Augmentation von Patellafrakturen und Patellarsehnenrupturen mittels McLaughlin-Cerclage

Augmentation of patella injuries was first described in 1946 by H.F. McLaughlin. We retrospectively analyzed 14 patients with patella fracture or patella tendon rupture who had been augmented with McLaughlin wiring between 1998 and 2004. The Insall-Salvati ratio was determined before and after removing the cerclage wire as well as on the opposite knee to assess the patella position; in addition the degree of retropatellar arthritis was determined. The functional results were ascertained by Larson and OAK score. McLaughlin wiring influenced the patella position in two patients. Most of the patients achieved a good or very good functional result (mean Larson score 82.39, mean OAK score 82.79). In six patients (42.86%) the degree of retropatellar arthritis was higher than in the opposite knee. Three patients (21.43%) needed secondary arthrolysis at the time of removal of the cerclage. Arthritis and functional results were worse in patients with complex knee trauma. Therefore augmentation with the McLaughlin cerclage in combination with standardized postoperative after treatment is a sufficient therapy of patella fractures and patella tendon ruptures.     

Augmentation of the coraco-clavicular ligament suture. Comparison between wire cerclage, vicryl tape and PDS cord

A total of 71 patients (average age 32 years) with acute grade III acromio-clavicular dislocation were all treated with the same surgical procedure: open reduction, transfixation of the acromio-clavicular joint with a Kirschner wire and suture of the coraco-clavicular ligaments with augmentation. The augmentation was done with a 1.2-mm wire cerclage in the first group (22 patients), a 3-mm wide Vicryl tape in the second group (30 patients) and a 1.5-mm PDS cord in the third group (19 patients). At follow-up (average time 4.4 years) the patients were questioned as well as being examined radiologically and clinically. Only two patients were not satisfied with the outcome of surgery. On clinical evaluation after wire cerclage augmentation of the suture, the distal end of the clavicle was found to be dislocated in 23% of cases. The incidence was 20% after Vicryl taping and 58% after PDS cord augmentation. At X-ray examination with 8 kg suspended from the wrist acromio-clavicular dislocation was found in 45% after wire cerclage, 23% after Vicryl taping and 58% after PDS cord augmentation of the suture. The results show that dislocation is more likely to persist after augmentation of the suture of the coraco-clavicular ligaments with wire cerclage or PDS cord than when the suture is augmented with a Vicryl tape. We conclude that a resorbable material is suitable for augmenting the suture of the coraco-clavicular ligaments, but that a filiform augmentation is less appropriate than a band.     

Quadrizeps- und Patellasehnenrupturen

Ruptures of the quadriceps or patellar tendon are uncommon but extremely relevant injuries. Early diagnosis and surgical treatment with a stable suture construction are mandatory for a good postoperative clinical outcome. The standard methods of repair for quadriceps and patellar tendon injuries include the placement of suture loops through transpatellar tunnels. Reinforcement with either a wire cerclage or a PDS cord is used in patellar tendon repair. The PDS cord can also be applied as augmentation in quadriceps tendon repair. In secondary patellar tendon repair an autologous semitendinosus graft can be used. For chronic quadriceps tendon defects a V-shaped tendon flap with a distal footing is recommended. The different methods of repair should lead to early functional postoperative treatment. The clinical outcome after surgical treatment of patellar and quadriceps tendon ruptures is mainly good.     

Mid to long-term results of open acromioclavicular-joint reconstruction using polydioxansulfate cerclage augmentation

Introduction  There is still controversy about the optimal operative treatment of acromioclavicular (AC)-joint dislocations. However, in the current literature, only few studies are available on mid- to long-term results of different stabilization methods. This retrospective study presents the clinical and radiographical results after open reduction and stabilization of AC-joint dislocations using polydioxanesulfate (PDS) cerclage augmentation. Methods  Fifty patients with a mean age of 35 years were treated with open reduction and PDS cerclage augmentation. Rockwood classification showed 44 type V, 5 type III and 1 type IV AC-joint dislocation. The clinical and radiographic follow-up (Constant Score, DASH Score, subjective shoulder value and stress radiographs of the shoulder girdle) were performed postoperatively at an average of 70 months. Results  Clinical scores were good to excellent with a mean constant score of 91.7 ± 8.7 points. The mean DASH Score was 5 ± 8.8 points and the mean subjective shoulder value was 92 ± 10.7. Radiographically, 80% showed a difference of coracoclavicular distance in comparison to the contralateral side of <5 mm, 14% of 5–10 mm and 6% of >10 mm. Radiographical signs of osteoarthritis were present in 37 and in 6% of all patients also evident during clinical examination. Coracoclavicular calcifications were seen in 68%. Complications were: one superficial wound infection, one extensive coracoclavicular calcification and two complete secondary redislocations. Conclusions  Treatment of AC-joint dislocation using PDS cerclage augmentation leads to good to excellent clinical results. However, mid- to long-term follow-up reveals a high incidence of radiographic signs of osteoarthritis of the AC-joint. Whether this is due to the surgical technique and could be reduced using other, more anatomical fixation techniques or whether the injury itself leads to these changes, need to be shown.     

