INTRODUCTION

Over the past 40 years of knee arthroplasty, significant advances have been made in the design of knee implants, resulting in high patient satisfaction. Patellar tracking has been central to improving the patient experience, with modern designs including an optimized Q-angle, deepened trochlear groove, and thin anterior flange.[1–4] Though many of today's femoral components are specific for the left and right sides, Total Joint Orthopedics’ (TJO) Klassic® Knee System features a universal design to achieve operating room efficiencies while providing all the advancements of a modern knee. The Klassic Femur achieves this through a patented double Q-angle to provide excellent patellar tracking whether implanted in the left or the right knee (Figure 1). The present study examines a prospective cohort of 145 consecutive TKA's performed using a modern universal femur and considers patients’ pre- and post-operative Knee Society Clinical Rating System score (KSS).

Two big problems exist with the all polyethylene cemented tibial component; the polyethylene and the cement. The polyethylene is too weak and flexible to bear high tibial load, so it deforms and loosens. The interface stresses are too high when two flexible structures are poorly bonded and heavily loaded.

Modularity between the polyethylene tibial component and the metal-backed tray was introduced in the mid-80's for versatility and to facilitate screw fixation for cementless implants. These designs allow exchange of various polyethylene thicknesses, and aids the addition of stems and wedges. Other advantages include the reduction of inventory, and the potential for isolated tibial polyethylene exchanges as a simpler revision procedure. Several studies have documented the high failure rate of isolated polyethylene exchange procedures, because technical problems related to the original components are left uncorrected. However, revision for wear is the simplest revision ever!

Since the late 1980's the phenomena of polyethylene wear and osteolysis have been observed much more frequently when compared with earlier eras. The reasons for this increased prevalence of synovitis, progressive osteolysis, and severe polyethylene wear remain unclear. There is some association with the widespread use of both cementless and cemented modular tibial designs. Improved polyethylene attachment is the answer even if a screw, a wire, or a pin is needed. Do not abandon the modular tibia.

The infected TKA is one of the most challenging complications of knee surgery, but spacers can make them easier to treat. An articulating spacer allows weight bearing and range of motion of the knee during rehabilitation. This spacer is made using antibiotic-impregnated bone cement applied to the tibial and femoral implants. For our purpose, 4.8g powdered tobramycin is mixed with 2gm vancomycin and one batch of antibiotic. Cement is applied early to the components, but applied late to the femur, tibia, and patella to allow molding to the defects and bone without solid adherence to bone. Patients have tailored intravenous antibiotic therapy for 6 weeks for treatment of various gram-positive and gram-negative organisms. At 10–12 weeks patients are revised to a cemented revision total knee arthroplasty using standard cementing techniques. From our experience, range of motion before reimplantation was 5 – 90 degrees. Follow-up averaged 73 months for fifty patients with 90% good to excellent results; 10% had a recurrence of infections. Use of an articulating spacer achieves soft tissue compliance, allows for ease of re-operation, reduced postoperative pain, improved function, and eradicates infection equal to standards reported in the literature.

Since 1997, a patented rim flared cup has been used for both primary and revision total hip arthroplasty with great success. The concept was based on a “stretched” hemispherical geometry to improve initial contact between cup and bone. This improved geometry provided a 1 mm press fit predominantly at the perimeter of the acetabulum much like the footprint of the native anatomic acetabulum. Thousands of these were implanted. A second version of this concept was introduced in August 2011. This similarly “stretched” geometry provides 1.6 mm of press fit. Building on what was learned from the original design, this updated, stretched geometry was created with a single radius for a smooth transition from the apex to the peripheral press fit. Porous coating is the key to implant durability. With this aggressive “sticky” porous coating, only 0.6 mm of press fit is required. This porous coating has 60% porosity, and 150–400 mm pore size. It has a tensile strength of 5000 psi (The FDA requires a minimum of 2900 psi) and a mean thickness of 0.8 mm. Three thousand cups have been implanted with the author contributing 400. In our own primary subgroup done in 2014–15, 142 had 2–4 year follow up with zero loosening. There was one infection and 2 dislocations. One implant was revised on a patient with psoas tendonitis from an oversized cup. At retrieval it showed excellent ingrowth into the porous coating with 38% ingrowth. This graduated rim fit concept has a proven track record spanning 2 decades and provides a stable and reproducible acetabular construct.

