Converting unicompartmental knee arthroplasty (UKA) to total knee arthroplasty can be difficult, and specialised techniques are needed. Issues include bone loss, joint-line, sizing, and rotation. Determining the complexity of conversion preoperatively helps predict the need for augmentation, grafting, stems, or constraint. We examined insert thickness, augmentation, stem use, and effect of failure mode on complexity of UKA conversion. Fifty cases (1997–2007) were reviewed: 9 implants (18%) were modular fixed-bearing, 4 (8%) were metal-backed nonmodular fixed-bearing, 8 (16%) were resurfacing onlay, 10 (20%) were all-polyethylene step-cut, and 19 (38%) were mobile bearing designs; 5 knees (10%) failed due to infection, 5 (10%) due to wear and/or instability, 10 (20%) for pain or progression of arthritis, 8 (16%) for tibial fracture or severe subsidence, and 22 (44%) due to loosening of either one or both components. Complexity was evaluated using analysis of variance and chi-squared 2-by-k test (80% power; 95% confidence interval). Insert thickness was no different between implants (P=0.23) or failure modes (P=0.27). Stemmed component use was most frequent with nonmodular components (50%), all-polyethylene step-cut implants (44%), and modular fixed-bearing implants (33%; P=0.40). Stem use was highest in tibial fracture (86%; P=0.002). Augment use was highest among all-polyethylene step-cut implants (all-polyethylene, 56%; metal-backed, 50%; modular fixed-bearing, 33%; P=0.01). Augmentation use was highest in fracture (86%) and infection (67%), with a significant difference noted between failure modes (P=0.003). Failure of nonmodular all-polyethylene step-cut devices was more complex than resurfacing or mobile bearing. Failure mode was predictive of complexity. Reestablishing the joint-line, ligamentous balance, and durable fixation are critical to assuring a primary outcome.

Background:

Coronal malalignment occurs frequently in total knee arthroplasty (TKA) and reduces implant longevity and function. Designed to improve consistency and efficiency, patient- specific positioning guides (PSPG) generated from preoperative imaging studies represent a paradigm shift from manual instrumentation (MI) and intraoperative computer navigation.

Resurfacing arthroplasty of the hip enjoyed a resurgence of enthusiasm. A recent article has documented that the media played a significant role in its popularity, making claims that were not substantiated in scientific literature. Proponents of resurfacing arthroplasty state that it is bone conserving, provides greater stability, enhances range of motion, leads to a more normal gait, facilitates increased activity levels, decreases risk of dislocation, decreases the risk of leg length discrepancy and find that it is easier to insert in the face of deformity or retained hardware. The naysayers state that it is a more difficult operative procedure associated with a higher learning curve. They note that there are few patients who meet the selection criteria and there is an increased risk of fracture of the femoral neck. Finally, there is concern over metal ion toxicity and adverse tissue reaction. Furthermore, as we explore the literature, several studies have observed that resurfacing requires a bigger cup and results in a significantly higher volume of normal bone reamed from the acetabulum. Other studies note decreased range of motion with resurfacing compared with total hip arthroplasty (THA) secondary to an unfavourable head to neck ratio resulting in increased impingement. While resurfacing is purported to enhance functional outcomes, one randomized trial of 48 patients, 24 each resurfacing and large head THA, compared with 14 healthy control subjects found no difference in gait speed and postural balance evaluations, functional test, and clinical data at 3, 6 and 12 months post-operative. In another study comparing 337 resurfacings with 266 ceramic-on-ceramic THA, at 24 months there was no difference in Harris hip score, pain score or function score, but a statistically greater improved Harris hip range of motion score in THA. In a large meta-analysis study comparing 3269 hip resurfacings (3002 patients) with average follow-up of 3.9 years to 5907 cementless THA (5907 patients) with average follow-up of 8.4 years, the observed rate of femoral revision due to mechanical failure was 2.6% for resurfacing versus 1.3% for THA, yielding annualized rates of 0.67% and 0.15% respectively. An analysis of hip resurfacing data from national joint registries found that hip resurfacing demonstrates an overall increased failure rate compared with THA, except in males younger than 65 years old having a diagnosis of primary osteoarthritis and except with head diameters larger than 50 mm, which may be especially relevant as a contraindication for use of the procedure in female patients.

