There have been differing descriptions of the anterolateral structures of the knee, and not all have been named or described clearly. The aim of this study was to provide a clear anatomical interpretation of these structures. We dissected 40 fresh-frozen cadaveric knees to view the relevant anatomy and identified a consistent structure in 33 knees (83%); we termed this the anterolateral ligament of the knee. This structure passes antero-distally from an attachment proximal and posterior to the lateral femoral epicondyle to the margin of the lateral tibial plateau, approximately midway between Gerdy’s tubercle and the head of the fibula. The ligament is superficial to the lateral (fibular) collateral ligament proximally, from which it is distinct, and separate from the capsule of the knee. In the eight knees in which it was measured, we observed that the ligament was isometric from 0° to 60° of flexion of the knee, then slackened when the knee flexed further to 90° and was lengthened by imposing tibial internal rotation.

Cite this article: Bone Joint J 2014;96-B:325–31.

We assessed hyperextension of the knee and joint laxity in 169 consecutive patients who underwent an anterior cruciate ligament reconstruction between 2000 and 2002 and correlated this with a selected number of age- and gender-matched controls. In addition, the mechanism of injury in the majority of patients was documented. Joint laxity was present in 42.6% (72 of 169) of the patients and hyperextension of the knee in 78.7% (133 of 169). All patients with joint laxity had hyperextension of their knee. In the control group only 21.5% (14 of 65) had joint laxity and 37% (24 of 65) had hyperextension of the knee. Statistical analysis showed a significant correlation for these associations. We conclude that anterior cruciate ligament injury is more common in those with joint laxity and particularly so for those with hyperextension of the knee.

We carried out a prospective study of 71 patients who had undergone reconstruction of the anterior cruciate ligament with the ABC scaffold. Their mean age was 28 years (18 to 50). All had either sub-acute or chronic traumatic deficiency of the ligament. The mean period of follow-up was five years (four to seven). Assessment included the use of the International Knee Documentation Committee score, the modified Lysholm score, the Tegner Activity score, the Knee Injury and Osteoarthritis Outcome score and measurement with the KT-1000 arthrometer. Two patients had mild recurrent synovitis. There were no infections and no failures of the ligament. During the period of study, two patients sustained a traumatic fracture of a femoral condyle. The implants retained their integrity in both cases. All patients returned to their previous or enhanced levels of daily activity by three months after operation and 56 (79%) achieved their pre-injury level of sporting activity by six months. The patients who were competing in National level sports returned to play at one level less after operation than before. The Lysholm score showed that 58% of the patients (41) were excellent, 34% (24) good, and 8% (6) fair, with a mean post-operative score of 93. According to the International Knee Documentation Committee score, 35% of knees (25) were ‘normal’, 52% (37) ‘nearly normal’ and 13% (9) ‘abnormal’. Complete satisfaction was noted in 90% of patients (64). The development of osteoarthritis and the management of anterior cruciate deficiency associated with laxity of the medial collateral ligament remains uncertain. Our results indicate that in the medium-term, the ABC ligament scaffold is suitable and effective when early and safe return to unrestricted activities is demanded. We acknowledge the current general hostility towards reconstruction of the anterior cruciate ligament with artificial materials following reports of early failure and chronic synovitis associatiated with the production of particulate debris. We did not encounter these problems.

A total of 218 patients with unilateral anterior cruciate ligament deficiency were randomly assigned to one of four groups. In group A an anatomical double bundle anterior cruciate ligament reconstruction was performed; group B were treated by a single bundle using an Endobutton for femoral fixation; in group C by a single bundle using RigidFix cross pins for femoral fixation; and in group D by a single bundle using a bioabsorbable TransFix II screw for femoral fixation. For tibial fixation a bioabsorbable Intrafix interference screw was used for all the groups and the graft was fashioned from the semitendinosus and gracilis tendons in all patients. In all, 18 patients were lost to follow-up. The remaining 200 were subjected to a clinical evaluation, with assessment of the anterior drawer, Lachman’s and the pivot-shift tests, and KT-1000 arthrometer measurement. They also completed the International Knee Documentation Committee, Lysholm knee and Tegner activity scores.

At a mean of 29 months (25 to 38) follow-up there were no significant differences concerning time between injury and range of movement and Lysholm knee scores among the four groups. However, the double bundle method showed significantly better results for the pivot-shift test (p = 0.002). The KT 1000 measurements showed a mean difference between the reconstructed knee and the patients’ normal knee of 1.4 mm in the double bundle group and 2.4 mm in the single bundle group; which was statistically significant. The Lachman and anterior drawer tests also showed superior results for the double bundle method. The International Knee Documentation Committee scale showed no significant difference among the groups (p < 0.001).

On clinical evaluation the double bundle group showed less laxity than the single bundle groups. However, regardless of the technique, all knees were improved by anterior cruciate ligament reconstruction compared with their pre-operative status.

