Total knee arthroplasty for osteoarthritis secondary to extra-articular malunions

Distal Femoral Osteotomy for the Management of Coronal Deformity Following Total Knee Arthroplasty: A Report of 2 Cases

CASE

We present 2 cases demonstrating the management of coronal malalignment with an existing total knee arthroplasty using opening wedge distal femur osteotomy. The mechanical axis was corrected, and the primary total knee implants were maintained. Patients resumed full activity 3 to 4 months after surgery.

CONCLUSION

In certain cases, opening wedge distal femoral osteotomy is an option to correct coronal malalignment with an existing total knee arthroplasty without revising the implant.

Impact of the diaphyseal femoral deformity on the lower limb alignment in osteoarthritic varus knees

The impact of a diaphyseal femoral deformity on knee alignment varies according to its severity and localization. The aims of this study were to determine a method of assessing the impact of diaphyseal femoral deformities on knee alignment for the varus knee, and to evaluate the reliability and the reproducibility of this method in a large cohort of osteoarthritic patients. All patients who underwent a knee arthroplasty from 2019 to 2021 were included. Exclusion criteria were genu valgus, flexion contracture (> 5°), previous femoral osteotomy or fracture, total hip arthroplasty, and femoral rotational disorder. A total of 205 patients met the inclusion criteria. The mean age was 62.2 years (SD 8.4). The mean BMI was 33.1 kg/m² (SD 5.5). The radiological measurements were performed twice by two independent reviewers, and included hip knee ankle (HKA) angle, mechanical medial distal femoral angle (mMDFA), anatomical medial distal femoral angle (aMDFA), femoral neck shaft angle (NSA), femoral bowing angle (FBow), the distance between the knee centre and the top of the FBow (DK), and the angle representing the FBow impact on the knee (C'KS angle). The FBow impact on the mMDFA can be measured by the C'KS angle. The C'KS angle took the localization (length DK) and the importance (FBow angle) of the FBow into consideration. The mean FBow angle was 4.4° (SD 2.4; 0 to 12.5). The mean C'KS angle was 1.8° (SD 1.1; 0 to 5.8). Overall, 84 knees (41%) had a severe FBow (> 5°). The radiological measurements showed very good to excellent intraobserver and interobserver agreements. The C'KS increased significantly when the length DK decreased and the FBow angle increased (p < 0.001). The impact of the diaphyseal femoral deformity on the mechanical femoral axis is measured by the C'KS angle, a reliable and reproducible measurement.

Total knee arthroplasty and femoral osteotomy with a patient-specific cutting guide to treat haemophilic arthritis with severe extra-articular deformity: A case report and review of literatures

Background

Total knee arthroplasty (TKA) is recommended for haemophilic patients with end-stage arthritis. TKA combined with a one-stage extraarticular osteotomy is uncommon in the treatment of haemophilic arthritis (HA) with severe extra-articular deformities (EADs) and a history of inhibitors under the guidance of a patient-specific cutting guide (PSI).

Case presentation

We reported a 20-year-old male patient with severe haemophilia, limited knee functionality, a 30° sagittal deformity on the femoral side and a history of inhibitors. We adopted the Van Creveld protocol to decrease the inhibitors. TKA and extra-articular osteotomy (EAO) were performed simultaneously and sequentially under the guidance of PSI. An appropriate central alignment of the lower limb was restored by using cement prostheses with antibiotics and femur shaft locking compression plates. The last follow-up showed that the knee function was good, the VAS score was 0, the WOMAC score was 18 and the ROM was 0°-95°.

Conclision

Regular haematology management can reduce the perioperative bleeding risk in haemophilic patients treated with inhibitors. PSI plays an important role in guiding the TKA and EAO of end-stage HA patients with severe EAD.

Single-Stage Total Knee Arthroplasty and Open-Wedge Distal Femoral Osteotomy for Osteoarthritis with Femoral Shortening and Extra-Articular Varus Deformity: A Case Report

CASE

A 76-year-old female patient with a history of pyogenic arthritis of the right knee in childhood presented with severe osteoarthritis of the right knee with 24-mm femoral shortening and severe extra-articular femoral varus deformity. She received single-stage total knee arthroplasty (TKA) combined with a medial open-wedge distal femoral osteotomy and achieved good postoperative clinical and radiological results.