The goals of total knee arthroplasty (TKA) are to relieve pain, restore function, and provide a stable joint. In regard to types of implants, the workhorses are posterior cruciate retaining (CR), posterior stabilised (PS), and posterior stabilised constrained (PSC) designs. However, the continuum of constraint now ranges from standard cruciate retaining (CR-S) to CR lipped (CR-L), to anterior stabilised (CR-AS), to posterior stabilised, to a PS “plus” that fits with a PS femoral component but provides a small degree of varus-valgus constraint, to a PSC or constrained condylar type of device, to a rotating hinge. As the degree of deformity, bone loss, contracture, ligamentous instability and osteopenia increases, so does the demand for prosthetic constraint. When deformity is minimal and the posterior cruciate ligament (PCL) is intact and functional, a CR-S device is appropriate. For moderate deformity with deficiency or compromise of the PCL, a CR-AS or posterior stabilised device is warranted. In severe cases, with attenuation or absence of either of the collateral ligaments, a constrained condylar device, with options of stems, wedges and augments, is advisable. In salvage situations, when both collaterals are compromised, a rotating hinge should be utilised. Prerequisites for use of a CR-S device are an intact PCL, balanced medial and lateral collateral ligaments, and equal flexion and extension gaps. With a CR-L bearing, a slight posterior lip is incorporated into the sagittal profile of the component to provide a small amount of extra stability in the articulation. It is important for the surgeon to be aware of the design features of the implant system he or she is using. For example, in a system where the CR-S bearing has 3° of posterior slope and the CR-L bearing has no slope, the thickness of a CR-L bearing posteriorly is approximately 2 mm greater than the CR-S. A CR-L bearing is indicated for to provide stability where the flexion gap is just slightly looser than the extension gap and the PCL is intact. If the patient's knee is somewhat lax in flexion and stable in extension, a CR-L bearing may help to stabilize both the flexion and extension gaps yet still allow the knee to obtain full extension, whereas if a CR-S bearing in the next thicker size is used to stabilise the flexion gap, a flexion contracture may result. CR-AS bearings are required less frequently. They are indicated when the flexion and extension gaps are balanced, but the PCL is deficient, and the surgeon does not want to change to a PS design, which requires additional bony resection of intercondylar notch. The PCL is one of the strongest ligaments in the knee, and affords inherent stability to the TKA. In flexion, the PCL not only affords AP stability, but also imparts flexion gap stability, acting as a lateral stabilizer of the medial compartment and a medial stabiliser of the lateral compartment. The PCL has a crucial role with respect to femoral rollback, which imparts added efficiency to the extensor mechanism. PCL retention is a more biologically preserving operative intervention than PS-TKA.

Introduction

This study compares the incidence of post-operative complications (within 90 days) following primary total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA).

With increased use of alternative bearings, surgeons have moved from utilization of 22, 26, 28 and 32mm heads to larger head diameters in total hip arthroplasty (THA). Reported benefits of large heads are enhanced stability secondary to the increased range of motion prior to impingement and the increased jump distance required for subluxation from the acetabulum.

This study evaluates the use of large diameter heads in primary THA comparing the rate of dislocation to a published study from our practice as a historic control.

Between October of 2001 and October 2008, 2015 THA with large heads were performed in 1743 patients. Femoral head sizes ranged from 36 to 60mm, with articulations consisting of metal-on-poly, ceramic-on-poly, and metal-on-metal. Operative approach was 63% less invasive direct lateral, 10% anterior supine intermuscular, and 27% standard direct lateral. In 1999 (Mallory et al., Clin Orthop Relat Res) we reported a low incidence of 12 dislocations (0.8%) in 1518 primary THA done with smaller femoral heads via a standard direct lateral approach. In the current series with large heads, follow-up averaged 22 months. There has been one dislocation requiring revision (0.05%), representing a significant reduction from our earlier report (p=0.0003). Forty additional acetabular components have been revised (2.0%), with eight related to sepsis (0.4%), 23 aseptic loosening (1.1%), six metal sensitivity (0.2%), one pseudotumor (0.05%), one failure of ingrowth (0.05%), and one acute early migration (0.05%).