Extensor tendon rupture associated with osteoarthritis of the distal radioulnar joint

Non-rheumatoid osteoarthritis of the distal radioulnar joint can cause extensor tendon rupture. We analysed the radiographic morphology of the distal radioulnar joint to identify the risk factors for this complication. Forty-one wrist X-rays of 37 patients with extensor tendon rupture caused by distal radioulnar joint osteoarthritis were evaluated retrospectively for the severity of osteoarthritis by the Kellgren/Lawrence scoring system. Measurements were obtained from posteroanterior views. All but one wrist had severe osteoarthritic changes exceeding grade 3. The radiographic features that were different from those of the contralateral wrists included deepening and widening of the sigmoid notch, radial shift of the ulnar head and dorsal inclination of the sigmoid notch. There was no significant association between tendon rupture and the morphology of the ulnar head or ulnar variance. The scallop sign, dorsal inclination of the sigmoid notch and radial shift of the ulnar head are radiological risk factors for extensor tendon ruptures.     

Extensor mechanism allografts in total knee arthroplasty.

Forty knees in 40 patients who had a chronic extensor mechanism disruption after knee arthroplasty underwent extensor mechanism allograft placement to restore extensor function. Thirteen knees were infected previously and 11 knees did not respond to previous attempts at direct extensor repair or reconstruction. Two patients died and two patients underwent above the knee amputation because of recurrent infection. The final group of 36 patients was studied for a mean followup of 3.6 years (range, 2-10 years). Clinical evaluations were performed using a modified Knee Society scoring system. The average range of motion in the entire group of patients was 1.4 degrees extension to 98 degrees flexion. The average extensor lag was 13 degrees in 15 of 36 patients. There were eight extensor allograft ruptures, which were treated by repeat extensor allograft placement. The average knee scores for function improved from 37 points preoperatively to 68 points postoperatively. Despite these initial ruptures, 34 of 36 patients had a successful clinical result. These results support the use of this technique for complete extensor mechanism loss after knee arthroplasty when direct repair is unfavorable.     

Patellar tendon rerupture in a footballer: Our personal surgical technique and review of the literature

Patellar tendon rerupture is a relatively uncommon condition that severely compromises the function of the extensor mechanism of the knee. Few cases described in the literature does not show a unique mode of treatment for this type of lesion. We report the case of a young athlete with traumatic patellar tendon rerupture. The first rupture was treated with the use of Statak anchors. Following a second rerupture incident as a result of a sporting accodent, the tendon was reconstructed with the use of an autologous graft tendon of semitendinosus and biological augmentation with gracilis tendon. For both tendons the distal insertion part was preserved to facilitate the healing process. The treatment was completed with the application of a neutralization cerclage wire and with local injection of plateket reach plasma (PRP). At 12 months follow up, a full recovery of the structure and function of the extensor mechanism was observed and the patient was able to resume normal sports competitive activity.     

A sixteen-year follow-up of three operative techniques for the treatment of acute ruptures of the anterior cruciate ligament

