We report on the long-term results of 163 bicruciate-retaining Hermes 2C total knee replacements in 130 patients at a mean follow-up of 22.4 years (20.3 to 23.5). Even when the anterior cruciate ligament had a partially degenerative appearance it was preserved as long as the knee had a normal anterior drawer and Lachman’s test pre-operatively. The description and surgical technique of this minimally constrained prosthesis were published in 1983 and the ten-year clinical results in 1999.

A total of 12% of the knees (20 of 163) in this study were revised because of wear of the polyethylene tibial insert. Excellent stability was achieved and the incidence of aseptic component loosening was 4.3% (seven of 163). The survival rate using revision for any reason as the endpoint was 82% (95% confidence interval 76.2 to 88.0).

Although this series included a relatively small number of replacements, it demonstrated that the anterior cruciate ligament, even when partially degenerated at the time of TKR, remained functional and provided adequate stability at a long-term follow-up.

Cite this article: Bone Joint J 2013;95-B:917–22.

Instability in flexion after total knee replacement (TKR) typically occurs as a result of mismatched flexion and extension gaps. The goals of this study were to identify factors leading to instability in flexion, the degree of correction, determined radiologically, required at revision surgery, and the subsequent clinical outcomes. Between 2000 and 2010, 60 TKRs in 60 patients underwent revision for instability in flexion associated with well-fixed components. There were 33 women (55%) and 27 men (45%); their mean age was 65 years (43 to 82). Radiological measurements and the Knee Society score (KSS) were used to assess outcome after revision surgery. The mean follow-up was 3.6 years (2 to 9.8). Decreased condylar offset (p < 0.001), distalisation of the joint line (p < 0.001) and increased posterior tibial slope (p < 0.001) contributed to instability in flexion and required correction at revision to regain stability. The combined mean correction of posterior condylar offset and joint line resection was 9.5 mm, and a mean of 5° of posterior tibial slope was removed. At the most recent follow-up, there was a significant improvement in the mean KSS for the knee and function (both p < 0.001), no patient reported instability and no patient underwent further surgery for instability.

The following step-wise approach is recommended: reduction of tibial slope, correction of malalignment, and improvement of condylar offset. Additional joint line elevation is needed if the above steps do not equalise the flexion and extension gaps.

Cite this article: Bone Joint J 2014;96-B:1644–8.

Chronic patellofemoral instability can be a disabling condition. Management of patients with this condition has improved owing to our increased knowledge of the functional anatomy of the patellofemoral joint. Accurate assessment of the underlying pathology in the unstable joint enables the formulation of appropriate treatment. The surgical technique employed in patients for whom non-operative management has failed should address the diagnosed abnormality. We have reviewed the literature on the stabilising features of the patellofemoral joint, the recommended investigations and the appropriate forms of treatment.

The June 2013 Trauma Roundup³⁶⁰ looks at: open foot fractures; the diagnostic accuracy of continuous compartment pressure monitoring; conservative treatment for supracondylar fractures; high complication rates in patellar fractures; vitamin D and fracture; better function with K-wires; and tensionless bands.

Coronal plane fractures of the posterior femoral condyle, also known as Hoffa fractures, are rare. Lateral fractures are three times more common than medial fractures, although the reason for this is not clear. The exact mechanism of injury is likely to be a vertical shear force on the posterior femoral condyle with varying degrees of knee flexion. These fractures are commonly associated with high-energy trauma and are a diagnostic and surgical challenge. Hoffa fractures are often associated with inter- or supracondylar distal femoral fractures and CT scans are useful in delineating the coronal shear component, which can easily be missed. There are few recommendations in the literature regarding the surgical approach and methods of fixation that may be used for this injury. Non-operative treatment has been associated with poor outcomes. The goals of treatment are anatomical reduction of the articular surface with rigid, stable fixation to allow early mobilisation in order to restore function. A surgical approach that allows access to the posterior aspect of the femoral condyle is described and the use of postero-anterior lag screws with or without an additional buttress plate for fixation of these difficult fractures.

Cite this article: Bone Joint J 2013;95-B:1165–71.

The routine use of patient reported outcome measures (PROMs) in evaluating the outcome after arthroplasty by healthcare organisations reflects a growing recognition of the importance of patients’ perspectives in improving treatment. Although widely embraced in the NHS, there are concerns that PROMs are being used beyond their means due to a poor understanding of their limitations.

This paper reviews some of the current challenges in using PROMs to evaluate total knee arthroplasty. It highlights alternative methods that have been used to improve the assessment of outcome.

Cite this article: Bone Joint J 2015;97-B:3–9.