The use of larger diameter heads has significantly lowered our dislocation rate in primary THA with only one occurrence observed in 2015 cases, for a rate of 0.05% at two years average follow-up.

Lateral retinacular release (LRR) may be necessary to balance the patellofemoral articulation in primary total knee arthroplasty (TKA). However, lateral retinacular release may be associated with an increased risk of patellar necrosis, loosening, perioperative bleeding, and pain.

Additionally, the need for lateral retinacular release may herald a more significant problem with implant positioning, rotation, and balance. The purpose of this study is to report the lateral retinacular release rate with a “patella friendly” femoral TKA design, and to identify if a less invasive approach is associated with reduced need for lateral retinacular release.

A retrospective review of our database identified 4667 primary TKA performed by two surgeons between October 2002 and January 2009. Beginning in 2002, a less invasive approach has been used in over 95% of primary TKA. Also beginning in 2002, the authors began using a new TKA design with a more swept back patellofemoral articulation (Vanguard Complete Knee System; Biomet). During the first two years of the study, the authors also used the Maxim Complete Knee System (Biomet). We previously reported a lateral retinacular release rate associated with the Maxim of 22%. There were 555 Maxim and 4112 Vanguard TKA performed. Lateral retinacular release with Maxim TKA was 12.8% (71/555), significantly less than that previously reported for the same implant design using a standard approach. Lateral retinacular release for Vanguard TKA was 1.8% (72/4112), significantly less than that with the Maxim TKA using either a standard or less invasive approach (p< 0.005).

Implant design, surgical technique, and a less invasive exposure combine to significantly reduce the need for lateral retinacular release in primary TKA.

Surgeons theorize smaller increments in sizing might better address different sized femurs and size differences between genders. This study examines utilisation of intermediate sized components to determine if availability affects outcomes of women and men undergoing total knee arthroplasty (TKA).

We reviewed 1903 consecutive, primary TKA in 1519 patients (64% women) performed with a single implant system. Originally, six femoral sizes were available; four intermediate sizes were added later. The system allows interchange ability of all femoral and tibial sizes and has seven constraint options. Four hundred and five TKA were done prior to intermediate size availability. In women before, 49% were 65mm, 47% 60mm, and 3% 70mm. After, 32% were 62.5mm, 21% 65mm and 8% 67.5mm. In men, 70mm was the most common representing 49% before and 41% after. The 65mm in men dropped from 29% before to 16% after and the 75mm dropped from 21% to 14%. After, 23% were 67.5mm. Minimum follow-up was two years.

When comparing women before versus after, women after had significantly better postoperative Knee Society (KS) pain (p=0.0000), clinical (p=0.003) and function scores (p=0.0000), and improvement in clinical (p=0.0000) and function scores (p=0.0001) while improvement in pain score was similar. Men done after had better postoperative KS pain (p=0.02) and function scores (p=0.002), and improvement in KS clinical (p=0.001) and function (p=0.0002) scores.

Both men and women undergoing TKA after availability of half sizes had better postoperative KS pain, clinical and functional scores, and improvement from preoperative levels compared with men and women before. We conclude a single TKA system with a wide variety of sizing and constraint options can provide consistently excellent results for both men and women undergoing TKA.

Introduction and Aims: Periprosthetic femur fractures, severe bone loss with loosening, infection and debridements, and non-union can all result in loss of bone stock following total hip (THA) and/or total knee arthroplasty (TKA). In the multiply-operated or osteopenic patient, few options exist when bone is severely compromised. We report results of a total femoral construct to salvage the severely compromised femur.