BACKGROUND: This study compares three surgical procedures that we used in the past to treat ruptures of the anterior cruciate ligament: acute primary repair, acute repair augmented with a synthetic ligament-augmentation device, and acute repair augmented with autologous bone-patellar tendon-bone graft. METHODS: This is the third report on a group of patients who were randomized to the three different procedures between 1986 and 1988. There were fifty patients in each group. The patients were evaluated prospectively at one, two, five, and sixteen years with use of the Tegner activity score and the Lysholm functional score. Stability of the knee was assessed with clinical examination and with use of the KT-1000 arthrometer. RESULTS: One hundred and twenty-nine (88%) of the 147 patients who were available for follow-up completed the study. Eleven patients (24%) who had a primary repair, four patients (10%) who had repair with a ligament augmentation device, and one patient (2%) who had augmentation with autologous bone-patellar tendon-bone graft underwent anterior cruciate ligament revisions between the primary operation and the sixteen-year follow-up examination. The rate of revision was ten times higher in the group that had primary repair than in the group that had repair with bone-patellar tendon-bone graft (p = 0.003). In the remaining patients, those who had repair with a bone-patellar tendon-bone graft had significantly more stable knees than those who had repair with a ligament augmentation device, as measured by the Lachman test (p = 0.026). Nine (11%) of the eighty-five patients for whom data were available had osteoarthritis in the primarily reconstructed knee, and three patients (3.5%) had osteoarthritis in the contralateral knee at sixteen years (p = 0.001); no difference was noted among the three groups. The mean Lysholm score at sixteen years was 88 points for the knees that had primary repair, 85 points for those that had repair with the ligament augmentation device, and 90 points for those managed with a bone-patellar tendon-bone graft (p = 0.286). CONCLUSIONS: At long-term (sixteen-year) follow-up, the rate of revision anterior cruciate ligament surgery is much higher following primary repair than after primary repair augmented by a bone-patellar tendon-bone graft. It can be expected that approximately 10% of patients undergoing anterior cruciate ligament reconstruction acutely will have osteoarthritis develop in the reconstructed knee. We no longer perform any of these surgical techniques as open procedures.     

Acute traumatic rupture of the patellar tendon in pediatric population: Case series and review of the literature

BackgroundIntact knee extensor mechanism is required for the normal function of the lower extremity. Patellar tendon rupture is a relatively rare injury with peak age incidence around 40 years and usually occurs midsubstance. The occurrence of pure patellar tendon rupture without bony avulsion is an extremely rare injury in the pediatric population with few cases reported in the literature with limited information regarding frequency, complications, and outcomes in children. However, due to increased participation in sports and high-energy recreational activities during childhood, the frequency of such injuries has progressively increased.ObjectiveTo evaluate the frequency of pediatric patellar tendon rupture injuries and describe the radiological findings, treatment modalities, and outcome of such injuries.MethodsDemographic and clinical data on a series of patients who sustained patellar tendon rupture were reviewed. These data included age at time of injury, sex, laterality, mechanism of injury, associated injuries, complications, presence or absence of Osgood-Schlatter disease, diagnostic imaging such as plain radiographs and magnetic resonance images (MRI), surgical technique, method of fixation, period of postoperative immobilization, total duration of physiotherapy, time to return to sports activities and follow-up duration. Insall-Salvati ratio was calculated on the preoperative lateral x-ray. The functional outcome was evaluated with regard to final knee active range of motion (AROM), manual quadriceps muscle testing, and presence or the absence of terminal extension lag. Clinical outcome rating using knee society score (KSS) was performed and functional outcome was further classified according to the calculated score.ResultsFive male patients with patellar tendon rupture (7%) were identified among 71 pediatric patients who sustained acute traumatic injury of the knee extensor mechanism. The mean age at the time of injury was 13.6 years (range: 12–15 years). The injury occurred in relation to sports activities in 4 patients. Osteogenesis imperfecta and Osgood-Schlatter disease were identified in 2 patients. High riding patella is the hallmark diagnostic sign detected in plain x-ray with preoperative Insall-Salvati ratio ranged from 1.7 to 2.5. Three patients had pure soft tissue avulsion distally from the proximal tibia, 1 patient had pure soft tissue avulsion proximally from the inferior patellar pole, and 1 patient with midsubstance tendinous disruption. No associated intra-articular lesions were identified. Suture bridge double row technique, transpatellar suturing, and transosseous suturing through the proximal tibia were used for patellar tendon reinsertion. After a mean follow-up period of 18. 4 weeks (range: 10–30 weeks), patients achieved AROM ranging from 0 to 120° to 0–137° without terminal extension lag. The mean time to return to sports activity was 22 weeks (range: 13–30 weeks). Quadriceps muscle strength was 5/5 at the final follow-up visit in all patients; however, relative muscle atrophy was noted in comparison to the other side in one patient. The mean KSS was 91.8 points (range: 79–100 points) with excellent outcome in 4 patients and good outcome in 1 patient.ConclusionPatellar tendon rupture is rare in the pediatric population and represents 7% of pediatric patients who sustained acute traumatic injury of the knee extensor mechanism. Ruptures may occur midsubstance, or from proximal or distal insertions. High riding patella is the hallmark diagnostic sign for such injury. Although rare, it is considered a serious injury that necessitates early diagnosis and surgical intervention. Functional range of motion was obtained in all patients with different modalities of treatment.     