We have investigated whether cells derived from haemarthrosis caused by injury to the anterior cruciate ligament could differentiate into the osteoblast lineage in vitro. Haemarthroses associated with anterior cruciate ligament injuries were aspirated and cultured. After treatment with β-glycerophosphate, ascorbic acid and dexamethasone or 1,25 (OH)₂D₃, a significant increase in the activity of alkaline phosphatase was observed. Matrix mineralisation was demonstrated after 28 days and mRNA levels in osteoblast-related genes were enhanced.

Our results suggest that the haemarthrosis induced by injury to the anterior cruciate ligament contains osteoprogenitor cells and is a potential alternative source for cell-based treatment in such injury.

This study reports on the first 150 consecutive Oxford cementless unicompartmental knee arthroplasties (UKA) performed in an independent centre (126 patients). All eligible patients had functional scores (Oxford knee score and high activity arthroplasty score) recorded pre-operatively and at two- and five-years of follow-up. Fluoroscopically aligned radiographs were taken at five years and analysed for any evidence of radiolucent lines (RLLs), subsidence or loosening. The mean age of the cohort was 63.6 years (39 to 86) with 81 (53.1%) males. Excellent functional scores were maintained at five years and there were no progressive RLLs demonstrated on radiographs. Two patients underwent revision to a total knee arthroplasty giving a revision rate of 0.23/100 (95% confidence interval 0.03 to 0.84) component years with overall component survivorship of 98.7% at five years. There were a further four patients who underwent further surgery on the same knee, two underwent bearing exchanges for dislocation and two underwent lateral UKAs for disease progression. This was a marked improvement from other UKAs reported in New Zealand Joint Registry data and supports the designing centre’s early results.

Cite this article: Bone Joint J 2015;97-B:1358–63.

An understanding of the remodelling of tendon is crucial for the development of scientific methods of treatment and rehabilitation. This study tested the hypothesis that tendon adapts structurally in response to changes in functional loading. A novel model allowed manipulation of the mechanical environment of the patellar tendon in the presence of normal joint movement via the application of an adjustable external fixator mechanism between the patella and the tibia in sheep, while avoiding exposure of the patellar tendon itself. Stress shielding caused a significant reduction in the structural and material properties of stiffness (79%), ultimate load (69%), energy absorbed (61%), elastic modulus (76%) and ultimate stress (72%) of the tendon compared with controls. Compared with the material properties the structural properties exhibited better recovery after re-stressing with stiffness 97%, ultimate load 92%, energy absorbed 96%, elastic modulus 79% and ultimate stress 80%. The cross-sectional area of the re-stressed tendons was significantly greater than that of stress-shielded tendons.

The remodelling phenomena exhibited in this study are consistent with a putative feedback mechanism under strain control. This study provides a basis from which to explore the interactions of tendon remodelling and mechanical environment.

The use of platelet-rich plasma (PRP) as an adjuvant to tissue repair is gaining favour in orthopaedic surgery. Tunnel widening after anterior cruciate ligament (ACL) reconstruction is a recognised phenomenon that could compromise revision surgery. The purpose of this study was to determine whether PRP might prevent tunnel widening in ACL reconstruction.

Patients undergoing ACL reconstruction using a hamstring graft were randomly allocated either to have PRP introduced into the tunnels peri-operatively or not. CT scanning of the knees was carried out on the day after surgery and at three months post-operatively and the width of the tunnels was measured. Patients were also evaluated clinically at three months, when laxity was also measured.

Each group comprised 25 patients, and at three months post-operatively all were pain-free with stable knees, a negative Lachman test and a good range of movement. Arthrometric results had improved significantly in both groups (p < 0.001). Despite slightly less tunnel widening in the PRP group, there was no significant difference between the groups at the femoral opening or the mid-tunnel (p = 0.370 and p = 0.363, respectively) nor at the tibial opening or mid-tunnel (p = 0.333 and p = 0.177, respectively).

We conclude that PRP has no significant effect in preventing tunnel widening after ACL reconstruction.

Cite this article: Bone Joint J 2013;95-B:65–9.

Conventional non-steroidal anti-inflammatory drugs (NSAIDs) and newer specific cyclo-oxygenase-2 (cox-2) inhibitors are commonly used in musculoskeletal trauma and orthopaedic surgery to reduce the inflammatory response and pain. These drugs have been reported to impair bone metabolism. In reconstruction of the anterior cruciate ligament the hamstring tendons are mainly used as the graft of choice, and a prerequisite for good results is healing of the tendons in the bone tunnel. Many of these patients are routinely given NSAIDs or cox-2 inhibitors, although no studies have elucidated the effects of these drugs on tendon healing in the bone tunnel.

In our study 60 female Wistar rats were randomly allocated into three groups of 20. One received parecoxib, one indometacin and one acted as a control. In all the rats the tendo-Achillis was released proximally from the calf muscles. It was then pulled through a drill hole in the distal tibia and sutured anteriorly. The rats were given parecoxib, indometacin or saline intraperitoneally twice daily for seven days. After 14 days the tendon/bone-tunnel interface was subjected to mechanical testing.