CONCLUSION

This case illustrated that extra-articular open-wedge distal femoral osteotomy and TKA performed simultaneously may be efficacious for severe extra-articular deformities with femoral shortening.

Extra-articular tibial deformity management in total knee replacement

BACKGROUND

Presence of an extra-articular deformity in the femur or tibia poses a challenge to the surgeon undertaking knee replacement procedure. The conundrum is whether to correct the deformity beforehand, or accept the deformity and compensate for this through placement of the implant.

MATERIAL AND METHODS

This is a retro-spective study comprising six patients who had a knee replacement in the presence of an extra-articular deformity of the tibia treated at our centre. All six had the knee replacement without correction of deformity. The data evaluated included clinical outcome, mechanical axis correction, type of implant, and the use of any software / computer guidance.

The deformity was managed through planning of tibial resection without the need for pre-operative deformity correction.

RESULTS

Mean age was 66.5 years. Mean coronal plane deformity in the tibia was 8.6 degrees. The hip- knee-ankle improved from a mean 12.6 degrees to 4 degrees. Mean Oxford knee score improved from a mean of 19 to 33.6.

CONCLUSION

Planning the tibial resection on the basis of mechanical axis of tibia allows correction of alignment without the need for preoperative correction.

Correction of the deformity may not be needed if the maximum tibial resection is less than 15 mm.

Total Knee Arthroplasty with Intra-Articular Resection of Bone for Knee Arthritis Secondary to Malunion of a Tibial Shaft Fracture: A Radiological Evaluation of Correction of the Tibial Deformity

This retrospective study was aimed to evaluate the clinical outcome and the extent of correction of the tibial deformity by a radiological evaluation following total knee arthroplasty (TKA) combined with intra-articular bone resection, in patients with knee arthritis and ipsilateral malunited tibial fractures. Fifteen patients (15 knees) with severe arthritis of the knee and extra-articular malunion of the tibia were treated using TKA with intra-articular bone resection. The extra-articular deformities in the coronal plane were 10 tibia vara (mean 15°, range 9°-30°), 4 tibia valgum (mean 12°, range 6°-20°), and one double deformity in the tibial shaft. The follow-up duration was 84 months (24–240). At the last follow-up, the mean Knee Society knee and function scores had improved, respectively (p = 0.001). The mean arc of knee motion improved from 97° preoperatively to 118.3° at the last follow-up (p < 0.001). The mean mechanical axis improved from a preoperative 15.5° to 1.5° of varus (p = 0.013). Excluding the patient with a double tibial malunion, in the 10 patients with varus tibial angulations, the tibia vara had improved from 15° preoperatively to 2.6° (p = 0.005). There were no observed complications except for one with a postoperative deep infection. In conclusion, our results indicated that TKA with intra-articular resection of the bone is an effective procedure for the treatment of severe arthritis of the knee with extra-articular malunion of the tibia in the coronal plane (≤30° of varus; ≤20° of valgus).

Single-stage total knee arthroplasty and femoral osteotomy for osteoarthritis with severe supracondylar deformity

Background

Knee osteoarthritis associated with extra-articular deformity (EAD) can confront the arthroplasty surgeons with challenges of bone resection and soft tissue balancing. The aim of this study was to describe a single-stage procedure associating corrective osteotomy with total knee arthroplasty (TKA), and to determine the outcome at mid- to long-term follow-up.

Methods

A total of seven patients (seven knees) with knee osteoarthritis and supracondylar deformity were included in this study. Six patients were female, and one was male, with the median age of 62 years (range, 37-76 years). All patients were treated with single-stage TKA and femoral osteotomy. Osteotomy was fixed with long cemented stem. Hospital of Special Surgery (HSS) scores, collateral ligament laxity, and range of motion (ROM) were clinically evaluated preoperatively and at each follow-up. Radiographic parameters including the mechanical axis deviation (MAD), mechanical lateral distal femoral angle (mLDFA), mechanical proximal tibial angle (mMPTA), and joint line congruence angle (JLCA) were also measured. The occurrence of perioperative complications was recorded.

