Analysis of Oxford medial unicompartmental knee replacement using the minimally invasive technique in patients aged 60 and above: an independent prospective series

We present the outcome of an independent prospective series of phase-3 Oxford medial mobile-bearing unicompartmental knee replacement surgery. Eight surgeons performed the 154 procedures in a community-based hospital between 1998 and 2003 for patients aged 60 and above. Seventeen knees were revised; in 14 cases a total knee replacement was performed, in 3 cases a component of the unicompartmental knee prosthesis was revised, resulting in a survival rate of 89% during these 2-7 years follow-up interval. This study shows that mobile-bearing unicompartmental knee replacement using a minimally invasive technique is a demanding procedure. The study emphasises the importance of routine in surgical management and strict adherence to indications and operation technique used to reduce outcome failure.     

The Oxford phase III unicompartmental knee replacement in patients less than 60 years of age

Treatment of younger patients with medial unicompartmental disease of the knee joint remains a challenging therapeutic dilemma. With the refinement of implant design, fixation and the minimally invasive techniques employed with unicompartmental knee replacement, indications have expanded to include its use in young patients. A prospective cohort of 46 unicompartmental knee procedures were performed with a 2-year minimum and 6-year maximum follow-up, using the Oxford phase III unicompartmental knee arthroplasty, in the younger patient group (age 60 or younger). We conclude that the unicompartmental knee arthroplasty is an important option for the treatment of medial compartment disease for patients 60 years or younger. Obesity can cause technical difficulties, increased risk of complications and early failure of this prosthesis.     

Assessment of the responsibility between a road traffic accident and medical defects after the traffic accident injury of knee joint

A 48-year-old Chinese woman was hit by a car in a road traffic accident. Local county hospital considered that her right knee was injured, but didn't find any sign of fracture from X-ray imaging. Then the hospital gave diagnosis of soft tissue contusion and the patient started to exercise with burden 21 days after her right lower limb was fixed by plaster slab. Four months later, she had to go back to the county hospital for recheck due to persistent pain on her right knee. Then, the right tibia outer plateau fracture was found. The patient rejected the advice of open reduction and internal fixation of right tibia plateau fracture. Instead, she accepted the unicompartmental knee arthroplasty in a hospital affiliated to a medical college. The patient felt the knee pain alleviated after surgery However, the joint dysfunction was aggravated even more. The patient used the legal procedure for personal compensation. Both driver and the insurance company disputed that the final consequence of the injured knee was due to not only the traffic accident, but also poor medical practice involved. Therefore the court consigned us to make judicial judgment of expertise. After investigation, we found the earliest X-ray graph after the accident had shown the fracture of right tibia outer plateau and right knee valgum, with articular surface involvement, and the traffic accident was considered as the primary cause of sequelae. At the same time, the county hospital missed the diagnosis of fracture, and led to insufficient fixation of right lower limb, which was not good for rehabilitation from fracture and joint injury. This was the secondary cause of sequelae. Additionally, instead of the standard therapy, the affiliated hospital of medical college made the unicompartmental knee arthroplasty four months later, which also had a little defect. It was the minor reason for the result.     

Extended sagittal saw cut significantly reduces fracture load in cementless unicompartmental knee arthroplasty compared to cemented tibia plateaus: an experimental cadaver study

Purpose

Periprosthetic tibial plateau fractures represent a rare but serious complication in unicompartmental knee arthroplasty and are associated with extended sagittal tibial bone cuts. These can occur during the surgery, weaken the posterior cortex of the tibia and are associated with periprosthetic tibial plateau fractures. Although excellent long-term results have been reported with cemented unicompartmental knee arthroplasty, there is high interest in cementless fixation. The aim of the study was to compare fracture loads of cementless and cemented unicompartmental knee arthroplasty.

Methods

Tibial components of the Oxford Uni were implanted in six paired fresh-frozen tibiae with a defined extended saw cut (10°) at the dorsal cortex of each specimen. In one set, surgery was performed with cement fixation, and in the other, cementless components were implanted. Vertical loads were then applied under standardised conditions to fracture the specimens.

Results

Median loads of 3.7 (0.7–6.9)?kN led to fractures in the cemented group, whereas cementless fixated tibiae fractured with a median load of 1.6 (0.2–4.3)?kN (P?=?0.02).

Conclusion

The loading capacity in tibiae with cementless components is significantly less compared to cemented fixation. The results show that in case of an extended sagittal bone cut patients especially those with poor bone quality who are treated with a cementless unicompartmental knee arthroplasty are at higher risk for periprosthetic tibial fractures.     

