Retrieval analysis of femoral zirconium components in total knee arthroplasty: preliminary results.

Safety of oxidized zirconium (OxZr) in total knee arthroplasty (TKA) has been supported by biomechanical, clinical, and radiologic data. Retrieved OxZr femoral components and corresponding polyethylene (PE) inserts were examined to rule out patterns leading to early failure. Sixteen retrieved TKA with an OxZr femoral component were included. The PE inlays were analyzed applying an established scoring system for wear and surface damage. Femoral components were screened for scratching, pitting, delamination, and striations. The prostheses were in situ for 16.4 ± 11.9 months. The average wear and damage score for the tibial PE inserts was 36.0 ± 12.7. The average score in the visual analysis of the OxZr femoral components was 1.3 ± 1.3. The data presented in this study did not show major wear of the PE in TKA using OxZr components. In this cohort, there were no failures directly related to this implant.

Revision knee arthroplasty including reconstruction of the lateral collateral ligament by allograft: a case report.

A 53-year-old woman presented with an unstable and painful total knee arthroplasty 6 months after the index procedure. Disruption of both collateral ligaments as a young adult and the subsequent development of traumatic arthritis required repeated surgical and extensive conservative treatment before a prosthesis was implanted. Examination disclosed marked instability of the lateral collateral ligament (LCL) and loosening of the tibial and the femoral components. Review of the MRI obtained prior to the total knee replacement revealed discontinuity of the LCL with intense scarring of the posterolateral ligament complex. Definitive management of this twofold problem was not helped by literature review, which failed to reveal a gold standard or a broad consensus as a rationale for treatment. Consequently, an individual approach to the problem was defined: A one-stage revision arthroplasty was performed using a modular non-articulated constrained prosthesis and a bone-tendon-bone allograft to reconstruct the LCL in a one-stage operation. Postoperative rehabilitation included continuous passive motion, which was begun immediately after surgery and was gradually increased to 90° of flexion. The LCL reconstruction was initially protected in a hinged knee brace and weight-bearing was initially limited to toe-touch and gradually increased over 6 weeks. Pain-free motion to 0-115° flexion was achieved at 3 months after surgery and the patient had returned to her normal activities. The 4-year-follow-up displayed a stable and functional knee with no evidence of loosening or wear.

Is minimally invasive surgery-total knee arthroplasty truly less invasive than standard total knee arthroplasty? A quantitative evaluation.

With recent technical advancements, the number of operative manipulations in the knee joint by minimally invasive surgery-total knee arthroplasty (MIS-TKA) is now considered to be the same as that using standard TKA (S-TKA). The question still remains, however, if MIS-TKA improves recovery compared to S-TKA. We compared MIS-TKA and S-TKA patients' physical activity as measured by an accelerometer. Physical activity expressed as cumulative acceleration was significantly higher in the MIS-TKA than in the S-TKA group on postoperative days (POD1, 2, 3, 4, 5, 10, 11) (P < .05). The recovery time, defined as the number of days required to achieve cumulative acceleration of 80% of the preoperative level, was significantly shorter (P < .05) in the MIS-TKA (3.0 +/- 3.3 days) group than in the S-TKA (7.0 +/- 3.5 days) group. Minimally invasive surgery-total knee arthroplasty appears to allow an earlier recovery after the operation than S-TKA. Less invasion to muscle during the surgery appears to contribute to shorter convalescence.

Varus gonarthrosis predisposes to varus malalignment in TKA.

