The purpose of this study was to evaluate the reasons for patellar instability in modular rotating hinge TKR, with regards to design of the prosthesis offering unlimited rotation, component positioning and the role of compromised soft tissues.

We reviewed six patients with rotating hinge TKR operated over the past 3½ years for either ligamentous instability, bone loss or both. The problem of patellar instability was identified in all patients. Five patients had realignment of extensor mechanism for patellar maltracking, while the remaining one patient with patellar instability was asymptomatic.

Post-realignment the HSS scores revealed good results in 3 knees, fair in 2 and poor in 1 patient. All patients had a well aligned knee with satisfactory component positioning.

The unlimited rotation offered by the modular rotating hinge TKR because of the absence of a rotational stop causes excessive demands on the soft tissue and is a reason for patellar instability in patients with compromised medial soft tissue integrity.

The high incidence of patellar instability compromises the results of TKR and is a cause of concern and this implant should be reserved for patients with severe ligamentous instability and bone loss not amenable to ligament balancing.

This study looks at the use of rotating hinge Total Knee Replacement (TKR) as a treatment option when dealing with fractures involving the knee.

The treatment of complex intra-articular fractures involving the knee has always proved challenging. Studies have investigated the outcome of various forms of treatment for such injuries, including internal fixation and primary knee arthroplasty. Recent advances in technology have brought about more sophisticated implants for both internal fixation and arthroplasty, including rotating hinge TKR.

The initial non-rotating hinged prostheses for total knee arthroplasty did not enjoy a good reputation. The cumulative survival rate has been quoted as 65% at 6 years, significantly lower than that of conventional prostheses. Therefore the use of such implants was restricted to complex primary or revision arthroplasty, and tumour surgery. Studies have been published advocating the use of hinged prostheses for distal femoral fractures in elderly patients. The average age in the most recent study was 82, of whom 42% had died within the first post-operative year.

This study is a case series of 16 patients with fractures who were treated with rotating hinge TKR. The age range is 36 to 92, with a mean of 69, lower than that of earlier studies. Outcome data as measured by the Oxford knee scoring system has been retrospectively collected. At follow up the range of Oxford knee scores was 14 to 52, with a mean of 36. We discuss the indications, experiences and outcomes in the management of these patients, and conclude that this is a valid treatment option in certain circumstances.

There is little data on the long-term outcome of rotating hinge total knee arthroplasty. We provide a clinical and radiographic assessment of survivorship of the Kinematic rotating hinge total knee arthroplasty (How-medica, Rutherford, NJ), in a series of 72 implants, performed by a single surgeon in one unit, between 1983 and 1997. Survival analysis using known all cause revision revealed a 92% five-year implant survival, but worst-case scenario was 31% at five years.

In a subset of 27 patients we used the Nottingham Health Profile (NHP) to assess prospectively the changes in health-related quality of life following rotating hinge arthroplasty. In this salvage arthroplasty setting we demonstrate a significant improvement in two modalities of the NHP (pain and physical mobility).

The following papers will be discussed during this session: 1) Staph Screening and Treatment Prior to Elective TJA; 2) Unfulfilled Expectations Following TJA Procedures; 3) Thigh Pain in Short Stem Cementless Components in THR; 4) Is the Direct Anterior Approach a Risk Factor for Early Failure?; 5) THA Infection - Results of a 2nd 2-Stage Re-implantation - Clinical Trial of Articulating and Static Spacers; 6) THA Revision - Modular vs. Non Modular Fluted Tapered Stems-Total Femoral Replacement for Femoral Bone Loss - Cage + TM Augment vs. Cup Cage for Acetabular Bone Loss; 7) Do Injections Increase the Risk of Infection Prior to TKA?; 8) Long-Acting Opioid Use Predicts Perioperative Complication in TJA; 9) UKA vs. HTO in Patients Under 55 at 5–7 years; 10) Stemming Tibial Component in TKA Patients with a BMI > 30; 11) The Effect of Bariatric Surgery Prior to Total Knee Arthroplasty; 12) Oral Antibiotics and Reinfection Following Two-Stage Exchange; 13) Two-Stage Debridement with Prosthetic Retention for Acute TKA Infections; 14) Patient-Reported Outcomes Predict Meaningful Improvement after TKA; 15) Contemporary Rotating Hinge TKA; 16) Liposomal Bupivacaine in TKA; and 17) Noise Generation in Modern TKA: Incidence and Significance

Rotating Hinge total knee replacement designs are currently more frequently used for revision total knee replacement. As the designs of these implants have improved over time, the threshold for using them has been lowered. Cases of global instability and severe bone loss have not been adequately addressed by the standard use of unlinked constrained designs. Recurrent dislocation and polyethylene post failure due to cold flow and wear make the use of the unlinked designs insufficient to address the mechanical forces developed in a grossly unstable knee. The linked rotating hinge designs have been able to address global ligamentous instability in four planes. Medial-lateral instability is well addressed by these implants. In cases of severe ankylosis with large flexion contractures, it is often necessary to resect the distal femur above the femoral insertions of the medial and lateral collateral ligaments. The absence of the tethering effect of severely contracted collateral ligaments demand the need for linked designs, although there has been reported success with the use of unlinked designs. Rotating hinges are particularly important for use in cases of recurvatum where an extension stop is incorporated in the design. The design permits slight hyperextension which permits application to clinical situations with incompetent quadriceps strength or paralysis. The clinical results are quite acceptable even though most reports present 65–75% success rates. However, it should also be stated that these patient cohorts represent the most severe cases of revision surgery. Current hinged designs should continue to lower the threshold for use