The infected TKA is one of the most challenging complications of knee surgery, but spacers can make them easier to treat. An articulating spacer allows weight bearing and range of motion of the knee during rehabilitation. This spacer is made using antibiotic-impregnated bone cement applied to the tibial and femoral implant. For our purpose, 4.8g powdered tobramycin is mixed with 2g vancomycin and one batch of cement. Cement is applied early to the components, but applied late to the femur, tibia, and patella to allow molding to the defects and bone without solid adherence to bone. Patients have tailored intravenous antibiotic therapy for 6 weeks for treatment of various gram-positive and gram-negative organisms. At 10–12 weeks patients are revised to a cemented revision total knee arthroplasty using standard cementing techniques. From our experience, range of motion before reimplantation was 5 – 90 degrees. Follow-up averaged 73 months for fifty patients with 90% good to excellent results; 10% had a recurrence of infections. Use of an articulating spacer achieves soft tissue compliance, allows for ease of re-operation, reduced post-operative pain, improved function, and eradicates infection equal to standards reported in the literature.

Exposure for revision knee requires using the previous incision, employing the “quad snip”, the “Banana Peel”, or the tubercle osteotomy.

The “quad snip” is a 45-degree incision of the proximal extensor mechanism that helps protect the distal insertion on the tubercle.

The “banana peel,” is my exposure of choice and has been used extensively for revision total knee arthroplasty (TKA) for more than 20 years in my community. We retrospectively reviewed use of this technique in a cohort of 100 consecutive patients who underwent tibial-femoral stemmed revision TKA. The technique involves peeling the patella tendon as a sleeve off the tibia, leaving the extensor mechanism intact with a lateral hinge of soft tissue. A quadriceps “snip” must be done proximally to avoid excessive tension. No patient has ever reported disruption of the extensor mechanism or decreased ability to extend the operative knee. With a mean Knee Society score of 176 (range, 95–200). Post-operative motion was 106 degrees. No patient reported pain over the tibial tubercle. The “banana peel” technique for exposing the knee during the revision TKA is a safe method that can be used along with a proximal quadriceps snip and does not violate the extensor mechanism, maintaining continuity of the knee extensors.

As a last resort, tibial tubercle osteotomy as described by Whiteside, is preferred for revising porous coated stemmed tibial components and is repaired with cerclage wire or cables. Keep the osteotomy fragment at least 8–10cm long leaving a lateral soft tissue attachment.

Two big problems exist with the all-polyethylene cemented tibial component; the polyethylene and the cement. The polyethylene is too weak and flexible to bear high tibial load, so it deforms and loosens. The interface stresses are too high when two flexible structures are poorly bonded and heavily loaded.

Modularity between the polyethylene tibial component and the metal-backed tray was introduced in the mid-80's for versatility and to facilitate screw fixation for cementless implants. These designs allow exchange of various polyethylene thicknesses, and aids the addition of stems and wedges. Other advantages include the reduction of inventory, and the potential for isolated tibial polyethylene exchanges as a simpler revision procedure. Several studies have documented the high failure rate of isolated polyethylene exchange procedures, because technical problems related to the original components are left uncorrected. However, revision for wear is the simplest revision ever!

Since the late 1980's the phenomena of polyethylene wear and osteolysis has been observed much more frequently when compared with earlier eras. The reasons for this increased prevalence of synovitis, progressive osteolysis, and severe polyethylene wear remain unclear. There is some association with the widespread use of both cementless and cemented modular tibial designs. Improved polyethylene attachment is the answer even if a screw, a wire, or a pin is needed. Do not abandon the module tibia.

