Immunohistochemical and immunocytochemical study of mechanoreceptors in anterior cruciate ligament reconstruction with the remnant-preserving technique using Achilles tendon allografts.

BACKGROUND: Attempts have been made to validate the significance of remnant preservation with anterior cruciate ligament (ACL) reconstruction using immunohistochemical and immunocytochemical techniques. The purpose of this study was to examine the expression of mechanoreceptors in the remnant tissue of ACL reconstruction performed with the remnant-preserving technique. METHODS: Tissue samples were obtained from 10 patients who underwent ACL reconstruction with the remnant-preserving technique. The specimens were obtained from remnant ACL tissue and Achilles allografts superficially and at the tibial attachment. The control group consisted of three normal ACLs procured from young males who underwent partial meniscectomy. Tissues and cells from the ACL remnants and Achilles allografts were characterized using hematoxylin and eosin (H&E) staining and immunohistochemical, immunocytochemical, and immunoblotting assays. In particular, the sensitivity of neural cell validation was improved using nerve growth factor (NGF) to stimulate the expression of neural cells. RESULTS: The results are summarized as follows. (1) In H&E staining and immunohistochemical assays, no neural cells were detected in remnant or allograft tissue. (2) In the immunocytochemical study, neural cells were detected in remnant tissue. (3) The increased proliferation of remnant ACL cells with NGF treatment suggested their identity as neural cells. (4) NGF treatment also stimulated protein and RNA expression of Nestin (a specific marker for neural cells) in remnant ACL cells. CONCLUSIONS: The improved immunocytochemical methodology proved useful. Although mechanoreceptors were detected relatively less frequently than expected, the authors consider that this finding does not negate the necessity of remnant-preserving ACL reconstruction.

The Fate of Allogeneic Femoral Head Bone Grafts Using Varus-Valgus Constrained Total Knee Arthroplasty in Neuropathic Joints.

BACKGROUND: This study was conducted to assess the clinical and radiological results of total knee arthroplasty (TKA) with an allogeneic bone graft using varus-valgus constrained (VVC) prostheses in knees with severe bone defects and unstable neuropathy. METHODS: This study included 20 knees of 16 patients who underwent TKA between August 2001 and January 2006 due to unstable knees with severe bone destruction resulting from neuropathic arthritis. At the time of surgery, the mean age of the patients was 56 years. The mean length of the follow-up period was 10.7 years. A VVC condylar prosthesis was used with an allogeneic femoral head graft to reconstruct large bony defects. Clinical results were evaluated using the Hospital for Special Surgery, Knee Society function, and Western Ontario and McMaster Universities Osteoarthritis scores. Three-dimensional computed tomography was used to evaluate the radiological parameters, which included the tibiofemoral angle, loosening or osteolysis of components, and incorporation of the bone graft. RESULTS: The preoperative mean Hospital for Special Surgery, Knee Society function, and Western Ontario and McMaster Universities Osteoarthritis scores were 40.5, 43.2, and 78.3, respectively, and these scores improved to 86.0, 64.6, and 33.8, respectively at the final follow-up. The mean postoperative alignment was 6.1° of valgus angulation. One knee had instability, another knee had partial bony absorption, which was confirmed using 3-dimensional computed tomography, and the other 18 cases (90%) had satisfactory results. No cases experienced radiolucency, fracture, or infection. CONCLUSIONS: TKA with an allogeneic bone graft using a VVC prosthesis provides a viable option for the treatment of severe bone defects with soft-tissue insufficiency in neuropathic knee arthropathy.

Arthroscopic Bioabsorbable Screw Fixation of Unstable Osteochondritis Dissecans in Adolescents: Clinical Results, Magnetic Resonance Imaging, and Second-Look Arthroscopic Findings.

