Long-term results of partial repair for irreparable rotator cuff tear.

BACKGROUND: The irreparability of rotator cuff repair is generally determined during surgery. We have been performing partial repairs for rotator cuff tears that are deemed irreparable with primary repair. The aim of this study is to report, for the first time, the long-term postoperative outcome of our partial repair method and to clarify the criteria for the irreparability of primary repair. METHODS: The UCLA score, radiographic findings, and magnetic resonance imaging findings of 156 shoulders that underwent rotator cuff repair (primary repair, 126 shoulders; partial repair, 30 shoulders) were retrospectively evaluated at preoperative and >10-year postoperative follow-up (mean evaluation time, 11.5 ± 1.0 years). Osteoarthritic (OA) changes were evaluated by radiographic findings, and the cuff integrity (Sugaya classification) and fatty infiltration (Goutallier classification) were evaluated by magnetic resonance imaging findings. These evaluations were compared between a primary repair group and partial repair group. RESULTS: Although no significant difference was observed between preoperative and postoperative findings for the UCLA score, the strength of forward flexion was significantly lower at 10 years postoperatively in the partial repair group. Preoperative image evaluation showed no significant difference in OA changes between the 2 groups; however, fatty infiltration showed significantly greater progression in the partial repair group than the primary repair group. At >10-year postoperative follow-up, the OA changes, cuff integrity, and fatty infiltration showed significantly greater progression in the partial repair group compared to the primary repair group. Although the long-term outcome of the partial repair group was inferior to that of the primary repair group in imaging evaluations, good functional outcome of the shoulder joint was maintained. CONCLUSION: Our results suggested that partial repair could be an effective treatment option for irreparable rotator cuff tear. In terms of the feasibility of primary repair, the cutoff value for preoperative fatty infiltration was stage 2; thus, we believe that primary repair should be performed for cases with stage 2 fatty infiltration or lower, and partial repair should be performed for cases with stage 3 fatty infiltration or higher. However, manual workers and athletes with stage 3 fatty infiltration or higher should be advised in advance that mild muscle weakness may remain after surgery.

Long-term clinical and imaging outcomes after primary repair of small- to medium-sized rotator cuff tears.

BACKGROUND: Rotator cuff tear is a common disease for middle-aged and elderly patients, and relatively good postoperative outcomes have been reported in the literature. The aim of the study was to examine cases that underwent miniopen rotator cuff repair and to clarify their long-term clinical and imaging outcomes. METHODS: A total of 68 patients who underwent a miniopen repair for small- to medium-sized rotator cuff tears with good cuff integrity and without retear on magnetic resonance imaging (MRI) at 1 year postoperatively were followed up for a minimum of 10 years (mean ± standard deviation: 11.4 ± 1.2 years) and analyzed retrospectively. One-year and 10-year postoperative University of California Los Angeles (UCLA) shoulder scores and radiographs were compared. MRI was used to evaluate cuff integrity and fatty infiltration, and staging at 1 and 10 years was compared. RESULTS: The 1-year and 10-year postoperative UCLA scores were 33.1 points and 32.9 points, respectively. There were no significant differences between the two groups. Plain radiography showed that osteoarthritis (OA) staging was significantly worse at 10 years postoperatively compared to 1 year postoperatively. Cuff integrity was maintained at an excellent level at 10 years postoperatively. Fatty infiltration significantly progressed up to 10 years postoperatively. CONCLUSIONS: At 10 years postoperatively, OA progression and fatty infiltration were observed; however, UCLA scores and cuff integrity remained well preserved.

Magnetic Resonance Imaging Staging to Evaluate the Stability of Capitellar Osteochondritis Dissecans Lesions.

BACKGROUND: Treatment for capitellar osteochondritis dissecans (COCD) lesions is usually based on their stability from the bony floor after arthroscopic or open direct observation. Thus, a noninvasive means of lesion stability assessment by use of imaging is desirable to preoperatively determine treatment strategy. PURPOSE: To evaluate our modified MRI staging system for COCD, we compared the results of MRI staging with the International Cartilage Repair Society (ICRS) classification for lesion stability. Intra- and interrater reliability for MRI staging was examined as well. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHODS: Fifty-two COCD lesions were preoperatively evaluated by T2-weighted MRI and classified into 5 stages: stage 1 = normally shaped capitellum with several spotted areas of high signal intensity that is lower than that of cartilage; stage 2 = as with stage 1 but with several spotted areas of higher intensity than that of cartilage; stage 3 = as with stage 2 but with both discontinuity and noncircularity of the chondral surface signal of the capitellum and no high signal interface apparent between the lesion and the floor; stage 4 = lesion separated by a high intensity line in comparison with cartilage; and stage 5 = capitellar lesion displaced from the floor or defect of the capitellar lesion noted. The MRI staging results were compared with the intraoperative ICRS classification for lesion stability of each patient. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were all determined for fragment instability. Intra- and interrater correlations for our MRI staging were calculated among 3 examiners. RESULTS: Preoperative MRI grading correctly matched ICRS classification in 49 of 52 patients (94%), with a sensitivity of 100% and a specificity of 80%. The PPV and NPV were 93% and 100%, respectively, for diagnosing lesion instability. Intrarater reliability (intraclass correlation coefficient [ICC]) for MRI staging was high at ICC(1, 1) = 0.86 and ICC(1, 2) = 0.90, as was interrater reliability at ICC(2, 1) = 0.82 and ICC(2, 3) = 0.88. CONCLUSION: The MRI staging system provides accurate and reliable evidence for estimating ICRS classification and instability of COCD and is useful to decide appropriate treatment.

