Debate has raged over whether a cruciate retaining (CR) or a posterior stabilised (PS) total knee replacement (TKR) provides a better range of movement (ROM) for patients. Various sub-sets of CR design are frequently lumped together when comparing outcomes. Additionally, multiple factors have been proven to influence the rate of manipulation under anaesthetic (MUA) following TKR. The purpose of this study was to determine whether different CR bearing insert designs provide better ROM or different MUA rates. All primary TKRs performed by two surgeons between March 2006 and March 2009 were reviewed and 2449 CR-TKRs were identified. The same CR femoral component, instrumentation, and tibial base plate were consistently used. In 1334 TKRs a CR tibial insert with 3° posterior slope and no posterior lip was used (CR-S). In 803 there was an insert with no slope and a small posterior lip (CR-L) and in 312 knees the posterior cruciate ligament (PCL) was either resected or lax and a deep-dish, anterior stabilised insert was used (CR-AS). More CR-AS inserts were used in patients with less pre-operative ROM and greater pre-operative tibiofemoral deformity and flexion contracture (p < 0.05). The mean improvement in ROM was highest for the CR-AS inserts (5.9° (-40° to 55°) vs CR-S 3.1° (-45° to 70°) vs CR-L 3.0° (-45° to 65°); p = 0.004). There was a significantly higher MUA rate with the CR-S and CR-L inserts than CR-AS (Pearson rank 6.51; p = 0.04). Despite sacrificing or not substituting for the PCL, ROM improvement was highest, and the MUA rate was lowest in TKRs with a deep-dish, anterior-stabilised insert. Substitution for the posterior cruciate ligament (PCL) in the form of a PS design may not be necessary even when the PCL is deficient. . Cite this article: Bone Joint J 2013;95-B, Supple A:129–32

Introduction. Modern implant systems offer a variety of options to address the posterior cruciate ligament (PCL) and afford stability in primary total knee arthroplasty (TKA). One system has three bearing options for cruciate retaining (CR) TKA: standard CR bearing (CR-S) with 3° posterior slope and no posterior lip; CR lipped bearing (CR-L) with no slope and small posterior lip, and deep-dished anterior stabilized bearing (CR-AS) with large anterior build-up to compensates for deficient or lax PCL. We previously reported on 1940 patients (2449 CR-TKA) at early follow-up comparing these three CR bearings and found CR-AS bearings had greater improvement in ROM and lower rate of manipulation despite their use in patients with greater preoperative deformity and lower ROM. The purpose of this study was to review a broader series by a single surgeon-designer with minimum 2-year follow-up to determine if there were differences between bearing types in terms of clinical outcomes and survival. Methods. From 2003 to 2014, 3348 patients (4500 knees) underwent primary CR-TKA and were available for review with minimum 2-year follow-up. An algorithmic approach to constraint was employed, choosing the least amount necessary to afford stability. Bearings used were 3883 CR-S (86%), 256 CR-L (6%), and 361 CR-AS (8%). CR-S bearings were used in patients with less preoperative tibiofemoral deformity (p=0.0316), less flexion contracture (p<0.0001), and better ROM (p<0.0001), but more mediolateral instability (p<0.0001) than CR-AS bearings. Results. Mean follow-up overall was 5.7 years (range, 2–14). Overall 106 TKA (2.4%) have been revised (46 fully, 56 partial, 4 unknown). Indications for revision were instability in 40 (all CR-S), 28 infection, 10 aseptic loosening, 8 arthrofibrosis, 7 periprosthetic fracture, 3 extensor related, 2 heterotopic ossification, 3 pain, and 5 other or unknown. Chi-squared analysis showed no difference between bearing groups for overall revision (p=0.1724). However, revision for instability was greater for CR-S (1.0%) versus CR-AS bearings (p=0.0454, Fisher's exact). Frequency of manipulation was no different between bearing groups (p=0.8512). CR-AS patients had greater improvement than CR-S patients in ROM (4.4° versus 1.6°, p=0.0003), and Knee Society pain (39.3 versus 35.9, p=0.0002), clinical (53.5 versus 47.0, p<0.0001), and function (18.9 versus 16.0, p=16.0). CR-L patients had greater improvement than CR-S in pain (38.2, p=0.0367) and clinical score (53.6, p<0.0001). Discussion. In this large single surgeon series, Kaplan-Meier survival free of any revision was similar between bearing groups and excellent overall with 96.0% (±0.49%) at 14.1 years. No revisions for instability were observed with CR-L or CR-AS bearings, but were the most frequent cause of revision with CR-S bearings. Manipulation rates were similar between bearing groups. ROM, pain, clinical, and functional improvements were greater with a deep-dished, anterior-stabilized bearing