Isolated patellofemoral arthritis is not an uncommon problem, with no clear consensus on treatment. Nonoperative and many forms of operative treatments have failed to demonstrate long-term effectiveness in the setting of advanced arthritis. Total knee arthroplasty (TKA) has produced excellent results, but many surgeons are hesitant to perform TKA in younger patients with isolated patellofemoral arthritis. In properly selected patients, patellofemoral arthroplasty (PFA) is an effective procedure with good long-term results. Contemporary PFA prostheses have eliminated many of the patellar maltracking problems associated with older designs, and short-term results, as described here, are encouraging. Long-term outcome and prospective trials comparing TKA to PFA are needed.

Two big problems exist with the all-polyethylene cemented tibial component; the polyethylene and the cement. The polyethylene is too weak and flexible to bear tibial load, so it deforms and loosens. The interface stresses are too high when two flexible structures are poorly bonded and heavily loaded.

Modularity between the polyethylene tibial component and the metal-backed tray was introduced in the mid-1980s for versatility and to facilitate screw fixation for cementless implants. These designs allow exchange of various polyethylene thicknesses, and aid the addition of stems and wedges. Other advantages include the reduction of inventory, and the potential for isolated tibial polyethylene exchanges as a simpler revision procedure. Several studies have documented the high failure rate of isolated polyethylene exchange procedures, because technical problems related to the original components are left uncorrected. However, revision for wear is the simplest revision ever!

Since the late 1980s the phenomena of polyethylene wear and osteolysis have been observed much more frequently when compared with earlier eras. The reasons for this increased prevalence of synovitis, progressive osteolysis, and severe polyethylene wear remain unclear. There is some association with the widespread use of both cementless and cemented modular tibial designs. Improved polyethylene attachment is the answer even if a screw, a wire, or a pin is needed. Do not abandon the modular tibia on any patient.

Stiffness remains one of the most common, and challenging postoperative complications after TKA. Preoperative motion and diagnosis can influence postoperative motion, and careful patient counseling about expectations is important. Postoperative stiffness should be evaluated by ruling out infections, metal allergy, or too aggressive physical therapy. A careful physical and radiographic examination is required. Manipulation under anesthesia (MUA) in selected cases can be helpful. The best timing to perform MUA is between the 6th and 10th week postoperatively. Careful technique is required to minimise the risk of fracture or soft tissue injury. This requires complete paralysis! For more chronic stiffness, revision may be indicated if an etiology can be identified. An excessively thick patellar resurfacing, an overstuffed tibia insert, an oversized femoral component, or gross malrotation should be corrected. During revision, thorough synovectomy, release of contractures, ligamentous balancing and restoration of the joint line is required. Careful attention to component rotation, and sizing is critical. Downsizing components is helpful to place less volume into the joint space. Patients should be counseled that the results of revision for stiffness are mixed and somewhat unpredictable. More frequent postoperative nurturing is helpful to guide rehabilitation progress. Manipulation after revision at 6 weeks is almost expected.

Systematic surgical exposure during revision total knee arthroplasty is essential for revision surgery. Surgical exposure protects the extensor mechanism, facilitates safe implant removal and allows for accurate reimplantation of components. The pre-operative plan is critical to achieving appropriate exposure in the revision setting. Evaluating the skin and previous incisions will aid in the exposure technique selected.

The key to revision total knee arthroplasty is systematic releases. Revision total knees can be exposed with a standard medial parapatellar arthrotomy, a proximal medial tibial peel, and a quad snip. This takes tension off the stiff knee, is easy to repair, and does not require limitation of rehabilitation protocols. The patella need not be everted in the revision surgery. The Banana Peel technique is very helpful for the stiff knee. The tibial tubercle osteotomy can also be utilised in patients with extreme stiffness and can aid in removal of well-fixed tibial stems. Keep the osteotomy long (8–10 cm) and leave a lateral soft tissue bridge. Other techniques such as the quadricepsplasty or V-Y turndown are rarely needed.

