Geriatric nutritional risk index as the prognostic factor in older patients with fragility hip fractures.

This study investigated the long-term survival and incidence of secondary fractures after fragility hip fractures. The 5-year survival rate was 62%, and the mortality risk was seen in patients with GNRI < 92. The 5-year incidence of secondary fracture was 22%, which was significantly higher in patients with a BMI < 20. BACKGROUND: Malnutrition negatively influences the postoperative survival of patients with fragility hip fractures (FHFs); however, little is known about their association over the long term. OBJECTIVE: This study evaluated the ability of the geriatric nutritional risk index (GNRI) as a risk factor for long-term mortality after FHFs. METHODS: This study included 623 Japanese patients with FHFs over the age of 60 years. We prospectively collected data on admission and during hospitalization and assessed the patients' conditions after discharge through a questionnaire. We examined the long-term mortality and the incidence of secondary FHFs and assessed the prognostic factors. RESULTS: The mean observation period was 4.0 years (range 0-7 years). The average age at the time of admission was 82 years (range 60-101 years). The overall survival after FHFs (1 year, 91%; 5 years, 62%) and the incidence of secondary FHFs were high (1 year, 4%; 5 years, 22%). The multivariate Cox proportional hazard analysis revealed the risk factors for mortality as older age (hazard ratio [HR] 1.04), male sex (HR 1.96), lower GNRI score (HR 0.96), comorbidities (malignancy, HR 2.51; ischemic heart disease, HR 2.24; revised Hasegawa dementia scale ≤ 20, HR 1.64), no use of active vitamin D3 on admission (HR 0.46), and a lower Barthel index (BI) (on admission, HR 1.00; at discharge, HR 0.99). The GNRI scores were divided into four risk categories: major risk (GNRI, < 82), moderate risk (82-91), low risk (92-98), and no risk (> 98). Patients at major and moderate risks of GNRI had a significantly lower overall survival rate (p < 0.001). Lower body mass index (BMI) was also identified as a prognostic factor for secondary FHFs (HR 0.88 [p = 0.004]). CONCLUSIONS: We showed that older age, male sex, a lower GNRI score, comorbidities, and a lower BI are risk factors for mortality following FHFs. GNRI is a novel and simple predictor of long-term survival after FHFs.

Relationship between baseline characteristics and response to risedronate treatment for osteoporosis: data from three Japanese phase III trials.

We evaluated the influence of baseline age, bone mineral density (BMD), and serum levels of vitamin D on the response to risedronate treatment. Risedronate consistently increased BMD, but our results suggest vitamin D supplementation may be necessary to achieve optimal treatment effect. Furthermore, early intervention may help prevent bone fractures. INTRODUCTION: We aimed to investigate the influence of baseline age, BMD, and vitamin D insufficiency on the response to risedronate treatment. METHODS: Data regarding 1447 patients was obtained from the registries of three phase III clinical trials of risedronate. The response to treatment was expressed in terms of BMD increase and occurrence of new vertebral fractures. The patients were stratified by baseline values for age (<65, 65-72, and ≥72 years), lumbar spine BMD T-score (osteoporotic, <-2.5; and non-osteoporotic, ≥- 2.5), and serum levels of 25-hydroxyvitamin D (deficient, <21 ng/mL; and non-deficient, ≥21 ng/mL). RESULTS: Risedronate consistently increased lumbar spine BMD in all the groups, with similar percentage and absolute increments in all the age tertiles. The percentage, but not absolute, increment in BMD was significantly higher (p = 0.0003) in the osteoporotic than that in the non-osteoporotic patients (baseline). Of the 1330 patients whose baseline serum levels of 25-hydroxyvitamin D were available, 44.7% had vitamin D deficiency (<20 ng/mL), while 89.2% had insufficiency (<30 ng/mL). The percentage and absolute increments in BMD were lower (p < 0.05 and p < 0.01, respectively) in the vitamin D-deficient than those in the non-deficient patients. New vertebral fractures occurred in 1.5 and 0.8% of the osteoporotic and non-osteoporotic patients, respectively (end of the treatment). CONCLUSIONS: Therapeutic response in elderly patients is consistent, but early initiation of risedronate treatment may help prevent fractures. Risedronate-induced increase in BMD is lower in patients with vitamin D deficiency, suggesting that vitamin D supplementation is important to achieve optimal treatment response.

Prognostic factors associated with a subchondral insufficiency fracture of the femoral head.