Management of unicompartmental arthritis in the anterior cruciate ligament-deficient knee

There exists a group of patients who are difficult to manage because they have both anterior knee instability secondary to anterior cruciate ligament deficiency and unilateral degenerative joint disease. A large majority of these patients report a history of previous meniscal injury or meniscectomy after knee trauma at a relatively young age. Active patients who report symptomatic knee instability or pain associated with athletics or activities of daily living after conservative treatment may be indicated for surgery. Current endoscopic methods of anterior cruciate ligament reconstruction result in low patient morbidity, the elimination of anterior knee instability, and a timely return of function. Osteotomies about the knee joint are an effective means of treating unicompartmental knee arthrosis. Long-term studies have demonstrated that knee osteotomy is a good surgical option for patients with unicompartmental arthritis who are considered too young for total knee arthroplasty. We describe a comprehensive treatment approach to the patient with anterior cruciate ligament deficiency and isolated medial or lateral osteoarthritis. An assessment of pain symptoms, instability symptoms, and lower extremity alignment is used to formulate a treatment plan.     

Kinematics of the knee after unicompartmental arthroplasty is not the same as normal and is similar to the kinematics of the knee with osteoarthritis

Purpose

It is common to assert that restoration of normal knee kinematics is essential for the best functional result after knee arthroplasty. Previous studies using the progression of the geometric centre axis have suggested that kinematics after unicompartmental arthroplasty is markedly different from the normal. For this study, the transepicondylar axis was used because this axis is closer to the flexion axis and should be a better reference for motion. The following hypothesis was tested: the transepicondylar axis would again show that the postoperative kinematics does not restore normal motion and is closer to that before replacement.

Methods

Seventeen osteoarthritic knees were tested before and after unicompartmental arthroplasty using a three-dimensional to two-dimensional registration technique tracking the transepicondylar axis to calculate translation and rotation of this axis. Results were compared for the seventeen knees before and after arthroplasty and were compared to the normal knee as measured in our previous study.

Results

Similar motion patterns in the pre- and postoperative knees were shown but both the pre- and postoperative motion were markedly different from the normal knee.

Conclusions

This result supported our hypothesis. The clinical relevance is that medial unicompartmental arthroplasty cannot restore the motion of the knee to normal in the living knee. Therefore, it would be expected that the patient for unicompartmental knee might not feel normal. It may not be possible depending on ligaments alone to restore the knee to normal, and the changes in the articular shapes and the surgical procedure may also be necessary.

Level of evidence

IV.     

Severe metallosis after unicompartmental knee arthroplasty

We report on a case of a patient who had femoral osteolysis and severe metallosis of the knee joint resulting from the secondary abrasive wear of the metal-backed tibial component of a unicompartmental knee arthroplasty due to massive wear of tibial polyethylene. The failure was diagnosed 11 years after implantation. This metallosis affected the intra-articular tissues and the subchondral bone.     

Extensive osteolytic cystlike area associated with polyethylene wear debris adjacent to an aseptic, stable, uncemented unicompartmental knee prosthesis: case report

We present the case of a patient who after uncemented unicompartmental knee arthroplasty developed a large osteolytic cystlike area in the lateral aspect of the tibial metaphysis, contralateral to a well-fixed tibial component at revision surgery. The lesion contained fibrotic soft tissue, evidence of a foreign-body giant cell reaction and polyethylene particles, but no metal wear debris, infection, or malignancy. This case demonstrates that there is a direct communication between the joint cavity and the cyst.     

The Oxford unicompartmental knee prosthesis: a 5-year follow-up

We present our medium-term results with the Oxford unicompartmental knee prosthesis for unicompartmental osteoarthrosis. After an average of 58 months the mean on the Hospital for Special Surgery knee score in 38 medial and 3 lateral prostheses (39 patients) was 87. There were three revisions; in the remaining 36 patients the results were: 29 excellent, 3 good, 2 moderate, and 2 poor. In two of the three revisions and in two of the four poor and moderate results, the indications for the procedure were debatable. Our findings confirm the good results reported in other studies and underline the importance of adhering to strict indications to reduce the number of poor results. Received: 12 July 1999/Accepted: 5 January 2000     

Combined single-photon emission computerized tomography and conventional computerized tomography (SPECT/CT): clinical value for the knee surgeons?

Single-photon emission computerized tomography in combination with conventional computer tomography (SPECT/CT) is an emerging technology that may hold great clinical value to the orthopaedic knee surgeon. Post-operative knee pain is a familiar condition seen in most orthopaedic clinics. Here, we present the value of SPECT/CT in three such cases of pain after surgical treatment of knee osteoarthritis (high tibial osteotomy, medial unicompartmental arthroplasty, total knee arthroplasty). In these patients with post-operative knee pain, SPECT/CT has proved to be beneficial in establishing the diagnosis and providing guidance for further treatment.     

