A prospective randomized trial examining the use of a closed suction drain shows no influence on strength or function in primary total knee arthroplasty.

AIMS: The aim of this study was to determine whether closed suction drain (CSD) use influences recovery of quadriceps strength and to examine the effects of drain use on secondary outcomes: quadriceps activation, intra-articular effusion, bioelectrical measure of swelling, range of movement (ROM), pain, and wound healing complications. PATIENTS AND METHODS: A total of 29 patients undergoing simultaneous bilateral total knee arthroplasty (TKA) were enrolled in a prospective, randomized blinded study. Patients were randomized to receive a CSD in one limb while the contralateral limb had the use of a subcutaneous drain (SCDRN) without the use of suction ('sham drain'). Isometric quadriceps strength was collected as the primary outcome. Secondary outcomes consisted of quadriceps activation, intra-articular effusion measured via ultrasound, lower limb swelling measured with bioelectrical impendence and limb girth, knee ROM, and pain. Outcomes were assessed preoperatively and postoperatively at day two, two and six weeks, and three months. Differences between limbs were determined using paired Student's t-tests or Wilcoxon's signed-rank tests. RESULTS: No significant differences were identified between limbs prior to surgery for the primary or secondary outcomes. No significant differences in quadriceps strength were seen between CSD and SCDRN limbs at postoperative day two (p = 0.09), two weeks (primary endpoint) (p = 0.7), six weeks (p = 0.3), or three months (p = 0.5). The secondary outcome of knee extension ROM was significantly greater in the CSD limb compared with the SCDRN (p = 0.01) at two weeks following surgery, but this difference was absent at all other intervals. Secondary outcomes of quadriceps activation, intra-articular effusion, lower limb swelling, and pain were not found to differ significantly at any timepoint following surgery. CONCLUSION: The use of CSD during TKA did not influence quadriceps strength, quadriceps activation, intra-articular effusion, lower limb swelling, ROM, or pain. These results have limited drain use by the authors in primary uncomplicated TKA. Cite this article: Bone Joint J 2019;101-B (7 Supple C):84-90.

Variations in microbial and biochemical components of four-day plaque during a four-week controlled diet period.

Variation in microbial and biochemical components of human four-day plaque was studied in seven subjects who were maintained on a high-sucrose diet during a four-week period. Significant changes in populations of lactobacilli dextranase-producing organisms, Streptococcus mutans, and S sanguis occurred during this period.

Effects of sodium trimetaphosphate supplementation of a high sucrose diet on the microbial and biochemical composition of four-day plaque and on urine calcium and phosphorus levels.

Daily supplementation of a high sucrose diet with 5 gm TMP resulted in significant alterations in certain human plaque components. Veillonella and Neisseria population (as percent total viable microorganisms), S sanguis (as percent streptococci), and levan hydrolase activity per milligram of plaque increased, whereas total viable microorganisms per milligram of plaque, streptococci per milligram of plaque, and specific fructosyltransferase activity decreased during the TMP-containing diet regimen.

Survivorship of unconstrained total shoulder arthroplasty.

The results of fifty-three unconstrained (Neer-II or Gristina) total shoulder arthroplasties were reviewed with the use of survivorship analysis. Failure was defined as the need for revision or the onset of the patient's dissatisfaction. The method of survivorship analysis is presented in detail. Fifty-one total shoulder arthroplasties were followed for a minimum of two years (average, sixty-seven months). The results are reported with the use of the American Shoulder and Elbow Surgeons' rating form. After eleven years, the survivorship was 73 per cent for all prostheses, 71 per cent for the Neer prostheses, and 92 per cent for all prostheses in patients who had rheumatoid arthritis. Data on survivorship of the Gristina prosthesis were available after four years only, at which time it was 100 per cent. The relief of pain, which was the primary reason for the operation, was good or excellent in 82 per cent, improved in 6 per cent, and poor in 12 per cent of the shoulders in these patients.

Mathematical model of the lower extremity joint reaction forces using Kane's method of dynamics.