Purpose. To establish the reliability of reporting and recording revision hip and knee arthroplasties by comparing data in the National Joint Registry (NJR), Hospital Episode Statistics (HES) and our local theatre records. Methods. The paper theatre registers for all orthopaedic theatres in the Royal Derby Hospitals NHS Trust were examined for details of revision hip and knee replacements carried out in 2007 and 2008. This was then cross-checked and merged with the local electronic theatre data to obtain a definitive local record of all revision hip and knee arthroplasties. Data for the same period was requested from the NJR and HES and these data were checked against our definitive local record for discrepancies. The HES codes used were the same codes used to compile the recent NJR annual reports. Results. The theatre registers and ORMIS identified 271 revision hip and knee arthroplasties in the study period. The NJR had corresponding data for 176 (65%) of these, and HES had 250 (92%). 10 cases (4%) were not recorded by either NJR or HES: 8 secondary resurfacings of patellae and 2 posterior lip augmentations in hips. Of those operations “missed” by HES, most had been assigned a correct “W” code, but had a “Y” or “Z” OPCS code not used in the NJR annual reports. Conclusion. When HES and the NJR data are combined, they are an accurate representation of real practice. More robust methods of reporting revision arthroplasty to the NJR are required. The OPCS codes used to indicate a revision need to be reviewed

We have examined the results obtained with 72 NexGen legacy posterior stabilised-flex fixed total knee replacements in 47 patients implanted by a single surgeon between March 2003 and September 2004.

Aseptic loosening of the femoral component was found in 27 (38%) of the replacements at a mean follow-up of 32 months (30 to 48) and 15 knees (21%) required revision at a mean of 23 months (11 to 45). We compared the radiologically-loose and revised knees with those which had remained well-fixed to identify the factors which had contributed to this high rate of aseptic loosening.

Post-operatively, the mean maximum flexion was 136° (110° to 140°) in the loosened group and 125° (95° to 140°) in the well-fixed group (independent t-test, p = 0.022). Squatting, kneeling, or sitting cross-legged could be achieved by 23 (85%) of the loosened knees, but only 22 (49%) of the well-fixed knees (chi-squared test, p = 0.001). The loosened femoral components were found to migrate into a more flexed position, but no migration was detected in the well-fixed group.

These implants allowed a high degree of flexion, but showed a marked rate of early loosening of the femoral component, which was associated with weight-bearing in maximum flexion.

Objectives

This systematic review and meta-analysis was conducted to determine the mid- to long-term clinical outcomes for a medial-pivot total knee replacement (TKR) system. The objectives were to synthesise available survivorship, Knee Society Scores (KSS), and reasons for revision for this system.

Radiological assessment of total and unicompartmental knee replacement remains an essential part of routine care and follow-up. Appreciation of the various measurements that can be identified radiologically is important. It is likely that routine plain radiographs will continue to be used, although there has been a trend towards using newer technologies such as CT, especially in a failing knee, where it provides more detailed information, albeit with a higher radiation exposure.

The purpose of this paper is to outline the radiological parameters used to evaluate knee replacements, describe how these are measured or classified, and review the current literature to determine their efficacy where possible.

We compared the incidence and severity of complications during and after closing- and opening-wedge high tibial osteotomy used for the treatment of varus arthritis of the knee, and identified the risk factors associated with the development of complications. In total, 104 patients underwent laterally based closing-wedge and 90 medial opening-wedge high tibial osteotomy between January 1993 and December 2006. The characteristics of each group were similar. All the patients were followed up for more than 12 months. We assessed the outcome using the Hospital for Special Surgery knee score, and recorded the complications. Age, gender, obesity (body mass index > 27.5 kg/m²), the type of osteotomy (closing versus opening) and the pre-operative mechanical axis were subjected to risk-factor analysis.

The mean Hospital for Special Surgery score in the closing and opening groups improved from 73.4 (54 to 86) to 91.8 (81 to 100) and from 73.8 (56 to 88) to 93 (84 to 100), respectively. The incidence of complications overall and of major complications in both groups was not significantly different (p = 0.20 overall complication, p = 0.29 major complication). Logistic regression analysis adjusting for obesity and the pre-operative mechanical axis showed that obesity remained a significant independent risk factor (odds ratio = 3.23) of a major complication after high tibial osteotomy.

Our results suggest that the opening-wedge high tibial osteotomy can be an alternative treatment option for young patients with medial compartment osteoarthritis and varus deformity.

We have studied the concept of posterior condylar offset and the importance of its restoration on the maximum range of knee flexion after posterior-cruciate-ligament-retaining total knee replacement (TKR). We measured the difference in the posterior condylar offset before and one year after operation in 69 patients who had undergone a primary cruciate-sacrificing mobile bearing TKR by one surgeon using the same implant and a standardised operating technique. In all the patients true pre- and post-operative lateral radiographs had been taken.

The mean pre- and post-operative posterior condylar offset was 25.9 mm (21 to 35) and 26.9 mm (21 to 34), respectively. The mean difference in posterior condylar offset was + 1 mm (−6 to +5). The mean pre-operative knee flexion was 111° (62° to 146°) and at one year postoperatively, it was 107° (51° to 137°).

There was no statistical correlation between the change in knee flexion and the difference in the posterior condylar offset after TKR (Pearson correlation coefficient r = −0.06, p = 0.69).