Factors Affecting Longer Surgical Times in Total Knee Arthroplasty for Obese Patients-A Comparative Study between High- and Nonhigh-Volume Surgeons.

Obesity has a negative influence on surgical times in total knee arthroplasty (TKA). Our purpose in this multicenter study was to compare surgical times between high- (HV) and nonhigh-volume (NHV) surgeons and clarify the important factors affecting longer surgical times in primary TKA for obese patients. A total of 798 knees, average age 75.1 years, were enrolled. All TKAs were done using the same measured resection technique by 25 surgeons at 12 facilities and were divided into three groups based on body mass index (kg/m2) of the patients (Group A: <24.9, Group B: 25-29.9, Group C: ≥30). Operative techniques including four surgical steps (surgical exposure, bone cutting, trial and fixation of the permanent component, and wound closure) were evaluated both in HV and NHV surgeons. In classifying surgeon volume, HV surgeons had performed >100 TKAs annually for many years, and other surgeons who had performed <100 TKAs annually were defined as NHV surgeons. Patient demographics, surgical details, and surgical times in each phase were compared using nonrepeated measures of analysis of variance and a post hoc Student-Newman-Keuls test. A total of 331, 327, 140 TKAs were allocated to Groups A, B, C, respectively. Regarding patient demographics, patients in Group C were younger and had the worst ranges of motion. The longest surgical time was observed in Group C of NHV surgeons (p < 0.05). Concerning each surgical phase, surgeons took much more time in surgical exposure and fixation of the permanent component for obese patients in NHV surgeons (p < 0.05). Our results suggest that younger age and lower range of motion were observed in obese patients, which led to longer surgical times. In addition, NHV surgeons took much time in surgical exposure and fixation of the permanent component for obese patients, while surgical time was similar among groups for HV surgeons.

What are the important manoeuvres for beginners to minimize surgical time in primary total knee arthroplasty?

PURPOSE: It was hypothesized that surgical time of beginners would be much longer than that of experts. Our purpose was to investigate and clarify the important manoeuvres for beginners to minimize surgical time in primary total knee arthroplasty (TKA) as a multicentre study. METHODS: A total of 300 knees in 248 patients (averaged 74.6 years) were enrolled. All TKAs were done using the same instruments and the same measured resection technique at 14 facilities by 25 orthopaedic surgeons. Surgeons were divided into three surgeon groups (four experts, nine medium-volume surgeons and 12 beginners). The surgical technique was divided into five phases. Detailed surgical time and ratio of the time in each phase to overall surgical time were recorded and compared among the groups in each phase. A total of 62, 119, and 119 TKAs were done by beginners, medium-volume surgeons, and experts, respectively. RESULTS: Significant differences in surgical time among the groups were seen in each phase. Concerning the ratio of the time, experts and medium-volume surgeons seemed cautious in fixation of the permanent component compared to other phases. Interestingly, even in ratio, beginners and medium-volume surgeons took more time in exposure of soft tissue compared to experts. (0.14 in beginners, 0.13 in medium-volume surgeons, 0.11 in experts, P < 0.05). CONCLUSION: Beginners took more time in exposure and closure of soft tissue compared to experts. Improvement in basic technique is essential to minimize surgical time among beginners. First of all, surgical instructors should teach basic techniques in primary TKA for beginners. LEVEL OF EVIDENCE: Therapeutic studies, Level IV.

A Novel Surgical Technique for Patellar Fracture: Application of Extra-articular Arthroscopy With Hanger-Lifting Procedure.

We describe a novel operative technique for patellar fracture. The patient is placed in the supine position for setup of both an image intensifier and arthroscopy. After routine intra-articular inspection with an arthroscope, an extra-articular space including the prepatellar bursa is developed. The space is created with a lifting hanger applied from a portal wherein an arthroscope can then afford both intra- and extra-articular observation of the articular and bony surface of the patella. By use of an image intensifier, the fracture can be treated and fixed in percutaneous fashion with the aid of an arthroscope. This new technique offers surgeons a magnified view of the patella, both intra- and extra-articularly, through a minimally invasive procedure. Although it includes inherent risks and limitations, this new application of arthroscopy would certainly help surgeons to treat patellar fracture.