BACKGROUND: This study aimed to evaluate the clinical and radiological outcomes of arthroscopic bioabsorbable screw fixation in osteochondritis dissecans (OCD) in adolescent patients with unstable lesions causing pain. METHODS: The study included 11 patients (10 males and 1 female) with OCD who underwent arthroscopic bioabsorbable screw fixation between July 2007 and February 2014 and were available for follow-up for more than 12 months. The mean age at diagnosis was 16.3 years (range, 11 to 19 years), and the average follow-up period was 51 months (range, 12 to 91 months). Clinical results were evaluated using the Knee Injury and Osteoarthritis Outcome Score (KOOS), Lysholm knee score, and International Knee Documentation Committee (IKDC) score measured before surgery and at follow-up. Functional evaluation was made using the Tegner activity scale. Magnetic resonance imaging (MRI) and second-look arthroscopy were performed at the 12-month follow-up. RESULTS: Between the preoperative assessment and follow-up, improvements were seen in the KOOS (range, 44.9 to 88.1), Lysholm knee score (range, 32.6 to 82.8), and IKDC score (range, 40.8 to 85.6). The Tegner activity scale also improved from 2.8 to 6.1. Based on postoperative MRI, there were eight Dipaola grade I cases and three grade II cases. No complications due to fixation failure developed in any case. Second-look arthroscopy at 12 months postoperatively revealed that the lesion was covered with cartilage in all cases. CONCLUSIONS: For unstable OCD lesions causing pain in adolescents, arthroscopic bioabsorbable screw fixation provided favorable outcomes with reduced pain and restoration of movement. Therefore, it should be considered as an effective treatment for OCD.

The Results of All-Inside Meniscus Repair Using the Viper Repair System Simultaneously with Anterior Cruciate Ligament Reconstruction.

BACKGROUND: Meniscus tears are commonly associated with anterior cruciate ligament (ACL) ruptures. It is essential to repair meniscal tears as much as possible to prevent early osteoarthritis and to gain additional stability in the knee joint. We evaluated the results of arthroscopic all-inside repair using the Meniscal Viper Repair System (Arthrex) on meniscus tears simultaneously with ACL reconstruction. METHODS: Nineteen out of 22 patients who were treated with arthroscopic all-inside repair using the Meniscal Viper Repair System for meniscus tear associated with ACL rupture were evaluated. ACL reconstructions were performed at the same period. The mean follow-up period was 16.5 months (range, 12 to 24 months). The clinical results of the meniscus repair were evaluated by symptoms (such as catching or locking), tenderness, effusion, range of motion limitation, and the McMurray test. Clinical success was defined by negative results in all five categories. The Hospital for Special Surgery (HSS) score was evaluated. Objective results were evaluated with secondary look arthroscopy or magnetic resonance imaging (MRI). The MRI results were categorized as completely repaired, incompletely repaired, and failure by Henning's classification. The results of second-look arthroscopy were evaluated with the criteria of meniscal healing. RESULTS: The clinical success rate was 95.4% and the HSS scores were 93.9 ± 5.4 at the final follow-up. According to Henning's classification, 15 out of 18 cases showed complete healing (83.3%) and two cases (11.1%) showed incomplete healing. Seventeen out of 18 cases that underwent second-look arthroscopy showed complete healing (94.4%) according to the criteria of meniscal healing. Only one case showed failure and the failure was due to a re-rupture at the sutured area. Complications of ACL reconstruction or meniscus repair were not present. CONCLUSIONS: The results demonstrate that arthroscopic all-inside repair using the Meniscal Viper Repair System is an effective treatment method when it is performed simultaneously with ACL reconstruction.

Clinical and radiological results of femoral head structural allograft for severe bone defects in revision TKA--a minimum 8-year follow-up.

BACKGROUND: Proper treatment of bone loss is essential for the long term durability of revision TKA. However, the method of choice in managing large bone defects is still under debate. We therefore assessed the mid to long term clinical and radiographic results of revision TKA using a fresh frozen femoral head allograft and a standard condylar implant or varus-valgus constrained prosthesis with a diaphyseal-engaging stem. METHODS: We retrospectively reviewed the records of 27 patients who had undergone revision TKA between August 1997 and March 2003 using a fresh frozen femoral head allograft and a standard condylar implant or varus-valgus constrained prosthesis with a diaphyseal-engaging stem. The median follow-up period was 107 months (range, 96-157 months). RESULTS: Clinical evaluation revealed that the mean range of motion had increased from 71° to 113° and the mean Hospital for Special Surgery knee score had improved from 46 to 83 points. The overall tibio-femoral angle improved from varus 7.3° to valgus 6.l°. In 26 out of 27 knees, union was demonstrated at an average of seven months postoperatively, and there were no cases of collapse, disease transmission or stress fractures. In one knee, an infection recurred. CONCLUSIONS: Our results demonstrate that femoral head allografts in treatment of severe bone defects are reliable and durable. If possible, less constrained prostheses with diaphyseal-engaging stems should be chosen for increased durability. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Mid-term Results of Single-Radius Cruciate Retaining Total Knee Arthroplasty: Minimum 5 Year Follow-up.