OBJECTIVE: The aim of this study was to identify the risk factors associated with the prognosis of a subchondral insufficiency fracture of the femoral head (SIF). METHODS: Between June 2002 and July 2009, 25 patients diagnosed with SIF were included in this study. Sequential radiographs were evaluated for the progression of collapse. Clinical profiles, including age, body mass index, follow-up period and Singh's index, were documented. The morphological characteristics of the low-intensity band on T(1) weighted MRI were also examined with regards to four factors: band length, band thickness, the length of the weight-bearing portion and the band length ratio (defined as the proportion of the band length to the weight-bearing portion of the femoral head in the slice through the femoral head centre). RESULTS: Radiographically, a progression of collapse was observed in 15 of 25 (60.0%) patients. The band length in patients with progression of collapse [22.5 mm; 95% confidence interval (CI) 17.7, 27.3] was significantly larger than in patients without a progression of collapse (13.4 mm; 95% CI 7.6, 19.3; p<0.05). The band length ratio in patients with progression of collapse (59.8%; 95% CI 50.8, 68.9) was also significantly higher than in patients without a progression of collapse (40.9%; 95% CI 29.8, 52.0; p<0.05). No significant differences were present in the other values. CONCLUSION: These results indicate that the band length and the band length ratio might be predictive for the progression of collapse in SIF.

Effect of intra-articular lesions on the outcome of periacetabular osteotomy in patients with symptomatic hip dysplasia.

In order to clarify how intra-articular lesions influence the survival of a periacetabular osteotomy in patients with dysplasia of the hip, we performed an observational study of 121 patients (121 hips) who underwent a transposition osteotomy of the acetabulum combined with an arthroscopy. Their mean age was 40.2 years (13 to 64) and the mean follow-up was 9.9 years (2 to 18). Labral and cartilage degeneration tended to originate from the anterosuperior part of the acetabulum, followed by the femoral side. In all, eight hips (6.6%) had post-operative progression to Kellgren-Lawrence grade 4 changes, and these hips were associated with the following factors: moderate osteoarthritis, decreased width of the joint space, joint incongruity, and advanced intra-articular lesions (subchondral bone exposure in the cartilage and a full-thickness labral tear). Multivariate analysis indicated subchondral bone exposure on the femoral head as an independent risk factor for progression of osteoarthritis (p = 0.003). In hips with early stage osteoarthritis, femoral subchondral bone exposure was a risk factor for progression of the grade of osteoarthritis. Although the outcome of transposition osteotomy of the acetabulum was satisfactory, post-operative progression of osteoarthritis occurred at a high rate in hips with advanced intra-articular lesions, particularly in those where the degenerative process had reached the point of femoral subchondral bone exposure.

Morphological analysis of collapsed regions in osteonecrosis of the femoral head.

In order to investigate the mechanisms of collapse in osteonecrosis of the femoral head, we examined which part of the femoral head was the key point of a collapse and whether a collapsed region was associated with the size of the necrotic lesion. Using 30 consecutive surgically removed femoral heads we retrospectively analysed whole serial cut sections, specimen photographs, specimen radiographs and histological sections. In all of the femoral heads, collapse consistently involved a fracture at the lateral boundary of the necrotic lesion. Histologically, the fractures occurred at the junction between the thickened trabeculae of the reparative zone and the necrotic bone trabeculae. When the medial boundary of the necrotic lesion was located lateral to the fovea of the femoral head, 18 of 19 femoral heads collapsed in the subchondral region. By contrast, when the medial boundary was located medial to the fovea, collapse in the subchondral region was observed in four of 11 femoral heads (p = 0.0011). We found that collapse began at the lateral boundary of the necrotic lesion and that the size of the necrotic lesion seemed to contribute to its distribution.

Radiological outcome analysis of transtrochanteric curved varus osteotomy for osteonecrosis of the femoral head at a mean follow-up of 12.4 years.

We investigated the factors related to the radiological outcome of a transtrochanteric curved varus osteotomy in patients with osteonecrosis of the hip. We reviewed 73 hips in 62 patients with a mean follow-up of 12.4 years (5 to 31.1). There were 28 men and 34 women, with a mean age of 33.3 years (15 to 68) at the time of surgery. The 73 hips were divided into two groups according to their radiological findings: group 1 showed progression of collapse and/or joint-space narrowing; group 2 had neither progressive collapse nor joint-space narrowing. Both of these factors and the radiological outcomes were analysed by a stepwise discriminant analysis. A total of 12 hips were categorised as group 1 and 61 as group 2. Both the post-operative intact ratio and the localisation of the necrotic lesion correlated with the radiological outcome. The cut-off point of the postoperative intact ratio to prevent the progression of collapse was 33.6%, and the cut-off point to prevent both the progression of collapse and joint-space narrowing was 41.9%. The results of this study indicate that a post-operative intact ratio of 33.0% is necessary if a satisfactory outcome is to be achieved after this varus osteotomy.