Ruptures of the extensor mechanism of the knee joint. Clinical results and patellofemoral articulation

The functional results of 28 cases of rupture of the quadriceps and patellar tendons are reported. Excellent or good results were noted in 15 of 18 quadriceps and 7 of 10 patellar tendons. Radiographic comparison with the opposite knee disclosed incongruences between the patella and the femoral groove in the tangential view and/or cranial-caudal position of the patella in the lateral view in 13 of the quadriceps tendon ruptures and seven of the patellar tendon ruptures. Patients with residual pain had patellofemoral incongruity but since two-thirds of the patients with incongruity were asymptomatic, incongruity alone may not be the cause of the symptoms. There was no positive correlation to muscular strength or range of movement. Nevertheless, exact adaptation of the patellar tendon and periarticular tissue seems necessary to obtain correct patello-femoral articulation. Reinforcement of the tendon with a wire cerclage is recommended to decrease the tension on the suture line and the consequent risk of a secondary rupture. In acute ruptures of the quadriceps tendon end-to-end sutures are sufficient.     

Spontaneous simultaneous bilateral quadriceps rupture: cerclage wire or Ticron augmentation?

Quadriceps tendon rupture is a common injury, particularly in the elderly. Transosseous suture repair is the standard reconstruction. Cerclage wire augmentation is advocated to protect the surgical repair and allow earlier rehabilitation. We present a case of this injury in which we elected to employ two different methods of repair augmentation using Ticron on one side and a cerclage wire on the other.     

Transossäre Naht der Patellarsehnenruptur

OBJECTIVE: Restoration of active knee extension. Restoration of active knee stabilization. Avoiding secondary patella alta. INDICATIONS: Acute rupture of the patellar tendon within 3-5 days. Chronic rupture of the patellar tendon. CONTRAINDICATIONS: Compromised general health status or associated injuries. Compromised local soft-tissue situation. SURGICAL TECHNIQUE: Exposure of the ruptured tendon. Coronal drill hole through the distal third of the patella and coronal drill hole through the tibial tuberosity. After anatomic positioning of the patella (adjusting correct height), patellotibial fixation with monofil or woven (Labitzke) cerclage wire or PDS cord. Suture repair of the patellar tendon and repair of the ruptured medial and lateral retinaculum. Drain insertion. Wound closure in layers. POSTOPERATIVE MANAGEMENT: Full load bearing in cylinder cast. Week 0-2: flexion restricted to 30 degrees , quadriceps muscle isometry. Week 2-4: flexion restricted to 60 degrees , strengthening of hip abductors and extensors. Week 4-6: flexion restricted to 90 degrees . After week 6: removal of cylinder cast. After week 12: return to sporting activities, removal of the cerclage wire. RESULTS: Good results after surgical therapy. Low rate of secondary rupture. Low rate of muscle weakness.     

Eine vereinfachte Methode zur Therapie der Quadrizepssehnenruptur mittels transpatellarer PDS-Kordel

Quadriceps tendon ruptures are relatively unusual injuries caused by direct or more frequently indirect trauma. Since complete ruptures lead to loss of active extension of the knee joint, operative treatment is usually indicated. Several techniques are described in the literature. However, relatively little is known about the functional outcome after operative treatment of acute quadriceps tendon ruptures. We present a new operative technique using a 1.3-mm PDS cord passed through a transverse drill hole in the proximal pole of the patella. We operated ten consecutive cases of complete quadriceps tendon ruptures with the technique described between January 2000 and June 2003. Eight of ten patients were evaluated after a mean follow-up time of 38 months by physical examination, IKDC Subjective score, Lysholm and Tegner score as well as an isokinetic test of the quadriceps strength. No complications were noted in this period. The average postoperative scores were 87 (IKDC), 98 (Lysholm), and 4.5 (Tegner). Isokinetic testing showed an average of 25% quadriceps strength deficit. The operative treatment of complete quadriceps tendon ruptures using a PDS cord through a drill hole in the patella is a safe and effective technique permitting functional postoperative treatment.     