Postoperative alignment is a predictor for long-term survival of total knee arthroplasty (TKA). The purpose of this study was to evaluate whether or not preoperative deformities predispose to intraoperative malposition of TKA components. A retrospective radiographic analysis of 53 primary TKA cases was performed. Preoperative AP hip to ankle and lateral knee radiographs were compared with postoperative views to evaluate component positioning. The following angles were measured: the hip-knee-ankle (HKA) angle expressing the mechanical axis of the leg, the mechanical lateral distal femur angle (mLDFA), the medial proximal tibia angle (MPTA), the posterior distal femur angle (PDFA), and the posterior proximal tibia angle (PPTA). Postoperative measurement of the HKA revealed 34.0% of the cases had a deviation of >+/-3 degrees from neutral alignment. Sixteen knees (30.2%) were in varus and, with one exception, all presented with severe varus gonarthrosis prior to surgery with a mean tibiofemoral angle of 12.4 degrees compared with 1.0 degrees of valgus in the optimally aligned group. Patients (93.3%) with preoperative valgus malalignment showed optimal postoperative HKA. Odds ratios for malalignment of TKA for varus knees in comparison with valgus knees were 7.1 for HKA, 2.4 for MPTA, 4.9 for PDFA, and 1.7 for PPTA. The overall number of outliers in the presented data corresponds well with reports from other authors using different implants and guide systems. The presented data indicate that patients with preoperative varus alignment have a higher risk of postoperative implant malposition than patients with valgus alignment. The data supports that preoperative varus deformity predisposes to varus malposition of TKA. The risk for intraoperative malposition is significantly lower in valgus knees.

The classic: total condylar knee replacement in patients who have rheumatoid arthritis. A ten-year follow-up study. 1990.

Eighty knee replacements with a total condylar prosthesis in patients who had rheumatoid arthritis were followed for ten years. At ten years, nineteen knees needed revision and sixty-one prostheses were still functioning. The major reasons for revision were loosening of the tibial component or late bacteremic seeding from another site. Radiolucency at the bone-cement interface adjacent to the tibial component was statistically related to malposition of the tibial component. According to the system of The Hospital for Special Surgery, the mean scores were 64 points preoperatively and 85 points postoperatively. Synovitis recurred in only 3 per cent of the knees. When revision, pain, or radiographic evidence of loosening were considered an indication of failure, the ten-year cumulative survival was 75 per cent.

The classic: modular total knee-replacement arthroplasty. A review of eighty-nine patients. 1976.

Fifty-eight osteoarthritic and thirty-one rheumatoid patients underwent modular total knee-replacement arthroplasty. The major indication for the operation was relief of pain. Contraindications to this resurfacing arthroplasty included varus-valgus instability of over 20 degrees, combined varus-valgus instability with flexion contracture of over 40 degrees, marked recurvatum, and predominant patellofemoral symptoms. In 59 per cent of the osteoarthritic and 58 per cent of the rheumatoid patients, complete relief of pain was evident when they were evaluated twenty-four months after surgery, while another 35 per cent of each group had only mild pain related to inclement weather. Their ability to walk long distances without support or limp was increased. Range of motion and ability to climb stairs were not significantly improved.

The mini-incision mid-vastus approach for total knee arthroplasty.

OBJECTIVE: Rapid functional recovery and improved range of motion after total knee arthroplasty (TKA) without compromising implant position. INDICATIONS: Osteoarthritis of the knee requiring TKA. CONTRAINDICATIONS: Preoperative flexion < 80 degrees. Flexion contracture > 20 degrees. Body mass index > 40 kg/m(2). Fixed valgus deformity > 15 degrees. Relative: previous open surgery on the knee; systematic steroids (skin fragility); tall muscular males. SURGICAL TECHNIQUE: Straight skin incision over the medial third of the patella from 2 cm proximal to the patella, and then to the level of the tibial tuberosity. Extension of capsular incision 2 cm into the vastus medialis muscle from a point 2 cm proximal to the patella. Deep incision around the medial border of the patella and distally to the level of the tibial tuberosity. The patella is displaced laterally but is not everted in flexion. Knee flexion and extension as necessary to move the soft-tissue surgical window for proximal or distal exposure. Hyperflexion of the knee only for insertion of the tibial component. POSTOPERATIVE MANAGEMENT: Knee flexion exercises extension/flexion 0-0-70 degrees using continuous passive motion the day after surgery. Weight bearing to tolerance allowed at 1st day after surgery (walker, two crutches). Thrombosis prophylaxis. RESULTS: 69 patients with 74 TKAs done through the mini-incision mid-vastus approach were available with a minimum 1-year follow-up. A control group was evaluated retrospectively including 52 patients with 57 total knee replacements in which a standard medial parapatellar arthrotomy with patella eversion was used. At all clinical evaluations flexion and the ability to climb stairs were significantly superior in the mid-vastus group indicating a faster recovery and return to functional activities. There were no complications and the radiographic evaluation found no implant or limb malalignment, or signs of early loosening.