Trochlear dysplasia is a developmental condition characterised by an abnormally flat or dome-shaped trochlea and is an important contributory factor to patellofemoral instability and recurrent dislocation. We studied prospectively a series of 54 consecutive patients (59 knees) with patellofemoral instability secondary to trochlear dysplasia, who were treated by a trochleoplasty by a single surgeon between June 2002 and June 2007.

Pre- and post-operative scores were assessed by the patients and a satisfaction questionnaire was completed.

Of the 54 patients (59 knees) in the series, 39 (44 knees) were female and 15 (15 knees) were male. Their mean age at surgery was 21 years and 6 months (14 years 4 months to 33 years 11 months). In 40 patients (42 knees) the mean follow-up was for 24 months (12 to 58). One patient was unable to attend for follow-up. An analysis of the results of those patients followed up for at least 12 months showed a statistically significant improvement in outcome (p < 0.001 for all scores). Overall, 50 patients (92.6%) were satisfied with the outcome of their procedure.

The early results of trochleoplasty are encouraging in this challenging group of patients.

The aim of this study was to review the early outcome of the Femoro-Patella Vialla (FPV) joint replacement. A total of 48 consecutive FPVs were implanted between December 2007 and June 2011. Case-note analysis was performed to evaluate the indications, operative histology, operative findings, post-operative complications and reasons for revision. The mean age of the patients was 63.3 years (48.2 to 81.0) and the mean follow-up was 25.0 months (6.1 to 48.9). Revision was performed in seven (14.6%) at a mean of 21.7 months, and there was one re-revision. Persistent pain was observed in three further patients who remain unrevised. The reasons for revision were pain due to progressive tibiofemoral disease in five, inflammatory arthritis in one, and patellar fracture following trauma in one. No failures were related to the implant or the technique. Trochlear dysplasia was associated with a significantly lower rate of revision (5.9% vs 35.7%, p = 0.017) and a lower incidence of revision or persistent pain (11.8% vs 42.9%, p = 0.045).

Focal patellofemoral osteoarthritis secondary to trochlear dysplasia should be considered the best indication for patellofemoral replacement. Standardised radiological imaging, with MRI to exclude overt tibiofemoral disease should be part of the pre-operative assessment, especially for the non-dysplastic knee.

Cite this article: Bone Joint J 2013;95-B:793–7.

Total knee arthroplasty (TKA) is known to lead to a reduction in periprosthetic bone mineral density (BMD). In theory, this may lead to migration, instability and aseptic loosening of the prosthetic components. Bisphosphonates inhibit bone resorption and may reduce this loss in BMD. We hypothesised that treatment with bisphosphonates and calcium would lead to improved BMD and clinical outcomes compared with treatment with calcium supplementation alone following TKA. A total of 26 patients, (nine male and 17 female, mean age 67 years) were prospectively randomised into two study groups: alendronate and calcium (bisphosphonate group, n = 14) or calcium only (control group, n = 12). Dual energy X-ray absorptiometry (DEXA) measurements were performed post-operatively, and at three months, six months, one, two, four, and seven years post-operatively.

Mean femoral metaphyseal BMD was significantly higher in the bisphosphonate group compared with controls, up to four years following surgery in some areas of the femur (p = 0.045). BMD was observed to increase in the lateral tibial metaphysis in the bisphosphonate group until seven years (p = 0.002), and was significantly higher than that observed in the control group throughout (p = 0.024). There were no significant differences between the groups in the central femoral metaphyseal, tibial medial metaphyseal or diaphyseal regions of interest (ROI) of either the femur or tibia.

Bisphosphonate treatment after TKA may be of benefit for patients with poor bone quality. However, further studies with a larger number of patients are necessary to assess whether this is clinically beneficial.

Cite this article: Bone Joint J 2015;97-B:337–45.

Total knee replacement (TKR) smart tibial trials have load-bearing sensors which will show quantitative compartment pressure values and femoral-tibial tracking patterns. Without smart trials, surgeons rely on feel and visual estimation of imbalance to determine if the knee is optimally balanced. Corrective soft-tissue releases are performed with minimal feedback as to what and how much should be released. The smart tibial trials demonstrate graphically where and how much imbalance is present, so that incremental releases can be performed. The smart tibial trials now also incorporate accelerometers which demonstrate the axial alignment. This now allows the surgeon the option to perform a slight recut of the tibia or femur to provide soft-tissue balance without performing soft-tissue releases. Using a smart tibial trial to assist with soft-tissue releases or bone re-cuts, improved patient outcomes have been demonstrated at one year in a multicentre study of 135 patients (135 knees).

Cite this article: Bone Joint J 2014;96-B(11 Suppl A):78–83.