Surgical treatment of acromioclavicular dislocation

Sixty-five patients were operated on for acromioclavicular dislocation between 1980 and 1991. Seventeen type II and 48 type III dislocations according to the criteria of Tossy et al. [15] were treated. Three different surgical techniques were employed. (1) tension band wiring, (2) a modification of the Bosworth repair [3], (3) reconstruction of the ligaments with augmentation by a PDS (polydioxanon) cord. Forty-four patients could be investigated retrospectively, and an additional 12 were recorded by questionnaire. The Taft score [14] was used, representing self-assessment, clinical statements and radiological findings. Of all investigated patients 87.5% had a normal range of motion without any loss of strength, and 32% suffered an osteoarthritis of the acromioclavicular joint. The average Taft score was 9.8. With respect to the three surgical techniques, reconstruction of the ligaments augmented by a PDS cord produced the best result, an average Taft score of 10.8.     

高强度聚酯纤维缝线减张治疗陈旧性髌腱断裂

目的 探讨陈旧性髌腱断裂的临床特点,介绍采用高强度聚酯纤维缝线减张治疗陈旧性髌腱断裂的手术方法 和术后康复方法 .方法 2002年1月至2007年2月,收治陈旧性髌腱断裂6例,手术切断超长的瘢痕愈合髌腱组织.恢复长度后重新吻合,并在胫骨结节和髌骨两端钻骨孔,采用4根高强度聚酯纤维缝线经骨孔减张保护.术后对患者采用积极的康复锻炼方案:术后第1天即町下地直立行走及被动屈膝90°,休息和睡眠时不须支具石膏固定保护;术后3周起开始练习主动抬腿;术后6周后开始练习快走,负重2 kg直腿抬高;术后12周后开始练习上下楼梯和下蹲;术后6个月后开始正常运动以及蹬跳运动.结果 术后随访1～5年,平均3.2年.患者早期即可以活动并可以下床直立行走,所有患者均未出现再断裂.手术6个月以后,患者均恢复正常的平地行走、跑步能力等,屈膝基本达到对侧的水平,股四头肌力量良好.Lysholm评分均能达到100分.结论 高强度聚酯纤维缝线减张治疗陈旧性髌腱断裂,创伤小,方法 简单,不须外加牵引,不须石膏固定,不须二次手术取内固定.积极的康复训练允许患者早期行走,效果可靠.     

Kinesiologic measurements of functional performance before and after geometric total knee replacemtn: one-year follow-up of twenty cases

Kinesiologic measurements were made in patients with severe arthritis before and after geometric total knee replacements to evaluate the nature, rate and extent of change in their functional ability. Preoperatively, patients with rheumatoid arthritis functioned at lower levels than patients with osteoarthritis. Most patients with rheumatoid arthritis improved steadily after surgery, while progress of those with osteoarthritis was often irregular. The group with rheumatoid arthritis improved more than those with osteoarthritis, but they did not generally reach the functional level attained by the patients with osteoarthritis, and neither group reached the lower limits of normal variability 1 year postoperatively. On the average, both groups gained knee extensions, lost knee flexion, and gained isometric knee flexor muscle strength postoperatively. Every patient with osteoarthritis lost extensor muscle strength 1 year after surgery, while most with rheumatoid arthritis gained. During quiet standing, most patients had straighter knees postoperatively and bore a greater percent of body weight on the operated limb. Patients with rheumatoid arthritis improved more than patients with osteoarthritis in the type and amount of force applied to canes and crutches. Most patients walked faster postoperatively, took longer and more rapid steps, improved the pattern of knee motion used, and had smoother forward, lateral and vertical head motion.     

经皮钢丝环扎术在胫骨螺旋形骨折治疗中的应用

目的 探讨经皮钢丝环扎术治疗胫骨螺旋形骨折的方法和疗效。方法采用经皮钢丝环扎术治疗胫骨螺旋形骨折62例。经皮钢丝环扎后行穿针石膏固定12例、支架外固定34例、经皮梅花针髓内固定16例。结果62例均获随访,时间6个月～4年,骨折全部愈合。环扎处无感染及骨髓炎发生。膝、踝关节无功能障碍,无成角及短缩畸形。51例已于门诊取出钢丝,无神经、血管损伤及再骨折发生。结论经皮钢丝环扎术是一种治疗胫骨螺旋彤骨折的辅助内固定方法。     