The Oxford unicompartmental knee prosthesis: a 2–14 year follow-up

Our medium- and long–term results obtained with the Oxford unicompartmental knee prosthesis for unicompartmental knee osteoarthrosis are presented. Ninety–seven prostheses were evaluated (87 medial, 10 lateral) in 86 patients, with the Hospital for Special Surgery knee score after 2–14 years (mean follow-up: 6 years 9 months). Five prostheses were lost to follow-up. Eight patients died, not related to surgery; none had undergone a revision. Fourteen revisions (of which one bilateral UKP), 11 medial and three lateral, were performed. The mean HSS score of the 69 UKPs was 178.8 (80% excellent, 10% good, 4% fair, 6% poor). These findings confirm the good results reported in other studies, regarding proper patient selection and a consistent operative technique.     

C反应蛋白在4种不同关节置换手术后变化趋势

目的 通过记录4种不同人工关节置换手术后C反应蛋白（CRP）的变化趋势及相关水平来研究这4种不同手术对机体造成的创伤反应.方法 研究96例不同关节置换（全膝关节置换、单髁膝关节置换、表面髋关节置换、全髋关节置换）患者,分别记录其术前、术后2d、术后7d的CRP水平.结果 CRP的峰值在术后第2天出现,表面髋关节置换组峰值低于全髋关节置换组,单髁膝关节置换组峰值低于全膝关节置换组,全髋关节置换组峰值低于全膝关节置换组.结论 术后CRP的反应程度是由手术过程中骨髓组织的破坏程度决定的,不是由手术部位或软组织的损伤程度决定的.     

Anterior cruciate ligament reconstruction after unicompartmental knee arthroplasty

Purpose  

ACL deficiency may cause abnormal knee kinematics and is associated with a tenfold increase in surgical failures after unicompartmental knee arthroplasty, such as aseptic loosening of the tibial compartment and medial bearing instability. The current investigators hypothesized that in a knee with UKA, single-bundle ACL reconstruction would restore tibiofemoral translation to levels similar to those of the intact ACL.     

MR imaging of the knee in patients with medial unicompartmental arthroplasty: comparison among sequences at 1.5 T

Purpose

This study was done to test a series of magnetic resonance (MR) imaging sequences of the knee after medial unicompartmental arthroplasty.

Materials and methods

Four patients who had undergone Oxford III medial unicompartmental arthroplasty underwent 1.5-T MR imaging of the operated knee using coronal sequences: T1-weighted spin-echo (SE), T1-weighted turbo SE (TSE), proton-density (PD)- and T2-weighted TSE, T1-weighted gradient echo (GE), short-tau inversion recovery (STIR), multi echo data image combination (MEDIC), T2*-weighted GE, volumetric interpolated breath-hold examination (VIBE), and dual-echo steady state (DESS). For each sequence, we evaluated the visibility of the anatomical structures of the central pivot, lateral compartment, and anterior compartment using a semiquantitative score (0=total masking; 1=insufficient visibility; 2=sufficient visibility; 3=optimal visibility). The sum of the scores given to each sequence was divided by the maximal sum, obtaining a percentage visibility index. Friedman and sign tests were used for statistical analysis.

Results

MR examination time was 30–32 min. No patients reported pain, heat or other local discomfort. The visibility index ranged between 83% and 89% for the first four sequences without significant differences among them, 58% for STIR and 11%–36% for the last five sequences. Significant differences were found between each of the four first sequences and the remaining sequences (p<0.004) and between STIR and the last five sequences (p<0.008).

Conclusions

MR imaging of the knee after medial unicompartmental arthroplasty was not associated with adverse events. An imaging protocol including SE, TSE and STIR sequences could be used to study the knee with unicompartmental arthroplasty.     

High tibial valgus osteotomy in unicompartmental medial osteoarthritis of the knee: a retrospective follow-up study over 13�C21?years

Purpose  

High tibial osteotomy is a well-established method for the treatment of medial unicompartmental osteoarthritis of the knee.     

Satisfactory outcomes following combined unicompartmental knee replacement and anterior cruciate ligament reconstruction

Purpose

There exist limited options for treatment of patients with combined medial compartment arthritis and anterior cruciate ligament (ACL) deficiency. Ideal treatment is one that offers lasting relief of symptoms not compromising any future surgery. Unicompartmental knee replacement has shown consistently good results in the relatively young and active population, but there is a high reported incidence of failure up to 20%, if performed in ACL-deficient knees. One of the recognized treatment modality is combined ACL reconstruction and unicompartmental arthroplasty. A systematic review was conducted looking at the demographics, techniques, complications and outcome of combined ACL reconstruction with unicompartmental knee arthroplasty.