Long-term outcome of transtrochanteric anterior rotational osteotomy for osteonecrosis of the femoral head in patients with systemic lupus erythematosus.

This study sought to examine the long-term outcomes of transtrochanteric anterior rotational osteotomy (ARO) as treatment for osteonecrosis of the femoral head (ONFH) in patients with systemic lupus erythematosus (SLE). Twenty-one patients (33 hips), aged 20-40 years, underwent ARO between 1980 and 1988. We examined 16 patients (25 hips), a 76% follow-up rate. A Kaplan-Meier curve was used for survivorship analysis. Patients with surviving hips were evaluated by the modified Oxford hip score and Short Form 36 (SF-36). Twelve hips in eight patients had survived at the final follow-up. The average length of hip survival was 24.6 years (range: 20.1-27.2 years). Three patients (six hips) had died of unrelated causes without any subsequent operation. Based on Kaplan-Meier analysis with the endpoint defined as the need for a subsequent operation, the hip survival rate at 25 years was 73.7% (95% confidence interval, +/-19.8%). Based on classification by the modified Oxford hip score, five hips were classified as excellent, two hips were good, and the remaining five hips were fair. The average SF-36 summary score for the physical and mental components was 38.7 and 47.2 points, respectively. The physical component summary scores for three patients exceeded the normal level of the Japanese population. Lupus (2010) 19, 860-865.

[Infective endocarditis with acute embolism to the lower extremity artery caused by a vegetation: report of a case].

Successful surgical treatment of a case of infective endocarditis with embolism to a lower extremity artery is reported. A 71-year-old man was referred to our hospital for the treatment of infective endocarditis. Echocardiography showed a vegetation on the non-coronary cusp of the aortic valve measuring 19 mm in diameter. We planned surgical treatment, including aortic valve replacement, however, embolism of a lower extremity artery by the vegetation occurred during the waiting period for the operation. We removed the offending vegetation from the popliteal artery and replaced the peccant aortic valve with a prosthetic valve in separate operations. The postoperative course was uneventful and the patient was transferred to another hospital on the 33rd day after the valve replacement surgery.

Th1 but not Th17 cells predominate in the joints of patients with rheumatoid arthritis.

OBJECTIVES: Recent animal studies have revealed critical roles of interleukin (IL)17, which is produced by a newly identified subset of helper T cells, Th17 cells, in the development of autoimmune diseases including arthritis. However, in human rheumatoid arthritis (RA), detailed characteristics and the prevalence of Th17 cells are unclear. METHODS: Peripheral blood mononuclear cells (PBMC) were obtained from 123 patients with RA and 28 healthy controls. Mononuclear cells were also prepared from synovial membrane or synovial fluid of 12 patients with RA. IL17 (IL17A) positive T cells were identified by a flow cytometer after ex vivo stimulation with phorbol myristate acetate and ionomycin. Disease activity was assessed with the 28-joint Disease Activity Score (DAS28). RESULTS: IL17 positive cells were detected in CD45RO+ CD4 T cells. Most IL17 positive T cells produced neither interferon (IFN)gamma nor IL4, but tumour necrosis factor (TNF)alpha similar to murine Th17 cells. The frequency of Th17 cells was neither increased in RA nor correlated with DAS28. Unexpectedly, the frequency of Th17 cells was significantly decreased in the joints compared with PBMC of the same patients with RA, whereas Th1 cells were more abundant in the joints than in PBMC. CONCLUSIONS: We could not obtain evidence that positively supports predominance of Th17 cells in RA. Further careful investigation is necessary before clinical application of IL17-targeting therapy.

Leg-length discrepancy after transtrochanteric curved varus osteotomy for osteonecrosis of the femoral head.