Analysis of pelvic movement in the elderly during walking using a posture monitoring system equipped with a triaxial accelerometer and a gyroscope.

The incidence of falls in the elderly is increasing with the aging of society and is becoming a major public health issue. From the viewpoint of prevention of falls, it is important to evaluate the stability of the gait in the elderly people. The pelvic movement, which is a critical factor for walking stability, was analyzed using a posture monitoring system equipped with a triaxial accelerometer and a gyroscope. The subjects were 95 elderly people over 60 years of age. The criteria for instability were open-eye standing on one leg for 15s or less, and 11s or more on 3m timed up and go test. Forty subjects who did not meet both of these criteria comprised the stable group, and the remaining 55 subjects comprised the unstable group. Pelvic movement during walking was compared between the two groups. The angle, angular velocity, and acceleration were analyzed based on the wave shape derived from the device worn around the second sacral. The results indicated that pelvic movement was lower in all three directions in the unstable group compared to the stable group, and the changes in the pelvic movement during walking in unstable elderly people were also reduced. This report is the first to evaluate pelvic movement by both a triaxial accelerometer and a triaxial gyroscope simultaneously. The characteristics of pelvic movement during walking can be applied in screening to identify elderly people with instability, which is the main risk factor associated with falls.

Carbon nanotubes with high bone-tissue compatibility and bone-formation acceleration effects.

Carbon nanotubes (CNTs) have been used in various fields as composites with other substances or alone to develop highly functional materials. CNTs hold great interest with respect to biomaterials, particularly those to be positioned in contact with bone such as prostheses for arthroplasty, plates or screws for fracture fixation, drug delivery systems, and scaffolding for bone regeneration. Accordingly, bone-tissue compatibility of CNTs and CNT influence on bone formation are important issues, but the effects of CNTs on bone have not been delineated. Here, it is found that multi-walled CNTs adjoining bone induce little local inflammatory reaction, show high bone-tissue compatibility, permit bone repair, become integrated into new bone, and accelerate bone formation stimulated by recombinant human bone morphogenetic protein-2 (rhBMP-2). This study provides an initial investigational basis for CNTs in biomaterials that are used adjacent to bone, including uses to promote bone regeneration. These findings should encourage development of clinical treatment modalities involving CNTs.

Volume changes of supraspinatus and infraspinatus muscles after supraspinatus tendon repair: a magnetic resonance imaging study.

Muscle volume was measured, by use of magnetic resonance imaging (MRI), as a direct indicator of functional recovery of the supraspinatus and infraspinatus muscles after supraspinatus tendon repair, because atrophy of the supraspinatus and infraspinatus muscles was observed in all patients with a torn supraspinatus tendon. Seventy-three patients who had a cuff tear limited only to the supraspinatus tendon were included in this study. The University of California, Los Angeles score improved significantly after surgery. MRI was carried out before surgery and 6, 12, and 24 months postoperatively in all patients. Muscle volume of the supraspinatus was assessed on images of the oblique coronal plane, and that of the infraspinatus was assessed on images of the axial plane. The width of the supraspinatus muscle did not recover until 6 months postoperatively. Direct measurement of the infraspinatus muscle volume by use of MRI can be a good indicator when evaluating whether the repaired rotator cuffs are actually functioning.

Atrophy of the deltoid muscle following rotator cuff surgery.

BACKGROUND: Less invasive procedures have recently been introduced to facilitate an earlier return to sports or work activities after rotator cuff repair. Few reports, however, have verified whether such procedures are really less invasive than conventional open repair. The purpose of this study was to compare the postoperative thickness of the deltoid muscle in patients treated with either conventional or mini-open rotator cuff repair. METHODS: Conventional open repair was performed from 1994 through 1997 in forty-three patients with rotator cuff tears. The mini-open deltoid-splitting approach was introduced in 1997, and the cases of thirty-five patients who underwent that procedure were reviewed. The two groups were compared with respect to the thickness of the anterior fibers of the deltoid muscle measured on the transverse magnetic resonance images, the degree of active forward flexion, and the times required for return to work and sports activities. RESULTS: The thickness of the anterior deltoid fibers did not change significantly after surgery in the mini-open repair group, whereas it was significantly decreased in the open repair group at six months as well as at twelve months postoperatively (p < 0.05). At three months postoperatively, the mean University of California at Los Angeles score for active forward flexion in the patients treated with the mini-open repair (4.9 points) was significantly greater than that in the patients in the conventional open repair group (4.6 points) (p < 0.05). In addition, the mean time-period required for return to work in the mini-open repair group (2.4 months) was significantly shorter than that required in the control group (3.4 months) (p < 0.05). CONCLUSIONS: The mini-open repair appeared to cause less postoperative atrophy of the deltoid muscle than did the conventional open rotator cuff repair, and patients treated with the mini-open repair recovered more quickly.