PURPOSE: The single-radius design of the knee implant was introduced to improve the results of total knee arthroplasty (TKA) by reducing maximum extensor forces, and it also represents more physiologic quadriceps force pattern, which could have a positive effect on knee function after TKA. We studied mid-term results of single-radius designed cruciate retaining (CR) TKA. MATERIALS AND METHODS: We analyzed the functional improvement and radiological osteolytic pattern after TKA using the single-radius Scorpio CR prosthesis. TKA was performed on 102 knees. The mean follow-up period was 73.8 months. For clinical assessment, the range of motion (ROM), Harris hip score, and functional outcome score were obtained preoperatively and at last follow-up. RESULTS: The average ROM was 100.2° preoperatively and 121.7° at last follow-up. The average knee score was 59.2 points preoperatively and 92.9 points at last follow-up. The average functional outcome score was improved from 51.9 points preoperatively to 85.4 points at last follow-up. Radiolucency was observed in four knees but all were non-progressive lesions smaller than 2 mm. CONCLUSIONS: The clinical outcome of TKA using the single-radius CR prosthesis was good during the mid-term follow-up and the incidence of osteolysis was very rare.

Infection following total knee arthroplasty.

For most orthopedists, total knee arthroplasty (TKA) has been regarded as the most effective surgery for patients with severe knee diseases. Though seldom occur, postoperative infection certainly remains one of the most devastating and dreaded complications of TKA. Thus, careful and early diagnosis is needed. After diagnosis, categorize the infection type and choose a rightful and sequential step of treatment are recommended.

Histological assessment of mechanoreceptors in Achilles allografts after anterior cruciate ligament reconstruction.

BACKGROUND: There is a lack of histological studies investigating the presence of mechanoreceptors in anterior cruciate ligament (ACL) allografts. HYPOTHESIS: Mechanoreceptors would not grow in Achilles allografts after ACL reconstruction. STUDY DESIGN: Case series study; Level of evidence, 4. METHODS: Tissue samples were obtained from 11 patients who underwent ACL reconstruction using Achilles tendon allografts. They underwent biopsies during second-look arthroscopies. The mean period from ACL reconstruction to harvesting tissue was 26.63 months (range, 12-120 months). The control group consisted of 2 normal ACLs procured from 42- and 45-year-old men who underwent amputation above the knee due to trauma. RESULTS: Ruffini corpuscles and free nerve endings were shown to be present in the specimens of the control group by processing hematoxylin-eosin stains and immunohistochemical stains with monoclonal antibodies against S-100. In the Achilles allografts, mechanoreceptors were not observed. However, fibroblasts, collagen fibers, and vessels that were not present in fresh-frozen Achilles allografts before surgery were observed. CONCLUSION: The results demonstrate that Achilles tendon allografts appeared similar to normal ligaments except for the lack of histological evidence of mechanoreceptors. In other words, there are no newly ingrown mechanoreceptors in ACL allografts.

Risedronate directly inhibits osteoclast differentiation and inflammatory bone loss.

Risedronate, a nitrogen-containing bisphosphonate, is widely used in the clinical field for the treatment of osteoporosis. Risedronate is known to exert its effects through binding to hydroxyapatite in bone tissue, inhibiting osteoclastic activity, and inducing apoptosis of osteoclasts. The purpose of this study was to determine the effects of risedronate on osteoclast differentiation in vitro and on an inflammatory bone loss model in vivo. Risedronate inhibited osteoclast differentiation in co-culture of bone marrow cells (BMCs) and osteoblasts, and suppressed receptor activator of nuclear factor (NF)-kappaB ligand (RANKL)-mediated osteoclast differentiation from bone marrow-derived macrophages (BMMs) in a dose-dependent manner without toxicity. Risedronate significantly inhibited expression of c-Fos and nuclear factor of activated T cells (NFAT) c1 induced by RANKL. To examine the effect of risedronate on bone loss in vivo, we used a mouse model of lipopolysaccharide (LPS)-mediated bone loss. Micro-CT analysis of the femurs showed that LPS treatment caused bone loss. However, bone loss was significantly attenuated in mice administered with risedronate. Taken together, we conclude that risedronate exerts beneficial effects on osteoporosis by inhibiting osteoclast differentiation both directly and indirectly. In infectious conditions, the inhibitory effect of risedronate on bone erosion was excellent. Thus risedronate could be a treatment option for osteoporosis caused by inflammatory and infectious conditions.