The current indications for functional restoration of extension of the knee following quadriceps resection or loss require reappraisal. The contribution of pedicled and free functional muscle transfer is likely to be over-emphasised in many studies, with good functional outcomes predominantly reported only in the context of cases with residual quadriceps function. In cases with total quadriceps resection or loss, all forms of reconstruction perform poorly. Furthermore, in smaller resections with loss of two or fewer components of the quadriceps, minimal impairment of function occurs in the absence of functional reconstruction, suggesting that functional restoration may not be warranted. Thus there is a paradox in the current approach to quadriceps reconstruction, in that small resections are likely to be over-treated and large resections remain under-treated.

This review suggests a shift is required in the approach and rationale for reconstructing functional extension of the knee after quadriceps resection or loss. A classification based on current evidence is suggested that emphasises more clearly the indications and rationale for functional transfers.

Although patients with a history of venous thromboembolism (VTE) who undergo lower limb joint replacement are thought to be at high risk of further VTE, the actual rate of recurrence has not been reported.

The purpose of this study was to identify the recurrence rate of VTE in patients who had undergone lower limb joint replacement, and to compare it with that of patients who had undergone a joint replacement without a history of VTE.

From a pool of 6646 arthroplasty procedures (3344 TKR, 2907 THR, 243 revision THR, 152 revision TKR) in 5967 patients (68% female, mean age 67.7; 21 to 96) carried out between 2009 and 2011, we retrospectively identified 118 consecutive treatment episodes in 106 patients (65% female, mean age 70; 51 to 88,) who had suffered a previous VTE. Despite mechanical prophylaxis and anticoagulation with warfarin, we had four recurrences by three months (3.4% of 118) and six by one year (5.1% of 118). In comparison, in all our other joint replacements the rate of VTE was 0.54% (35/6528).

The relative risk of a VTE by 90 days in patients who had undergone a joint replacement with a history of VTE compared with those with a joint replacement and no history of VTE was 6.3 (95% confidence interval, 2.3 to 17.5). There were five complications in the previous VTE group related to bleeding or over-anticoagulation.

Cite this article: Bone Joint J 2014;96-B:1515–19.

There is a high risk of the development of avascular necrosis of the femoral head and nonunion after the treatment of displaced subcapital fractures of the femoral neck in patients aged < 50 years. We retrospectively analysed the results following fixation with two cannulated compression screws and a vascularised iliac bone graft. We treated 18 women and 16 men with a mean age of 38.5 years (20 to 50) whose treatment included the use of an iliac bone graft based on the ascending branch of lateral femoral circumflex artery. There were 20 Garden grade III and 14 grade IV fractures. Clinical and radiological outcomes were evaluated. The mean follow-up was 5.4 years (2 to 10). In 30 hips (88%) union was achieved at a mean of 4.4 months (4 to 6). Nonunion occurred in four hips (12%) and these patients had a mean age of 46.5 years (42 to 50) and underwent revision to a hip replacement six months after operation. The time to union was dependent on age with younger patients achieving earlier union (p < 0.001). According to the Harris hip score which was available for 27 of the 30 hips with satisfactory union, excellent results were obtained in 15 (score ≥ 90 points), fair in ten (score 80 to 90 points), and poor in two hips (≤ 80 points). One patient aged 48 years developed avascular necrosis of femoral head six years after operation and underwent total hip replacement.

The management of displaced subcapital fractures of the femoral neck, in patients aged <  50 years, with two cannulated compression screws and an iliac bone graft based on the ascending branch of lateral femoral circumflex artery, gives satisfactory results with a low rate of complication including avascular necrosis and nonunion.

Cite this article: Bone Joint J 2014;96-B:1024–8.

We report ten-year clinical and radiological follow-up data for the Sigma Press Fit Condylar total knee replacement system (Sigma PFC TKR). Between October 1998 and October 1999 a total of 235 consecutive PFC Sigma TKRs were carried out in 203 patients. Patients were seen at a specialist nurse-led clinic seven to ten days before admission and at six and 18 months, three, five and eight to ten years after surgery. Data were recorded prospectively at each clinic visit. Radiographs were obtained at the five- and eight- to ten-year follow-up appointments. Of the 203 patients, 147 (171 knees) were alive at ten years and 12 were lost to follow-up. A total of eight knees (3.4%) were revised, five for infection and three to change the polyethylene insert. The survival at ten years with an endpoint of revision for any reason was 95.9%, and with an endpoint of revision for aseptic failure was 98.7%. The mean American Knee Society Score (AKSS) was 79 (10 to 99) at eight to ten years, compared with 31 (2 to 62) pre-operatively. Of 109 knee with radiographs reviewed, 47 knees had radiolucent lines but none showed evidence of loosening.

