nonunions. The nonunions were present for a median of 1.8 years (range, 1.2-3.4 years). All achieved a solid union with a union period of 5.2 +/- 1.6 months. There was one complication of a renewed infection in a septic nonunion. The functional rating score improved from all unsatisfactory before treatment to 13 satisfactory after treatment. The other four (all were infected nonunions) also improved from poor to a fair outcome. In conclusion, the technique described is a simple and effective method to treat some complex distal tibial nonunions.

Back pain after thoracolumbar fracture treated with long instrumentation and short fusion

The purposes of this retrospective study are to evaluate the degeneration of facets in unfused segments immobilized by Harrington rods and to see how often back pain developed after treatment with this method. Sixty patients with thoracolumbar fracture were treated with the Harrington rod long-fuse short technique. Harrington rods are removed an average of 14 months after initial surgery. Every case showed solid fusion during implant removal exploration. Thereafter, all cases were followed for a minimum of 5 years. Roentgenographic studies and a bone scan were performed to evaluate the degeneration of facet joints. Back pain complaint was found in 11 patients (18.3%). The degeneration of unfused facets was visualized in six patients by roentgenograms. Increased activity in the instrumented spine by bone scan examination also was noted in six patients: three cases were at unfused area, one at a fused area, and two at fused and unfused areas. In conclusion, degeneration in the immobilized and unfused segments after rod long and fused short was rarely seen clinically after long-term follow-up. Back pain was experienced in only 18.3% of the patients and seldom required medication.

Prevalence of antibody to hepatitis E virus among healthy individuals in southern Taiwan

The seroprevalence of hepatitis E virus (HEV) among 997 healthy individuals aged 6 to 84 years, collected between July 1993 and June 1994 at Kaohsiung-Pingtung area in Southern Taiwan was studied. Of the study populations of vegetable farmers, elementary school children, volunteer blood donors and college students, the prevalence of IgG anti-HEV ranged from 6.4% to 8.8%. In suburban elemantary school children of Mang-Chou Village at Pingtung-Hsien, the seroprevalence rate (9.6%) was significantly higher than the positive rate (1.5%) found in rural aboriginal elementary school of San-Min Village at Kaohsiung-Hsien. IgG anti-HEV antibodies were widely distributed among all age groups, with a significantly higher percentage (13.1%) in the age group of 46-55 years old.

Ilizarov femoral lengthening in adults

From January 1990 to December 1991, we treated 12 cases of length discrepancy due to femoral inequality with the technique of Ilizarov femoral lengthening. The patients' ages ranged from 20 to 33 years (average, 28 years). Of these, nine patients were men and three were women. Corticotomy was performed either at the distal metaphysis or at the junction of distal metaphysis and diaphysis. After a latency of seven to ten days, distraction commenced at a rate 0.25 mm every six to twelve hours. Bone generation was obtained in all patients without the need of bone grafting. The average length gained in femoral bone was 4.7 cms (range, 3 to 7 cms). The average duration of total treatment was 10.1 months (range, 7 to 15 months). The healing index was 2.2 (number of months per 1 cm elongation) on average. All patients were satisfied with the results, but all felt that it was an uncomfortable procedure. According to our experience, we conclude that the method of Ilizarov is an useful technique for femoral lengthening. However, it is an uncomfortable and tedious procedure.

The quantitative measurements of hip isometric muscle torques in Chinese young adults--a preliminary report

A standard procedure for measurement of hip muscle strength (maximal isometric torque) with the Cybex 340 isokinetic dynamometer is presented. Twenty-two healthy males aged 30-40 years (average 34.3 years) were tested on hip flexors, extensors and abductors; in which the factors as sex, age, dominant side and testing session were all eliminated. The test was redone two weeks later on the same 10 males to evaluate its reproducibility. The results disclosed the maximal isometric torque of the hip flexors was stronger than that of extensors and abductors in both sides hips. The comparison between two sides hips showed only the abductors of right side hip significantly stronger than that of left side (P = 0.0259). The tests between the two different periods were quite compatible. The results have clinical implications for objective assessment of preoperative and postoperative hip strengths in patients with hip arthropathy and thus giving a reasonable guidance for physiotherapeutic management.

Surgical treatment for deltoid contracture in adults

In a retrospective study, 60 shoulders in 38 adults with deltoid contracture were surgically treated by proximal or distal releases. Twenty-three patients, representing 34 treated shoulders, were followed up for at least 2 years (median was 4 years). By the last follow-up, all patients achieved satisfactory outcomes: freedom from pain, full range of motion, and normal muscle power. The proximal release was used in patients with one-portion (one of the deltoid origins) involvement, and the distal release was used in patients with two- or three-portion involvement. Three shoulders (5%) had postoperative complications in the form of intramuscular hematomas, which were resorbed spontaneously within 3 weeks. The authors recommend surgical release to treat deltoid contracture whenever indicated.