Significantly lower maximum pull-out strength (p < 0.001), energy absorption (p < 0.001) and stiffness (p = 0.035) were found in rats given parecoxib and indometacin compared with the control group, most pronounced with parecoxib.

We sought to determine whether smoking affected the outcome of reconstruction of the anterior cruciate ligament. We analysed the results of 66 smokers (group 1 with a mean follow-up of 5.67 years (1.1 to 12.7)) and 238 non-smokers (group 2 with a mean follow-up of 6.61 years (1.2 to 11.5)), who were statistically similar in age, gender, graft type, fixation and associated meniscal and chondral pathology. The assessment was performed using the International Knee Documentation Committee form and serial cruciometer readings.

Poor outcomes were reported in group 1 for the mean subjective International Knee Documentation Committee score (p < 0.001), the frequency (p = 0.005) and intensity (p = 0.005) of pain, a side-to-side difference in knee laxity (p = 0.001) and the use of a four-strand hamstring graft (p = 0.015). Patients in group 1 were also less likely to return to their original level of pre-injury sport (p = 0.003) and had an overall worse final 7 International Knee Documentation Committee grade score (p = 0.007).

Despite the well-known negative effects of smoking on tissue healing, the association with an inferior outcome after reconstruction of the anterior cruciate ligament has not previously been described and should be included in the pre-operative counselling of patients undergoing the procedure.

The potential harm to the growth plate following reconstruction of the anterior cruciate ligament in skeletally-immature patients is well documented, but we are not aware of literature on the subject of the fate of the graft itself. We have reviewed five adolescent males who underwent reconstruction of the ligament with four-strand hamstring grafts using MR images taken at a mean of 34.6 months (18 to 58) from the time of operation. The changes in dimension of the graft were measured and compared with those taken at the original operation. No growth arrest was seen on radiological or clinical measurement of leg-length discrepancy, nor was there any soft-tissue contracture. All the patients regained their pre-injury level of activity, including elite-level sport in three. The patients grew by a mean of 17.3 cm (14 to 24). The diameter of the grafts did not change despite large increases in length (mean 42%; 33% to 57%). Most of the gain in length was on the femoral side. Large changes in the length of the grafts were seen.

There is a considerable increase in the size of the graft, so some neogenesis must occur; the graft must grow.

The April 2013 Knee Roundup³⁶⁰ looks at: graft tension and outcome; chondrocytes at the midterm; pre-operative deformity and failure; the designer effect; whether chondroitin sulphate really does work; whether ACL reconstruction is really required; analgesia after TKR; and degenerative meniscus.

We examined the association of graft type with the risk of early revision of primary anterior cruciate ligament reconstruction (ACLR) in a community-based sample. A retrospective analysis of a cohort of 9817 ACLRs recorded in an ACLR Registry was performed. Patients were included if they underwent primary ACLR with bone–patellar tendon–bone autograft, hamstring tendon autograft or allograft tissue. Aseptic failure was the main endpoint of the study. After adjusting for age, gender, ethnicity, and body mass index, allografts had a 3.02 times (95% confidence interval (CI) 1.93 to 4.72) higher risk of aseptic revision than bone–patellar tendon–bone autografts (p < 0.001). Hamstring tendon autografts had a 1.82 times (95% CI 1.10 to 3.00) higher risk of revision compared with bone–patellar tendon–bone autografts (p = 0.019). For each year increase in age, the risk of revision decreased by 7% (95% CI 5 to 9). In gender-specific analyses a 2.26 times (95% CI 1.15 to 4.44) increased risk of hamstring tendon autograft revision in females was observed compared with bone–patellar tendon–bone autograft. We conclude that allograft tissue, hamstring tendon autografts, and younger age may all increase the risk of early revision surgery after ACLR.

Cite this article: Bone Joint J 2013;95-B:623–8.

The menisci of the knee have an important role in load-bearing and shock absorption within the joint. They may also function as secondary stabilisers, have a proprioceptive role, and aid the lubrication and nutrition of the articular cartilage. Complete or partial loss of a meniscus can have damaging effects on a knee, leading to serious long-term sequelae.

This paper reviews the consequences of meniscectomy and summarises the body of evidence in the literature regarding those factors most relevant to long-term outcome.

The LockDown device (previously called Surgilig) is a braided polyester mesh which is mostly used to reconstruct the dislocated acromioclavicular joint. More than 11 000 have been implanted worldwide. Little is known about the tissue reaction to the device nor to its wear products when implanted in an extra-articular site in humans. This is of importance as an adverse immunological reaction could result in osteolysis or damage to the local tissues, thereby affecting the longevity of the implant.

We analysed the histology of five LockDown implants retrieved from five patients over the last seven years by one of the senior authors. Routine analysis was carried out in all five cases and immunohistochemistry in one.

The LockDown device acts as a scaffold for connective tissue which forms an investing fibrous pseudoligament. The immunological response at the histological level seems favourable with a limited histiocytic and giant cell response to micron-sized wear particles. The connective tissue envelope around the implant is less organised than a native ligament.

Cite this article: Bone Joint J 2015;97-B:83–8.