A mini-midvastus capsular approach with patellar displacement decreases the prevalence of patella baja.

Our aim in this study was to evaluate the prevalence of patella baja after total knee arthroplasty (TKA) using 2 different surgical techniques. Postoperative changes in patella height were measured on serial radiographs of 74 TKAs implanted using a mini-midvastus capsular approach without patella eversion (group 1) and 57 TKAs implanted using a standard medial parapatellar capsular approach with patella eversion (group 2). Preoperative and postoperative Knee Society scores, operative data, and complications were compared. With a cutoff level of 5% shortening, the prevalence was 12% in group 1 and 37% in group 2 (P = .001). The presence of patella baja was related to reduced flexion and increased pain as early as 1 year after TKA.

Ten-year results of the first 100 Genesis II total knee replacement procedures.

The first 100 consecutive Genesis II (Smith & Nephew; Memphis, Tenn) total knee replacements (TKR) procedures performed in 97 patients by the senior investigators (RBB, RSL) had a Kaplan-Meier survivorship of 96% +/- 2% at 12 years with any reoperation as the endpoint. Significant improvements in health-related quality-of-life outcome measures were noted. There were no revisions for implant-related factors (ie, polyethylene wear, osteolysis, or aseptic loosening). No implant demonstrated radiographic loosening. The features of this device are discussed as well as its long-term performance.

The effect of a high-flex implant on postoperative flexion after primary total knee arthroplasty.

Compared to a statistically similar cohort, patients implanted with a high-flex poster-stabilized prosthesis achieved greater return of flexion than that with a standard posterior stabilized implant. In addition, patients with a high flexion arc preoperatively retained this high arc of flexion after surgery. Finally, there was an increase in the range of flexion seen after surgery in both groups of patients, but larger in the group in which the modified high-flexion implant was used.

Surgical exposure for total knee arthroplasty: for everything there is a season.

The author has used a mini midvastus lesser-invasive knee approach for 5 years for patients undergoing a primary total knee arthroplasty. The approach involves a modified capsular and muscular incision, displacement but not eversion of the patella, and avoidance of anterior dislocation of the tibia before bony resections. This has resulted in a more rapid return of flexion and functional ability with a lesser amount of postoperative pain as compared with previous larger median parapatellar approaches with patellar eversion. The approach is indicated for patients who preoperatively have good knee flexion, a mild to moderate coronal deformity, and no prior open procedures on the joint. It is difficult to use in patients who have large, heavy and/or muscular thighs; those with severe angular or flexion deformities; those with limited flexion; and those with severe inflammatory arthritis of the knee.

What would you do? Challenges in knee surgery.

Evaluation and management of 4 challenging knee case scenarios were discussed in an interactive session with a moderator and 5 experts in knee reconstruction. Case-based discussion included total knee arthroplasty in the presence of femoral deformity, deficient patellar bone, and patella baja, and treatment of infected total knee arthroplasty.

Intramedullary arthrodesis of the knee in the treatment of sepsis after TKR.

Infection is a devastating complication following total knee replacement (TKR). In the majority of cases, single- or two-stage revision has excellent results in eradicating infection and restoring function. Rarely, recurrent infection requires alternative treatments such as resection, amputation, or arthrodesis. A review of infections following TKR treated at two joint replacement centers identified 29 cases of resistant knee sepsis treated with a long intramedullary fusion nail. Clinical outcome and radiographs were reviewed at an average follow-up of 48 months (13-114). After the initial intramedullary arthrodesis union occurred in 24 of 29 patients (83%). The average time to fusion was 6 months (3-18 months). Failures included two cases of nail breakage, one of which subsequently achieved fusion following revision nailing, and three cases of recurrent infection requiring nail removal and permanent resection. At a minimum 2-year follow-up, 28% of the patients that achieved fusion complained of pain in the fused knee, 28% complained of ipsilateral hip pain, and two patients complained of contralateral knee pain. Four of the 25 fused patients (16%) remained nonambulatory after fusion, 17 required walking aids (68%) and only four ambulated unassisted. There was no association between age, number of previous procedures, the use of two-stage versus single stage technique, or infecting organism and failure of arthrodesis. Intramedullary arthrodesis is a viable treatment for refractory infection after TKR. Patients undergoing fusion should be informed of the potential for nonunion, recurrence of infection, pain in the ipsilateral extremity, and the long-term need for walking aids.