Transtrochanteric curved varus osteotomy was designed to avoid some of the disadvantages of varus wedge osteotomy, such as post-operative leg-length discrepancy. In this retrospective study we investigated the leg-length discrepancy and clinical outcome after transtrochanteric curved varus osteotomy undertaken in patients with osteonecrosis of the femoral head. Between January 1993 and March 2004, this osteotomy was performed in 42 hips of 36 patients with osteonecrosis of the femoral head. There were 15 males and 21 females with a mean age at surgery of 34 years (15 to 68). The mean follow-up was 5.9 years (2.0 to 12.5). The mean pre-operative Harris hip score was 64.0 (43 to 85) points, which improved to a mean of 88.7 (58 to 100) points at final follow-up. The mean varus angulation post-operatively was 25 degrees (12 degrees to 38 degrees ) and the post-operative mean leg-length discrepancy was 13 mm (4 to 25). The post-operative leg-length discrepancy showed a strong correlation with varus angulation (Pearson's correlation coefficient; r = 0.9530, p < 0.0001), which may be useful for predicting the leg-length discrepancy which can occur even after transtrochanteric curved varus osteotomy.

Effects of local infusion of OP-1 on particle-induced and NSAID-induced inhibition of bone ingrowth in vivo.

Excessive polyethylene wear particles from joint replacements may lead to periprosthetic osteolysis and loosening. Nonsteroidal anti-inflammatory drugs (NSAIDs) decrease fracture healing and bone ingrowth. We hypothesized that continuous local infusion of OP-1 (BMP-7) would increase local bone formation in the presence of two different adverse stimuli, polyethylene particles, and an oral NSAID. The Drug Test Chamber (DTC) was implanted in the proximal tibia of mature rabbits. The tissue growing into the chamber was exposed to OP-1 solution (110 ng/day), which was infused via an osmotic pump. Infusion of OP-1 alone for 6 weeks enhanced local bone formation in the chamber by 80% (p < 0.05) over infusion of carrier alone. In the presence of polyethylene particles, infusion of OP-1 increased local bone formation by 38% (p < 0.05) over treatment with particles and carrier. Oral administration of NSAID reduced local bone formation by 58% (p < 0.05); this suppressive effect caused by NSAIDS was completely reversed by the infusion of OP-1 (p < 0.05). These findings underline a potential role for local treatment with OP-1 to increase bone formation in the presence of potentially adverse stimuli such as polyethylene wear particles or NSAID use.

[Lung cancer in patients with idiopathic interstitial pneumonia].

The purpose of this study was to determine the outcome of surgical treatment for lung cancer concomitant with idiopathic interstitial pneumonia (IIP). Between 1994 and 2003, 673 patients with primary lung cancer were treated. Forty-four patients (6.54%) of 673 patients were complicated with IIP. Their data were retrospectively reviewed. There were 37 male and 7 female with an average age of 67 years. They underwent 7 wedge resections of the lung, 3 segmentectomies, 32 lobectomies and 2 bi-lobectomies as surgical treatment for lung cancer. Five of these 44 patients died of acute exacerbation of IIP after the operation. The exacerbation occurred in an average postoperative day of 5 (range, 3 to 7) day. Preoperative values of serum CRP, LDH, SP-D and KL-6 failed to predict the occurrence of the exacerbation of IIP after the surgery. The preoperative value of %DLCO was lower in patients with the exacerbation than patients without the exacerbation (42.3+/-9.6% versus 66.8+/-18.8%, p=0.018). The postoperative 5-year survival rate for pathological stage I lung cancer were 84.9% and 70.2% (p=0.134) for patients without IIP and patients with IIP, respectively. Although the acute exacerbation of IIP after the surgery caused catastrophic outcomes, the long-term results in surgical treatment for stage I lung cancer simultaneously concomitant with IIP were not so poor. It is very important to avoid the postoperative exacerbation and further effort and research are required to avoid the exacerbation.

[Removal of a steel bar after Nuss procedure for pectus excavatum; report of a case].

Recently, an increasing number of patients have been treated with the Nuss procedure for pectus excavatum. One of the merits is that this surgical procedure is less invasive and leads to good cosmetic results compared with the former traditional procedures such as sternal turn over. We have repaired 60 cases of pectus excavatum using the Nuss procedure at our institute since July 1999. We have experienced the removal of a steel bar, which was the first case of Nuss procedure at our institute.

The accuracy of image-guided knee replacement based on computed tomography.

Our study evaluated the accuracy of an image-guided total knee replacement system based on CT with regard to preparation of the femoral and tibial bone using nine limbs from five cadavers. The accuracy was assessed by direct measurement using an extramedullary alignment rod without radiographs. The mean angular errors of the femur and tibia, which represent angular gaps from the real mechanical axis in the coronal plane, were 0.3 degrees and 1.1 degrees, respectively. The CT-based system, provided almost perfect alignment of the femoral component with less than 1 degrees of error and excellent alignment with less than 3 degrees of error for the tibial component. Our results suggest that standardisation of knee replacement by the use of this system will lead to improved long-term survival of total knee arthroplasty.