The anatomic resection approach is based on the patient's unique anatomy adjusting for worn cartilage or bone loss. The femoral component is aligned around the primary transverse distal femoral axis around which the tibia follows a multi-radius of curvature. The tibia cut is made according to the patient's native anatomy adjusting for worn cartilage and bone loss, and applying an anatomic amount of tibial slope. This technique minimises the need for ligamentous releases to a large degree preserving the competence of the patient's soft tissue. Ligament and capsular releases can be used in difficult cases. Adjustments for the natural varus up to 3 degrees and slope of the tibial bone cut (3 – 10 degrees) further aids in knee balancing. The final alignment may not agree with a neutral hip-knee-ankle mechanical alignment on full length standing x-rays, leaving varus knees in slight varus, and valgus legs in neutral. Since little or no balance is required, this operation can be performed efficiently.

Personalise the reconstruction and alignment as much as possible for each patient. The traditional “one size fits all” method where all patients have a center hip, knee, and ankle alignment needs to be reevaluated and reserved for the valgus leg.

Infected TKA is one of the most challenging complications of knee surgery, but spacers can make them easier. An articulating spacer allows partial weight bearing and range of motion of the knee during rehabilitation. This spacer is made using antibiotic-impregnated bone cement applied to the implant. For our purpose, 4.8 g powdered tobramycin is mixed with 2 g vancomycin and one batch of cement. Cement is applied early to the components, but applied late to the femur, tibia, and patella to allow molding to the defects and bone without solid adherence to bone. Patients have tailored intravenous antibiotic therapy for 6 weeks for treatment of various gram-positive and gram-negative organisms. At 10–12 weeks patients receive a cemented revision total knee arthroplasty using standard cementing techniques. From our experience range of motion before reimplantation is 5–90 degrees. Follow-up averaged 73 months for 50 patients with 90% good to excellent results, 10% may have a recurrence. Use of an articulating spacer achieves soft tissue compliance, allows for ease of operation, reduced post-operative pain, improved function, and eradicates infection equal to standards reported in the literature.

Measured resection approach (anatomic) is based on the patients' unique anatomy adjusting for worn cartilage or bone loss. The femoral component is aligned around the primary transverse distal femoral axis around which the tibia follows a multi-radius of curvature. The tibia cut is made according to the patient's native anatomy adjusting for worn cartilage and bone loss, and applying an anatomic amount of tibial slope. This technique minimises the need for partial ligamentous releases to a large degree preserving the competence of the patient's soft tissue, though ligament and capsular releases can be used in difficult cases. Adjustments for the varus/valgus (up to 3 degrees) or slope of the tibial bone cut (3–10 degrees) further aids in knee balancing. The final alignment may not agree with a neutral hip-knee-ankle mechanical alignment on full length standing x-rays, leaving varus knees in slight varus, and valgus legs in neutral. Since little balance is required this operation can be performed in less than 40 minutes.

Infection is a devastating complication following total hip arthroplasty. For chronically infected total hip arthroplasty; we utilise a 2-stage articulating antibiotic hip spacer technique. Our success rate with the technique is 90% with patients clinically free of infection at an average of five years postoperatively. 80% of the patients had a positive identification of the infecting organism. The other 20% had a positive frozen section and clinically infected joints. All patients receive a minimum of 6 weeks of intravenous antibiotics. Postoperative hip scores average 90 points. Some patients elected to keep their antibiotic spacers for up to 2 years before the 2nd stage. Advantages of this technique include improved patient function, maintenance of bone stock and soft tissue tension, thus simplifying reimplantation.