Methods

A systematic literature search within the online Medline, PubMed Database, EMBASE, Web of Science, Cochrane and Google Scholar was carried out until October 2016 to identify relevant articles. A study was defined eligible if it met the following inclusion criteria: the surgical procedure combined unicompartmental knee arthroplasty and anterior cruciate ligament reconstruction; patient’s clinical and/or functional outcomes were reported; any complications intra-operatively and post-operatively were reported; and the full-text articles, written in English, German, Italian, Dutch or Spanish, were available. Quality and risk of bias assessments were done using standardized criteria set.

Results

A total of 8 studies met the inclusion criteria encompassing 186 patients who were treated with simultaneous ACL reconstruction and unicompartmental knee arthroplasty. The mean age was 50.5 years (range from 44 to 56) with a mean follow-up of 37.6 months (range from 24 to 60). There was an improvement in mean Oxford Score from 27.5 to 36.8. Complications reported included tibial inlay dislocation (n = 3), conversion to a total knee arthroplasty (n = 1), infection requiring two-stage revision (n = 2), deep-vein thrombosis (n = 1), stiffness requiring manipulation under anaesthesia (n = 1), retropatellar pain requiring arthroscopic adhesiolysis (n = 1).

Conclusion

Unicompartmental knee arthroplasty combined with ACL reconstruction can be a valid treatment option for selected patients, with combined medial unicompartmental knee osteoarthritis and ACL deficiency.

Level of evidence

Systematic Review of Level IV Studies, Level IV.

     

The immediate effect of navigation on implant accuracy in primary mini-invasive unicompartmental knee arthroplasty

The success of unicompartmental knee arthroplasty (UKA) is highly dependent on the accuracy of the component alignment. Objective of the present study was to evaluate the immediate effect of image-free computer navigation technology on implant accuracy in primary mini-invasive UKA. This study reviews 40 patients with primary isolated arthritis of the medial compartment of the knee that underwent unicompartmental knee arthroplasty through a minimally invasive approach. A cohort of the 20 most recent consecutive UKA's implanted with standard instrumentation was followed by a cohort of the very first 20 consecutive cases after conversion to the navigated technique. There was no variability regarding implant (Oxford meniscal unicompartmental knee system--Biomet Orthopedics, Inc., Warsaw, Indiana 46580, USA), surgeons and surgical technique, except for the use of the navigation system (Treon plus--Medtronic Inc., Minnesota, MI, USA). The axis alignment and accuracy of implant positioning was measured on postoperative long-leg standing radiographs and standard lateral X-rays with regard to the valgus angle and the coronal and sagittal component angle. In addition, preoperative deformities of the mechanical leg axis, tourniquet time, age, gender, and body mass index were correlated. Statistical analyses were performed using the SPSS 14.0 (SPSS Inc., Chicago, IL, USA) software package. Optimal implant alignment including all measurements in the desired angular range was significantly (P=0.041) higher in the navigated cohort. Navigation eliminated outliers in the frontal mechanical alignment and coronal orientation of the femoral component totally and significantly (P<0.02). Furthermore, navigation narrowed the range of outliers in all other planes of component orientation. There were no statistically significant differences in the mean numerical values between the cohorts, except for the frontal mechanical alignment (P<0.009) and coronal tibial alignment (P<0.037). The average tourniquet time was increased by 10.95 min in the navigated cohort. Our results indicate that navigation immediately improves accuracy of bone cuts and reduces the number of outliers with implementation in UKA.     

Bilateral osteochondritis dissecans of the medial trochlea femoris: an unusual case of patellofemoral pain

We report a case of bilateral osteochondritis dissecans of the medial trochlea femoris. Arthroscopic removement of loose bodies in the symptomatic left knee led to an excellent result; the untreated right knee showed effusion and locking one year later. This condition should be considered in the diagnosis of patellofemoral pain.     

The Oxford unicompartmental knee prosthesis: an independent 10-year survival analysis

One hundred forty-nine medial prostheses were implanted in 140 patients between 1988 and 1996. After a mean of 67 months 28 patients had died, without the need for revision. Seventeen prostheses were lost to follow-up. Revision surgery using a total knee prosthesis was performed in 16 cases. In four others, a lateral prosthesis was implanted subsequently to a medial one. One of these four was revised to a total knee prosthesis 6 years later. In another four cases, late complications of the meniscal bearing were treated with replacement of this bearing. The surviving prostheses were seen back after a mean of 126 months. The cumulative survival rate at 10 years was 82% for the whole population and 84% when knees with a previous high tibial osteotomy were excluded. Since these results compare poorly to the survival of total knee arthroplasty, this prosthesis is not the first-choice implant. Because it preserves a maximum of bone stock and is revised to a total prosthesis almost without difficulty, it is the first-choice implant for medial unicompartmental osteoarthritis in patients younger than 65. Further research is mandatory to confirm that this prosthesis very rarely needs revision in patients older than 75. It should not be used in osteotomized knees.