This report describes a new mathematical model for defining the joint reaction forces of the lower extremity using Kane's method of dynamics. Our model utilized average lower extremity joint motion and force/plate data from one healthy female patient during gait. From a cadaver specimen, the anatomical mass centers of the pelvis, femur, tibia, and foot were determined. Joint angular motion during the normal gait cycle was computed using Cardan angles for each distal segment relative to the proximal segment. Fluoroscopy of four normal knees determined average femorotibial and patellofemoral contact positions throughout flexion. A three-dimensional model of the lower extremity was defined in weight-bearing motion by 30 differential equations. During normal walking, the joint reaction forces for the subject tested ranged from 1.9 to 2.6 times body weight at the hip joint and 1.7-2.3 times body weight at the knee joint, depending primarily on gait speed. The method correlates well with known in vivo telemetrically measured forces at the hip joint.

"In vivo" determination of hip joint separation and the forces generated due to impact loading conditions.

Numerous supporting structures assist in the retention of the femoral head within the acetabulum of the normal hip joint including the capsule, labrum, and ligament of the femoral head (LHF). During total hip arthroplasty (THA), the LHF is often disrupted or degenerative and is surgically removed. In addition, a portion of the remaining supporting structures is transected or resected to facilitate surgical exposure. The present study analyzes the effects of LHF absence and surgical dissection in THA patients. Twenty subjects (5 normal hip joints, 10 nonconstrained THA, and 5 constrained THA) were evaluated using fluoroscopy while performing active hip abduction. All THA subjects were considered clinically successful. Fluoroscopic videos of the normal hips were analyzed using digitization, while those with THA were assessed using a computerized interactive model-fitting technique. The distance between the femoral head and acetabulum was measured to determine if femoral head separation occurred. Error analysis revealed measurements to be accurate within 0.75mm. No separation was observed in normal hips or those subjects implanted with constrained THA, while all 10 (100%) with unconstrained THA demonstrated femoral head separation, averaging 3.3mm (range 1.9-5.2mm). This study has shown that separation of the prosthetic femoral head from the acetabular component can occur. The normal hip joint has surrounding capsuloligamentous structures and a ligament attaching the femoral head to the acetabulum. We hypothesize that these soft tissue supports create a passive, resistant force at the hip, preventing femoral head separation. The absence of these supporting structures after THA may allow increased hip joint forces, which may play a role in premature polyethylene wear or prosthetic loosening.

Fluoroscopic analysis of kinematics after posterior-cruciate-retaining knee arthroplasty.

We used fluoroscopy to study the kinematics of the knee in 47 patients with total knee arthroplasty (TKA) and four control subjects with normal knees while performing a single-leg deep-knee bend. The videos were analysed using still photographs taken at 5 degrees increments of flexion. Femorotibial contact points, patellar ligament rotation, and patellar rotation were calculated from each image. Maximum weight-bearing flexion was determined for each knee. Compared with the control group, posterior-cruciate-retaining TKA did not reproduce normal knee kinematics in any case, but showed a starting point posterior to the tibial midline which translated anteriorly with flexion. The curves from successive knee bends could not be consistently reproduced. Under weight-bearing conditions, the maximum flexion for any PCR TKA was 98 degrees and several patients could not flex beyond 70 degrees.

Femoral condylar lift-off in vivo in total knee arthroplasty.

We carried out weight-bearing video radiological studies on 40 patients with a total knee arthroplasty (TKA), to determine the presence and magnitude of femoral condylar lift-off. Half (20) had posterior-cruciate-retaining (PCR) and half (20) posterior-cruciate-substituting (PS) prostheses. The selected patients had successful arthroplasties with no pain or instability. Each carried out successive weight-bearing knee bends to maximum flexion, and the radiological video tapes were analysed using an interactive model-fitting technique. Femoral lift-off was seen at some increment of knee flexion in 75% of patients (PCR TKA 70%; PS TKA 80%). The mean values for lift-off were 1.2 mm with a PCR TKA and 1.4 mm with a PS TKA. Lift-off occurred mostly laterally with the PCR TKA, and both medially and laterally with the PS TKA. Separation between the femoral condyles and the articular surface of the tibia was recorded at 0 degrees, 30 degrees, 60 degrees and 90 degrees of flexion. Femoral condylar lift-off may contribute to eccentric polyethylene wear, particularly in designs of TKA which have flatter condyles. Coronal conformity is an important consideration in the design of a TKA.