Results

The median follow-up time was 91 months (range, 38-104 months). At the last follow-up, all components were stable and no patients required revision. Nonunion of the osteotomy occurred in one patient. In all patients, the lower limb mechanical alignment improved greatly. The mean angle of MAD was restored from 10.49±6.05 cm preoperatively to 1.11±4.97 cm postoperatively. The 90° mLDFA was almost acquired in all cases, with the postoperative value of 90.79±2.40°. After operation, the mMPTA improved from 84.18±6.13° to 91.33±3.13°. The JLCA changed from 2.94±1.61° to −0.71±3.50°. The median HSS score improved from 45 (range, 34-56) preoperatively to 90 (range, 82-97) postoperatively, with the outcome of all patients rated good to excellent. The median ROM improved from 70° (range 0–110°) preoperatively to 105° (range 90–125°) postoperatively. No instability of knee joint was observed. Complications included an intraoperative split fracture of distal femur and one case of wound exudation resulting from fat liquefaction.

Conclusions

For knee osteoarthritis with femoral supracondylar deformity, single-stage TKA and corrective osteotomy was feasible but technically demanding. The use of long cemented stem for osteotomy fixation can provide reliable rotational control of the bone segments.

Same-stage total knee arthroplasty and osteotomy for osteoarthritis with extra-articular deformity. Part II: Femoral osteotomy, prospective study of 6 cases

BACKGROUND

Same-stage (1S) total knee arthroplasty (TKA) and femoral osteotomy (FO) may deserve consideration in patients with both knee osteoarthritis and severe extra-articular knee deformity (EKD). The objective of this study was to assess clinical and radiological outcomes and morbidity (complications and revisions) in 6 patients managed with S1-TKA-FO.

HYPOTHESIS

1S-TKA-FO produces satisfactory outcomes and is not associated with higher morbidity rates compared to two-stage TKA-TO or TKA with intra-articular EKD correction, while also significantly shortening total treatment duration.

MATERIAL AND METHODS

A prospective study was performed in 6 patients managed with 1S-TKA-FO between 1999 and 2011; mean age was 64 years (range, 59-72 years) and mean body mass index was 29.5 (range, 26-35). The EKD was consistently greater than 10°. The cause was post-traumatic mal-union in 4 patients, constitutional EKD in 1 patient, and FO in 1 patient. In each patient, the clinical International Knee Society (IKS) score and the hip-knee-ankle angle (HKA), femoral mechanical angle (FMA) and tibial mechanical angle (TMA), were recorded prospectively before and after surgery.

RESULTS

A long uncemented extension stem was used in all 6 patients and a posterior-stabilised implant in 5 patients. No hinged implants were used. In 4 patients, internal fixation of the FO was performed. Mean follow-up was 10 years (range, 4-15 years). From baseline to last follow-up, the mean IKS score increased from 46 to 161 and mean flexion from 95° (range, 70-110°) to 107° (range, 90-120°). The HKA measured radiographically was between 178° and 182° in all 6 patients. The complications consisted of deep vein thrombosis in 1 patient and knee stiffness requiring manipulation under general anaesthesia in 1 patient. No patient experienced mal-union or required revision surgery.

DISCUSSION

Apart from a case-series study of 11 patients, very few data are available on 1S-TKA-FO. In our small population, no major complications were recorded. The encouraging long-term outcomes warrant a recommendation to perform 1S-TKA-FO in patients with knee osteoarthritis and an intra-femoral deformity greater than 10°.

LEVEL OF EVIDENCE

IV, prospective observational cohort study.

Same-stage total knee arthroplasty and osteotomy for osteoarthritis with extra-articular deformity. Part I: Tibial osteotomy, prospective study of 26 cases

BACKGROUND

In patients with advanced knee osteoarthritis and extra-articular knee deformity (EKD), ligament balance may be difficult to achieve during total knee arthroplasty (TKA). Treatment options include two-stage surgery with the first stage involving correction of the EKD and same-stage TKA and tibial osteotomy (1S-TKA-TO). The objective of this study was to assess outcomes in 26 patients managed with 1S-TKA-TO.

HYPOTHESIS

1S-TKA-TO produces satisfactory clinical and anatomical outcomes and is not associated with higher morbidity rates compared to TKA alone or two-stage TKA-TO.

