Impingement following anterior cruciate ligament reconstruction: comparing the direct versus indirect femoral tunnel position.

PURPOSE: During anterior cruciate ligament (ACL) reconstruction, authors have suggested inserting the femoral tunnel at the biomechanically relevant direct fibres, but this higher position can cause more impingement. Therefore, we aimed to assess ACL graft impingement at the femoral notch for ACL reconstruction at both the direct and indirect tunnel positions. METHODS: A virtual model was created for twelve cadaveric knees with computed tomography scanning in which a virtual graft was placed at direct and indirect tunnel positions of the anteromedial bundle (AM), posterolateral bundle (PL) or centre of the both bundles (C). In these six tunnel positions, the volume (mm3) and mid-point location of impingement (°) were measured at different flexion angles. RESULTS: Generally, more impingement was seen with the indirect position compared with the direct position although this was only significant at 90° of flexion for the AM position (97 ± 28 vs. 76 ± 20 mm3, respectively; p = 0.046). The direct tunnel position impinged higher at the notch, whereas the indirect position impinged more towards the lateral wall, but this was only significant at 90° of flexion for the AM (24 ± 5° vs. 34 ± 4°, respectively; p < 0.001) and C position (34 ± 5° vs. 42 ± 5°, respectively; p = 0.003). CONCLUSION: In this cadaveric study, the direct tunnel position did not cause more impingement than the indirect tunnel position. Based on these results, graft impingement is not a limitation to reconstruct the femoral tunnel at the insertion of the biomechanically more relevant direct fibres.

Arthroscopic ankle arthrodesis: are results reproducible irrespective of pre-operative deformity?

BACKGROUND: Arthroscopic ankle arthrodesis is gaining in popularity. It has been shown to have a shorter time to union and less morbidity than traditional open procedures. The arthroscopic technique has been mainly used for ankles with minimal deformity. Our aim was to find out whether we could reproduce the good results of arthroscopic ankle arthrodesis in both minimally and markedly deformed ankles. METHODS: We reviewed 62 patients who underwent an arthroscopic ankle arthrodesis for end stage arthritis. The average follow up was 63 months (range 21-92 months). Patients were evaluated subjectively and objectively using the Mazur grading system. 4 patients died before final review and 3 were lost to follow-up leaving 55 patients for evaluation. The pre-operative tibiotalar angle in the coronal plane was between 26° valgus and 24° varus. We divided our patients into 2 groups based on the tibiotalar angle. Group A (n=31) had a varus or valgus deformity of less than 15 and Group B (n=24) had a deformity equal to or more than 15°. RESULTS: The overall fusion rate was 91%. Fusion occurred in 29 of 31 (94%) ankles in Group A compared to 21 of 24 (88%) in Group B (p=0.64).The overall mean time to union was 10.4 weeks. The time to union in Group A was 8.8 weeks compared to 12.7 weeks for Group B (p=0.001). Using the Mazur ankle grading system, 84% of the cases in Group A had a good to excellent result compared to 79% in Group B (p=0.73). There were 2 superficial infections, 2 cases of deep vein thrombosis and 3 patients required removal of prominent screws. CONCLUSIONS: We have shown that arthroscopic ankle arthrodesis yields reliable and reproducible results in a District General Hospital setting with high union rates, short time to union and low complication rates. It can be satisfactorily employed for ankles with significant deformity, although this resulted in a longer time to union. The end results remain uniformly good to excellent.

Schwannoma of the posterior tibial nerve: the problem of delay in diagnosis.

Schwannomas are the most common tumours of the sheath of peripheral nerves. The clinical diagnosis is usually straightforward, but may be delayed for many years in a schwannoma of the posterior tibial nerve. The symptoms are often attributed to entrapment neuropathy or to lumbosacral radiculopathy. We describe 25 patients with a schwannoma of the posterior tibial nerve. Only three were diagnosed within a year of presentation. The mean time to diagnosis was 86.5 months with a median of 48 months (2 to 360). All the patients complained of pain, which was felt specifically in the sole of the foot in 18. A Tinel sign was detected in all 25 patients. MRI confirmed the diagnosis in all the cases in which it had been undertaken. Surgical resection of the lesion abolished the neuropathic pain. In patients with a long history of neuropathic pain in the lower limb in whom lumbar and pelvic lesions have been excluded, a benign tumour of the sheath of a peripheral nerve may explain the symptoms. Surgical resection of the tumour is safe and effective.

