Introduction

Osteoarthritis (OA) represents a leading cause of disability and a growing burden on healthcare budgets. OA is particularly vexing for young, active patients who have failed less invasive therapies but are not yet candidates for arthroplasty. Often, patients suffering in this wide therapeutic gap face a debilitating spiral of disease progression, increasing pain, and decreasing activity until they become suitable arthroplasty patients. An implantable load absorber was evaluated for the treatment of medial knee OA in this patient population.

Joint overload has been cited as a contributor to OA onset or progression. In response, the KineSpring® System (Moximed, Inc, USA) has been designed to reduce the load acting on the knee. The absorber is implanted in the subcutaneous tissue without violating the joint capsule, thus preserving the option of future arthroplasty. The implant is particularly useful for young, active patients, given the reversibility of the procedure and the preservation of normal flexibility and range of motion.

Statement of Purpose

The UK and Australian clinical experience of an implantable load absorber was reviewed for knee OA patients who have exhausted conservative care, but are not ideal candidates for HTO or arthroplasty due to age, activity level, obesity, or disinclination.

Aim: To assess the safety and efficacy of a mini-incision surgical (MIS) approach to knee arthroplasty (TKA) compared to a traditional standard approach.

Background: TKA through less invasive approaches have become increasingly popular in recent years. These range from smaller skin incisions to the ‘quadriceps-sparing’ procedures. Claims of improved recovery time and other clinical/economic advantages have been tempered by concerns about the safety of such procedures. This study was designed to evaluate any potential advantages of a specific approach (MIS) whilst studying peri-operative, radiological and outcome data to examine procedural safety.

Patients and Methods: 80 patients undergoing TKA were randomised to a standard or MIS (mini-midvastus) approach. The latter involved patella subluxation, rather than eversion. The operative, anaesthetic and post-operative treatments were standardised including rehabilitation protocols. Strict discharge criteria were established and independently verified and patients were discharged directly to their homes capable of independent care. Specifically the study evaluated patient demographics, operative time, blood loss and hospital stay. Outcome data including Knee Society Scores, Oxford Knee Scores and SF36 were recorded regularly in the early recovery period and up to 1 year post-operatively. Independent radiological review of implant positioning and alignment was obtained.

Results: There were no significant differences in operative time, blood loss, or other intra-operative data. Accelerated discharge was achieved in both groups (compared to historic data), however the length of stay (LOS) was significantly shorter in the MIS patients (mean – 3.5 days compared with 4.4 days in the standard patients). There was no statistical difference in clinical outcome analyses between the groups.

Discussion: Less invasive approaches to TKA have been reported over recent years but most studies have been anecdotal comparing patient recovery with historic controls which potentially can exaggerate clinical and economic benefits. Concerns have also been raised regarding the safety of these modified procedures. This study demonstrates a reduction in hospital stay and recovery in all patients as a result of accelerated rehabilitation. The MIS patients benefited from an additional significant reduction length of stay compared to controls with no evidence of compromise in terms of safety or efficacy.

Conclusions: This study has demonstrated the safety of the MIS mini-midvastus approach and a clear reduction in hospital length of stay. MIS surgery can offer substantial clinical and economic benefits but procedures must be closely evaluated to ensure equivalent or enhanced outcomes are achieved.

Introduction: The use of simultaneous bilateral knee replacement surgery remains controversial–several studies have reported increased rates of complications, and the use of the technique remains in question. However, many of these procedures are not truly simultaneous, meaning it is difficult to draw accurate conclusions on the safety of this technique from the published literature.

Method: A retrospective notes based review of all those patients undergoing bilateral knee replacement surgery between 2000 and 2005 at Harrogate District Hospital was performed. Patients undergoing both unicompartmental (UNI) and total knee replacement (TKR) were included. Procedures were performed by a consultant orthopaedic surgeon and his knee fellow with one scrub team. The post operative morbidity and mortality was assessed both 30 days post operatively and also at six month follow up.

Results: A total of 112 procedures were performed over the five year period. There were no deaths reported within the study group. Within the group there were 3 DVT’s, 2 superficial wound infections and one case of aseptic loosening at six months. Average tourniquet time was 76 minutes for the TKR group and 82 minutes for the UNI group. Average length of stay over the five year period was 8.6 nights (TKR) and 6.6 nights (UNI).

Conclusion: Bilateral truly simultaneous knee replacement surgery is a safe technique with favourable rates of complications. It offers the benefit of improved efficiency with regard to both theatre time and length of hospital stay, which is valuable in the modern climate of economic strain within health services worldwide. It also offers an excellent opportunity to the trainee to operate independently within a controlled environment, and is favoured by patients–offering a single admission and rehabilitation period.