Five-year comparison of oxidized zirconium and cobalt-chromium femoral components in total knee arthroplasty: a randomized controlled trial.

BACKGROUND: In vitro analysis has shown that oxidized zirconium on ultra-high molecular weight polyethylene has better wear properties than cobalt-chromium on ultra-high molecular weight polyethylene. The purpose of this study was to determine if oxidized zirconium femoral components performed better than cobalt-chromium in vivo and if the use of oxidized zirconium components had clinical adverse effects. METHODS: Forty consecutive patients (eighty knees) underwent simultaneous bilateral cruciate-retaining total knee arthroplasty for primary osteoarthritis from January 2002 to December 2003. For each patient, the knees were randomized to receive the oxidized zirconium femoral component, with the contralateral knee receiving the cobalt-chromium component. Outcome measures included the Western Ontario and McMaster Universities Osteoarthritis Index, Knee Injury and Osteoarthritis Outcome Score, Knee Society score, and British Orthopaedic Association patient satisfaction scale. Radiographic outcomes include the Knee Society total knee arthroplasty roentgenographic evaluation and scoring system and measurement of radiographic wear. Patients and assessors were blinded to the treatment groups and results. RESULTS: There were no significant differences in clinical, subjective, and radiographic outcomes between the two implants at five days, six weeks, and one, two, or five years postoperatively. At five years following surgery, 38% of the patients preferred the cobalt-chromium knee compared with 18% who preferred the oxidized zirconium knee (p = 0.02) and 44% had no preference. CONCLUSIONS: Five-year outcomes after total knee arthroplasty with oxidized zirconium and cobalt-chromium femoral components showed no significant differences in clinical, subjective, and radiographic outcomes. Patients had no preference or preferred the cobalt-chromium prosthesis to the oxidized zirconium prosthesis at the time of the five-year follow-up. There were no adverse effects associated with the use of oxidized zirconium femoral implants.

Fifteen-year outcome of endoscopic anterior cruciate ligament reconstruction with patellar tendon autograft for "isolated" anterior cruciate ligament tear.

BACKGROUND: Few studies report the long-term results of anterior cruciate ligament rupture and single-incision endoscopic reconstructive surgery. Outcomes are often clouded by concomitant meniscal, chondral, or ligament injuries. PURPOSE: To determine the 15-year outcomes of anterior cruciate ligament ruptures treated with endoscopic anterior cruciate ligament reconstruction using middle-third patellar tendon autograft. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Between January 1993 and April 1994, 333 consecutive patients underwent anterior cruciate ligament reconstruction. Patients with associated ligamentous injury requiring surgery, previous meniscectomy, or meniscal injury requiring more than one-third meniscectomy; chondral injury diagnosed at arthroscopy; and an abnormal contralateral knee were excluded. Ninety patients met the inclusion criteria. Outcomes included range of motion, Lachman and pivot-shift tests, instrumented ligament testing, single-legged hop test, Lysholm Knee Score, the International Knee Documentation Committee evaluation, and radiographic assessment. RESULTS: Thirty percent of patients had further anterior cruciate ligament injury. Twenty-four percent of patients (n = 22) sustained contralateral anterior cruciate ligament ruptures, and 8% (n = 7) ruptured the graft (P = .009). Graft rupture was associated with a graft inclination angle <17° (P = .02). Contralateral anterior cruciate ligament rupture was associated with age <18 years at time of primary injury (P = .001). All patients had normal or nearly normal (International Knee Documentation Committee evaluation) Lachman and instrumented testing, and 91% had a negative pivot-shift result. Seventy percent of patients had kneeling pain. Median subjective International Knee Documentation Committee evaluation was 91 of 100. Fifty-one percent of patients had radiographic evidence of osteoarthritis (41% grade B; 10% grade C). CONCLUSION: Good results are maintained at 15 years after surgery with respect to ligamentous stability, subjective outcomes, and range of motion. Kneeling pain remains a significant problem. Concern remains regarding the incidence of further anterior cruciate ligament injury and the increasing number of patients with radiographic and clinical signs of osteoarthritis despite surgical stabilization.