In properly chosen patients, cementless total knee arthroplasty has achieved success rates equal to cemented designs. The initial variable results of early cementless total knee replacements were a function of design, surgical technique and patient selection. Important design considerations that have enhanced biologic ingrowth include the use of commercially pure titanium with optimal pore size and porosity, and avoidance of porous-coated stems and plugs that cause stress shielding of the bone-implant interface. Factors in surgical technique that enhance bone ingrowth include precise bone cuts that maximise bone-implant contact, and the application of autogenous bone slurry to cut surfaces. Additional factors are restoration of normal alignment, appropriate ligament balance, and the reproduction of the patient's native tibial slope in order to prevent tibial component subsidence. Young and active patients are ideal biological hosts for the use of cementless knee fixation. Their relatively dense cancellous bone and rich blood supply provides for robust purchase for initial fixation and the appropriate milieu for long-term biologic fixation. With increasing life expectancy, this more durable interface is desirable. With avoidance of porous-coated stems and pegs and prevention of fibrous tissue attachment, potential future revisions are more bone-sparing relative to methylmethacrylate fixation. Numerous reports, as well as the authors’ published 10- to 14-year results, demonstrate that cementless fixation in appropriately selected patients provides results comparable to cemented TKA, with the advantage of conserving bone stock and eliminating the potential problems of cement fixation.

Isolated patellofemoral arthritis is not an uncommon problem, with no clear consensus on treatment. Nonoperative and many forms of operative treatments have failed to demonstrate long-term effectiveness in the setting of advanced arthritis. Total knee arthroplasty (TKA) has produced excellent results, but many surgeons are hesitant to perform TKA in younger patients with isolated patellofemoral arthritis. In properly selected patients, patellofemoral arthroplasty (PFA) is an effective procedure with good long-term results. Contemporary PFA prostheses have eliminated many of the patellar maltracking problems associated with older designs, and short-term results, as described here, are encouraging. Long-term outcome and prospective trials comparing TKA to PFA are needed.

The ultracongruent insert has been used since 1991 beginning with the Natural-Knee, then manufactured by Sulzermedica. It has posterior stabilising ability with the 12.5mm anterior build up with a significantly more congruent articulation. This translates to higher contact areas and theoretically lower wear. The higher central eminence provides some medial lateral stability. This style insert is now available from at least seven different manufacturers.

The first study was reported in the 2000 Journal of Arthroplasty with Hofmann et al., comparing 100 ultracongruent inserts with 100 PCL sparing inserts with an average five-year follow up. Knee scores and range of motion were similar or no dislocations or subluxations were noted. We found this bone sparing since there is no box cut and requires less time for surgery. This insert provided excellent stability in all ranges of motion.

Indications for this surgery are deficiency or compromise of the PCL.

Contraindications are attenuation or absence of either one or both collateral ligaments where a more constrained device is suggested.

The ultracongruent insert has been used since 1991 beginning with the Natural- Knee, then manufactured by Sulzermedica. It has posterior stabilising with the 12.5mm anterior build up with a significantly more congruent articulation. This translates to higher contact areas and theoretically lower wear. The higher central eminence provides some medial lateral stability. This style insert is now available from at least seven different manufacturers.

The first study was reported in the 2000 Journal of Arthroplasty with Hofmann et al., comparing 100 ultracongruent inserts with 100 PCL sparing inserts with an average five-year follow-up. Knee scores and range of motion were similar or no dislocations or subluxations were noted. We found sparing since there is no box cut and requires less time for surgery. This insert provided excellent stability in all ranges of motion.

Indication for this surgery is deficiency or compromise of the PCL.

Contraindications are attenuation or absence of either one or both collateral ligaments where a more constrained device is suggested.

Isolated patellofemoral arthritis is not an uncommon problem, with no clear consensus on treatment. Nonoperative and many forms of operative treatments have failed to demonstrate long-term effectiveness in the setting of advanced arthritis. Total knee arthroplasty (TKA) has produced excellent results, but many surgeons are hesitant to perform TKA in younger patients with isolated patellofemoral arthritis. In properly selected patients, patellofemoral arthroplasty (PFA) is an effective procedure with good long-term results. Contemporary PFA prostheses have eliminated many of the patellar maltracking problems associated with older designs, and short-term results, as described here, are encouraging. Long-term outcome and prospective trials comparing TKA to PFA are needed.