An in vivo determination of patellofemoral contact positions.

OBJECTIVE: To determine patellofemoral contact patterns in two-dimensions for normal and implanted patients. DESIGN: An in vivo, weightbearing fluoroscopy analysis of 14 subjects with normal knees, 12 with anterior cruciate ligament deficient knees, 14 with a posterior cruciate retaining implant, and 25 with a posterior cruciate substituting implant. BACKGROUND: Most previous experimental studies involving the knee joint have been either in vitro or under nonweightbearing conditions. METHODS: Subjects were studied under fluoroscopic surveillance performing deep knee bends to maximum flexion. Video images were analyzed on a computer with a two-dimensional technique of digitizing discrete points on the patella, femur, and tibia. RESULTS: The contact position, measured from the patella mass center, was inferior on the patella at extension and moved superior during flexion. Average contact positions of the implanted knee groups were more superior than the normal knee group throughout the flexion cycle. Analysis of patellar tilt angle demonstrated a flexed posture of the patella relative to the tibia. Increase in patellar tilt angle with increasing femorotibial flexion was substantially greater in implanted knees versus normal knees. Separation of the patella from the femur in full extension was absent in normal knees, but present in 86% and 44% of posterior cruciate retaining and posterior cruciate substituting total knee arthroplasties, respectively. CONCLUSIONS: The patellofemoral kinematics of the total knee arthroplasties analyzed in the study was statistically different than the normal and anterior cruciate ligament-deficient knees. The kinematic variations observed between normal and implanted knees may be related to disturbed femorotibial kinematics previously observed to occur following total knee arthroplasty. RELEVANCE: Patellofemoral complications, including polyethylene wear, are a major concern in total knee arthroplasty. Since the causes of polyethylene wear are multi-factorial, abnormal patellofemoral kinematics may play a role in patellar failure.

Wound complications in total knee arthroplasty.

Wound problems are a dreaded complication following TKA and the ideal is to avoid them. Preventive measures include proper choice of the skin incision, gentle handling of the soft tissues, meticulous hemostasis, and wound closure without excessive tension. Should persistent wound drainage or soft-tissue necrosis occur, early intervention is imperative, because delay risks deep infection and failure of the TKA. Cases associated with full-thickness soft-tissue necrosis often require transfer of well-vascularized tissue, such as a medial gastrocnemius myocutaneous flap reconstruction.

Mobile-bearing knee replacement: concepts and results.

In summary, if TKRs are to be performed in patients who are younger and more active than those who had the initial procedures in the 1970s and 1980s, better wear performance is imperative for long-term durability, especially if surgeons continue to consider the versatility associated with modular knee-replacement systems to be a necessity. At least with some designs, including the Oxford knee and the LCS knee, the results after a minimum follow-up of 10 years are comparable with the best results after arthroplasty with fixed-bearing designs in terms of wear, loosening, and osteolysis (Table 7). As with fixed-bearing designs, there are additional challenges in terms of optimizing bearing-surface conformity and improving kinematics. Improvements in future designs of mobile-bearing total knee replacements should include better control of bearing mobility patterns to reduce the prevalence of the abnormal kinematic motions that have been observed in fluoroscopic evaluations.

A novel approach to knee kinematics.

We describe our experience with in vivo dynamic fluoroscopy that uses simple 2-plane video fluoroscopy of subjects performing maneuvers such as deep knee-bends, gait, and stair climbing after total knee arthroplasty (TKA). Kinematic analysis has evolved from 2-dimensional vector calculations to automated 3-dimensional computer-assisted design matching techniques that are accurate to 0.75-mm translation and 0.75 degrees rotation and that allow simultaneous determination of medial and lateral condyle contact positions. TKAs that retain the posterior cruciate ligament (PCL) have consistently shown posterior contact in extension and anterior translation with flexion with a large variability among subjects. PCL-stabilized implants and mobile bearings with high conformity have posterior femoral rollback more consistent with normal knees--which is a function of prosthetic geometry. Condylar liftoff and screw-home rotation are typical kinematic features of all TKAs.