MATERIAL AND METHODS

A prospective study was conducted in 25 patients (26 knees) managed with 1S-TKA-TO between 1995 and 2014. There were 16 males and 9 females with a mean age of 64 years (range, 29-80 years) and a mean body mass index of 29.6 (range, 24-49). The EKD was constitutional in 14 knees, post-traumatic in 5 knees, and induced by TO in 7 knees. None of the patients received a hinged knee implant. In each patient, the clinical International Knee Society (IKS score) was assessed and the hip-knee-ankle angle (HKA), tibial mechanical angle (TMA), and femoral mechanical angle (FMA) were measured on radiographs before surgery and at last follow-up.

RESULTS

The mean IKS score increased significantly, from 70 before surgery to 170 at the end of the mean 9-year follow-up. Mean flexion range increased from 98° to 107°. The clinical and anatomical outcomes were satisfactory in 25 patients. In the remaining patient, who had a history of multiple surgeries for Blount disease and a body mass index of 49, a severe complication consisting in massive skin necrosis followed by infection occurred; this was the only patient who required revision surgery with implant removal.

DISCUSSION

These findings are consistent with the satisfactory outcomes observed in earlier studies, most of which included small numbers of patients. The alternatives to 1S-TKA-TO are under evaluation. The best indication for 1S-TKA-TO may be knee osteoarthritis with a greater than 10° intra-osseous deformity.

LEVEL OF EVIDENCE

IV, prospective observational cohort study.

Medial Open-wedge Osteotomy with Double-plate Fixation for Varus Malunion of the Distal Femur

Objective

To present our clinical experience of treating varus malunion of the distal femur through a medial open‐wedge osteotomy with double‐plate fixation.

Methods

A prospective cohort study was performed. From January 2005 to February 2015, 15 consecutive patients with varus malunion following distal femur fractures were surgically treated at a single level I trauma center. The coronal and sagittal deformity were corrected by a medial open‐wedge osteotomy of the distal femur. A medial buttress plate was used to maintain the realignment. A lateral locking plate was additionally used as a protection plate. The mean age of patients at the time of the surgery was 35.5 years (range, 22–58 years). The radiographical evaluation included the mechanical femorotibial angle, the mechanical lateral distal femoral angle, the anatomic posterior distal femoral angle, and the leg length discrepancy. Clinical outcome evaluation consisted of the range of motion (ROM) and Hospital for Special Surgery (HSS) score.

Results

Mean follow‐up was 7.4 years (range, 4–11.5 years). Varus and flexion malalignment and limb discrepancy were adequately corrected in all patients. The mechanical femorotibial angle, the mechanical lateral distal femoral angle, and the anatomic posterior distal femoral angle were restored from 17.5° (range, 13°–25°) to 2.3° (range, − 2°–7°), 102.3° (range, 95°–112°) to 85.2° (range, 81°–92°), and 77.1° (range, 65°–87°) to 82.7° (range, 76°–88°), respectively. The leg length discrepancy was diminished from 3.4 cm (range, 2.4–4.5 cm) to 0.8 cm (range, 0–1.7 cm). The average bone healing time was 4.1 months (range, 2.5–6 months). The average ROM of the affected knees at 24‐month follow‐up was 3.4°–112.55°. The score of HSS at 4‐years follow‐up was 76.1 (range, 64–88). No internal fixation failure or secondary operation was noted until the last follow‐up.

Conclusion

Medial open‐wedge osteotomy can adequately correct the posttraumatic varus malunion of the distal femur. With fixation of the double plate, non‐displaced bone healing and good functional outcome are expected.

Outcomes after knee arthroplasty in extra-articular deformity

PURPOSE

To assess functional outcomes in patients undergoing total knee arthroplasty (TKA) without previous corrective osteotomy for treatment of knee osteoarthritis associated with extra-articular deformity.

METHODS

From January to December 2016, patients with knee osteoarthritis with extra-articular deformities who presented for preoperative assessment before TKA were evaluated prospectively. Physical and radiological characteristics were documented pre- and postoperatively.

RESULTS

TKA was performed in 33 knees; 25 were considered for analysis. The mean age was 65.2 years (range, 48-79 years). Sixteen deformities were secondary to fractures and nine to failed osteotomies. The mean Knee Society Score (KSS) improved from 27.1 pre-operatively to 68.7 post-operatively (p = 0.000). Pre-operative mechanical axis ranged from 32° varus (negative) to 26° valgus. After correction, 20 knees were within 3° (varus or valgus) of mechanical alignment.