Quadrizepssehneninsuffizienzen und -rupturen

Quadriceps tendon injuries and insufficiencies in total knee arthroplasty are rare, but are followed by a devastating complication that left untreated leads to a complete loss of function of the knee. This review article summarizes the functional anatomy, risk factors, and the prevalence and diagnosis of quadriceps tendon injuries, in addition to the possible management options for partial and complete ruptures. The treatment options are adapted according to the extent of the loss of function (partial, complete) and the duration of the injury (acute vs chronic). Furthermore, the choice of treatment should take into account the quality and availability of primary tissue, the patient’s general health, along with their likely functional requirements. Conservative treatment is often justified in partial ruptures with good results. Complete ruptures require surgical intervention and multiple operative techniques are described. Treatment options for acute ruptures include direct primary repair with autogenous or synthetic tissue augmentation. In the case of chronic insufficiency and a lack of soft-tissue surroundings, reconstruction with the aid of a muscle flap or allograft tissue can be considered. All surgical intervention techniques used so far have been fraught with complications and rarely lead to satisfactory results. A new surgical approach to the reconstruction and augmentation of the extensor mechanism consists of the use of a synthetic mesh. The technique is described here in detail.     

Management of displaced inferior patellar pole fractures with modified tension band technique combined with cable cerclage using Cable Grip System

IntroductionWe present a modified tension band technique combined with cable cerclage using Cable Grip System for the treatment of displaced inferior patellar pole fractures and report the knee functional outcome.Patients and methodsThe patients who had had operative treatment of a displaced inferior patellar pole fracture (AO/OTA 34-A1) between December 2013 and December 2015 were studied retrospectively. Eleven consecutive patients had had open reduction and internal fixation with the modified technique using Cable Grip System, of whom, five males and six females with an average age of 60.9 years (range, 29–81 years). All fractures occurred from direct fall onto the knee. The average time from injury to surgery was 6.1 days (range, 2–12 days). The range of motion (ROM) was measured in degrees by goniometry at postoperative intervals of 1, 2, 4, 12, and 48 weeks; Knee function was evaluated using the Rasmussen scores at final follow-up.ResultsNo patients had nonunion, loss of reduction, migration of wire, irritation from the implant and fixation breakage during the follow-up period. Recovery of ROM was achieved at 12 weeks, with the average ROM at 1 week was 72° (range, 65°–78°), 86.4° (range, 78°–92°) at 2 weeks, 115.5° (range, 103°–122°) at 4 weeks, 129.6° (range, 122°–133°) at 12 weeks, 134.5° (range, 129°–139°) at 48 weeks after the operation. Concerning the knee function outcome assessment, all patients showed excellent results at final follow-up. The average Rasmussen scores was 27.9 out of 30 (range, 27–29).ConclusionsThe modified tension band technique combined with cable cerclage using Cable Grip System for displaced inferior patellar pole fractures can provide stable fixation with excellent results in knee function, allows for immediate mobilization and early weight-bearing, which is a simple and valuable technique in routine clinical practice.     

Is knee osteoarthritis a symmetrical disease? Analysis of a 12-year prospective cohort study

ABSTRACT: BACKGROUND: The aim of this study was to document the development of bilateral knee osteoarthritis over a 12 year period using a middle-aged population-based cohort with knee pain at inclusion. METHODS: One hundred and forty three patients aged 35 to 54 were recruited from a population based cohort of 279 subjects who had knee pain at baseline and assessed with clinical and radiographic data, with 5 and 12 year follow up. The data was analysed with regard to the development and progression of uni- and bilateral knee osteoarthritis over 12 years. A definition of KL = 1 was used to define radiographic disease. RESULTS: 24 of the 30 (80%) patients with unilateral disease at baseline developed bilateral disease after 12 years. At baseline 37 patients (26%) had bilateral disease, whereas that number increased to 65 (52%) at 5 years and 100 (70%) at the 12 year follow up. The most common pattern was medial compartment involvement in both knees. Six patients had lateral compartment disease in one knee and medial in the other whereas only two had lateral compartment disease bilaterally. CONCLUSIONS: Bilateral knee osteoarthritis is very common with time, as the majority of sufferers will eventually develop radiographic disease in both knees. Clinicians need to be aware of the 'joint at risk' and researchers need to remember to account for both knees when assessing the relationship between physical function, pain and structural disease. The other knee should not be used for comparison, even if it appears to be normal at baseline.