Structural allografting in revision total knee arthroplasty.

While morsellized cancellous autograft or allograft have been shown to be highly successful in the management of smaller cavitary defects in revision TKA, structural allografts are often required for large, noncontained osseous defects. Early clinical results of revision TKA utilizing structural allografts have been encouraging with high allograft-host union rates if adequate allograft fixation is obtained. The use of intramedullary stems engaging diaphyseal bone is recommended to lessen load transmission to the structural allograft and the risk of late allograft collapse. Extensive preoperative planning, meticulous operative technique, and an extended period of postoperative rehabilitation are required for optimal results.

The stiff total knee arthroplasty: causes and cures.

Stiffness following TKA can be related to patient factors, intraoperative technical errors, or postoperative surgical complications. The best management is prevention by providing thorough preoperative patient education, aggressive postoperative physiotherapy, and avoidance of technical errors.

Wound complications in total knee arthroplasty.

Wound problems are a dreaded complication following TKA and ideally are avoided. Preventative measures include proper choice of the skin incision, gentle handling of the soft tissues, meticulous hemostasis, and wound closure without excessive tension. Should persistent wound drainage or soft-tissue necrosis occur, early intervention is imperative as delay risks deep infection and failure of the TKA. Cases associated with full-thickness soft-tissue necrosis often require transfer of well-vascularized tissue such as a medial gastrocnemius myocutaneous flap reconstruction.

Repairing minor bone defects: augmentation & autograft.

Numerous options exist for management of minor bone defects associated with TKA. Biomechanical data demonstrate that filling defects with methylmethacrylate, with or without screw augmentation, results in inferior load transfer. Rectangular augmentations may be superior to angular wedges due to reduction in shear stresses. Controversy persists regarding superiority of use of bone graft versus augmentation. The author favors bone graft for cavitary defects, massive bone loss, and in younger patients in whom additional revision surgery is likely. Prosthetic augmentation is favored in peripheral defects of moderate size in more elderly patients.

Total knee arthroplasty in chronic hemophilic arthropathy.

Nine total knee arthroplasties were performed in seven patients with either Hemophilia A (factor VIII deficiency) or Hemophilia B (factor IX deficiency) and followed for an average of 52 months. A total condylar prosthesis was used in eight virgin knees and a stemmed variable axis prosthesis was used in one revision case. All knees demonstrated the severe joint destruction and cartilage erosion characteristic of chronic hemophilic arthropathy. The average age at operation was 32 years. All patients were evaluated using the knee disability assessment of The Hospital for Special Surgery. All knees were postoperatively rated as either excellent or good. Pain, function, and range of motion were markedly improved. Postoperative radiographic alignment averaged 4 degrees of valgus with half of the virgin knees demonstrating 1 mm or less of non-progressive tibial radiolucency without clinical loosening. The only complication was hemarthrosis from 37 to 59 months postoperatively. This was thought to be secondary to trauma to residual synovium. Total knee arthroplasty in the hemophiliac is a viable alternative to conventional methods of treatment for chronic arthropathy and expectations for pain relief and functional gain can be high.

Principles of total knee arthroplasty.

Experience over the last two decades has demonstrated total knee arthroplasty to be a durable and reliable procedure for relief of pain and improved function. Proper patient and prosthesis selection are important for optimal results. Operative keys to a successful total knee arthroplasty include satisfactory exposure, soft tissue balance, proper alignment, and reconstruction of the patellofemoral joint.

Blood conservation in revision total hip arthroplasty.

Blood loss from major orthopedic procedures such as spine and revision total joint arthroplasty often necessitates perioperative blood transfusion. The risk of infectious disease transmission associated with homologous blood transfusion, particularly hepatitis and acquired immune deficiency syndrome, mandates use of blood conservation techniques. Methods available to the orthopedic surgeon include preoperative autologous donation, intraoperative and postoperative blood salvage, hemodilution, and other selective anesthetic techniques such as hypotensive anesthesia and epidural or spinal anesthesia. The safest blood patients can receive is their own. With full use of these blood conservation methods, the need for homologous blood transfusion for elective orthopedic procedures should be minimal.