Repair of a proximal femoral bone defect in dogs using a porous surfaced prosthesis in combination with recombinant BMP-2 and a synthetic polymer carrier.

Total hip arthroplasty (THA) has become an almost standard procedure for the treatment of various hip lesions. However, one of the limitations has been the mechanical loosening of the prosthesis, a condition termed peri-prosthetic osteolysis. Consequently, at revision surgery, various grades of bone defect are often noted. Alternative approaches aimed at overcoming this problem have included a special design of the revision prosthesis and allo- or autogeneic bone grafting in combination with or without biomaterials. In a further attempt to address the loosening of the prosthesis, we have combined human bone morphogenetic protein-2, produced by DNA recombination (rhBMP-2) with a new synthetic biodegradable polymer (poly-D,L-lactic-acid-para-dioxanone-polyethyleneglycol block co-polymer; PLA-DX-PEG). We present data on the efficacy of the rhBMP-2 laden prosthesis to reconstruct a bone defect in a canine model. In this model, medial half of the proximal femur was surgically resected to create a bone defect that was repaired with the rhBMP-2/PLA-DX-PEG composite. Twelve weeks after implantation, the original bone defects in the rhBMP-2 treatment groups had been repaired. Thus, this type of 'hybrid' prosthesis may provide a new modality to repair bone defects or restore lost bone mass encountered in revision arthroplasty.

[Repair of bone defects with rhBMP2 and a synthetic polymer].

Titanium is a material with good bone affinity and bone inductive properties. We used it for new type of titanium implant to facilitate bone induction through BMPs and a carrier polymer. The carrier used for rhBMP-2 was poly-lactic acid-polyethyleneglycol block copolymar (PLA-PEG). Cylindrical titanium implants were formed with a porous surface saturated with the composite BMP/PLA-PEG. A bone defect was created in the humerus of a Japanese white rabbit, and the titanium/rhBMP-2/PLA-PEG composite was implanted with the nail fixation. After eight weeks, the defect in the humerus has been completely covered over with new bone tissue. New bone formation was also found inside the titanium pores. These results suggest that the BMP/PLA-PEG composite, with which porous titanium surface had been impregnated, exuded from that surface and caused the surface of the implant to become covered with new bone. This titanium/rhBMP/PLA-PEG implant promises to be effective in treating lager bone deficits.

Vein grafting with telescoping anastomoses for repair of a double-cut artery.

The rat femoral artery was cut in two places, and the telescoping anastomosis technique was used for all vascular repairs in combination with vein grafting, to determine whether the telescoping technique could safely be used more than three times for repair of an artery that has been injured at two places. One cut was repaired with vein grafting, and the other with either a telescoping anastomosis (the triple group) or with a second vein grafting (the quadruple group). The patency rate 3 weeks postoperatively was 86.4% for the triple group, and 90.5% for the quadruple group. Although tension of the repaired vessel was kept low by vein grafting, and deformities of the inserted vessel were carefully minimized, the patency rate was not 100%. It appears that a telescoping anastomosis should not be used more than three times on the same artery in combination with vein grafting.

Repair of segmental defects in rabbit humeri with titanium fiber mesh cylinders containing recombinant human bone morphogenetic protein-2 (rhBMP-2) and a synthetic polymer.

To develop a new technology that enhances the regeneration potential of bone and the repair of large intercalated defects in long bone, recombinant human bone morphogenetic protein-2 (BMP-2; 20 microg or 40 microg) was mixed in a polymer gel (poly-lactic acid-polyethyleneglycol block copolymer; PLA-PEG; 200 mg) and incorporated into titanium fiber-mesh cylinders. Three 5-mm cylinders were placed end-to-end to fill a 15-mm defect created in the humeri of adult rabbits and were stabilized by an intramedullary rod. In controls, the titanium fiber-mesh cylinders were combined with PLA-PEG in the absence of BMP. Six weeks after implantation, new bone had formed on the surface of the implant and had bridged the defect. All of the defects (5/5) treated by cylinders containing 120 microg (40 microg x 3) of BMP were repaired completely. New bone formation was also found inside the pores of the cylinders. The defect was not repaired in the control animals. These results demonstrate that these new composite implants fabricated by combining rhBMP, synthetic degradable polymers and compatible biomaterials enhance the regeneration potential of bone. Thus, it is possible that large skeletal defects can be repaired using this prosthesis in lieu of autogenous bone graft.