[Strategy for surgical treatment for small peripheral carcinoma of the lung especially on systemic nodal dissection].

The diagnosis of small-sized (< or = 2 cm) non-small cell lung cancer (NSCLC) has increased with the development of computed tomography (CT), whereas unexpected extensive mediastinal involvement has been occasionally detected in such a small-sized lung cancer. We retrospectively analyzed the clinicopathological features to determinate the predictors for lymph node involvement in patients with a small-sized adenocarcinoma. One hundred and eighty one patients who underwent pulmonary resection and systematic nodal dissection for a peripheral small-sized adeno-carcinoma were reviewed. Of these, 24 patients (13.3%) had lymph node involvement. These patients were divided into 2 groups according to the existence of lymph node involvement, and the predictors for lymph node involvement were determined using univariate analysis and multivariate regression analysis. Univariate analysis revealed GGOR (ground glass opacity area/tumor area at the level of the greatest dimension of the lesion on chest computer tomography) > or = 25% (p = 0.0137) and pleural lavage fluid involvement (p = 0.0467) as predictors for lymph node involvement. No patients had lymph node involvement if their GGOR was higher than 50%. Multivariate regression analysis revealed GGOR > or = 25% (p = 0.0274), pleural tags on the lesion on chest CT (p = 0.0138) and pleural lavage fluid involvement (p = 0.0415) as predictors. We recommend performing systemic nodal dissection even if small peripheral adeno-carcinoma's maximal diameter is 20 mm or less. Systemic nodal dissection is unnecessary if the patients' GGOR > or = 50% or they do not have pleural tags or pleural lavage fluid involvement.

[Complications of major lung resections by video-assisted thoracoscopic surgery].

Lobectomy by video-assisted thoracoscopic surgery (VATS) is gradually being performed more frequently because of advantages regarding pain and pulmonary function. Complications sometimes occur during or after VATS lobectomy. The purpose of this study was to analyze the incidence and the causes of the complications. From 1997 to 2003, 185 patients underwent VATS lobectomies. Selected diseases for this approach included primary lung cancer (n = 172), metastatic lung cancer (n = 7), benign lung tumors (n = 3) and lung sequestration (n = 3). The VATS approach was converted to open thoracotomy in 15 (8.1%) of 185 patients because of bleeding (n = 8), dense hilar adenopathy (DHA, n = 3), local extent of disease (n = 3) of intraoperative cardiac trouble (n = 1). Intraoperative complications involved injury to a blood vessel (n = 21), stapling failure (n = 15), lung injury (n = 7), nerve injury (n = 3), and others. Predictive factors for injury to pulmonary arteries was DHA (OR 37.0, p < 0.0001). Postoperative surgical death occurred in 2 patients due to pneumonia. Postoperative morbidity was 22.9%. A surgical operation without any good direct or thoracoscopic view or the use of a thoracoscopic tool without knowledge of the directions on its use should be avoided. The VATS approach should be replaced by open thoracotomy if there are DHA.

[Congenital tracheal stenosis due to complete cartilage rings with right pulmonary agenesis].

A 2-month-old male infant with severe dyspnea was diagnosed as having right pulmonary agenesis at birth and was admitted to our hospital after tracheal intubation with an endotracheal tube of 3 mm in diameter. However, the trachea was too stenotic to place the tube in the proper position. Chest X-ray on admission showed pneumonia of the left lung. Preoperative chest computed tomography (CT) scan and bronchoscopy showed that from the level of 12 mm beneath the coricoid cartilage, the trachea tapered and continuing to the tracheal carina and that the smallest tracheal level was located 18 mm distal from the coricoid cartilage, the area of which was 4 mm2. His respiratory condition rapidly deteriorated in spite of intravenous administration of antibiotics and mechanical ventilation. Percutaneous cardiopulmonary support (PCPS) was used to maintain his pulmonary function, and pericardial tracheoplasty was performed. Chest X-ray immediately after the operation did not show left lung reexpansion due to severe pulmonary edema. High-dose steroid pulse therapy was performed, but it was not effective. He died from acute respiratory failure due to infantile respiratory distress syndrome (IRDS) on postoperative day 3. The outcome in this case shows that it is very risky to repair tracheal stenosis in a patient with pneumonia using PCPS.