CONCLUSION

In patients with extra-articular deformities, TKA with asymmetric intra-articular resection and ligament balancing can relieve pain and realign the mechanical axis of the lower limb.

Extra-articular deformities in arthritic knees-a grueling challenge for arthroplasty surgeons: An evidence-based update

Critical to the success of a total knee arthroplasty (TKA) is the anatomical alignment. This may appear as a challenge in an extra-articular deformity (EAD) that may be inherent in certain people or result from fracture malunion, congenital disorders, nutritional, metabolic and infective causes. This appraisal aimed at providing the reader with an up-todate overview of the research carried out on, and existent evidence of EAD correction while planning a TKA. We reviewed the current English literature on TKA in extra-articular knee deformities. Among the published data, a common initial approach of mandatory clinical and radiological assessment emerges as an obligatory step while handling cases with EAD. While several methods of managing the deformity and arthritis have been described, a broad division into intra-articular and extra-articular means can be deciphered. The relatively old-school, yet reliable thought process of extra-articular correction allows an all-inclusive restoration of alignment with the inherent complications related to the necessary osteotomy. A cohort of younger and more venturesome surgeons seem inclined towards performing navigated, intra-articular correction for mild to moderate and sometimes, severe deformities. The crux of the matter lies is obtaining a well-balanced knee without violating the all-important cruciates. Restoring the patient’s ambulatory status seems sooner with the intra-articular methods which are also more precise in determining the axes and while removing minimum bone. Greatest satisfaction is accomplished in those with less grotesque, rotationallyaligned knees while meticulously balancing soft-tissues and encouraging earlier weightbearing.

[Effectiveness of total knee arthroplasty using three-dimensional printing technology for knee osteoarthritis accompanied with extra-articular deformity]

Objective

To evaluate the effectiveness of total knee arthroplasty (TKA) using three-dimensional (3D) printing technology for knee osteoarthritis (KOA) accompanied with extra-articular deformity.

Methods

Between March 2013 and December 2015, 15 patients (18 knees) with extra-articular deformity and KOA underwent TKA. There were 6 males (6 knees) and 9 females (12 knees), aged 55-70 years (mean, 60.2 years). The mean disease duration was 10.8 years (range, 7-15 years). The unilateral knee was involved in 12 cases and bilateral knees in 3 cases. The clinical score was 57.44±1.06 and the functional score was 60.88±1.26 of Knee Society Score (KSS). The range of motion of the knee joint was (72.22±0.18)°. The deviation of mechanical axis of lower limb was (18.89±0.92)° preoperatively. There were 8 cases (10 knees) with extra-articular femoral deformity, 5 cases (5 knees) with extra-articular tibial deformity, and 2 cases (3 knees) with extra-articular femoral and tibial deformities. Bone models and the navigation templates were printed and the operation plans were designed using 3D printing technology. The right knee joint prostheses were chosen.

Results

The operation time was 65-100 minutes (mean, 75.6 minutes). The bleeding volume was 50-150 mL (mean, 90.2 mL). There was no poor incision healing, infection, or deep venous thrombosis after operation. All patients were followed up 12- 30 months (mean, 22 months). Prostheses were located in the right place, and no sign of loosening or subsidence was observed by X-ray examination. At last follow-up, the deviation of mechanical axis of lower limb was (2.00±0.29)°, showing significant difference when compared with preoperative one ( t=13.120, P=0.007). The KSS clinical score was 87.50±0.88 and function score was 81.94±1.41, showing significant differences when compared with preoperative ones ( t=27.553, P=0.000; t=35.551, P=0.000). The range of motion of knee was (101.94±1.42)°, showing significant difference when compared with preoperative one ( t=31.633, P=0.000).

Conclusion

For KOA accompanied with extra-articular deformity, TKA using 3D printing technology has advantages such as individualized treatment, reducing the difficulty of operation, and achieving the satisfactory function.