Cite this article: Bone Joint J 2013;95-B:177–80.

The August 2014 Knee Roundup³⁶⁰ looks at: re-admission following total knee replacement; out with the old and in with the new? computer navigation revisited; approach less important in knee replacement; is obesity driving a rise in knee replacements?; knee replacement isn’t cheap in the obese; cruciate substitution doesn’t increase knee flexion; and sonication useful diagnostic aid in two-stage revision.

There have been several studies examining the association between the morphological characteristics seen in acetabular dysplasia and the incidence of the osteoarthritis (OA).

However, most studies focus mainly on acetabular morphological analysis, and few studies have scrutinised the effect of femoral morphology. In this study we enrolled 36 patients with bilateral acetabular dysplasia and early or mid-stage OA in one hip and no OA in the contralateral hip. CT scans were performed from the iliac crest to 2 cm inferior to the tibial tuberosity, and the morphological characteristics of both acetabulum and femur were studied.

In addition, 200 hips in 100 healthy volunteer Chinese adults formed a control group. The results showed that the dysplastic group with OA had a significantly larger femoral neck anteversion and a significantly shorter abductor lever arm than both the dysplastic group without OA and the controls. Femoral neck anteversion had a significant negative correlation with the length of the abductor lever arm and we conclude that it may contribute to the development of OA in dysplastic hips.

Cite this article: Bone Joint J 2014; 96-B:1586–93.

The August 2014 Children’s orthopaedics Roundup³⁶⁰ looks at: Conservative treatment still OK in paediatric clavicular fractures; Femoral anteversion not the usual suspect in patellar inversion; Shoulder dislocation best treated with an operation; Perthes’ disease results in poorer quality of adult life; Physiotherapy little benefit in supracondylar fractures; Congenital vertical talus addressed at the midtarsal joint; Single-sitting DDH surgery worth the effort; and cubitus valgus associated with simple elbow dislocation

We assessed the reproducibility and accuracy of four ratios used to measure patellar height, namely the Blackburne-Peel, Caton-Deschamps, Insall-Salvati and modified Insall-Salvati, before and after total knee arthroplasty. The patellar height was measured, by means of the four ratios, on the pre- and post-operative lateral radiographs of 44 patients (45 knees) who had undergone total knee arthroplasty. Two independent observers measured the films sequentially, in identical conditions, totalling 720 measurements per observer. Statistical analysis, comparing both observers and ratios, was carried out using the intraclass correlation coefficient.

Before operation there was greater interobserver variation using either the Insall-Salvati or modified Insall-Salvati ratios than when using the Caton-Deschamps or Blackburne-Peel methods. This was because of difficulty in identifying the insertion of the patellar tendon. Before operation, there was a minimal difference in reliability between these methods. After operation the interobserver difference was greatly reduced using both the Caton-Deschamps and Blackburne-Peel methods, which use the prosthetic joint line, compared with the Insall-Salvati and modified Insall-Salvati, which reference from the insertion of the patellar tendon.

The theoretical advantage of using the Insall-Salvati and modified Insall-Salvati ratios in measuring true patellar height after total knee arthroplasty needs to be balanced against their significant interobserver variability and inferior reliability when compared with other ratios.

The management of patients with a painful total knee replacement requires careful assessment and a stepwise approach in order to diagnose the underlying pathology accurately. The management should include a multidisciplinary approach to the patient’s pain as well as addressing the underlying aetiology. Pain should be treated with appropriate analgesia, according to the analgesic ladder of the World Health Organisation. Special measures should be taken to identify and to treat any neuropathic pain. There are a number of intrinsic and extrinsic causes of a painful knee replacement which should be identified and treated early. Patients with unexplained pain and without any recognised pathology should be treated conservatively since they may improve over a period of time and rarely do so after a revision operation.

We report the clinical and radiological results of a two- to three-year prospective randomised study which was designed to compare a minimally-invasive technique with a standard technique in total knee replacement and was undertaken between January 2004 and May 2007. The mini-midvastus approach was used on 50 patients (group A) and a standard approach on 50 patients (group B). The mean follow-up in both groups was 23 months (24 to 35).

The functional outcome was better in group A up to nine months after operation, as shown by statistically significant differences in the mean function score, mean total score and the mean Oxford knee score (all, p = 0.05). Patients in group A had statistically significant greater early flexion (p = 0.04) and reached their greatest mean knee flexion of 126.5° (95° to 135°) 21 days after operation. However, at final follow-up there was no significant difference in the mean maximum flexion between the groups (p = 0.08). Technical errors were identified in six patients from group A (12%) on radiological evaluation.

Based on these results, the authors currently use minimally-invasive techniques in total knee replacement in selected cases only.