Surgical treatment of tuberculous spondylitis. 50 patients followed for 2-8 years

We treated 50 adult patients with tuberculous spondylitis surgically and followed them for a mean of 5 (2-8) years. All had persistent back pain, 32 had neurologic deficit, and 13 had gibbus deformity. Anterior debridement and fusion were the main operative procedures. Additional posterior stabilization was performed in 14 patients who had loss of a vertebral body or for correction of severe kyphosis. 30 of the 32 patients with neurological impairment had an improvement of 1-3 Frankel's grades after operation. All patients had some relief of pain. Solid bony union of the fusion was found in 46 patients and 4 had nonunion after anterior operation only. The average correction of the kyphotic angle was 10 degrees.

Double-rib composite free transfer to reconstruct a single-spared lower extremity defect

The case of a 43-year-old man is reported in which a 15-cm defect of the tibia sustained 8 months previously was treated by the double-rib composite microvascular free transfer. The fracture site united, and the grafted ribs showed some hypertrophy at 1 year. He returned to his job. At 5 years follow-up, the x-ray film showed good hypertrophy of the grafted ribs.

Pulmonary tuberculosis as a source of infection after total hip arthroplasty. A report of two cases

Two cases of septic loosening due to a tuberculosis infection occurred 18 months and 14 years after total hip arthroplasties. The primary source was pulmonary tuberculosis. Treatment was by removal of the prosthesis and radical debridement with the local implantation of gentamicin PMMA beads, followed by antituberculosis chemotherapy for one year. In the first case, a revision arthroplasty was carried out 20 months later; the second was reconstructed with a vastus lateralis transposition one month later. There was no recurrence of infection after a follow up of 3 and 2 years respectively. Although this is a rare complication, the possibility must be born in mind. Early diagnosis and treatment of pulmonary tuberculosis may prevent the secondary infection of a total hip arthroplasty.

[Floating shoulder (ipsilateral scapular neck and clavicle fracture)--two cases report]

Fracture of either clavicle or scapular neck alone are generally stable and have satisfactory results by conservative treatment. However, displaced scapular neck and ipsilateral clavicle fractures are relatively unstable. Those sequelae as drooping shoulder and limited range of motion may develop if treated conservatively. Surgical intervention either fixation of clavicle alone or fixation of clavicle and scapular neck simultaneously can achieve stable reduction of the fractures and prevent those sequelae. We present two cases of floating shoulder treated surgically with excellent results.

Incorporation of allograft for acetabular reconstruction. Single photon emission CT in 21 hip arthroplasties followed for 2.5-5 years

We studied 21 hips in 20 patients who had acetabular reconstruction with a femoral head allograft in primary (n 2) and secondary (n 19) total hip arthroplasty. The fate of the graft was evaluated by serial bone SPECTs (single photon emission computed tomography). With a mean follow-up period of 37 (30-60) months, 14 of the 21 hips showed evidence of incorporation at earliest 13 (6-18) months after operation. There was no correlation between the fate of allograft and the compatibility of A, B, O blood typing between host and donor, the use of bone cement in the fixation of acetabular component, or loosening of the acetabular component.

Irreducible volar rotatory dislocation of the proximal interphalangeal joint

Volar rotatory dislocation of the proximal interphalangeal (PIP) joint often cannot be reduced by closed manipulation because of interposition of soft tissues. In this case, the condyle of the proximal phalanx was trapped between the central slip and the lateral band. This case is reported to reemphasize the importance of recognizing serious injuries involving the soft tissues around the PIP joint. Deprival of its normal dorsal stabilizing forces can cause a loss of both static and dynamic joint support. Secondary scarring and contractures affect all damaged structures of the joint.

The intra-articular migration of the broken wire: a rare complication of circumferential wiring in patellar fractures

Patellar fractures are frequently encountered in emergency situations. With proper treatment, the outcome is usually favorable. This study focuses on a rare complication of circumferential wiring in a case of patellar fracture treated by open reduction. A technical error which may have caused this complication is analyzed.

Acetabular allograft reconstruction in total hip arthroplasty: preliminary report with clinical, roentgenographic and scintigraphic analyses