Varus-valgus constrained implants in total knee arthroplasty: indications and technique

Total knee arthroplasty is a successful operation that significantly improves patient's quality of life. However, studies demonstrated as only 82% to 89% of patients are satisfied with their surgery, being the other disappointed with regard to their expectations. Two to 5.7% of total knee arthroplasties (TKAs) require revision within 5 years. Both complex primary cases and revision TKA often necessitate for a higher degree of constrain than cruciate retaining or postero-stabilized implant design. In the 1970s varus-valgus constrained (VVC) or semi-constrained implants have been developed by Insall and associates from the PS design, which provide varus-valgus stability preserving a fair amount of host bone. VVC TKAs allows for a small amount of movement in the coronal, antero-posterior and axial planes. In this paper, the authors give an overview of the indications, outcomes and technique for varus-valgus constrained implants, both in the setting of primary and revision knee arthroplasty.

Knee replacement in chronic post-traumatic cases

Post-traumatic knee arthritis is a challenging condition. Prosthetic surgery is demanding and the risk of complications is relatively high.

Planning is an essential element of this surgery; correct diagnosis (to exclude latent infection) and adequate considerations regarding approach, axis, bone loss, choice of implant and level of constraint are indispensable.

There are two main categories of post-traumatic arthritis: extra-articular deformities and articular deformities.

Use of an algorithms can support the surgeon’s choice of implant.

Correct implant positioning and limb alignment restoration is associated with very good results, similar to those achieved with standard total knee arthroplasty.

Cite this article: Benazzo F, Rossi SMP, Combi A, Meena S, Ghiara M. Knee replacement in chronic post-traumatic cases. EFORT Open Rev 2016:1:211-218. DOI: 10.1302/2058-5241.1.000025.

A Comparison of the Medium-Term Results of Total Knee Arthroplasty Using Computer-Assisted and Conventional Techniques to Treat Patients With Extraarticular Femoral Deformities

BACKGROUND

We compared the medium-term results of total knee arthroplasty (TKA) performed using computer-assisted surgery (CAS) and conventional techniques in patients with extraarticular femoral deformities.

METHODS

The clinical and radiographic data of 40 knees (34 patients) with extraarticular femoral deformities that underwent consecutive CAS-TKA were compared with those of a control group that underwent conventional TKA (80 knees, 63 patients). No demographic data (in particular, the causes of the extraarticular deformities) differed between the two groups. The follow-up periods of the CAS and conventional TKA groups were 6.0 and 6.3 years, respectively.

RESULTS

In the CAS group, the average knee score increased from 48.2 to 89.6 at the final follow-up (P < .001); the average function score increased from 51.4 to 91.4. The range of motion averaged 105.5° preoperatively and 123.3° postoperatively. No significant differences were found in the knee score, function score, or range of motion after TKA between the 2 groups. The average preoperative mechanical axes were 18.1° varus in both groups. The average postoperative mechanical axis was 1.4° varus in the CAS group and 3.3° varus in the conventional TKA group (P = .001). The proportion of postoperatively aligned knees was 77.5% in the CAS group and 32.5% in the conventional group (P < .001).

CONCLUSION

Although the medium-term clinical results of TKA in extraarticular femoral deformities were satisfactory in both the CAS and conventional TKA groups, the former group exhibited more accurate postoperative coronal alignment. It was useful to employ navigation in patients with extraarticular deformities of various etiologies.

Total knee arthroplasty for treatment of post-traumatic arthritis: Systematic review

AIM

To review and report functional outcomes, complications, and survivorship associated with total knee arthroplasty (TKA) in the treatment of post-traumatic arthritis (PTA).

METHODS

We conducted a systematic review according to the PRISMA guidelines. We searched PubMed, Cochrane Library, and SCOPUS in December 2015 for English-language clinical research studies, both prospective and retrospective, examining the use of TKA for the treatment of PTA. All relevant articles were accessed in full. The manual search included references of retrieved articles. We extracted data on patients’ demographics and clinical outcomes, including preoperative diagnosis and pre- and post-operative functional scores. We summarized the data and reported the results in tables and text.

RESULTS

Sixteen studies, four prospective and ten retrospective, examined patients who underwent TKA for PTA due to fractures of the proximal tibia, patella, and/or distal femur. Eleven studies utilized the Knee Society Scores criteria to assess functional outcomes. All studies utilizing these criteria reported an improvement in functional and knee scores of patients following TKA. Further, studies reported an increased range of motion (ROM) and reduction of pain following surgery. The most commonly reported complications with TKA included infection, stiffness, wound complications, intraoperative rupture of tendons, and osteolysis/polyethylene wear. The overwhelming majority of these complications occurred within the first two years following surgery. Six studies examined the survivorship of TKA with subsequent revision for any reason as an endpoint. Compared to patients with osteoarthritis, patients with PTA required more revisions, the majority for polyethylene wear.