Congruence and joint space width alterations of the medial compartment following lateral unicompartmental knee arthroplasty.

Progressive degenerative changes in the medial compartment of the knee following lateral unicompartmental arthroplasty (UKA) remains a leading indication for revision surgery. The purpose of this study is to evaluate changes in the congruence and joint space width (JSW) of the medial compartment following lateral UKA. The congruence of the medial compartment of 53 knees (24 men, 23 women, mean age 13.1 years; sd 62.1) following lateral UKA was evaluated pre-operatively and six weeks post-operatively, and compared with 41 normal knees (26 men, 15 women, mean age 33.7 years; sd 6.4), using an Interactive closest point algorithm which calculated the congruence index (CI) by performing a rigid transformation that best aligns the digitised tibial and femoral surfaces. Inner, middle and outer JSWs were measured by sub-dividing the medial compartment into four quarters on pre- and post-operative, weight bearing tunnel view radiographs. The mean CI of knees following lateral UKA significantly improved from 0.92 (sd 0.06) pre-operatively to 0.96 (sd 0.02) (p < 0.001) six weeks post-operatively. The mean CI of the healthy control group was 0.99 sd 0.01. Post-operatively, the mean inner JSW increased (p = 0.006) and the outer decreased (p = 0.002). The JSW was restored post-operatively as no significant differences were noted in all three locations compared with the control group (inner JSW p = 0.43; middle JSW p = 0.019, outer JSW p = 0.51). Our data suggest that a well conducted lateral UKA may improve the congruence and normalise the JSW of the medial compartment, potentially preventing progression of degenerative change.

The outcome of resection of the distal ulna for tumour without soft-tissue or prosthetic reconstruction.

In patients with a tumour affecting the distal ulna it is difficult to preserve the function of the wrist following extensive local resection. We report the outcome of 12 patients (nine female, three male) who underwent excision of the distal ulna without local soft-tissue reconstruction. In six patients, an aggressive benign tumour was present and six had a malignant tumour. At a mean follow-up of 64 months (15 to 132) the mean Musculoskeletal Tumour score was 64% (40% to 93%) and the mean DASH score was 35 (10 to 80). The radiological appearances were satisfactory in most patients. Local recurrence occurred in one patient with benign disease and two with malignant disease. The functional outcome was thus satisfactory at a mean follow-up in excess of five years, with a relatively low rate of complications. The authors conclude that complex reconstructive soft-tissue procedures may not be needed in these patients.

Vitamin D deficiency in patients with osteoarthritis undergoing total hip replacement: a cause for concern?

We measured the plasma 25-hydroxyvitamin D(3) (25(OH)D(3)) levels in 62 consecutive Caucasian patients undergoing total hip replacement for osteoarthritis. The patients were divided into two groups based on whether they were vitamin D sufficient or deficient. The groups were matched for age, gender and the American Society of Anaesthesiologists (ASA) grade. The prevalence of vitamin D deficiency in our patients was comparable with recent population-based studies performed in the United Kingdom. Patients with vitamin D deficiency had lower pre-operative Harris hip scores (Mann-Whitney test, p = 0.018) and were significantly less likely to attain an excellent outcome from total hip replacement (chi-squared test, p = 0.038). Vitamin D levels were found to positively correlate with both pre- and post-operative Harris hip scores. These results warrant further study of vitamin D deficiency in patients undergoing joint replacement as it is a risk factor for a suboptimal outcome which is relatively simple and cheap to correct.

A prospective randomised controlled trial of autologous retransfusion in total knee replacement.

We undertook a prospective randomised controlled trial to investigate the efficacy of autologous retransfusion drains in reducing the need for allogenic blood requirement after unilateral total knee replacement. We also monitored the incidence of post-operative complications. There were 86 patients in the control group, receiving standard care with a vacuum drain, and 92 who received an autologous drain and were retransfused postoperatively. Following serial haemoglobin measurements at 24, 48 and 72 hours, we found no difference in the need for allogenic blood between the two groups (control group 15.1%, retransfusion group 13% (p = 0.439)). The incidence of post-operative complications, such as wound infection, deep-vein thrombosis and chest infection, was also comparable between the groups. There were no adverse reactions associated with the retransfusion of autologous blood. Based on this study, the cost-effectiveness and continued use of autologous drains in total knee replacement should be questioned.