Method: We retrospectively reviewed 59 consecutive total femurs. Revision THA and/or TKA was performed utilising a custom total femoral construct: a constrained acetabular component, proximal femoral replacement, diaphyseal segment, and rotating hinge knee. Return to ambulation, pain, functional capacity, and subsequent surgery outcomes were measured. All cases involved severe bone loss: 13 aseptic loosening of revision THA and TKA, 24 periprosthetic fractures, five failed non-unions around implants, and 17 cases of multiple debridements for sepsis.

Results: Mean age was 74 years, mean follow-up was 38 months. One peri-operative death occurred. Pain scores improved by 18 points. Average post-operative hip flexion was 90 and knee flexion 93. All but one patient achieved ambulatory capability. Four of 17 septic cases recurred, three successfully treated and one disarticulation. Three other infections occurred in the aseptic and periprosthetic groups, all treated successfully. There were five dislocations, one acetabular revision, and two knee revisions for aseptic loosening.

Conclusion: Total femoral replacement represents a viable salvage procedure for the compromised femur associated with THA and/or TKA. Rapid return to ambulating, relief of pain and improved function can be expected from this, the ultimate revision surgery.

Introduction and Aims: With interest in minimally invasive surgery, and smaller incisions for total hip arthroplasty (THA), ways to ensure appropriate alignment are critical. Femoral stem varus has been associated with poorer results. We report the incidence of varus placement of a tapered, proximally plasma-sprayed, titanium femoral component and describe the outcomes of varus at minimum five-year follow-up.

Method: Between 1986 and 1997, 1080 tapered, proximally plasma-sprayed femoral components were implanted in primary cementless THA at one institution. Twenty-six components in 25 patients were placed in five degrees or more of varus. Two patients were lost to follow-up. The need for further surgery was assessed and Harris hip scores evaluated.

Results: Harris hip scores improved an average of 44 points. All femoral components were judged to be osteo-integrated. There was no displacement or progression into further varus, or impending failures. One well-fixed stem was revised at an outside institution for unexplained pain at 2.5 years. Survival with aseptic loosening as an end-point is 100 percent. Overall survival of the femoral component is 96 percent at 10 years average follow-up.

Conclusion: As visualisation decreases with decreasing incision length, a component that is reliably placed into appropriate position is required. Implant position with this component is forgiving. It may be an excellent choice for less-invasive techniques with compromised visualisation. In varus, the stem performs well, with no revisions for aseptic loosening and a 96 percent survival at up to 16 years.

Introduction and Aims: Adequacy of post-operative pain control can effect total knee arthroplasty (TKA) outcomes. We examine the effectiveness of a simple and inexpensive method using long-acting local anesthetic (bupivacaine) with epinephrine and morphine injection on controlling pain, blood loss, and motion in primary TKA.

Method: We retrospectively reviewed 170 patients who underwent 208 primary TKA, by a single surgeon between October 2001 and December 2002. The control group of 75 patients (99 knees) had received no intra-operative injections. The study group of 95 patients (109 knees) had received intra-operative injection of 0.25 percent bupivacane with epinephrine and morphine divided two-thirds soft-tissue injection and one-third intra-articular injection. Bilateral simultaneous TKA in the study group received a divided anaesthetic dose.

Results: The control group required significantly more breakthrough narcotic (85 percent vs 67 percent; p=0.004); and required more narcotic reversal for over-sedation. The study group had significantly higher ROM at discharge 63 degrees vs 52 degrees. Lower ROM at discharge was associated with manipulation (p equals 0.001). The study group required less transfused blood (mean 0.03 vs 0.1 units), and had significantly lower bleeding indices 2.7 vs 3.5.

Conclusion: Preemptive analgesia with intra-articular and soft-tissue injection of long-acting local anesthetic with epinephrine and morphine appears to decrease need for rescue narcotics and reversal agents. The use of the injection also increases ROM at discharge, which reduces the need for manipulation. Lastly, the bleeding index and transfusion requirements are significantly reduced. This inexpensive method is effective in improving the post-operative course of primary TKA.