The "coiling-up procedure": a novel technique for extra-articular arthroscopy.

The "coiling-up procedure" is a novel technique for extra-articular arthroscopy. A coil-shaped lifter is used to create the extra-articular working space, and a dry arthroscopy is performed. It can be combined with conventional intra-articular arthroscopy to enable direct vision from both inside and outside the joint. We have successfully used this technique to perform a vastus lateralis release in cases of painful bipartite patella. This is an innovative technique that offers the possibility of expanding the indications for extra-articular arthroscopy to other areas of the body. We describe in detail the technique for this new procedure in the knee.

Medial patellofemoral ligament reconstruction with hanger lifting procedure.

Medial patellofemoral ligament (MPFL) reconstruction has become a common surgical procedure in the treatment of recurrent dislocation of the patella. A technique of MPFL reconstruction with the "hanger lifting procedure" using extra-articular arthroscopy is presented. After conventional intra-articular arthroscopy, an incision about 1 cm long is made at the superomedial edge of the patella. A bone tunnel is created with a guide pin and overdrilling method, from this portal to the subcutaneous surface of the patella. Using a semi-loop-shaped hanger, the harvested Gracillis tendon is passed through the bone tunnel using a passing pin. Under extra-articular arthroscopy with the "hanger lifting procedure", this tendon is then led back to the superomedial portal. Both ends of the Gracillis tendon are then led to the femoral fixation site posterosuperior to the medial epicondyle with a tendon passer, and fixed by an absorbable interference screw. This procedure can be performed under a minimum incision using a hanger, but control radiographs should be taken to confirm appropriate placement of bone tunnels.

Hanger-lifting procedure in knee arthroscopy.

We propose a unique arthroscopic technique, the "hanger-lifting procedure." Unlike conventional arthroscopy, the space in which the arthroscope is placed is not a joint space filled with water but a subcutaneous space filled with air. The space is kept lifted by a semi-loop-shaped hanger and a retraction system by use of a wire. In general, arthroscopes are unable to be applied outside the joint because of the lack of a cavity. However, this method can provide extra-articular visualization of the knee in addition to standard intra-articular visualization. This approach is useful for lateral release of the knee extensor and bipartite patellae, allowing direct vision from both outside and inside the joint. One possible complication is subcutaneous effusion or interstitial edema. Compressive dressings should be applied to prevent subcutaneous effusion after surgery. However, the combination of conventional arthroscopy by use of saline solution and the hanger-lifting technique by use of air arthroscopy can provide an excellent view inside and outside the joint. This technique may continue to evolve, and although some points in the technique can be improved, this method is useful in joint surgeries.

Repair of full-thickness articular cartilage defects using injectable type II collagen gel embedded with cultured chondrocytes in a rabbit model.

BACKGROUND: Recently, tissue-engineered chondrocyte transplantation has been tried to treat full-thickness cartilage defects. We developed an injectable type II collagen gel scaffold by chemically reacting type II collagen with polyethylene glycol crosslinker. This type II collagen was prepared from the nasal septa of cattle. In the present study, chondrocytes embedded in type II collagen gel were injected into rabbit full-thickness cartilage defects without a periosteal graft, and the feasibility for clinical application of the gel was evaluated. METHODS: Chondrocytes were isolated from 1-kg New Zealand white rabbits. A full-thickness articular cartilage defect (5 mm diameter, 4 mm depth) was created on the patellar groove of the femur of 16 male 3-kg New Zealand white rabbits. A type II collagen solution of mixed chondrocytes at a density of 1 x 10(7) cells/ml was injected and transplanted into the defect in the right knee. The controls were the defect only in the left knee. At 4, 8, 12, and 24 weeks after operation, four cases from each group were evaluated macroscopically and histologically. RESULTS: After injection into the cartilage defect, the gel bonded to the adjacent cartilage and bone within several minutes. Macroscopic examination revealed that the surface of the transplanted area was smooth and exhibited similar coloration and good integration with the surrounding cartilage at 12 and 24 weeks after transplantation. Histological examination at 8 weeks revealed favorable hyaline cartilage regeneration with good chondrocyte morphology. At 12 and 24 weeks, reparative cartilage remained rich in type II collagen. According to O'Driscoll histological scores, significant differences between the transplanted and control groups were apparent at 12 and 24 weeks. Immunohistochemical staining indicated sufficient type II collagen synthesis in regenerated cartilage 8 weeks after transplantation, and it was maintained until 24 weeks. CONCLUSIONS: These results indicate that type II collagen gel is suitable for injection into cartilage defects without any covering of a graft and offers a useful scaffold during chondrocyte transplantation.