From January 1986 to June 1991, we used structural allografts to augment major acetabular deficiencies during primary or revision total hip arthroplasty (THA) in 54 patients. Forty-four patients (46 hips) with a minimal follow-up of two years were reviewed. The average patient age was 50.2 years. The diagnosis was loose THA component in 36 hips, six failed Austin-Moores, three septic hip sequelae, and one failed bipolar hemiarthroplasty. Their preoperative hip ratings (modified d'Aubigne and Postel rating system) averaged 10.7 points. Forty-five allografts (98%) united roentgenographically with an average union period of 11.8 months. Five acetabular components (10.9%) developed aseptic loosening; one of them underwent revision using a healing allograft and one hip needed further acetabular reconstruction with allograft due to complete necrosis of the original allograft. One additional hip required resection arthroplasty for septic loosening. The 43 surviving hips had a mean hip score of 16.7 points at the latest follow-up. Radiographic evidence of graft resorption was seen in eight hips, which was not correlated with acetabular loosening. Serial single photon emission computed tomography (SPECT) study was employed postoperatively in 20 patients (21 hips) to assess the healing process and graft viability. Seven allografts (33.3%) were nonviable on serial SPECT studies, while 14 allografts (66.7%) were viable. The compatibility of host-donor A, B, O blood typing and the use of cement did not correlate with allograft viability. Allograft viability did not contribute to the failure of cup components. Considering the major acetabular deficiency and the absence of sufficient autograft material, the use of frozen allografts appears to be justified.(ABSTRACT TRUNCATED AT 250 WORDS)

Semiopen cancellous bone grafting. A 2 step method for closing small infected tibial bone defects

Thirteen infected small tibial bone defects with overlying skin loss were treated with a 2 stage procedure. In the 1st stage, antibiotic impregnated polymethylmethacrylate bead chains were used to obliterate the debrided osseous cavity and a meshed porcine skin graft was used for temporary wound coverage. In the 2nd stage, the bead chains were replaced with autogenous cancellous bone graft, and the wound was again covered with a meshed porcine skin graft. All wounds and bone grafts healed without the need for an additional autogenous skin or bone graft. The patients were hospitalized an average of 23 days. The length of time to the completion of secondary epithelialization of the wound ranged from 2 to 5 months (average, 3 months). The length of time to bone union ranged from 5 to 8 months (average, 6.4 months). An additional application of porcine skin graft was required in 3 patients. Minor pin tract infections were seen in 2 patients. There was no recurrence of osteomyelitis during an average followup of 37 months (range, 24-54 months). This method was helpful in securing the closure of infected tibial bone defects with small skin losses and avoided both prolonged hospitalization and the morbidity usually accompanying free tissue transfer or the Papineau method of open cancellous bone grafting.

Intercondylar fractures of the distal humerus: routine anterior subcutaneous transposition of the ulnar nerve in a posterior operative approach

Intercondylar fractures of the distal humerus in adults are rare and notoriously difficult to treat. The goals of open reduction are to preserve the articular surface and restore elbow function. We treated 20 patients by open reduction with dual-plate internal fixation and routine anterior subcutaneous transposition of the ulnar nerve. The follow-up period ranged from 15 to 35 months. The fractures were classified according to Muller's system. The results were evaluated using the Cassebaum rating system and subjective functional status. Excellent or good results were achieved in 15 elbows (75%), two had a fair result, and three, poor. A clearer understanding of fracture patterns, rigid dual-plate internal fixation, and early rehabilitation are needed to improve the results from this vexing injury. We recommended routine ulnar nerve anterior subcutaneous transposition using a posterior approach. Compared with published reports, our preliminary results demonstrated no postoperative ulnar nerve compression syndrome at follow-up. Routine anterior subcutaneous transposition of the ulnar nerve to avoid the postoperative ulnar nerve compression syndrome is required.

Muscular recovery around the hip joint after total hip arthroplasty

A prospective study was conducted to quantitatively measure the relative muscle torque strengths in 20 consecutive women with unilateral osteoarthritic hips and 20 consecutive men with unilateral osteonecrotic hips before and after primary cementless total hip arthroplasty. Maximal isometric torque strengths in the muscles of flexion, extension, and abduction around the hip joint were measured preoperatively and postoperatively at six months and one year, using a Cybex 340 dynamometer. The results showed improved muscle function after total hip arthroplasty in both diseased and healthy hips. In the diseased hips, all muscle groups improved significantly, from 150 to 250% of the preoperative levels, at six months and one year postoperatively, except in the osteoarthritic women, in whom the improvement at six months was minimal. Preoperatively, all muscle groups in the diseased hips were weaker than those in the uninvolved hips, especially in the osteonecrotic men (51-79% of healthy side). In both groups, however, the torques strengths of the diseased hips had not caught up to the healthy hips in the one-year follow-up period (84-89% in the osteonecrotic male group, and 79-81% in the osteoarthritic female group). The authors recommended that muscle strengthening exercises for the hip should be continued for at least one year, and perhaps longer, after total hip arthroplasty.

Localized femoral osteolysis in cementless ceramic total hip arthroplasty

A retrospective review revealed localized femoral osteolysis occurred in 8 out of 134 cementless ceramic total hip arthroplasties (6.0%) performed during an average 9-year period. The average latent period was 8 years. The lesion was usually located in the deeper periprosthetic area. Localized osteolysis usually occurred after loosening of the femoral stem, suggesting the pathogenesis may be a foreign-body reaction to the ceramic debris.