VenaFlow plus Lovenox vs VenaFlow plus aspirin for thromboembolic disease prophylaxis in total knee arthroplasty.

Two hundred seventy-five patients undergoing unilateral total knee arthroplasty were prospectively randomized to receive spinal epidural anesthesia (SEA), a VenaFlow calf compression device, and enoxaparin (group A) or SEA, VenaFlow, and aspirin (group B). Aspirin was started on the day of surgery, whereas enoxaparin was started 48 hours after surgery. Anticoagulants were continued for 4 weeks after surgery. All patients had an in-hospital ultrasound screening test on postoperative days 3 to 5 and a second follow-up ultrasound 4 to 6 weeks after surgery. The overall deep venous thrombosis rates in groups A and B were 14.1% and 17.8% (P = not significant), respectively. When used in combination with pneumatic compression devices and SEA, enoxaparin was not superior to aspirin in preventing deep venous thrombosis after total knee arthroplasty.

Computer-assisted navigation in TKA: where we are and where we are going.

When compared to standard intramedullary and extramedullary referencing systems, computer-assisted navigation systems have been shown in multiple randomized studies to increase the accuracy of bone resections in total knee arthroplasty. Accuracy to within 1 degrees in the coronal plane resections can routinely be obtained. Recent modifications of the software programs address the problem of proper soft tissue balance. Newer techniques of bone morphing have obviated the use of preoperative imaging in most cases. Despite these advances, the systems remain somewhat cumbersome to use and costly to acquire. As these limitations are addressed, computer-assisted navigation may become a valuable part of the knee surgeon's armamentarium, especially for the patient with a deformed femur or tibia in whom conventional navigation instruments are difficult to use accurately.

Mini-incision: occasionally desirable, rarely necessary in opposition.

Using a mini mid vastus limited incision for primary total knee arthroplasty, the authors noted the ability to decrease postoperative pain while speeding up the rate of recovery of motion and of return of function. By specific flexion and extension of the knee, the surgical window could be mobilized to visualize the articular surfaces at various stages during the surgery. Radiographic evaluation revealed that component position and limb alignment were excellent despite the use of the more limited incision.

What would you do? Case challenges in knee surgery.

Six cases representing a variety of orthopedic issues were presented to a panel of senior surgeons. These included the following: (1) developmental patella baja with degenerative arthritis, (2) high valgus knee with attenuated medial collateral ligament, (3) degenerative arthritis with near-ankylosis, (4) depressed tibial plateau fracture with degenerative arthritis, (5) degenerative arthritis with laterally dislocating patella, and (6) degenerative arthritis with distal femoral malunion.

Minimally invasive total knee arthroplasty: the results justify its use.

UNLABELLED: A mini-midvastus capsular incision was used in a feasibility study of 100 patients having primary total knee arthroplasty. Patients with marked limitation of motion were excluded from the study. Patients were followed up for a minimum of 2 years after surgery. The exposure yielded excellent results clinically and radiographically with restoration of stability and motion. The length of the skin incision varied from 8 to 15 cm with a mean of 10.5 cm. Using the limited exposure did not result in implant malpositioning. The surgical approach was not applicable in patients with a BMI > 40 or in those patients with a severe fixed valgus deformity. LEVEL OF EVIDENCE: Therapeutic study, Level IV-1 (case series). See the Guidelines for Authors for a complete description of levels of evidence.