CONCLUSION

Although associated with higher complication rates, TKA is an effective treatment for PTA, as it improves ROM, pain and functional outcomes.

Total knee arthroplasty in patients with extra-articular deformity

Multiple acceptable options are available for the correction of distal femoral deformity associated with knee arthritis. The treatment modality should be chosen based on the extent of deformity and attention to preservation of the collateral ligaments. Surgical options range from osteotomy alone, arthroplasty with intra-articular correction, or arthroplasty with extra-articular correction. Different implant choices and fixation methods for the osteotomy possess advantages and disadvantages which need to be considered carefully. In addition to discussing principles of management based on current literature, this article includes a case report using a previously undescribed technique using corrective osteotomy, intramedullary nail fixation, and total knee arthroplasty with computer navigation.

One-stage total knee arthroplasty with pre-existing fracture deformity: post-fracture total knee arthroplasty

The aim of the study was to assess the results of treating knee osteoarthrosis with total knee arthroplasty (TKA) after previous tibia and/or femur fractures resulting in axial limb deformities. Thirty-six knees (34 patients) were operated on. At the most recent follow-up, 4.8 years after surgery, all but one patient demonstrated an improvement in both clinical and functional KSS. This male patient required revision after 2 years. Improved range of motion was generally noted, especially extension, however, two patients with both tibia and femur fractures had worse results. TKA is an effective method of treatment for patients with arthrosis after a previous femur or tibia fractures. When deformity is severe semi-constrained or constrained, implants with extensions may be necessary.

Femoral bow predicts postoperative malalignment in revision total knee arthroplasty

Diaphyseal bowing may compromise axial alignment in revision total knee arthroplasty (TKA). 277 patients undergoing revision TKA were evaluated for coronal bowing and hip-knee-ankle (HKA) axis. The mean femoral bow was 1.52° ± 0.18° varus (-10.1° to +8.4°). The mean tibial bow was 1.25° ± 0.13° valgus (-5.9° to +10°). HKA axis averaged 3.08° ± 0.35° varus preoperatively compared to 0.86° ± 0.25° varus postoperatively. Inter-rater and intra-rater reliability was high. Femoral bow greater than 4° significantly correlated with postoperative HKA axis malalignment (r = 0.402, P = 0.008). 39.7% of patients deviated 3° or greater from a neutral mechanical axis with a significant difference in femoral bow (0.94° ± 0.31°, P = 0.003). Diaphyseal bowing clearly has an important effect on postoperative limb alignment in revision TKA.

The predictors of outcome in total knee arthroplasty for post-traumatic arthritis

BACKGROUND

The outcomes of total knee arthroplasty (TKA) for post-traumatic arthritis are less reliable than for idiopathic osteoarthritis. These patients tend to be younger, present with varying degrees of deformity, and often have a history of prior surgery, resulting in a wide spectrum of pathology. We hypothesized that preoperative variables, in particular the location of deformity, would predict pain and functional outcomes.

METHODS

The outcomes of total knee arthroplasty for post-traumatic arthrosis were studied in 47 knees treated at our institution. All patients were administered the Knee Society Score (KSS) preoperatively and at follow-up (mean 52months, range 16 to 124). We classified the defects into four categories: intra-articular, metaphyseal, diaphyseal, and combined femoral and tibial deformities.

RESULTS

There was a significant improvement in KSS scores for pain (p<0.0001) and a trend toward higher function (p=0.06) comparing preoperative scores to final follow-up. The largest improvements in pain and functional scores were in patients with isolated articular deformities, while patients with combined tibial and femoral deformities did not have significant improvements in pain or function. Soft-tissue defects requiring flap coverage were associated with worsening in the pain score (p=0.027).

CONCLUSIONS

The location of post-traumatic deformity and compromise of the soft-tissue envelope influence the pain and functional outcomes of total knee arthroplasty for post-traumatic arthritis. Specifically, isolated articular deformities have the largest improvement in pain and function while patients with combined tibial and femoral deformities as well as patients with soft-tissue compromise experience poor outcomes.

LEVEL OF EVIDENCE

IV-Retrospective Case Series.