D.S. Johnson

The potential of stem cells in the treatment of knee cartilage defects

Cartilage is frequently damaged but only shows a limited capacity for repair. There are a number of treatment strategies currently available for the repair of articular cartilage defects including abrasion chondroplasty, subchondral drilling, microfracture and mosaicplasty but these show variable results. For the younger patients, there is great interest in the potential of cell-based strategies to provide a biological replacement of damaged cartilage using autologous chondrocytes. The results of clinical studies using these cell-based techniques do not conclusively show improvement over conventional techniques. These techniques also do not consistently result in the formation of the desired hyaline cartilage rather than fibrocartilage. Mesenchymal stem cells present a promising cell source for cartilage repair. Mesenchymal stem cells have been isolated from a number of adult tissues including the bone marrow and the synovial fat pad. These cells have the ability to proliferate in culture and differentiate down different pathways including the chondrogenic pathway. In the first instance, differentiated stem cells can be used for the repair of localised cartilage defects by producing hyaline cartilage. In the future, this strategy has the potential to be extended to treat more generalised cartilage defects, especially as the cell source is not a limiting factor. The use of cell-based therapies also allows the versatility of using scaffolds and growth factors, with recombinant proteins or gene therapy. A number of challenges however still need to be overcome including further work on identifying the optimal source of stem cells, along with refining the conditions that enhance expansion and chondrogenesis.

A comparison of the biomechanical effects of valgus knee braces and lateral wedged insoles in patients with knee osteoarthritis

Increases in the external knee adduction moment (EKAM) have been associated with increased mechanical load at the knee and progression of knee osteoarthritis. Valgus knee braces and lateral wedged insoles are common approaches to reducing this loading; however no study has directly compared the biomechanical and clinical effects of these two treatments in patients with medial tibiofemoral osteoarthritis. A cross-over randomised design was used where each intervention was worn by 28 patients for a two week period. Pre- and post-intervention gait kinematic/kinetic data and clinical outcomes were collected to evaluate the biomechanical and clinical effects on the knee joint. The valgus knee brace and the lateral wedged insole significantly increased walking speed, reduced the early stance EKAM by 7% and 12%, and the knee adduction angular impulse by 8.6 and 16.1% respectively. The lateral wedged insole significantly reduced the early stance EKAM compared to the valgus knee brace (p=0.001). The valgus knee brace significantly reduced the knee varus angle compared to the baseline and lateral wedged insole. Improvements in pain and function subscales were comparable for the valgus knee brace and lateral wedged insole. There were no significant differences between the two treatments in any of the clinical outcomes; however the lateral wedged insoles demonstrated greater levels of acceptance by patients. This is the first study to biomechanically compare these two treatments, and demonstrates that given the potential role of knee loading in osteoarthritis progression, that both treatments reduce this but lateral wedge insoles appear to have a greater effect.

Arthroscopic anterior cruciate ligament surgery: Results of autogenous patellar tendon graft versus the Leeds-Keio synthetic graft Five year follow-up of a prospective randomised controlled trial

We conducted a prospective, randomised controlled trial comparing anterior cruciate ligament reconstruction using middle third patellar tendon graft (PT) to synthetic Leeds-Keio (LK) ligament. The patients were randomised (26 PT, 24 LK). Subjective knee function was classified (Lysholm, Tegner activity, IKDC scores), laxity was measured (Lachman test, Stryker laxometer), and functional ability was assessed (one-hop test). There were no significant differences between Lysholm or IKDC scores at any stage by 5 years. Significant differences were found between the groups at 2 years for Tegner activity scores, laxity and one-hop testing. By 5 years there were no significant differences. Clinical equivalence was demonstrated between the two groups for the Lysholm score and one-hop test but not for the Tegner activity score at 5 years. The use of the LK ligament has been largely abandoned due to reports of its insufficiency. Our results demonstrate that it is not as inferior as one might expect. We conclude that the results of LK ligament ACL reconstruction are as acceptable as those using PT. It may provide an additional means of reconstruction where no suitable alternative is present.

Arterial Injury in Total Knee Arthroplasty

Arterial complications associated with knee arthroplasty are relatively rare, although probably underreported, complications of knee arthroplasty that carry a risk of significant morbidity. Thorough preoperative assessment and close liaison with a vascular surgeon, combined with an appreciation of common anatomical variants or distorted anatomy, may help prevent both thromboembolic and direct injuries from occurring. Clinical features of arterial complications following knee arthroplasty may vary significantly from acute hemorrhage or ischemia in the immediate postoperative period to chronic pain and swelling presenting even months following the procedure. There is potential for diagnostic confusion and delay that may adversely affect outcome. Early diagnosis along with vascular surgical review and intervention is key to successful management.

Does the Lachman testing method affect the reliability of the International Knee Documentation Committee (IKDC) Form

The aim of this study was to evaluate the effect of manual and instrumented means of Lachman testing on the reliability of the IKDC form. A single observer assessed 102 patients with ACL deficiency (direct comparison group). Another observer assessed 35 of these patients (inter-observer group) and the initial observer re-assessed 47 patients (test-retest group). The Lachman test was performed by both manual and instrumented means and the IKDC form was completed. Direct comparison of the manual and instrumented Lachman test revealed satisfactory levels for use. Further comparison revealed satisfactory test re-test and unsatisfactory inter-observer reliability for both means. On application into the IKDC form, direct comparison of both means of testing revealed satisfactory agreement for the overall score, but not the ligament group or Lachman item scores. Test-retest and inter-observer reliability testing revealed unsatisfactory agreement for the overall, ligament group and Lachman item scores for both means of testing. When using the IKDC form we recommend that a single observer perform the Lachman test by manual means on each occasion. If the original IKDC form is used only the overall score should be presented. Where the new IKDC form is used we recommend caution in the presentation of the examination section. We call into question the usefulness of the original IKDC form and the examination section of the new IKDC form in clinical research.

The relationship of the angle of immobilisation of the knee to the force applied to the extensor mechanism when partially weight-bearing A GAIT-ANALYSIS STUDY IN NORMAL VOLUNTEERS

We describe the influence of the angle of immobilisation during partial weight-bearing on the forces across the extensor mechanism of the knee. Gait analysis was performed on eight healthy male subjects with the right knee in an orthotic brace locked at 0 degree, 10 degrees, 20 degrees and 30 degrees, with the brace unlocked and also without a brace. The ground reaction force, the angle of the knee and the net external flexion movement about the knee were measured and the extensor mechanism force was calculated. The results showed a direct non-linear relationship between the angle of knee flexion and the extensor mechanism force. When a brace was applied, the lowest forces occurred when the brace was locked at 0 degree. At 30 degrees the forces approached the failure strength of some fixation devices. We recommend that for potentially unstable injuries of the extensor mechanism, when mobilising with partial weight-bearing, the knee should be flexed at no more than 10 degrees.

BASK survey of The Knee readership 2015.

A convenience sample of the attendees of the 2015 annual meeting of the British Association of Knee showed that the majority of the attendees who responded read The Knee, would like a section on surgical tips, more themed supplements and guest editorials. There is still not enough support for purely electronic publication. For those that have submitted papers, the experience with the publication process was positive.