Patellar impingement against the tibial component after total knee arthroplasty.

Patella baja developed in seven knees in five patients after posterior stabilized total knee arthroplasties when the patella became impinged against the tibial component. Patellar replacement was performed in four knees, and all patients were able to achieve deep flexion postoperatively. The mean followup was 50 months (range, 24-73 months) for these patients. The mean Insall-Salvati ratio changed from 0.87 (range, 0.70-1) immediately postoperatively to 0.66 (range, 0.55-0.84) at followup. Patellar erosion occurred in three knees without patellar replacements, accompanied by pain and reduced range of flexion. The four knees with patellar replacements showed marked erosion of the patellar component or the patella, but all remained asymptomatic. Achieving deep flexion in addition to patella baja was thought to be a key element. Patellar replacement, joint line preservation, shaving the anterior portion of the tibial component, preventing surgically induced patella baja, and careful radiographic followup should be considered when deep flexion is achieved in a knee with patella baja after a total knee arthroplasty.

Phenotypic characteristics of joint fluid cells from patients with continuous joint effusion after total knee arthroplasty.

Joint effusion after total joint arthroplasty (TJA) is a manifestation of inflammatory reactions within the prosthetic joint. Among the various causes for joint effusion following TJA, deep infection (DI), wear particle-induced synovitis (PS) and metal sensitivity to the implant should be excluded as soon as possible, as these may result in the failure of TJA. The present study analyzed joint fluid cells from patients after total knee arthroplasty (TKA) using fluorescence-activated cell sorter (FACS), and examined the feasibility of using FACS to exclude the possibility of biomaterial-related complication. A total of 72TKAs from 64 patients suffering from joint effusion were examined in this study. Joint fluid was aspirated in outpatient clinics and applied to FACS. The results indicated that patients could be clearly classified into four types based on forward/side scatter profiles. Analysis of specific CD markers revealed that leukocytes were selectively recruited from blood to inflamed prosthetic joints. Dominant cell types were CD16+neutrophils in DI and increased rheumatoid activity, CD14+macrophages in PS, and CD3+CD45RO+T cells in metal sensitivity. These findings suggest the feasibility of diagnosing joint effusion by analyzing dominant cell type recruited using FACS. In conclusion, FACS may offer a useful tool for analyzing joint fluid cells from post-TJA patients and for excluding biomaterial-related complication following TJA.

The effect of calcium ion concentration on osteoblast viability, proliferation and differentiation in monolayer and 3D culture.

Our research group aims to develop an osteochondral composite using type II collagen gel with hydroxyapatite (HAp) deposited on one side. Soaking gels in Ca2+ and phosphate solution is indispensable to HAp deposition, so relationships between cell behavior and Ca2+ concentration were examined in two- and three-dimensional cultures. The present results indicate that 2-4 mM Ca2+ is suitable for proliferation and survival of osteoblasts, whereas slightly higher concentrations (6-8 mM) favor osteoblast differentiation and matrix mineralization in both 2- and 3-dimensional cultures. Higher concentrations (>10 mM) are cytotoxic. Purely from the perspective of calcium deposition, higher concentrations lead to increased accumulation of Ca2+. Culturing cells in phosphate-containing gel in media with Ca2+ also leads to time-dependent formation of HAp in the gel. Considering the viability of embedded cells, culturing scaffolds in media with Ca2+ concentrations around 5mM is useful for both HAp deposition and osteoblast behavior.