[Surgery for metastatic lung tumors at our department during the last ten years].

We report on 86 cases (112 operations) who underwent surgery for metastatic lung tumors at our department during the last 10 years. The study subjects comprised 53 men and 33 women, and the average age was 51 (+/- 19) years. Of the 112 metastatectomies performed, 53 were conducted by video-assisted thoracic surgery (VATS), and 59 were performed via thoracotomy. The procedures employed for metastatectomy were lobectomy (22 cases), segmentectomy (4 cases), and partial resection. wedge resection (86 cases). The primary origin of the metastatic tumors was colorectal carcinoma in 22 cases, osteosarcoma in 13 cases, renal carcinoma in 10 cases, and breast carcinoma in 6 cases. The 5-year survival rates in subjects undergoing first and second resection for pulmonary metastases were 46% and 44%. Metastatectomy was performed 1, 2, 3, 4, 5, and 7 times in 73, 7, 1, 2, 2, 1 cases, respectively. The average number and maximum diameter of the metastatic pulmonary lesions at first metastatectomy were 1.9 and 27.6 mm. Metastatectomy is performed, as a rule, by VATS at our department, because the more highly invasive thoracotomy procedure influences the activity of the cancer cells in a suspended phase in an unfavorable manner. Furthermore, we believe that to the maximum extent possible, re-metastatectomy should also be performed by VATS. The survival rates at our institution have been satisfactory, and we attribute this to our following strict indications for metastatectomy. Re-metastatectomy should always be considered, as the survival rates are as favorable as those following the first metastatectomy.

Bronchial stump reinforcement in right pneumonectomy with fascia lata and gelatin resorcin formalin (GRF) glue: case report.

We reinforced the bronchial stump with fascia lata and Gelatin Resorcin Formalin (GRF) glue in a right pneumonectomy. This method was found to be simple and useful. We describe our case and the method herein. A 62-year-old woman had a malignant polypoid lesion which completely occluded the introitus of the right main bronchus and deviated to the introitus of the left main bronchus. Right pneumonectomy was done but materials (pleura, pericardium, intercostal muscle, etc.) obtained from the thoracic cavity were insufficient for bronchial stump reinforcement due to severe adhesion caused by prior tuberculosis. Therefore, we reinforced the bronchial stump using the fascia lata and GRF glue. Fascia lata is a superior material for reinforcement in terms of strength and ease of molding, as well as harvesting. GRF glue is a superior adhesive with rapid and strong fixation. We consider this method of reinforcing the bronchial stump with fascia lata and GRF glue to be feasible, in particular, for pneumonectomy or lobectomy without adequate material in the thoracic cavity because of severe adhesion or lesions.

Mixture of hyaluronic acid and phospholipid prevents adhesion formation on the injured flexor tendon in rabbits.

Dipalmitoyl phosphatidylcholine, a highly surface-active polar lipid, has been implicated as a potential boundary lubricant for synovial joints. We examined the effects of dipalmitoyl phosphatidylcholine on the flexor tendon and its protective effect against postoperative adhesion in two experimental steps. First, the flexor digitorum fibularis and the distal pulley of rabbits were set for a friction test. The test was performed with saline solution, sodium hyaluronate, or a mixture of dipalmitoyl phosphatidylcholine and sodium hyaluronate as the lubricant. The friction coefficient was significantly lower with the mixture of dipalmitoyl phosphatidylcholine and sodium hyaluronate than with saline solution or sodium hyaluronate. We concluded that the decreased friction coefficient indicates that dipalmitoyl phosphatidylcholine could complement the boundary-lubricating ability of the tendon. In the second experiment, we used an experimental adhesion model of the flexor digitorum fibularis in the rabbit. During the operation, either saline solution, sodium hyaluronate, or a mixture of dipalmitoyl phosphatidylcholine and sodium hyaluronate was injected into the tendon sheath. The specimen was sent to another tester, and the work required to tear off the adhesion was measured. The work required was significantly greater for the tendons that had been injected with saline solution than for those given injections of dipalmitoyl phosphatidylcholine and sodium hyaluronate. Our findings suggest that dipalmitoyl phosphatidylcholine plays an important role in the boundary lubrication of the tendon and that after tendon injury, the administration of a mixture of dipalmitoyl phosphatidylcholine and sodium hyaluronate may improve tendon lubrication and prevent adhesion formation.